# Introducing the Matrix M-Stage HPA-3U and HPA-3B, review to follow!



## keanex

I'm going to assume that many of you guys who are familiar with the Matrix M-Stage amplifier are familiar with project86's largely successful and detailed review of the original M-Stage; if you’re not definitely give it a read! Well Matrix Audio is back with the third iteration of the popular M-Stage line which you can read about here!
  
*HPA-3U - $419.95*
The M-Stage HPA-3U is an updated singled ended amp with increased power output, a front panel gain switch, and a built in USB DAC that supports PCM 24/192 and DSD X64. It also features a new case design for better cooling and the fuse is now accessible externally. 
  
Headphone power output: 2800mW @ 33ohms; 420mW @ 300ohms; 210mW @ 600ohms
SNR: >-120dB
THD: >0.0003% at 33ohms 90mW
Output Impedance: 0.2ohms
  
DAC is capable of 24/192 and DSD audio
  
  
  
  
*HPA-3B - $419.95*
The M-Stage HPA-3B is a fully balanced version with even more power (in balanced mode), a rear panel gain switch, and a single XLR input (RCA to XLR adapters are included). It also features the same new case design (for better cooling and the fuse is now accessible externally). 
  
Headphone power output unbalanced: 2100mW @ 33ohms; 430mW @300ohms; 220mW @600ohms
SNR: >-108dB
THD: 0.0004% at 300ohms 320mW 1kHz
Output Impedance: 0.4ohms
  
Headphone power output balanced: 3800mW @ 33ohms; 1500mW @ 300ohms; 800mW @ 600ohms
SND: >-114dB
THD: 0.0003 at 300ohms 135 mW 1kHz
Output Impedance: 0.6ohms
  
There is no integrated DAC with the HPA-3B.
  
  
  
 The M-Stage series can be purchased through Matrix Audio and are available now!

More specifications and details to follow, as well as a full review!


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## keanex

*Pros: *Low output impedance, powerful output power, low heat output, sturdy build, 3 gain settings, clean output
*Cons:* Warm signature
*Tone:* Slightly emphasized lows with natural mids and highs
*Cost at Time of Review:* $420
  
Reviewing Process I’ve had the HPA-3U for approximately 1 month and have used it primarily with Sennheiser HD600, Audio Technica Ad2000, Audio Zenith PM-x2 and Life Acoustics LIFE IEMS. I have used the HPA-3U for approximately 100 hours total between the three headphones and feel confident in my experience with the unit to share my experiences with it. Despite this, I encourage all readers to demo a product before buying it, when possible, as your experience may vary from mine.
  
Build Quality & Features The HPA-3U internals are encased in black brushed metal with ample heat dissipation, allowing for the HPA-3U to constantly remain mildly warm, at worst, even when left on for multiple days. The inputs all feel sturdy as does the potentiometer and switches, no signs of shoddy parts or build. There are no visible signs of concern from the outside and everything I’ve interacted with has felt sturdy, because of this I have no concerns about the build quality of this.
  
 The HPA-3U allows for DSD as well as 24/192k high-resolution files through USB as well as plug and play with many iOS and Android devices. 
  
Sound Quality *TLR *
 So how does the HPA-3U sound? Well overall it sounds rather natural with a good amount of detail retrieval, all while having absolutely no noise even with sensitive IEMs. 
  
*Tonality*
 I’ve come to the conclusion that the HPA-3U is a slightly warm amplifier, offering a natural sounding midrange that is balanced effortlessly with the treble. The lows are mildly emphasized which adds a bit of thickness as well as sluggishness, making the HPA-3U a better match with my quick and bass lean Audio Technica Ad2000 than the mid-bass prominent LIFE IEMs. The bass isn’t overly emphasized though and I don’t find the added warmth to be intrusive; as a whole, the tone is relaxed and natural sounding.
  
*Presentation*
 I’m happy to say that the HPA-3U adds a bit of depth and width to the sound, which enhances the already great soundstage of the HD600 and opens up the LIFE IEMs a bit, allowing for more breathing room. In addition, the HPA-3U’s clean output allows for nuances to come through unencumbered, only limited to what the headphone plugged in has to offer.
  
*Pairing*
 Because the HPA-3U has a low output impedance with a low noise floor in conjunction with multiple gain settings I feel that it is capable of powering a wide variety of headphones, from IEMs to planars. Due to the warm leaning sound signature I feel that it best pairs with a headphone that may benefit from a mild addition of warmth.
  
Conclusion In the end my only gripe is that the HPA-3U adds a mild warmth to the lows as I prefer a neutral sound from an amplifier and DAC. That isn’t to say that I dislike the HPA-3U though, the pros far outweigh the cons of the sound signature to me. The low output impedance coupled with the high amounts of power and multiple gain settings makes the HPA-3U a widely versatile amplifier. I think that this is a worthy buy for those in the market for an all-in-one combination to power their IEMs or orthos.


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## inseconds99

Awesome,I am so glad I just read this as I was about to purchase a hpa-2 from massdrop but now that I know a 3rd gen is on its way I'll hold out. Looking forward to hearing a review, hopefully the hd800 will be part of the testing. Also when and where can I purchase this from?


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## keanex

I had the HD800 but they are now back to their owners hands. I didn't get a chance to play with the HD800 with the HPA-3B but the unit certainly packs enough power it. 
  
 The unit should be available soon, I will update as I have more information.


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## inseconds99

keanex said:


> I had the HD800 but they are now back to their owners hands. I didn't get a chance to play with the HD800 with the HPA-3B but the unit certainly packs enough power it.
> 
> The unit should be available soon, I will update as I have more information.




Thank you, I appreciate it. Hopefully the amp will have good synergy as the hpa-2 was regarded to have with the hd800.


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## keanex

Just updated the OP, both units are available through http://matrix-digi-usa.com/


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## Suopermanni

Woah, that has some serious oomph in it.


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## keanex

suopermanni said:


> Woah, that has some serious oomph in it.


yup! I was happy about that too


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## jtam

Both models are available through Tam Audio as well.


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## inseconds99

jtam said:


> Both models are available through Tam Audio as well.


 
 Awesome, this will be my next purchase once I see a small decline in price, either by a promo code or a sale. They're already $10 less on amazon through a Chinese based seller.


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## keanex

I've heard that products purchased from outside USA will not have the warranty in USA, you will need to ship to China in case of any issues. Spare the $10 and buy from a trusted source imo.


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## inseconds99

keanex said:


> I've heard that products purchased from outside USA will not have the warranty in USA, you will need to ship to China in case of any issues. Spare the $10 and buy from a trusted source imo.




Isn't m-stage a Chinese company and therefore if I purchase direct I would be purchasing from China or am I mistaken? Also tamaudio on Amazon shows the product shipping from China. Where would I buy the product where it wouldn't come from China?


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## keanex

inseconds99 said:


> Isn't m-stage a Chinese company and therefore if I purchase direct I would be purchasing from China or am I mistaken? Also tamaudio on Amazon shows the product shipping from China. Where would I buy the product where it wouldn't come from China?


 
 From my understanding the item would have to go through China's support, which you may or may not have to pay for shipping. Keep that in mind. These are the listed authorized sellers per country.
  
 Your mileage may vary, but I would go with http://www.matrix-digi-usa.com/ if you're in the USA to play it safe.


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## inseconds99

keanex said:


> From my understanding the item would have to go through China's support, which you may or may not have to pay for shipping. Keep that in mind. These are the listed authorized sellers per country.
> 
> Your mileage may vary, but I would go with http://www.matrix-digi-usa.com/ if you're in the USA to play it safe.




Excellent I appreciate your help, looking forward to reading your review.


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## inseconds99

jtam said:


> Both models are available through Tam Audio as well.




Can you confirm the information in this thread regarding the warranty if I purchase from you? Would I need to ship the unit to China if it was in need of repair?


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## jtam

inseconds99 said:


> Can you confirm the information in this thread regarding the warranty if I purchase from you? Would I need to ship the unit to China if it was in need of repair?




I am currently base in Chicago IL, so you can send returns and repairs to Chicago instead of China. I'm shipping the HPA-3 from China (directly from Matrix) for now because I am not yet able to stick it in Chicago and Amazon. It doesn't really matter because delivery usually takes only 3-5 days from China to most part of US.

"matrix-digi-usa" is a distributor like I am. I offer the same level of service and warranty.


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## inseconds99

jtam said:


> I am currently base in Chicago IL, so you can send returns and repairs to Chicago instead of China. I'm shipping the HPA-3 from China (directly from Matrix) for now because I am not yet able to stick it in Chicago and Amazon. It doesn't really matter because delivery usually takes only 3-5 days from China to most part of US.
> 
> "matrix-digi-usa" is a distributor like I am. I offer the same level of service and warranty.


 
 Wonderful, thank you for the helpful and insightful info. I will be placing my order at some point next week.


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## inseconds99

Anyone have a listen to this dac/amp yet and can give a first impression?


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## keanex

inseconds99 said:


> Anyone have a listen to this dac/amp yet and can give a first impression?


 
 I may or may not be the first in the US. Maybe? 
  
 Anyway, it seems rather neutral from mids to highs with a slight bass warmth. Lots of power.


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## inseconds99

keanex said:


> I may or may not be the first in the US. Maybe?
> 
> Anyway, it seems rather neutral from mids to highs with a slight bass warmth. Lots of power.




Did you own the hpa-2? If so how similar are they?


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## keanex

inseconds99 said:


> Did you own the hpa-2? If so how similar are they?


 
 From what I was told, the 1 and 2 are near the same while the 3 is a truly new model.


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## burdie

Any review/owner on HPA-3B yet? I emailed Matrix to find out more details on HPA-3B, and received very short reply from them.
 1) my most concern, silver version? _There is no plan for the silver version_
 2) Opamps?_ LME49860......_, well, I have some TO-99 LME49720....and dip-8 socket
 3) Sound? _nature... errrrrr _please elaborate more...
 4) able to use Neutrik RCA to XLR adapter? _we used YongSheng_....   hmmm didn't answer my question
  
 without much info or reviews, I proceed to order 1 unit, should be arriving tomorrow.


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## keanex

Review posted on post #2!


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## GaToMaLaCo

@keanex please post some pics of the internals.


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## burdie

keanex said:


> Review posted on post #2!


 
 In fact I am looking at the HPA-3B, the balanced headphone amp. I am not interested in HPA-3U as I already owned Matrix mini-i pro 2014 which I believed should be slightly better than 3U in term of decoding etc.
 Hopefully HPA-3B won't be far away from HPA-3U in sound signature as the warm sound is what I looking for.


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## burdie

Today I received the Matrix HPA-3B (balanced amp), it came with 1 x power cable, 2 x RCA to XLR adaptor, 1 warranty card and 1 CD.

 rear view, 2X 3 pin XLR balanced input. The toggle switch for gain stage seems sturdy
  
  

 Front view, the volume knob is fastened by hex bolts, so replace with good looking volume knob won't be a problem. (I don't really like the original volume knob, I also change the volume knob of my Schiit Mojo)
  

 China made RCA to XLR adaptor, both adaptors came in white RCA head. They don't have red RCA head?
  
  

 Are you on par with Schiit Mojo in driving LCD 2.2? Well, may be need some break in.
  
 It has enough power to drive LCD 2.2, I obtained same level of loudness at around 10.30 - 11.00 o'clock for both HPA-3B and Mojo. The sound of HPA-3B is slightly warm (what to expect from Class A amp), lows are tight but not as deep as Mojo, highs quite clean but still behind Mojo. I will try swapping LME49990 and LME49720 to see any improvement or not.


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## adobotj

Wow thank burdie! Now this is the review that I was looking for. I'm also interested in the 3B and you nailed my concern regarding the xlr inputs with detailed pics including accessories. And like you, my preference is a warm sounding amp. 

I am wondering if it's a good synergy with the HD800? Will keep an eye on this. Subbed!


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## burdie

*The Interior of Matrix HPA-3B*
  

 The transformer, fuse holder, voltage selector, 2x XLR input
  

 6.3mm/4 pin XLR - gold plated contact
  

 PCB version 1.1
  

 Nichicon KG Gold Tune 4700uf 35V
  

 Wima MKS4 cap, will MKP10 improve it?
  

 opamp LME49860 x 2
  

 TOSHIBA audio expansion flow tube A1358/C3421, normal headphone amp uses 2 pairs, but HPA-B uses 4 pairs (for balanced?) one pair capable to drive 60-80 watts, no wonder the casing is so 'hot'
  
*The Exterior*
  

 Volume knob (replaceable)
  

 We hardly see people upload the bottom of any product, here it is.
  
*Little Mob*
  

 Opamp swapping, replace the stock LME49860MA to TO-99 LME49720HA, same specs but some people claimed that TO-99 metal can package used better silicon die. Well, will you believe that it gave better transparency and clarity especially in my LCD 2.2? With this metal can, it came closer to Schiit Mojo... This weekend I will try LME49990 (bundled with the disposal of iBasso PB2, this weekend will borrow it )
  

 highly recommend to replace the ugly stock volume knob, I put in the stock volume knob from Schiit Mojo and I think it look better. The stock knob measurement is 31mm*24mm, replacement volume knob with standard sizing of 30mm*22mm will fit perfectly. The shaft is 6mm (D) and 19mm (L).


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## conquerator2

I like the stock better 
But great reviews! Brings some fond HPA2 memories


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## reeseg

Has anyone been able to enable DSD through Audirvana?  I show DSD64 and DSD128 grayed out.


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## burdie

*HPA-3B : LME49990 vs LME49720ha*

 High: LME49990 > LME49720 (LME49990 definitely clearer, LME49720 not far behind)
 Mid:  LME49990 = LME49720
 Low:  LME49990 < LME49720 (bass on LME49990 not solid as LME49720)
 The better performance on high for LME49990 cannot 'compensate' the worser bass performance. So I stick to LME49720HA.
  
*Volume Knob*

 I still prefer the volume knob to be one big round shape


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## keanex

reeseg said:


> Has anyone been able to enable DSD through Audirvana?  I show DSD64 and DSD128 grayed out.


 
 Did you install the drivers?


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## reeseg

No drivers necessary on the Mac.  It must be a setting in preferences somewhere.  I did figure out that I should only get DSD 64...but still looking.


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## lucasseijikc

Has anyone tried the Matrix M-Stage HPA-3U with the AKG K702s yet?
  
 I am considering buying this amp/DAC to pair up with my K702s.
  
 I really like the sound to be as neutral as possible, and was wondering if the HPA-3U would be a good match for that.
  
 Thanks in advance!


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## Ultrainferno

I have just published Dave's review of the "new" HPA-3U on the site. I only had the pleasure to listen to the original M-Stage myself, too bad they aren't this present in Europe. Dave does really like it with his HD650 it seems.


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## DigitalFreak

My reviews up folks


http://headphone.guru/the-new-matrix-audio-m-stage-hpa-3u/


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## raoultrifan

burdie said:


> *HPA-3B : LME49990 vs LME49720ha*
> 
> High: LME49990 > LME49720 (LME49990 definitely clearer, LME49720 not far behind)
> Mid:  LME49990 = LME49720
> ...


 
  
 Hi burdie, 
  
 You do realize that you're actually rolling +/-22V OPAMPs with +/-17V OPAMPs (LME49720)? HPA-3B has NJM7818/NJM7918 (JRC actually) power regulators installed and these two are regulating a power voltage of +/-18V, so the two audio dual-OPAMPs from inside HPA-3B and also all output transistors are actually powered by +/-18V; this is why manufacturer choose LME49860, because there are not many OPAMPs out there designed to work 24/7 at +/-18V (36V) voltage (Violectric/Lake People choose LME49860 from the same reason, but also because the sound is very good when used as voltage gain OPAMP). OPA134/2134 might handle +/-18V as well, but this is max. recommended voltage for them, like LME49990.
  
 Feel free to use LME49990 if you like them, but at least place a decent heatsink on top (glued with Arctic Alumina or with a good heat transfer tape). Their max. recommended voltage by manufacturer would be +/-18V.
  
 As for the LME49720HA, I would strongly recommend you to take them out from HPA-3B, because you'll most likely kill'em slowly...sorry.  
http://www.ti.com/lit/ds/symlink/lme49720.pdf - their max. recommended voltage by manufacturer would be +/-17V, despite their absolute max. voltage of +/-18V. Also, "(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur", so keeping LME49720 for long time at +/-18V would really not be a very good idea.
  
 Thank you, 
 Raul.
  
 P.S.: I like the sound of this headamp: it's strong and powerful and can drive all phones around here, balanced and unbalanced as well. Quite decent construction I'd say and good sounding amp, strongly recomended for its price.
  
 L.E.: Adding a couple of pictures with the 2 regulators:


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## raoultrifan

lucasseijikc said:


> Has anyone tried the Matrix M-Stage HPA-3U with the AKG K702s yet?
> 
> I am considering buying this amp/DAC to pair up with my K702s.
> 
> ...


 
 Hi, 
  
 It sounds very well on my K701; gain of +10dB should be perfect, but also at gain of +5dB will work just fine. Gain of +20db should not be pressed while listening to K701/K702, unless volume knob is on the left half (between 7 o'clock to 12 o'clock).
  
 This little beast headamp can drive perhaps all headphones from the planet.  Give it a try if you have the opportunity, but to be honest there's nothing not to like here (MOSFET sound is quite good and neutral).
  
 Cheers,
 Raul.


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## burdie

raoultrifan said:


> Hi burdie,
> 
> You do realize that you're actually rolling +/-22V OPAMPs with +/-17V OPAMPs (LME49720)? HPA-3B has NJM7818/NJM7918 (JRC actually) power regulators installed and these two are regulating a power voltage of +/-18V, so the two audio dual-OPAMPs from inside HPA-3B and also all output transistors are actually powered by +/-18V; this is why manufacturer choose LME49860, because there are not many OPAMPs out there designed to work 24/7 at +/-18V (36V) voltage (Violectric/Lake People choose LME49860 from the same reason, but also because the sound is very good when used as voltage gain OPAMP). OPA134/2134 might handle +/-18V as well, but this is max. recommended voltage for them, like LME49990.
> 
> ...


 
 Hi Raul,
 Thanks for your advise. In fact I have consider the regulated max 18V power voltage supplied to the opamps and other components. The max voltage that 49720 can handle if not mistaken should be 17V+0,7V, so that is very close to the 18V supply power. After considering that the power voltage pass through few components/resistor and theoritically voltage should drop a bit, I risk burning the opamps and proceed with the rolling.
 However, I have 4 pieces of 49720HA, two of it (with heatsink) are not stable and causing HPA-3B enter into protection mode, i.e. cut off power itself, when gain set at +20db, but it works perfectly when the gain set at +10db or below. The other two 49720HA just work perfectly under +20db. I tried 49720NA (DIP-8) also and let it ran for 2-3 hours and nothing happened.
 This protection design (which found on other Matrix product as well) somehow protect the opamps and I really don't like LME49990 as it lacks of bass.


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## burdie

raoultrifan said:


> Hi,
> 
> It sounds very well on my K701; gain of +10dB should be perfect, but also at gain of +5dB will work just fine. Gain of +20db should not be pressed while listening to K701/K702, unless volume knob is on the left half (between 7 o'clock to 12 o'clock).
> 
> ...


 
 You will be amazed by how well HPA-3B paired with '_*balanced*_' AKG K701, comparing to single ended K701. Please do so if you haven't
	

	
	
		
		

		
			




  
 I did compare HPA3 with WA6 (both in SE mode) with a group of head-fier. Well, HPA3 can drive perhaps all headphones from the planet but it doesn't mean it can drive at good sounding, at least not on Beyer T1 gen 1/gen 2. However, HPA3 do give better sounding than WA6 in few headphones we try, LCD 2.2, K701, K712, DT1770, ATH-R70X etc when the opamps are 49990 and 49720, and all of us ranked HPA3 below WA6 when it equipped with LME49860, as clarity gone with LME49860.


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## raoultrifan

Thank you burdie for your thoughts on the LME49720HA and for the "protection circuit" that needs to get "investigated" somehow.
 Also, helps reading http://sjostromaudio.com/pages/index.php/miscellaneous/170-how-does-it-sound about LME49860 sound and like I said before Violectric/Lake People guys are building quite nice headamps around LME49860, so I really think that this OPAMP could be a keeper in HPA-3B, unless upgraded with something discrete like Audio-GD or Burson (ofc, able to operate at +/-18V).
  
 Thanks a lot for the info about balanced K701; will do this in the next few days. I just finished last night my balanced DT880/600: 2 cables CORDIAL CMK ROAD 250 BK having 2x0.5mm2 copper wires with good shielding inside (outer plastic/PVC was stripped by me because of outer diameter was too big and heavy, so right now cable is very shiny because of the copper shielding being visible; will add some nice sleeving soon, so no worries) + Amphenol 4-pin 100% metallic shielded plug. This evening I'm gonna give'em a spin.  BTW, original DT880/600 cable had 1 ohm on each hot wire and 2 ohms for the GND, quite a lot I'd say; the new cable has 0.086 ohms/meter. 
  
 Raul.


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## burdie

raoultrifan said:


> Thank you burdie for your thoughts on the LME49720HA and for the "protection circuit" that needs to get "investigated" somehow.
> Also, helps reading http://sjostromaudio.com/pages/index.php/miscellaneous/170-how-does-it-sound about LME49860 sound and like I said before Violectric/Lake People guys are building quite nice headamps around LME49860, so I really think that this OPAMP could be a keeper in HPA-3B, unless upgraded with something discrete like Audio-GD or Burson (ofc, able to operate at +/-18V).
> 
> Thanks a lot for the info about balanced K701; will do this in the next few days. I just finished last night my balanced DT880/600: 2 cables CORDIAL CMK ROAD 250 BK having 2x0.5mm2 copper wires with good shielding inside (outer plastic/PVC was stripped by me because of outer diameter was too big and heavy, so right now cable is very shiny because of the copper shielding being visible; will add some nice sleeving soon, so no worries) + Amphenol 4-pin 100% metallic shielded plug. This evening I'm gonna give'em a spin.  BTW, original DT880/600 cable had 1 ohm on each hot wire and 2 ohms for the GND, quite a lot I'd say; the new cable has 0.086 ohms/meter.
> ...


 

 Many have argued on LME49720/49860 family and mostly think they are identical in both specs and sound, 49720HA merely a metal can version over LME49720NA and LME49860. Many now support LME49990 as claimed it is one of the best spec among many compatible opamps out there.
 As of LME49720/49720HA/49860, I still think that the metal can version LME49720HA has the best sounding among the family members..
  
 reading from the specs, CORDIAL CMK ROAD 250 BK using bare copper which will be oxidized, why not consider others that using OFC., ultra pure OFC, linear crystal OFC, silver plated OFC, hybrid or silver cable?


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## raoultrifan

burdie said:


> Many have argued on LME49720/49860 family and mostly think they are identical in both specs and sound, 49720HA merely a metal can version over LME49720NA and LME49860. Many now support LME49990 as claimed it is one of the best spec among many compatible opamps out there.
> As of LME49720/49720HA/49860, I still think that the metal can version LME49720HA has the best sounding among the family members..


 
  
 I've seen some time ago a pretty good explanation about why metallic and ceramic OPAMPs might sound better, sorry I can't remember where exactly, but the explanation was quite plausable. Meantime, here's a good pool: http://www.head-fi.org/t/521972/lm4562-lme49720-lme49860-do-they-sound-different-to-you. BTW, 6moons says that "LME49720HA make sense as they are basically the metal can version of the LME49860", but I was sure it's the metal version of LME49720...hmmm, strange.
  


burdie said:


> reading from the specs, CORDIAL CMK ROAD 250 BK using bare copper which will be oxidized, why not consider others that using OFC., ultra pure OFC, linear crystal OFC, silver plated OFC, hybrid or silver cable?


 
  
 Couldn't find a better cable right now, but I wouldn't worry about this too much, because the 2 "hot wires" from inside each cable have 2 decent outer sheets + the outer copper shield + future sleeving. Anyway, cable is really thick (AWG 20), so if oxidation will occur that will happening only to the outside of the copper wires and perhaps after at least 10 years of service. If I will ever find better cables I will probably upgrade them, but right now I bought these because lack of time and because I need right now some balaced headphones to test the new M-Stage headmp. 
  
 Might worth reading:
 http://www.head-fi.org/t/408073/why-oxygen-free-copper-cables-sound-no-different-than-etp-copper
 http://www.avsforum.com/forum/89-speakers/1014081-speaker-wire-does-oxygen-free-matter.html
  
 P.S.: I have a friend having a small recording studio and he told me these CORDIAL ROAD cables are quite decent, so if his high impedance and very sensitive microphones are sounding OK after a couple of years of intensive usage, I'm preety sure my heapdhones should sound great after at least 10 years with these cables


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## burdie

raoultrifan said:


> Couldn't find a better cable right now, but I wouldn't worry about this too much, because the 2 "hot wires" from inside each cable have 2 decent outer sheets + the outer copper shield + future sleeving. Anyway, cable is really thick (AWG 20), so if oxidation will occur that will happening only to the outside of the copper wires and perhaps after at least 10 years of service. If I will ever find better cables I will probably upgrade them, but right now I bought these because lack of time and because I need right now some balaced headphones to test the new M-Stage headmp.
> 
> 
> P.S.: I have a friend having a small recording studio and he told me these CORDIAL ROAD cables are quite decent, so if his high impedance and very sensitive microphones are sounding OK after a couple of years of intensive usage, I'm preety sure my heapdhones should sound great after at least 10 years with these cables


 
 Just for precaution, I have seen stock cable with bare copper of few flagship headphone oxidize in 2 - 3 years time, which including T1 and LCD series,
  
 Expecting your thoughts on balanced DT880 on HPA-3B


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## raoultrifan

DT880/600 sounds great on HPA-3B. With this new balanced cable soundstage increased and details seem more focused. I really think that moving from single-end to balanced is a real upgrade for anyone, especially if DAC is really-balanced as well.
  
 BTW, I'm already thinking in doing few "mods":
 - upgrading volume knob with a black anodized aluminium knob as *burdie *suggested (headamp will look much better)
 - adding an EMI/RFI AC noise filter (should take care of any possible AC line hum/noise)
 - shielding toroidal transformer with G.O.S.S. (Grain Oriented Silicon Steel)
 - replacing WIMA MKS 4 (Metallized Polyster) with JB JFX Premium Film Cap (Polypropylene Film)
 - replacing 2SC3421/2SA1358 1A/10W transistors with 2SC5171/2SA1930 2A/20W transistors used in Burson HA-160 (I don't think sound will change, but the heatsinks temp should decrease with at least 5C)
 - increasing heatsinks on the voltage-gain transistors (these 4 small heatsinks inside the headamp are incredible hot!)
  
 I don't really believe I will have the time to do all of these mods, but at least some of them will probably do sometimes. 
  
 Thanks,
 Raul.


----------



## raoultrifan (Apr 21, 2018)

So, I did a bit of "modding" last night:

 - 1) I had replaced WIMA MKS 4 (Metallized Polyster) with JB JFX Premium Film Cap (Polypropylene Film) bought recently from TME.
 I might be inclined to tell that trebles are a bit more upfront and detailed now, but to be honest without proper A/B testing it's quite hard to tell if any real difference occured. Anyway, acording to audiophile forums & resources Polypropylene is better than Polyester, so I'm pleased that I swaped Wima with JB (I was tempted to use MIFLEX MKP10 or MKP11, but they were too big to fit properly). Caps links: 1, 2, 3, 4, 5, 6.

​ 
 -2) I had installed G.O.S.S. (Grain Oriented Silicon Steel) to shield the toroidal transformer.
 Initially, with my sensitive AKG K550 and without any source connected to XLR inputs, when using +20dB gain setting I was able to hear a bit of a hum noise when volume pot was at 3 o'clock or more, especially on the right channel. Now after partially shielding the transformer that noise is COMPLETELY gone!

​ 
 -3) EMI/RFI noise suppression filter got installed as well, but that made the amp to get a bit of hum noise again, perhaps because the AC lines were too close to XLR inputs (also, PCB traces from XLR were right besides the noise suppression filter). So, I moved the filter from right to the left side, just above the 120/230V selector, as the red arrow shows (sorry for not providing a picture of the actual noise suppression filter positioning, but I was quite struggling with fitting the filter inside the case and I totally forgot to get another picture). Also, please ignore the big red wire, it was connected to the 2 Y-capacitors, but it's not really needed, so I removed it from lack of space (it also did a quite nice short-circuit with flame, so next time I'll be more careful).


​ 

​ 

 
 -4) Arctic Silver MX4 thermal paste has been correctly applied between transistors heatsinks and the case, just to be sure thermal transfer is OK (just realized that outer side of both heatsinks were not perfectly flat, so thermal paste should help a little bit here).

 Burdie, feel free to have a look to my DT880/600. Now that's what I call shiny headphones! 
 Perhaps on Friday I'll receive some decent mash sleeving from Distrelec/Austria and I'll see if I'll dress those phones or not.

​L.E.: Re-edited few pictures for better understanding of what I've did.

WARNING: Mod 3) is really dangerous to DIY and electric hazard might happen, so I don't recommend it! Instead, please use a power strip with common-mode filter inside or change the inside power outlet with one containing common-mode filter within.


----------



## burdie

raoultrifan said:


> Burdie, feel free to have a look to my DT880/600. Now that's what I call shiny headphones!
> Perhaps on Friday I'll receive some decent mash sleeving from Distrelec/Austria and I'll see if I'll dress those phones or not.


 
 Very good looking cable, suggest to retain the shiny look by adding tranparent heat shrink (just like lapp kable ÖLFLEX CLASSIC 100 CY), instead of mash sleeve.If still prefer mash sleeve then must go with multifilament type to reduce microphonic noise caused by those expandable sleeve.
 By the way, since you started to mod HPA-3B, are you considering to add permanant 0.1uf bypass cap to pin 4 and pin 8 of the opamps? Or may be you able to find out the earth/ground point so that 2 bypass cap can add to each pin. I really have no time to mod it.


----------



## raoultrifan

burdie said:


> Very good looking cable, suggest to retain the shiny look by adding tranparent heat shrink (just like lapp kable ÖLFLEX CLASSIC 100 CY), instead of mash sleeve.If still prefer mash sleeve then must go with multifilament type to reduce microphonic noise caused by those expandable sleeve.


 
 Thank you, I couldn't find transparent heat shrink easily, but I'll probably give it a 2'nd chance...I'll see about it soon.


burdie said:


> By the way, since you started to mod HPA-3B, are you considering to add permanant 0.1uf bypass cap to pin 4 and pin 8 of the opamps? Or may be you able to find out the earth/ground point so that 2 bypass cap can add to each pin. I really have no time to mod it.


 
 I was actually thinking of this one myself the other day, especially that even Burson is recommending this easy mod, but AFAIK this decoupling technique should reduce OPAMP oscillations (if any) and not really improve sound in our case, but perhaps I'm wrong, so I'll keep reading about it. I had prepared  the other day a couple of WIMA MKP 0.1uF for this task and I'm also interested in adding a couple of 1uF tantalums as well in parallel with existing 1uF caps, but I'm not sure I'll gain anything out of this mod because PSU looks OK, no AC ripple issues, OPAMPs are not oscillating, so I'll think about it perhaps soon. Thanks!


----------



## burdie

raoultrifan said:


> Thank you, I couldn't find *transparent heat shrink* easily, but I'll probably give it a 2'nd chance...I'll see about it soon.
> I was actually thinking of this one myself the other day, especially that even Burson is recommending this easy mod, but AFAIK this decoupling technique should reduce OPAMP oscillations (if any) and not really improve sound in our case, but perhaps I'm wrong, so I'll keep reading about it. I had prepared  the other day a couple of WIMA MKP 0.1uF for this task and I'm also interested in adding a couple of 1uF tantalums as well in parallel with existing 1uF caps, but I'm not sure I'll gain anything out of this mod because PSU looks OK, no AC ripple issues, OPAMPs are not oscillating, so I'll think about it perhaps soon. Thanks!


 
 The transparent heat shrink should be easily source from Europe. Have you tried RS Components Europe or your country?


----------



## raoultrifan

Will try finding some transparent shrink soon, thank you burdie. Right now I finished re-wiring with balanced cables my K701 headphones and "burning in" the new cables.


----------



## raoultrifan

Just measured the DC on XLR output plug (no phones connected, no input signal applied, amp was powered since about 15 minutes):
  
* Gain:    Left   /   Right*
  +5dB:  1.20mV/-0.60mV
 +10dB: 0.42mV/0.40mV
 +20dB: 0.65mV/0.63mV
  
 DC was constant, no matter of volume knob position.
  
 AFAIK, an output DC lower than 10mV is really safe, even for 8 Ohms IEMs, so less than 1mV I would call this as being perfect. 
 If speaking about low-sensitivity planars or 600 Ohms headphones, then even 30mV should not have any negative influence at all.
 My O2 amplifier has around 3.0-3.5mV of DC and everyone says this is a very good value. Also, my LME49720/LME49600 DIY headamp has between 1.5-3.0mV of output DC.
 I was unable to see any DC offset circuit on the PCB, just the protection from output jack/XLR plugs, so I don't know why the DC is so low; perhaps the transistors are all very well matched...who knows...
  
 I've also checked the XLR output with my PicoScope and spectrogram was looking very well, with no spikes or anything suspicious from 0Hz to 10MHz. SNR was around 100dB RMS with volume knob to the min. This is not Audio Precision, but if there's something wrong like an oscillation or some voltage spikes then I should be able to observe it with the scope. 
  
 Temperature on the case, after about 2 hours since powered up, was about 50C; measurement was done with an IR gun and also with a metallic thermometer. Quite hot I'd say, so I'll try to swap the 4 small rubber feet from the bottom with something bigger and higher (1cm height perhaps), because a small part of this heat was probably caused by the warmth of Essence One from below HPA-3B. So, this headamp should probably not be stacked at all.


----------



## raoultrifan

I did a sort of a "in-house RMAA", though I don't have a sound-card with a decent ADC chip inside, I've used my EssenceOne as player and my PicoScope to interpret the results as well. 
 I trust the ADC from my scope more than the ADC from a sound-card anyway, also PicoScope's input OPAMPs are AD8065A having 7nV/√Hz of noise.
  
 I've downloaded a lot of -3 dB 48Khz WAV files from AudioCheck website, played them through Foobar (no plugins used!) and connected the scope to XLR output (only left channel I've used).
 I've used for this test 21 WAV files having the following frequencies (Hz): 20, 30, 40, 50, 63, 80, 100, 125, 250, 500, 750, 1000, 2000, 3150, 4000, 5000, 6300, 8000, 10000, 12000, 16000 (usually people does RMAA only from 40Hz to 15KHz).
  
 Signal level I choose for testing was 389 mV peak-to-peak; couldn't use more than 400mV because I was loosing graph resolution to my scope and I needed a good resolution to see if the sine-waves are perfect or not. Anyway, at this level with my DT880/600ohms headphones connected this was the highest supportable volume for my ears for the 1KHz frequency; for higher frequencies than 1KHz I was actually unable to keep the headphones on my head! In the end, I've removed my headphones to do this test, because I needed the XLR plug available to connect my scope probe. To get this voltage the head-amp gain was +10 dB and volume knob was around 9 o'clock (I usually listed to music with volume knob between 11 and 13 o'clock with my DT880/600 at gain of +10 dB, but looks like with these pure sine-waves I can't even get over 9 o'clock without starting my ears to bleed).
  
 From 20Hz to 12KHz I haven't seen even a 0.1mV modification in volume and all the sine-waves were perfectly reproduced (graphs were looking perfect). At 16KHz I've seen around 1mV roll-off and that means less than 0.05dB, so I find this an exceptional value.
  
 If someone has a decent sound-card with an acceptable ADC inside, I would also be interested in finding out a real RMAA test. Thanks!
  
 P.S.: In case it matters for someone, the R-C input filter of the HPA-3B is created by using 4 x 47KOhm resistors and 4 x 2.2uF capacitors. That means that at 1.5Hz there's a -3dB signal and starting with 15Hz the signal should be 0dB flat line. So, perhaps this is why there's no roll-off at all when applying 0.4V sine-wave with a frequency of 20Hz.


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## Suopermanni

Have to ask a stupid question but what is the RCA output for on this unit?


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## raoultrifan

It has XLR and RCA inputs only, but based on adapters from XLR 3-pins to RCA. Check the back side of the headamp on pictures from previous pages and you'll see the 2 XLR plugs and also the 2 RCA-XLR metallic adapters.
  
 On outputs you can only see XLR 4-pins plug and 6.3mm jack.
  
 Cheers!


----------



## Suopermanni

Sorry, should of mentioned i have unbalanced version. Im not sure why it has rca out and what purpose it serves.


----------



## WilCox

suopermanni said:


> Sorry, should of mentioned i have unbalanced version. Im not sure why it has rca out and what purpose it serves.


 
  
 Those are the pre-amp outputs.  You can use them to drive powered speakers or an amplifier.


----------



## raoultrifan

Oh, sorry..
  
Most headamps have IN and OUT, mostly because you may need to connect an external DAC and now you want to listen to your headphones, but latter you might want to listen to your power integrated amplifier + speakers.
  
So, it's quite OK to have RCA In and RCA Out in case you'll need to use external source (DAC, CD whatever) and use HPA-3U and external speakers/amp.
  
 L.E.: Please disregard this not so intelligible speech/post and go straight to post_12144919 or to http://www.matrix-digi.com/pdf/HPA-3U_Manual_EN.pdf. Thanks!


----------



## Suopermanni

Wait, this thing is a pre-amp also? I had no idea! Now i can try it.


----------



## raoultrifan

I'm sorry if I wasn't very explicit, but here's the manual: http://www.matrix-digi.com/pdf/HPA-3U_Manual_EN.pdf.
  
 Matrix M-Stage 3U has 2 input sources:
 - internal DAC
 - external RCA input
  
 There are also 2 x RCA output plugs are only used in case you want to feed with internal DAC (as source) an external amplifier (another headamp or speakers amp); you can also use headphones plug when feeding audio signal using RCA output (listen to headphones while feeding an external amp/speakers). So, no preamp unfortunatelly...


----------



## raoultrifan

I did a couple of A/B tests today.
 - DAC used: ASUS Essence One Muses MKII (internal power source moded + dedicated power source for both PCM1795 DACs).
 - Headphone amplifiers used: Essence One's internal amplifier and M-Stage 3B (balanced input).
 - Headphones used: 2 x K701 (one balanced and another one unbalanced).
  
 - 1) K701+Essence1/SingleEnded against K701+MStage3B/SingleEnded: not much of a difference I'd say, same imaging, same sound...quite similar sounding (perhaps E1 has a bit fuller bass, but this needs to get investigated a bit more latter).
 - 2) K701+Essence1/SingleEnded against K701+MStage3B/Balanced: hmmm, how can I put this...it's like *mono vs. stereo*!  Soundstage increased a lot and all scene and voices are all around of you when going balanced; every voice and every sound is much more clear now, it's like a veil just uncovered and now all sound is better and clear, upfront and with a way much better soundstage.
  
 Notes:
 1'st test was done by using only one single ended headphone and pressing a button to choose between the 2 headamp's outputs.
 2'nd test was done by quickly replacing the headphones around the head.
 At least 50 tests were done for each of the 2 A/B's from above and 100% of them were conclusive!
  
 P.S.: I realized from the first hour of listening to M-Stage 3B that going balanced improved the scene a lot (vs. unbalanced), but I thought it's just a psychological effect of my new headamp.  I was almost going to install Meier Corda's foobar plugin for "crossfeed" to diminish the larger scene and bigger stereophonic image created by this balanced upgrade. But to be honest, until today's A/B test I didn't thought the difference is so huge! So, now I strongly recommend to everyone to move to balanced DAC/headamp/headset, because this is a really step up in audiophile's world and you'll never go back to unbalanced/single-ended.


----------



## Aplle

Has anyone compared the dac that's buit into the 3U with other dacs, and if so how did it fare?


----------



## raoultrifan

http://www.head-fi.org/products/matrix-m-stage/reviews/13475
 http://www.headfonia.com/review-matrix-m-stage-hpa-3u/
 http://headphone.guru/the-new-matrix-audio-m-stage-hpa-3u/
  
 So, DAC inside 3U seems decent, but the amp itself can do better with external sources.


----------



## raoultrifan

I think I'll buy some bigger heat-sinks for drivers transistors, because they heat up very high (I estimate *at least 70C* with case closed). I'll also buy a couple of heat-sinks for the OPAMPs as well (they heat up very well too, at least 50C).
  
 By looking at these drivers closer I can see written on them *.T-S* and *:H-S.*, but I can't really say what exact transistors are they, maybe a head-fier might help here, please. Anyway, after reading datasheets for some of these SOT-23 SMD transistors (hope I'm not wrong about the case type) are usually able to work up to until 150C internally, here's some examples of ST-marking transistors I found:
 - 2SC3929A: Max. power dissipation: 150mW, max.junction temp: 150C, 55VCBO, 55VCEO, cont./peak current: 50mA/100mA
 - 2SC2406: Max. power dissipation: 200mW, max.junction temp: 150C, 55VCBO, 55VCEO, cont./peak current: 50mA/100mA
  

  
  
 Also, we can notice the 6 x OMRON relays, each costing 5 USD + VAT. 

  
  
 I had installed, after all, 4 x WIMA MKP 0.1uF/100V from each V+/GND & V-/GND for both OPAMPs, 4 x WIMA MKP 0.1uF/100V for each of the 4 x 330uF Nichicon capacitor from the middle of the board and 2 x AVX 10uF/35V tantalums for each of the 2 x 330uF capacitors from output of power regulators.

  
 I measured again AC ripple  and noise with my 10MHz PicoScope and max. peak-peak value was less than 1mV (first time I did that I used a 100KHz true-RMS VOLTCRAFT multimeter and the value was lower, because of lower bandwidth and accuracy). I find this being quite decent from 0Hz to 10Mhz bandwidth, especially that LME49860 has a PSRR and CMRR that exceed 120dB, so there should be no noise getting from power rails to headphones output.
  
 I measured on the transformer the following voltages:
 - 8.35V between the 2 remaining windings or 1x3.85V between GND and first winding and 1x12.3V between GND and second winding (perhaps used for the blue LED, for output protection circuit and also for +5V OMRON's)
 - 2x21.70V used for power regulators
  
 I found a 0.65V difference between the 2 regulators:
 - JRC7818:  18.45V
 - JRC7918: -17.80V
 but this is not going to influence negatively headamp's functionality, because this circuit only knows about the total voltage of 36V between +Vcc and -Vcc. Also, the very low DC output speaks for itself. 
  
 I unscrewed for about 1 turn the 4 screws from bottom of PCB that keeps aligned the big heat-sink from output transistor (2 screws for each heat-sink), because of a wrong angle of the heat-sinks were not perfectly aligned with the aluminum case:

 You can see that the thermal paste MX-4 is missing from the bottom-mid of the heat-sink because of the wrong angle. Now, after unscrewing the 2 screws for both heat-sinks I'm hoping the heat-sinks will perfectly get aligned with the case, for a perfect heat transfer.


----------



## raoultrifan

Like I said before drivers heat-sinks heat up pretty high: I measured with my IR thermometer between 62-64C without any signal input and case open. Output transistors heat up a bit lower...around 52-55C and OPAMPs a couple degrees less. So I ended up replacing drivers heat-sink with bigger ones and I also installed 2 x heat-sinks for OPAMPs as well.
  
​  
 I filed drivers heat-sinks by using a pile and a vise and I still got trouble with one heat-sink almost touching an output resistor of 10 ohms, so I removed the resistor and solder it 1-2 mm forward.
  
 Initially I used thermal Scotch tape to stick heat-sinks to drivers transistors, but I wasn't pleased with thermal transfer because these heat-sink are 3 times bigger and 4 times heavier than the originals and I can't really stuck them in place properly, so I used Arctic Alumina thermal glue. Even if thermal transfer is now even better than original thermal tape and heat-sinks are bigger and thicker drivers temperatures are not much lower than it used to be before, just 2-3C better.  I still have 60-61C with case open and I'm not very comfortable with this, because this probably means that with case closed drivers heat-sinks will reach up to 75C and their internal junctions will most likely heat to 85C or even more.
  
 So, I had installed a small fan from an old video card:
​​  
 Power supply I got it from an existing 8.35V AC (white and black wires from transformer's plug) and I used a small rectifier bridge and a 100uF/25V capacitor. Final DC voltage was 10.6V and the little fan was powered through a 50 ohms/0.25W resistor and was sticked with 1mm thick 3M double tape directly on OPAMPs heat-sinks, perfectly centered. Now drivers heatsink are having between 42-45C with case open and no input signal applied, so I suppose with case closed and music singing drivers transistors will heat up no more than 60C or maybe less.
​  
 One thing's for sure: initially I had around 48-50C on top of 3B's case and now, with bigger heat-sinks for driver transistors and OPAMPs + a small fan inside, I have around 41-42C.


----------



## shatrukov

```
[color=rgb(34, 34, 34)] Вы обеспокоены температуре  75 ° С? Вообще  допустимой температурой  на МОП транзистора  150 °. 70 - 85C  является  нормальная температура  для класса  А.[/color]
```


----------



## raoultrifan

shatrukov said:


> ```
> [color=rgb(34, 34, 34)] Вы обеспокоены температуре  75 ° С? Вообще  допустимой температурой  на МОП транзистора  150 °. 70 - 85C  является  нормальная температура  для класса  А.[/color]
> ```


 
 Thanks to Google translate: "Are you concerned about a temperature of 75 ° C? Generally allowable temperature of the MOSFET 150 °. 70 - 85C is the normal temperature for Class A."
  
 Indeed, absolute max. temp. of these transistor drivers is probably 150C (perhaps 125C to be on the safe side), but this is calculated on internal junction temperature and not on top of transistor's heat-sink. Usually I don't care if a TO-126 or a TO-220 case transistor heats up to 100C, but a small plastic SOT-23 transistor having it's top heat-sink with a temperature of 75C worries me a little bit, yes.
  
 Anyway, 75C measured on top of this heat-sink probably means 90-95C inside transistor's junctions, because original heat-sinks were stick with thermal tape and amplifier's case is closed anyway, so there's no ventilation inside. If the aluminum case would be made with proper vent haules on top and also on bottom, like Schiit Asgard is, then I wouldn't be worried about internal temperature anymore. I'm not saying M-Stage 3B has temperature issues, not at all actually, but all I'm saying is that I'm not feeling comfortable with a 50C top-case temperature.
  
 If it was my speakers amplifier then I wouldn't probably bothered at all, but I don't really like to place my hand on top of a headphone amplifier and to almost get burned, if you know what I'm saying.  And same feeling have it OPPO HA-1 owners on DIY-AUDIO forum and we all know how good HA1 is and how well it measures.
  
 By lowering internal case temperature with almost 10C I had also decreased all internal passive components temperature as well, because PCB was initially hot and all capacitors, resistors and even the ALPS potentiometer were quite warm and we all know that warm resistors means more Johson/thermal noise, right? 
  
 I don't know about other headamps, but Beyerdynamic A1 and Burson HA-160 have about 35C on top, Schiit Asgard 2 has around 45C on top (pure Class-A again), so original Matrix M-Stage 3B with its 50C is quite hot I'd say, perhaps because it's balanced and it has twice as many transistors.


----------



## shatrukov

```
[color=rgb(34, 34, 34)] Thanks for the translation!))) Google translated well. Interesting to know the quiescent current MOSFET . There is such a possibility?[/color]
```


----------



## raoultrifan

Well, I'm not sure the driver transistors are MOSFETs after all; could you please check this post from top of this page, please? Perhaps you know better, but I've seen on Internet that H-S and T-S notations correspond to bipolar transistors, but I can't be 100% sure of that.
  
 Anyway, now that I glued the heat-sinks on top of driver transistors I can't really measure any voltage drop across their legs. In case you have some suggestions how to easily check quiescent current, please tell me.
  
 Now I'm listening at moderate volume on my 32-ohms AKG K550 headphones and while case is completely closed, internal air temperature of M-Stage 3B is *around 43C* (sometimes more, depending on probe position inside M-Stage case). Measurement was done with the external sensor of UNI-T UT58C multimeter stuck inside M-Stage 3U through upside vent-holes for about 4-5cm.
  
 While my IR thermometer shows an acceptable temperature of *43C on top of case* (although it feels hotter when placing my palm on top), UT58C shows *between 57-60C* when temp probe touches drivers heat-sinks (with aluminum case closed, spot led lantern used to guide the small probe inside M-Stage vent holes). 60C seems quite OK to me, too bad I haven't done this measurement before installing the bigger heat-sinks and the small fan inside the case (I was only approximating the "case close" temp based on "open case" temp); perhaps drivers heatsinks had about 75C indeed when case closed.
  
 Thank you!


----------



## raoultrifan

In case you guys missed that: AUDEZE DECKARD headamp is quite similar with M-STAGE 3U (perhaps the same manufacturer?!?): http://www.head-fi.org/t/749486/audeze-deckard-class-a-amp-usb-dac/150#post_12160801.


----------



## raoultrifan

Just realized that output power specs for THD+N=0.01% published by Matrix manufacturer (http://www.matrix-digi.com/en/specifications/76/index.html) are quite simmilar with the ones published by Texas Instruments on LME49860's datasheet graphs (http://www.ti.com/lit/ds/symlink/lme49860.pdf) and could be achieved with a gain of "only" +15dB gain (at least for 300ohms and 600ohms, because for 33ohms output buffers can't output so much power). So, I wonder if anyone has decent equipment to do some measurements for this amp and to publish some numbers.
  
 I estimate that for an input source having 2V RMS/4V RMS (single-ended/balanced) full power specified by manufacturer will be achieved by using the max. gain setting of +20dB and volume knob around 3'o clock, at least for high impedance headphones.
  
 Based on Matrix specs, max. output voltage for HPA-3B for a THD+N of only 0.01% would be:
 - around 11.5V RMS for single-ended operation for high impedance phones (220mW in 600ohms)
 - around 22V RMS for balanced operation for high impedance phones (800mW in 600ohms)
 I used http://www.sengpielaudio.com/calculator-amplification.htm to find out that these figures are equivalent to a gain of +15dB if input source is 2V RMS/4V RMS (single-ended/balanced).
  
 Based on TI http://www.ti.com/lit/ds/symlink/lme49860.pdf datasheet max. output voltage would be:
 - around 11.8V RMS: 232mW in 600ohms for single-ended operation
 - around 23.6V RMS: 929mW in 600ohms for balanced mode.
 Have no idea about the real THD+N at these power figures, but I estimate would probably be less than 1%.
  
*NOTE*: For checking if this amp is fully compatible with your headphones, at least based on pure specs and requirements, also for checking the correct gain setting to be used you could fill in http://www.digizoid.com/power.php and calculate necessary power to correctly handle your headphones (max. peaks of 115dB should suffice, I'd say, for most people). All you need to do is check your headphone specs or datasheet and enter impedance and correct SPL values. Double check if your headphones manufacturer is using dB/mW or dB/V before calculating amp power requirement. For example Hifiman HE-6, the most hard to drive headphones I know, need 8.65V RMS/163.21 mA/1411.75 mW to be driven as loud as 115dB. That means in either single-ended or balanced mode HPA-3B will handle these headphones with ease and pleasure; too bad I don't have a pair of HE6 to test them myself now.
  
 P.S.: I am doing now some A/B testing between HPA-3B and Essence One and also Objective2 and I realize that HPA-3B soundstage is much better than it used to be in its first days when I bought it. I'm not sure this might be related to the mods I've done here or to the caps I've added here because I haven't done these A/B test immediately after I've finished those mods, but I'm sure I really love the soundstage I'm having now.


----------



## burdie

raoultrifan said:


> Just realized that output power specs for THD+N=0.01% published by Matrix manufacturer (http://www.matrix-digi.com/en/specifications/76/index.html) are quite simmilar with the ones published by Texas Instruments on LME49860's datasheet graphs (http://www.ti.com/lit/ds/symlink/lme49860.pdf) and could be achieved with a gain of "only" +15dB gain (at least for 300ohms and 600ohms, because for 33ohms output buffers can't output so much power). So, I wonder if anyone has decent equipment to do some measurements for this amp and to publish some numbers.
> 
> I estimate that for an input source having 2V RMS/4V RMS (single-ended/balanced) full power specified by manufacturer will be achieved by using the max. gain setting of +20dB and volume knob around 3'o clock, at least for high impedance headphones.
> 
> ...


 
 Sorry, I thought LME49860 was used as I/V stage and the high current amplication was done by the Toshiba A1358/C3421?


----------



## raoultrifan

Yes, LME49860 OPAMP is used for Voltage-Gain stage, so the final voltage of amplifier is given by the OPAMP itself. Output stage made by transistors only provides enough current to drive low impedance headphones.
  
 I believe 3B's THD is mostly given by the OPAMP used, especially for high impedance headphones, but it would be great if somebody could take some measurements on this amp with dedicated equipment.


----------



## raoultrifan

I did a couple of tests last evening to roughly check for max. output power and also for THD or any possible oscillations when driving the Matrix M-Stage 3B amplifier to max. power.
  
*Source*: Balanced outputs from ASUS Essence MUSES MKii + audiocheck.net FLAC file -3dB 1KHz sinusoidal signal connected to desktop computer (1.2mV noise+ripple on USB port)
*Scope*: PicoScope 2204A, latest app. version, connected to Lenovo T430 laptop on battery (for galvanic decoupling probes from AC mains)
*Dummy load*: 4 x 240ohms/1W paralleled resistors (about 60ohms/4W) connected to one end of original Beyerdynamic DT880 cable (I had this one left after I balanced my headphones). So, as you can see, there's also a real cable capacitive load as well on output circuit, so it's almost like driving regular headphones.  The cable has about 2 ohms: 1 ohm for signal wire and 1 ohm for GND. I've only published results from one channel.
  

 *Not-clipping SE: a​**bout 1.425 W RMS power*​ *(26.65V p-p, 9.402V RMS)​*​  ​  *Clipping SE: a​**bout 1.687W RMS power*​ *(28.14V p-p, 10.23V RMS)​*​  ​  *Not clipping SE: about 1.5 W RMS power - no strange harmonics*​  *Clipping SE: about 1.7 W RMS power - lot of harmonics​*​    *Not clipping BAL: a**bout 4.327 W RMS power*​ *(46.7V p-p, 16.38V RMS)​*​  ​  *Clipping BAL: a**bout 4.617 W RMS power*​ *(47.58V p-p, 16.92V RMS)*​  
 *Not clipping BAL: about 4.4 W RMS power - no strange harmonics​*​  *Clipping BAL: about 4.6 W RMS power - lot of undesired harmonics​*​ 
  
 Volume knob when starting to clip was around 3 o'clock and moving the knob even 1mm more or less made the output voltage to increase/decrease with at least 0.5V RMS. So, I estimate that with 60ohms headphones this _baby _can get up to *1.5W RMS power on single-ended* and up to *4.5W RMS power in balanced operation*, which theoretically should be good enough to drive any headphone from this planet, HE6 included. I'm very curious if someone can pair this amp with HE6 balanced headphones, to see about quality of the sound.
  
 I hope someone will be able to do some decent RMAA or AP-precision tests, because I can't trust the THD+N of my scope (see note below).
  
*Note*: On the FFT graphs the resolution and granularity of 2204A scope sucks, because I've used a gain of 10x for my probes and dB and THD are definitely not accurate. I need to use the +/-50mV peak-peak scale to get actual dB THD+noise (I can only do this with volume pot. to the min.), but that means I'm unable to check for max. power or for harmonics because I'll blow away my scope. So, this is why I used the +/-200V peak-peak scale (actually +/-20V with a gain of 10X setup to my probe).
  
*L.E.*: I must confess that the dummy resistors were extremely hot during these tests, untouchable by fingers, but none of them changed their color to brown or black.


----------



## BlutoSlice

Im thinking of upgrading my hpa1 to b3 can someone suggest which adapters I would need for a Sony mdr-z7 it has a balanced cable but with mini jacks. Would I need xlr > twin female phono?


----------



## raoultrifan

I believe you can try doing this by yourself, because it may be hard to find such an adapter. 2 x 3.5mm female jacks to XLR male should be fine or you can get rid of existing small jacks and solder  directly a high-quality 4-pin XLR-male.


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## Villy

I just wanted to express my appreciation for what you've done here in this tread, and specifically the information on 3B. I have been considering it as an alternative to Gustard H10 (I wish it had balanced cans output), and I think of getting it - burdie's and raoultrifan's discussion is very informative and helpful, thank you guys for taking the time! It will take awhile until I receive the amp from China, but whenever that is I'll post my impressions as well.


----------



## raoultrifan

Thank you Villy, I'm sure you'll be pleased with the new 3B.
  
 P.S.: I hope I'll be able to test this baby soon with a pair of V5's from Burson. I'll probably need to replace power regulators to adjust voltage to +/-15V for this.


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## Villy

I'm not sure the Bursons will withstand the voltage - they've been melting on H10 as it is.Granted, that was before Burson took steps to up the QC requirement and from 15V to 17V (the new batches according to a post on the Gustard trail were suppose to start coming out mid-February), but even at 17V I have some reservations they'll be safe for prolonged initial burning which I will certainly subject the amp to (I always put new equipment, whatever it might be - amps, dacs, cans, cables, everything for at least a week thru non-stop burning).
  
 I'll check with Burson, as well as  Sparko's Labs (also I am eager to try their opamps, have great reviews) if there is a chance their modules will be ok with the amp's supply voltage. There is another descrete opamps maker I am also interested in - Sonic Imagery Labs. Each of these adds between $140 and $180 of additional cost, I'll swallow it though as long as any of these opamps can be a match.
  
 Alternatively, I will try 4X LME49710HA, 2x on 2 browndogs, one on each socket as suggested by YoYo Jocker in his review of 3B.


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## raoultrifan

Burson's V5 are not OK with either 17V or 18V, this is why I'll replace power regulators from my Matrix 3B to give them a test. I've already spoke with Burson and they confirmed that I'll need +/-15V for this test.


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## Villy

Here is the page on the H10 trail where Burson confirmed they'll start releasing the opamps with tolerance for +/-17 starting 2 weeks ago. In any event, if power regulator mod works that will be awesome. My soldering skills are pretty much nonexistent and my engineering knowledge just about the same, but I'm not afraid to tinker with my stuff and will no doubt go for it


----------



## Villy

Oops, the link:

http://www.head-fi.org/t/735828/gustard-h10-high-current-discrete-class-a-output-stage-headphone-amplifier/4125


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## raoultrifan

villy said:


> [..] In any event, if power regulator mod works that will be awesome. My soldering skills are pretty much nonexistent and my engineering knowledge just about the same, but I'm not afraid to tinker with my stuff and will no doubt go for it


 
  
 Will get back here with news regarding Matrix HPA-3B and Burson V5's, if I'll grab a couple of V5s in Mars (I hope). All I need is a bit of time to do the tests.


----------



## Villy

Just saw this posted this on the Burson's blog: http://www.bursonaudio.com/ss-audio-discrete-op-amp-review-from-poland/
  
 Here's the thing though - the test for the quoted review, as well as Burson's own test of V5 with the H10, did not emulate real-live, that is loooong sessions, including weeks-long really, when one burns in new equipment. That worries me a bit...more than bit actually. As they noted themselves, in their lab testing they didn't go for prolonged sessions, else it is likely they would have gotten a whiff of the issue causing the meltdowns in H10 (hope they have learned a lesson here; and btw, I've come across online comments in regards to Burson's QC, ranking them just about as low as HiFiMan...we'll see, regardless I'm always willing to take a plunge, for nothing ever happens if one just stays put).


----------



## Villy

In the end I decided to go with Yulong A18 as the balanced amp in my headphones chain. In the end of my research it came down to these two models, so I weighted, and weighted the pros and cons of each one, and in the end .... Yulong's overall package (design / built / performance / price), and to a great extend the fact that it utilizes OPA2604 opamp (lot easier to and more options for upgrade), won it for me. So that's the direction I'm going, and modding all of my cans to make them balanced, balanced all the way, and I'm sure once I get there the'll be no going back


----------



## raoultrifan

It would be great if you could borrow a Matrix M-Stage HPA-3B to make a direct compare with Yulong A18.
  
 BTW, same OPA2604 can be used with success in Matrix HPA-3B.


----------



## burdie

villy said:


> In the end I decided to go with Yulong A18 as the balanced amp in my headphones chain. In the end of my research it came down to these two models, so I weighted, and weighted the pros and cons of each one, and in the end .... Yulong's overall package (design / built / performance / price), and to a great extend the fact that it utilizes OPA2604 opamp (lot easier to and more options for upgrade), won it for me. So that's the direction I'm going, and modding all of my cans to make them balanced, balanced all the way, and I'm sure once I get there the'll be no going back


 
 Yulong A18 is single ended amp, so you won't benefited from its balanced output as it just simply adding more power to balanced out and yet the signal processing still in single ended form.. Please refer to the following post on Yulong A28, the brother of A18 but with fully balanced implementation.
 http://www.head-fi.org/t/699772/yulong-a28#post_10164154
 I used to own A28 (heard other head-fier described it as more neutral than A18), but traded it as it cannot keep up with Schiit Mjolnir.
 But when 3B was introduced, I was impressed with the specs, and proceed to get one for office use. And yes, it come very closed to Schiit Mjolnir (of course, after swap opamps).


----------



## Villy

Hi burdie, typo on my part, I actually meant A28, yes of course, A18 isn't balanced. Already have ordered it and the amp is on its way. You said it 'cannot keep up with Schiit Mjolnir', in what way? My DAC is Matrix's X-Sabre btw, which I think has an outstanding resolution (haven't heard many high-end DACs, but from those that I have it sounds better than Violectric's V800, to my ears that is).


----------



## burdie

villy said:


> Hi burdie, typo on my part, I actually meant A28, yes of course, A18 isn't balanced. Already have ordered it and the amp is on its way. You said it 'cannot keep up with Schiit Mjolnir', in what way? My DAC is Matrix's X-Sabre btw, which I think has an outstanding resolution (haven't heard many high-end DACs, but from those that I have it sounds better than Violectric's V800, to my ears that is).


 
 It is just personal opinion that A28 cannot keep up with Schiit Mojo. My view is that A28 have enough power, it drive my HE500/LCD-2 very well, and I like the bass both delivered.
 However, when I compare these two amps on K701 & T1, A28 just simply not on the same league with Mojo, especially on clarity, Furthermore, the bass is kind of muddy, I believed there is no perfect amp that can feeds all types of headphone well, since Mojo performed better than A28 (matching with my cans and to my ears) , I decided to let go A28. But, it is one of the great headphone amps.
 My DAC is Matrix Mini-i Pro 2014 (but loaded with 2015 driver to support higher DSD/DXD), the SQ is quite closed to X-Sabre (my friend owns one, in fact my initial choice but it have no preamp function)
 Though I prefer Schiit Mojo and 3B over A28, my favourite amp now is EL84 tube amp speaker out via resistor adaptor.


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## Villy

Thx for the input. I will replace the opamps with discrete ones, Sonic Imagery's 994enh to be precise (the most expensive option but by all accounts, a step above anything else out there), so that should pretty much take care of/resolve any shortcomings in the detail and clarity of A28. Plan to replace the voltage regulators with discrete too.  
  
 It wasn't an easy decision for me, not to follow my instinct and go with HPA-3B, since I already have X-Sabre. It was almost done deal, but in the end I decided to go with Yulong even if it costs a bit more - just looking at both circuit boards, A28's built is more solid, I also like the fact it has more room in the box for EMI isolation, and also....it's Yulong (Matrix quality is just as good, but I always though Yulong edges it out when it comes to desing). Still, I think the main factor in influencing my decision was how easy it is to replace the opamps with discrete. There is a lot of talk about Burson's V5 around here when discussing discrete opamps. I researched extensively the subject though, as I can't really buy, burn and test them all, so I created my own wish list: Sonic Imagery comes on top, and Sparko's 2nd, Dexa and Burson coming next in that order though not really close to the first two. Which then would naturally be my choice and is where swapping opamps probably ends for me. And it happened so that my first choice Sonic 994enh's specs match A28 very, very well, and that sealed the deal. With that said, If I have an opportunity to get my hands on (relatively) cheap 3B, I'll swipe right away, certainly. That will be the real test then...maybe, some day.


----------



## burdie

villy said:


> Thx for the input. I will replace the opamps with discrete ones, Sonic Imagery's 994enh to be precise (the most expensive option but by all accounts, a step above anything else out there), so that should pretty much take care of/resolve any shortcomings in the detail and clarity of A28. Plan to replace the voltage regulators with discrete too.
> 
> It wasn't an easy decision for me, not to follow my instinct and go with HPA-3B, since I already have X-Sabre. It was almost done deal, but in the end I decided to go with Yulong even if it costs a bit more - just looking at both circuit boards, A28's built is more solid, I also like the fact it has more room in the box for EMI isolation, and also....it's Yulong (Matrix quality is just as good, but I always though Yulong edges it out when it comes to desing). Still, I think the main factor in influencing my decision was how easy it is to replace the opamps with discrete. There is a lot of talk about Burson's V5 around here when discussing discrete opamps. I researched extensively the subject though, as I can't really buy, burn and test them all, so I created my own wish list: Sonic Imagery comes on top, and Sparko's 2nd, Dexa and Burson coming next in that order though not really close to the first two. Which then would naturally be my choice and is where swapping opamps probably ends for me. And it happened so that my first choice Sonic 994enh's specs match A28 very, very well, and that sealed the deal. With that said, If I have an opportunity to get my hands on (relatively) cheap 3B, I'll swipe right away, certainly. That will be the real test then...maybe, some day.


 
 Discrete opamps is one of the way to improve sound, but right now I am quite satisfied with LME49720 on 3B.
  
 A little advise on A28, you can't find any info on impedance output online (3B have very low impedance output at 0.4 ohms), but I got a confirmation from Yulong (Xiao Long himself) that minimum headphone requirement for A28 is 16 ohms, this could be on the safe side, but better don't try those headphone with lower impedance than 16 ohms
 .
 I have no idea on how solid is A28 circuit board, but I do face one minor problem on on-board RCA female socket, one of the femae jack is 'bigger' than the other one, I need to wider the ring of male RCA on the interconnect and push very hard to fully 'inserted' into the female RCA. And another problem is opa2604 is soldered on the PCB, extra works to swap opamps and might void warranty.
  
 If compare the body/case, I don't think Yulong is better than Matrix, especially on your X-Sabre, which is 1 big block of aluminium cut by CNC.
  
 However, SQ decides everything.


----------



## raoultrifan

burdie said:


> Discrete opamps is one of the way to improve sound, but right now I am quite satisfied with LME49720 on 3B.
> [...]


 
  
 Hi burdie, 
  
 I recently got 2xV5-duals from BURSON and I'm so waiting to test'em in my HPA-3B. I only did a test with my Objective2 headamp and I couldn't believe this solid-state op-amp is able to provide more details for O2 when used in voltage-gain stage. I'm so hoping I'll have the time to test'em both in my HPA-3B, but that means time to change power regulators first, to decrease voltage to +/-15V. 
  
 Regards, 
 Raul.


----------



## burdie

raoultrifan said:


> Hi burdie,
> 
> I recently got 2xV5-duals from BURSON and I'm so waiting to test'em in my HPA-3B. I only did a test with my Objective2 headamp and I couldn't believe this solid-state op-amp is able to provide more details for O2 when used in voltage-gain stage. I'm so hoping I'll have the time to test'em both in my HPA-3B, but that means time to change power regulators first, to decrease voltage to +/-15V.
> 
> ...


 
 If the outcome is good, it will be great for all the 3B owners.


----------



## raoultrifan

Well, someone already did this test and even didn't bothered of replacing power regulators: http://www.audiofanatyk.pl/recenzja-wzmacniacza-dyskretnego-burson-supreme-sound-v5/; looks like both V5s survived this test at +/-18V and this is a good thing I'd say. Test looks very promising, but until I'll do a test myself with V5s and my HPA-3B I will not be able to comment (also, I'm not sure the upfront case will fit, because the height of V5 is too much, but I'll see about this soon).


----------



## burdie

raoultrifan said:


> Well, someone already did this test and even didn't bothered of replacing power regulators: http://www.audiofanatyk.pl/recenzja-wzmacniacza-dyskretnego-burson-supreme-sound-v5/; looks like both V5s survived this test at +/-18V and this is a good thing I'd say. Test looks very promising, but until I'll do a test myself with V5s and my HPA-3B I will not be able to comment (also, I'm not sure the upfront case will fit, because the height of V5 is too much, but I'll see about this soon).


 
 Hi Raul,
 Have you ever check on the actual voltage supply to opamps? We knew the power regulator supplied 18V but have yet to find out the exact voltage for opamps.
 If it still supply roughly 18V to opamps, a minor mod to put DC step down voltage regulator like LM7815, in between V5 and opamps socket, and isolated +18V DC power to pin 7 of the socket, so that the regulated 15V (perhaps clean DC) was supplied to pin 7 of opamps (if space allowed)


----------



## raoultrifan

HPA-3B has exactly +/-18V, so I'll need to change regulators with NJM7815 (already bought them). BURSON confirmed that max. voltage for V5's is +/-15V; perhaps their next solid-state op-amp version will be designed for a higher voltage.


----------



## burdie

raoultrifan said:


> HPA-3B has exactly +/-18V, so I'll need to change regulators with NJM7815 (already bought them). BURSON confirmed that max. voltage for V5's is +/-15V; perhaps their next solid-state op-amp version will be designed for a higher voltage.


 
 Good luck on lowering the voltage by using NJM7815, which hopefully will not affect other components that may require +18V. There must be a reason why 18V regulators were used.
 Assuming you also replace NJM7918 to NJM7915 as well for -15V.


----------



## raoultrifan

Thank you burdie, output stage should be perfectly fine with +/-15V and headphone output protection I believe has a dedicated rail (this I'll need to investigate further). I'll get back to you when I'll have some news; in case will not work, then I'll see if I'll be able to make some space nearby the 2 op-amps for 2x7815 regulators and do what you suggested.
  
 Thanks, 
 Raul.


----------



## Bruch

I'm watching this post with interest as I'll try the same thing with my HPA-3B once I see how you get on.
  
 I'm wondering whether your WIMA upgrade went far enough or whether some even better caps might have made an even bigger difference. Some Jupiters or Mundorf SGO's? but I note your point about it all still fitting within the case. And I will end up spending more on the caps than on the amp!
  
 What do you think about the power supply? Scope for improvement here? Caps again?
  
 Really very interested in the Burson V5 and the effect that will have.


----------



## raoultrifan

Well, I'm not sure I'll be able to close HPA-3B's case with BURSON V5 inside. I'll see about it when I'll have the time for. 
  
 JB JFX Premium Film Cap are polypropylene caps and theoretically should be an upgrade in audio signal over polyester WIMA MKS caps, though I was unable to get any noticeable differences between JB and WIMA, especially because I had no access to an identical HPA-3B to A/B test it and I also don't have another amp at home to sound close enough to HPA-3B to compare with so I can tell differences.
  
 What I really think it was great: the GOSS steel sheet around the transformer and the EMI filter on mains, because with sensitive headphones I really have no other noise besides normal amplifier's noise.
  
 In one of my previous posts I think I published ripple & noise measured with my scope for HPA-3B internal PSU and I believe it was less than 1mV peak-to-peak value, which is quite OK for me. The CMRR/PSRR for LME49860 is quite high and I believe less than 1uV of PSU noise will get injected into audio signal, so no need to get worried about internal PSU's noise I'd say. With gain=Low my HPA-3B is about as dark as my Objective2 amplifier (aprox. the same gain used in O2) when AKG K550 headphones are used in A/B test.


----------



## canthearyou

I have a HE-500 on the way. Would this amp have enough power for it?

It should. Lol

I'll know soon enough.


----------



## raoultrifan

Hi, 
  
 I believe I did some measurements here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12250417. Looks like we're speaking about 1.5 Watts in single-ended and about 4.5 Watts in balanced operation (tests done with about 60 ohms cable + resistor). So, I'm pretty sure you'll mostly listed to lowest gain of +5dB on your Matrix HPA-3B. 
  
 Looking forward for your review with your new headphones,
 Raul.


----------



## raoultrifan

burdie said:


> Good luck on lowering the voltage by using NJM7815, which hopefully will not affect other components that may require +18V. There must be a reason why 18V regulators were used.
> Assuming you also replace NJM7918 to NJM7915 as well for -15V.


 
 Hi again, 
  
 Looks like I did it after all. 
  

 ​  
 ​  
   ​  
 ​  
   ​  ​  ​  
*NJM7915*​*NJM7815*​
  
 I was actually able to get rid of existing JRC7818/7918 by removing all the 12 screws from both lateral black aluminum heat-sinks from power transistors, then with a small clipper/cutter I cut, one by one, all the legs for each power regulator. The new NJM7815/7915 were placed above by carrefull soldering (legs were also carefully cut to accommodate with heat-sink holes, of course). I choose NJM manufacturer because they say noise from 10-100KHz would be 90uV/170uV RMS for 7815/7915 regulators, quite a decent value I'd say; bought them from PROFUSION UK, authorized JRC/NJM/MUSES dealer.
  
 First thing I noticed was a lower noise than original LME49860, which is quite an improved I'd say, because with max. gain of +20dB and sensitive 32 ohms headphones we all know that there is some noise out there, especially when volume is fully max. 
  
 Noise estimation was done by comparing left channel with right channel with AKG K550 headphones and my own ears. Right channel had installed the default LME49860 op-amp and left channel had installed the below op-amps, in order of background noise estimated by my own ears:
 - BURSON V5-dual: about 30-40% lower noise than original LME49860
 - MUSES8920: about 25% lower noise than LME49860
 - LM4562: about the same noise
 - AD8599: about 3 times the noise of LME49860 (have no idea why, I thought this op-amp is low-noise, based on it's datasheet).
 Headphones used for these tests: AKG K701 (used for scene presentation and layering), BEYERS DT880/600 (used for details, saxophone and women voices) and AKG K550 (used to get background noise and overall musicality).
  
*CONCLUSION*: I perceived a very good sound presentation from BURSON V5-D solid state op-amps and I can strongly recommend them for serious DIY-ers. I very much liked women voices  and instrument separation, so I'm going to keep the BURSONs inside my HPA-3B for awhile and I hope I'll have the time to do some more tests and reviews.
  
 Please keep in mind that besides replacing both power regulators you also need to remove both DIP8 sockets and to solder V5s directly onto the PCB, because HPA-3B case can't be perfectly closed otherwise; BURSON V5s are about 2mm taller than HPA-3B can support!
  
*PROS*:
 - BURSON V5-D are definitely having a lower noise than original HPA-3B's op-amps, so great job BURSON! These are definitely the lowest noise op-amps I ever tested.
 - I liked women voices and instrument separation a lot.
 - Cymbals sound a bit more clean and natural with V5s.
  
*NEUTRALS*:
 - Details are about the same as LME49860, with just a slight advantage for V5s (BURSON V5 did a great job in revealing more details and clarity with my Objective2 amplifier: http://www.head-fi.org/t/616331/o2-amp-odac/4965#post_12382477).
 - Sound-scene is about the same as original op-amp, but I'll test this again the next days and get back to you.
  
*CONS*:
 - Need to replace power regulators for decreasing the voltage from +/-18V to +/-15V, otherwise lifetime of V5s will decrease.
 - Height is 2 mm more than it should be to perfectly fit inside HPA-3B, so you'll need to remove the DIP-8 sockets and solder V5s directly onto motherboards to fit the case
 - A bit pricey (about 25% of the price of Matrix HPA-3B).
  
_*Note*: Many thanks to BURSON for providing these solid-state op-amps for this test!_
  
 Will get back here when I'll have the time to compare more op-amps and more songs,
 Raul.


----------



## burdie

canthearyou said:


> I have a HE-500 on the way. Would this amp have enough power for it?
> 
> It should. Lol
> 
> I'll know soon enough.


 
 enough to drive HE500, but suggest mod your HE500 stock cable to balanced or get a custom balanced cable to enjoy with 3B.


----------



## canthearyou

raoultrifan said:


> Hi,
> 
> I believe I did some measurements here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12250417. Looks like we're speaking about 1.5 Watts in single-ended and about 4.5 Watts in balanced operation (tests done with about 60 ohms cable + resistor). So, I'm pretty sure you'll mostly listed to lowest gain of +5dB on your Matrix HPA-3B.
> 
> ...



Nice! And I like your mod to use the Bursons




burdie said:


> enough to drive HE500, but suggest mod your HE500 stock cable to balanced or get a custom balanced cable to enjoy with 3B.




It comes with a balanced cable.


----------



## Bruch

Wow, well done, you have done such a neat job of that soldering.
  
 When you remove the DIP8 socket does the V5 fit straight into the mother board without any further modification? It looks like a perfect fit from the pictures. But for 2mm I think I would be more inclined to drill a couple of holes in the roof!
  
 From you description it sounds like it raises the HPA-3B up to the next level.
  
 I also note that on other mods you are not afraid to say that you can't tell any difference in sound quality, which is a good thing. It gives us confidence that the differences that you do describe are real.


----------



## burdie

raoultrifan said:


> Hi again,
> 
> Looks like I did it after all.
> 
> ...


 
 Raul, you did it again. Any further update on the listening?
 Since you got very good soldering skill, would you mind to do one more thing on V5? since V5 is 2mm taller even you remove the dip-8 socket, will it be able to fit in the case if you diy a L shape dip-8 socket (extend the pins and bend it down for 90 degress) and lay the V5 to the left and right. or may be relocate the 2 big cap...


----------



## burdie

Raul, I am talking about this right angle dip-8 socket, which can be found on 
 http://www.digikey.com/product-search/en?mpart=299-93-308-10-001000&v=54


----------



## raoultrifan

In case you intend to get rid of existing DIP8 sockets and solder 2 x SS V5s inside HPA-3B there will still remain about 4-5 mm of space left on top of each V5, so no worries about it. In the below pictures you can see a V5 standing on the PCB and HPA-3B case is completely closed top/bottom.
  

​​*No flash*​*With flash*​
  
 burdie, thanks for the 90 degrees angled DIP8 socket. I don't think would be winner for HPA-3B, but I might try something like that inside my Objective2 headamp.


----------



## Bruch

Really what's needed is a DIP-8 socket extender via a short ribbon cable so that the V5 can be fixed somewhere convenient. I think that I saw something like that once but I can't find anything now - not even to make yourself.


----------



## burdie

raoultrifan said:


> In case you intend to get rid of existing DIP8 sockets and solder 2 x SS V5s inside HPA-3B there will still remain about 4-5 mm of space left on top of each V5, so no worries about it. In the below pictures you can see a V5 standing on the PCB and HPA-3B case is completely closed top/bottom.
> 
> 
> ​​*No flash*​*With flash*​
> ...


 
 If the clearance is about 4 to 5mm, may be still possible to put a dip8 socket to ease opamps swapping. The shortest i can find is 4.4mm to 4.5mm (above pcb), and if still out by 0.X mm, then have to consider removing the red case?


----------



## raoultrifan

bruch said:


> Really what's needed is a DIP-8 socket extender via a short ribbon cable so that the V5 can be fixed somewhere convenient. I think that I saw something like that once but I can't find anything now - not even to make yourself.


 
 I really don't think there's enough room for extenders. Now honestly, removing the DIP8 sockets is easy, the only downside I can see would be no more op-amp rolling possible (well, at least not without resoldering again). What I am thinking right now is to use a drilling machine with a 1 or 1.5 mm spiral and increase PCB holes diameter so I can get both DIP8 sockets inside the PCB with few mms. This is how DIP8 sockets look like: http://g01.a.alicdn.com/kf/HTB1aIzEKVXXXXcbXXXXq6xXFXXXr/20pcs-DIP8-8-Pin-Gold-Plated-Socket-for-DIP-8-round-hole-8-pin-Op-Amp.jpg & http://www.retroamplis.com/WebRoot/StoreES2/Shops/62070367/4B99/037E/6882/C75B/0F91/C0A8/28BA/3F8A/DIP8.jpg. Now I don't know if PCB traces are big enough to accomodate these bigger holes. 
  
 Burdie, inside the SS V5 there's something yellow inside that looks like a melted plastic and I believe it has thermal conductivity. Without cutting the red case out I don't see how to get to inside electronic parts...and I don't want to get rid of the beautiful red case.


----------



## raoultrifan

As I reduced recently rail voltages from +/-18V to +/-15V so I can test BURSON V5 op-amps now I need to find out what's max. power of my HPA-3B. I was able to connect my HPA-3B to a single-ended cable (left over from my 600 ohms DT880 Beyers) and 3 resistors, each having 10 ohms and I measured a total of 34.5 ohms resistance (cable included).
  
 Here are my scope graphs for single-ended output only (can't find my spare balanced plug/cable, sorry):

​​*32 ohms - non-clipping (1.33 Watts)*​*32 ohms - clipping  (1.45 Watts)*​   ​  ​ *32 ohms - FFT shows no strange harmonics @ 1.33 Watts*​*500 ohms - non-clipping (185 mWatts)*​ ​ ​
 
​*60 ohms - non-clipping 1.07 Watts (8.042 V RMS)*​
  
 Comparing with my old values from http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12250417 looks like lowering voltage with +/-3V also lowered output voltage & power to about 75%. For example for 60 ohms now I have about 1.1 Watts and initially I had about 1.45 Watts.
  
 Anyway, HPA-3B has plenty of power even when powered from +/-15V on rails.
  
 The main advantages for lowering voltage rails:
 - ability of testing almost all op-amps from Earth 
 - temperature inside HPA-3B drops with a couple of degrees, perhaps increasing internal components life
  
 Disadvantage:
 - power reduces to about 75% of initial values


----------



## canthearyou

raoultrifan said:


> As I reduced recently rail voltages from +/-18V to +/-15V so I can test BURSON V5 op-amps now I need to find out what's max. power of my HPA-3B. I was able to connect my HPA-3B to a single-ended cable (left over from my 600 ohms DT880 Beyers) and 3 resistors, each having 10 ohms and I measured a total of 34.5 ohms resistance (cable included).
> 
> Here are my scope graphs for single-ended output only (can't find my spare balanced plug/cable, sorry):
> 
> ...



That's awesome!


----------



## raoultrifan

I found my "magic" 4-pin XLR plug and I was able to measure HPA-3B's max. power in balanced operation when 60 ohms resistors & headphones cables are attached.
  

​*60 ohms BALANCED - non-clipping 3.5 Watts (41.41 V peak-to-peak, 14.55 V RMS)*​
  
 Looks like this little headamp still remains a little beast, even after lowering power rails to +/-15V; a decrease with about 20% over the initial 4.5 Watts is quite OK. After all, 3.5 Watts should be OK for most balanced headphones, even for Hifiman HE5 & HE6 I'd say.


----------



## canthearyou

raoultrifan said:


> I found my "magic" 4-pin XLR plug and I was able to measure HPA-3B's max. power in balanced operation when 60 ohms resistors & headphones cables are attached.
> 
> 
> 
> ...




Yup, this will be my next purchase.


----------



## raoultrifan

bruch said:


> Wow, well done, you have done such a neat job of that soldering.
> 
> When you remove the DIP8 socket does the V5 fit straight into the mother board without any further modification? It looks like a perfect fit from the pictures. But for 2mm I think I would be more inclined to drill a couple of holes in the roof!
> 
> ...


 
 Thanks Bruch!
  
 I can tell you for sure that the best mod for this amp was shielding the transformer and also grounding the shield. I also changed input caps because technically speaking polypropylene is better than polyester, at least in audio field (well, best cap is no cap, I know).
  
 Changing op-amps in HPA-3B was not something like night & day difference in trebles, bass, clarity or scene, instead the changes are quite subtle here, because LME49860 is already one of the best in class op-amp. For example OPA2604 had a little bit less clarity and details than all others tested in HPA-3B, but at least this op-amp was not heating so much like all the others tested. 
  
 With BURSON V5s the best improvement was perhaps related to HPA-3B internal noise, though HPA-3B already has a low SNR, when using high-gain (+20dB) and low impedance/high sensitivity headphones there's some noise coming up (especially in balanced mode). Perhaps my amp upgraded with V5s is having now a SNR of -116dB instead of original -114dB, but most people will really not notice this change unless max. power + sensitive headphones are used.
  
 Also, BURSON sound character pleased my ears when women voices were present. Instruments spacing is better too, but we're speaking about a very small margin here (LME49860 is a very good op-amp as well).
  
 P.S.: Other op-amps I liked would be MUSES8820 and MUSES8920.


----------



## raoultrifan

canthearyou said:


> Yup, this will be my next purchase.


 

 MATRIX HPA-3U is about the same as AUDEZE DECKARD: http://www.head-fi.org/t/749486/audeze-deckard-class-a-amp-usb-dac/150#post_12160801.
  
 Also, HPA-3B is around the same electronic schematic as well, so I really believe that both HPA-3U and HPA-3B are "the best bang for the buck".


----------



## Bruch

Thanks for your feedback Raoul,
  
 My 3B should be coming this week and I already have a pair of LME49720HA's to try. I don't have any Grain Oriented Silicon Steel f​or shielding but I do have some lead sheet which I will try. I note your point about grounding.
  
 Although the V5 route does seem like quite a lot of trouble for what you describe as subtle changes in sound quality it is probably something that I will try at some stage. I also want to try the V5's in an EHP-O2 amp (I note that you had success with that) so my thoughts are to buy 2xV5 singles with a DIP-8 doubler for the O2. If I like what I hear I will buy a V5 Double for the O2.
  
 Well done for leading this mod thread. It takes someone like you with knowledge and a bit of courage to lead so that the rest of us can follow!
  
 Kind regards
  
 Bruch.


----------



## raoultrifan

bruch said:


> [...] so my thoughts are to buy 2xV5 singles with a DIP-8 doubler for the O2. If I like what I hear I will buy a V5 Double for the O2.


 
  
 Hi Bruch, 
  
 Why single V5s? I used one double V5 in my O2 and my next step would be to get out the batteries, remove the metallic battery connectors so I can get a 90 degrees DIP8 socket adapter to install a dual V5 for good (will get me more details and the great BURSON sound).
  
*Note*: Perhaps many times I wrote V5s, so my bad...but I actually meant the plural for V5 and not V5-single...sorry. So, I only tested V5-dual op-amps in both Objective2 and Matrix HPA-3B amplifiers.
  
 Raul.


----------



## Bruch

raoultrifan said:


> *Note*: So, I only tested V5-dual op-amps in both Objective2 and Matrix HPA-3B amplifiers.
> 
> Raul.


 
  
 Sorry, although I realised that you were using a double in the O2 I had thought that you were using a pair of singles in the HPA-3B. A pair of doubles does add to the price quite considerably but I'm one of those people who will still probably end up doing it anyway!


----------



## raoultrifan

Well, in O2 I've used 1 x SS V5-dual op-amp (2 channel amplifier) and in HPA-3B I used 2 x SS V5-dual op-amps, because this is a 4-channel amplifier (it's fully balanced from IN to OUT).
  
 I believe 2 x SS V5-dual op-amps would be around 30% of HPA-3B's price and around 15% of HPA-3U's price (HPA-3U only needs 1 dual op-amp, like AUDEZE DECKARD).


----------



## burdie

Lots of argument also to use 2 x single or dual opamp. Some claims 2 x single gave better sounds whereas some claims certain dual opamp have separate circuit internally (i believed V5 is one of them) and it has no different to 2 x single, but there are also some comments on extra heat on dual opamp or it shares the same power source etc
 Anyway, to 'me' it is very subjective, I tried opa2604 and opa604 on iBasso PB2, but couldn't hear any differences.


----------



## burdie

raoultrifan said:


> I found my "magic" 4-pin XLR plug and I was able to measure HPA-3B's max. power in balanced operation when 60 ohms resistors & headphones cables are attached.
> 
> 
> ​*60 ohms BALANCED - non-clipping 3.5 Watts (41.41 V peak-to-peak, 14.55 V RMS)*​
> ...


 
 Raoul, will you consider to add separate power regulator to V5 just to get back the loss of power?


----------



## raoultrifan

burdie said:


> Anyway, to 'me' it is very subjective, I tried opa2604 and opa604 on iBasso PB2, but couldn't hear any differences.


 
  
 I know what you're saying and I have the same feeling most of the time, but I was able to hear differences in HPA-3B when I placed OPA2604 (less detailed) instead of original op-amp. So, it's up to PCB, power rails quality, op-amp decoupling and of course main schematic used that make a difference if an op-amp will sound better or not as another.
  
 For example:
 - in my Essence One DAC MUSES01 made a night/day difference when used in I/V stage, but when used in LPF, BUFFER or VAS I was not able to get any noticeable differences (or at least not to justify the high price).
 - same DAC, MUSES02 made a bit of a difference only when used in LPF and VAS, but couldn't get a real difference when used in I/V or BUFFER (at least comparing with NE5532 or LME49720 or similar op-amps).
 - V5-dual in HPA-3 (VAS stage) created a darker background, made all voices to sound better and also increased instruments separation, but in Objective 2 (same VAS stage) V5 increased details and clarity (complete A/B test), though the same V5-dual used in Objective 2 but in BUFFER stage made not much difference in sound output (though, women voices sound a bit more clear and not "high pitch" and I can feel a bit of BURSON character in the final sound)
  
 So, yes, same op-apamp in different equipment and different stages may or may not improve the sound.


----------



## raoultrifan

burdie said:


> Raoul, will you consider to add separate power regulator to V5 just to get back the loss of power?


 
  
 I honestly don't know where's the place for another 2 power regulators... Perhaps between input caps and XLR plugs would be some space, but that means to cut PCB traces and all traces are black and not quite visual appealing...if you know what I mean, though I might unplug pins no. 4 & 8 for each op-amp and try to power them from free-air, but still not happy with this workaround because would not be quite pleasant to my eyes. 
  
 To be honest, I'm not sure about the benefits of this, perhaps a little bit of more power, but to be honest right now I'm using the low-gain with all my headphones (DT880/600ohms needs the most amount of voltage and in balanced operation max. power for DT880 is around 2 o'clock).
  
 Also, if you're looking at any op-amp datasheet you'll see that the final voltage output will decrease if lowering power voltage, so feeding with +/-15V both op-amps from HPA-3B and with +/-18V the drivers and buffers will most likely not provide the same output power as with op-amps feed from +/-18V. So, again I say that I don't see any benefit by powering the only drivers & buffers from +/-18V, unless using really power hungry and low-impedance headphones that need at least 1.5W/32 ohms of power.


----------



## burdie

raoultrifan said:


> I know what you're saying and I have the same feeling most of the time, but I was able to hear differences in HPA-3B when I placed OPA2604 (less detailed) instead of original op-amp. So, it's up to PCB, power rails quality, op-amp decoupling and of course main schematic used that make a difference if an op-amp will sound better or not as another.
> 
> For example:
> - in my Essence One DAC MUSES01 made a night/day difference when used in I/V stage, but when used in LPF, BUFFER or VAS I was not able to get any noticeable differences (or at least not to justify the high price).
> ...


 
 Yes, same opamp on different equipment may not provide the same improvement as there are other things affecting the sound. 
 Different opamp on one single equipment I still can hear the differences but not on the opamp that having both dual and single version, e.g. BB OPA604 and OPA2604 which claims to be identical by factory but reviewers said otherwise. iBasso PB2 on-board socket can accept 4 single opamp or 2 dual opamp, By comparing both OPA604 (4 pieces) and OPA2604 (2 pieces) on PB2, I really cannot identified any differences, but some of my friends said OPA604 have lower noise. So to some people's ear 2 x single opamp is better than dual opamp from the same design.


----------



## raoultrifan

Well, at least BURSON V5-dual is actually 2xV5-single inside.  Yes, two small identical PCBs populated and completely identical; also, the distance between those 2 PCBs is higher than would be inside of a DIP8 op-amp, so I believe crosstalk will measure better in V5-dual than on regular DIP8 dual op-amp (just my 2-cents!).


----------



## Vobluda

Please can anyone help - is line out DAC only output or DAC + amplification?
 Respectively is it possible to use HPA-3U as DAC only?


----------



## raoultrifan

Based on http://www.matrix-digi.com/pdf/HPA-3U_Manual_EN.pdf I believe it has dedicated RCA outputs.


----------



## vadergr

Anyone knows or measured the watts@50ohm ?
 2800mw@32 is pretty nice, i just want to know if it is way aobve 2000m@50ohm for use with planars.


----------



## burdie

vadergr said:


> Anyone knows or measured the watts@50ohm ?
> 2800mw@32 is pretty nice, i just want to know if it is way aobve 2000m@50ohm for use with planars.


 
  


vadergr said:


> Anyone knows or measured the watts@50ohm ?
> 2800mw@32 is pretty nice, i just want to know if it is way aobve 2000m@50ohm for use with planars.


 
 if do simple maths, 210mW@600ohm or 420mW@300ohm equals to 126,000mW, so 50ohm will be 2,520mW
 but for 2,800mW@33ohms, it will be 1,848mW. Therefore, it should be between 1.8W to 2.5W @50ohms, 
 However, it is just calculation. 
 BTW, it should have enough power to drive planars.


----------



## burdie

Today I 'measure' 2 things for HPA-3B, just to see whether burson V5 will be able to fit in...
 1) space, I am thinkng to use the right angle dip8 adaptor but the space to the side is about 24mm but V5 is 29mm.
 The best place to place V5 is not removing the soldered dip socket, will be next to the transformer, using the dip extension adaptor, and have to cosider the shielding of the transformer
  
 2) Voltage to opamps
 Well, the DC measured is 17.5V (Japan analog multimeter) and 17.7 (China digital multimeter). So my LME49720 (max 17.7v) already operated at the border maximum voltage, Probably have to get few more for spares as Ti ceased production of 49710/49720.
 If want to maintain power yet swapping burson V5, have no other choice but to add NJM7815/7915 to the pin 8/4 of the opamps.


----------



## canthearyou

vadergr said:


> Anyone knows or measured the watts@50ohm ?
> 2800mw@32 is pretty nice, i just want to know if it is way aobve 2000m@50ohm for use with planars.




It works great with planars. Powered my HE-500 w/out a problem on low gain. After hearing it yesterday I'm planning on getting one myself. I will do a direct comparison with the Gustard H-10.


----------



## vadergr

canthearyou said:


> It works great with planars. Powered my HE-500 w/out a problem on low gain. After hearing it yesterday I'm planning on getting one myself. I will do a direct comparison with the Gustard H-10.




That is great because i am down to the hpa-3u , the gustard and the lake people g109.

When you get it, please give us a feedback.


----------



## raoultrifan

vadergr said:


> Anyone knows or measured the watts@50ohm ?
> 2800mw@32 is pretty nice, i just want to know if it is way aobve 2000m@50ohm for use with planars.


 
 Here http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12250417 I was able to measure about *1.5 Watts in single-ended* and about *4.5 Watts in balanced operation* with *60-62 ohms* cables + resistors, so in 50 ohms it should have a little bit more power (perhaps with 10-15% more).
  


burdie said:


> Today I 'measure' 2 things for HPA-3B, just to see whether burson V5 will be able to fit in...
> 1) space, I am thinkng to use the right angle dip8 adaptor but the space to the side is about 24mm but V5 is 29mm.
> The best place to place V5 is not removing the soldered dip socket, will be next to the transformer, using the dip extension adaptor, and have to cosider the shielding of the transformer
> 
> ...


 
 1) Good luck with this, I'm waiting for some nice screenshots and also for your first tests and opinions. I'm sure everything will go just fine, but take care anyway. 
  
 2) On the negative rail you should have around -18.2V, so from + to - there's still almost 36V anyway, very high for these BURSON op-amps that can support up to 30V max. Feel free to check what "only" +/-16.5V can do to them in Gustard H10 thread: http://www.head-fi.org/t/735828/gustard-h10-high-current-discrete-class-a-output-stage-headphone-amplifier/4260#post_12276557 and many other posts as well showing the V5s overheating and loosing the red case.  Despite being completely users fault (nobody measured the voltage from inside H10 before starting to roll op-amps) BURSON created special op-amps for all H10 customers and the're gonna replace them all; these special op-amps can tolerate +/-17V and higher temps. They also created an aluminum bridge to get rid of the heat from inside H10. Now that's what I call customer service. 
  


canthearyou said:


> It works great with planars. Powered my HE-500 w/out a problem on low gain. After hearing it yesterday I'm planning on getting one myself. I will do a direct comparison with the Gustard H-10.


 
 Really waiting for your test; if you can find an A/B testing device or if you can do some by yourself it would be great.
  
 Thanks!


----------



## canthearyou

raoultrifan said:


> Here http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12250417 I was able to measure about *1.5 Watts in single-ended* and about *4.5 Watts in balanced operation* with *60-62 ohms* cables + resistors, so in 50 ohms it should have a little bit more power (perhaps with 10-15% more).
> 
> 1) Good luck with this, I'm waiting for some nice screenshots and also for your first tests and opinions. I'm sure everything will go just fine, but take care anyway.
> 
> ...




I would not say it was completely the users fault as the Burson website stated it was a direct replacement for the stock op-amps.

And I might pick up a Schiit Sys for direct comparisons.


----------



## canthearyou

vadergr said:


> That is great because i am down to the hpa-3u , the gustard and the lake people g109.
> 
> When you get it, please give us a feedback.




The 3U and 3B are different amps.


----------



## vadergr

I believed the only difference was the bananced and the dac.


----------



## canthearyou

vadergr said:


> I believed the only difference was the bananced and the dac.




Yes. No DAC, balanced and twice the power in the 3B.


----------



## raoultrifan

The output buffer transistors are bridged inside HPA-3U and this why there's more power than HPA-3B in single-ended.
 Also, in HPA-3U there's only one op-amp inside, so cheaper to do some "rolling".


----------



## burdie

raoultrifan said:


> 1) Good luck with this, I'm waiting for some nice screenshots and also for your first tests and opinions. I'm sure everything will go just fine, but take care anyway.
> 
> 2) On the negative rail you should have around -18.2V, so from + to - there's still almost 36V anyway, very high for these BURSON op-amps that can support up to 30V max. Feel free to check what "only" +/-16.5V can do to them in Gustard H10 thread: http://www.head-fi.org/t/735828/gustard-h10-high-current-discrete-class-a-output-stage-headphone-amplifier/4260#post_12276557 and many other posts as well showing the V5s overheating and loosing the red case.  Despite being completely users fault (nobody measured the voltage from inside H10 before starting to roll op-amps) BURSON created special op-amps for all H10 customers and the're gonna replace them all; these special op-amps can tolerate +/-17V and higher temps. They also created an aluminum bridge to get rid of the heat from inside H10. Now that's what I call customer service.
> 
> ...


 
 Hi Raoul,
 I will get some clarification from Burson regarding the max voltage that new batches of V5 can handle, those melted V5 on Gustard H10 are scary and hopefully Burson already have solution to it.
 Have a second thought on how to regulate +/- 18V to +/- 15V, adding voltage regulator required cooling heat sink, and it may draw more current and produce more heat, So I may be getting a zener diode with matching resistor which help to regulate the DC to +/- 15V..


----------



## raoultrifan

canthearyou said:


> I would not say it was completely the users fault as the Burson website stated it was a direct replacement for the stock op-amps.
> 
> And I might pick up a Schiit Sys for direct comparisons.


 
  
 I'm not sure how will you A/B test headphones with Schiit Sys, because this only has RCA plugs. Perhaps this would be a very good A/B testing tool for single-ended DACs only, but not for single-ended headphone amplifiers.
  
 Here's what I'm using for A/B testing, either single-ended DACs, either single-ended headphone amplifiers (6.3mm jack directly plugged into 6.3mm amplifier's output connector):
  
  ​  
 It's completely DIY and quite easy to build and with good components quality. One PCB divided into 2 sides: the left half used for headamp testing and the right half for DAC testing.
  
 On the left side of PCB there are 2 x 6.3mm jacks used as source inputs that might be connected to 2 different headphone amplifiers and the blue 6.3mm connector can be connected to a good and detailed pair of headphones. The silver/red switch can be used for rapid switching between the 2 sources.
  
 On the right side there are 2 sets of RCA inputs that might be connected to 2 DACs and the 3'rd set of RCA plugs is used as output to a transparent headphone amplifier connected to a good detailed pair of headphones. The silver/red switch can be used for rapid switching between the 2 sources.


----------



## canthearyou

raoultrifan said:


> I'm not sure how will you A/B test headphones with Schiit Sys, because this only has RCA plugs. Perhaps this would be a very good A/B testing tool for single-ended DACs only, but not for single-ended headphone amplifiers.
> 
> Here's what I'm using for A/B testing, either single-ended DACs, either single-ended headphone amplifiers (6.3mm jack directly plugged into 6.3mm amplifier's output connector):
> 
> ...




I see. I really didn't think it through. I could build something like that.


----------



## canthearyou

Ok. I placed an order for the 3B. When I get it I will compare with the Gustard H10. I will keep the one I prefer and sell the other. After that I believe I am going to try an Audio-GD NFB-1 amp.


----------



## raoultrifan

Great news! Waiting for your thoughts after the burn-in.
  
 BTW, the AudioGD has some power:
 9900MW /  25 ohm
 8000MW /  40 ohm
 3500MW  /  100 ohm
 1200MW / 300 ohm
 600MW  /  600 ohm

 Perhaps overkill, unless HE-500 or HE-600 HE-5 or HE-6 planar needs to be used with; also for this high power you may need to pay for the additional custom gain of +9dB. (Later edit).


----------



## canthearyou

raoultrifan said:


> Great news! Waiting for your thoughts after the burn-in.
> 
> BTW, the AudioGD has some power:
> 9900MW /  25 ohm
> ...




It will be powering HE-500. I will also be running Burson V4 op-amps in the 3B.


----------



## raoultrifan

Waiting for some pictures win HPA-3B and SS V4. Hmmm...wondering how and if will fit inside the case.


----------



## canthearyou

raoultrifan said:


> Waiting for some pictures win HPA-3B and SS V4. Hmmm...wondering how and if will fit inside the case.




It does not fit inside the case. The V4s are larger than the V5s. There was one at the last Head-Fi meet I attended. The owner had cut an opening in the cover to allow the V4s to fit. It looked very cool, and from what I heard it sounded great. I want to give it a more thorough listen under better conditions. Whats real nice is the V4s will run on 20v.

With that said: http://www.head-fi.org/t/804503/burson-audio-op-amp-2-v5-dual-for-2-v4-dual#post_12491075


----------



## gordec

Anyone compared the 3B to the Liquid Carbon. I'm looking for an amp to pair with ifi micro iDSD and LCD3. This is only half the price of the Liquid Carbon seems to perform really well.

Sent from my SM-N920V using Tapatalk


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## canthearyou

Did a little mod. Makes this amp run nice and cool. Wired a small AC to DC converter to the power switch. Installed a small and quiet fan. Amp has been running for 5 hours and is cool to the touch. I did clean up the wiring after I was finished.


----------



## raoultrifan

If it does the job well, then "mission accomplished". 
 Hope that small AC/DC switching supply is not inducing any noise; I see it's positioned nearby input traces and plugs.


----------



## canthearyou

raoultrifan said:


> If it does the job well, then "mission accomplished".
> Hope that small AC/DC switching supply is not inducing any noise; I see it's positioned nearby input traces and plugs.




No noise that I can hear. That's why the power wire was long in the pic. I was testing areas to see if it introduces noise. The power supply is actually an old usb phone charger I had lying around. I gutted it and soldered some power and output leads on. Then I used thick heat shrink tubing to cover it. 

It's been running continuously since around noon. Hottest spot I can find on the case is 83.9*F. That's right where the heatsinks are bolted to the cover.


----------



## migasson

The HPA-3U sounds brilliant!
  
 I'm using HD600's, standard cable, stock amp, and DSD64, Brubeck, "Time Out" There's nothing wrong with this amp as it stands. Maybe I'm less picky, but this images great, soundstage is just spot on, bass delivery is just right for me. 
  
 I don't think I need anything else. It's a great natural sounding system. I won't hang around here.. starts giving me ideas. 
  
 Signing off HeadFi again.


----------



## canthearyou

I'll be trying the Sparkos Labs op-amps here shortly.

Placed the order today. Hope they sound great!

***Received the op-amps today. Very first things noticed are the soundstage and instrument separation. Improved upon compared to the stock op-amps. 

Will add more after more listening.


----------



## canthearyou

Ok. After a few hours listening I have a few more things to add. The Sparkoslabs op-amps are crystal clear! I am hearing new things in songs I've heard a hundred times before. I can't even really describe it. Pitch black background, extreme instrument separation and positioning. 
Compared to the stock op-amps it's not a night and day difference. More like a black hole and a supernova. 

I wish I didn't just sell my Gustard H10 because I would've liked to hear a full set of Sparkos in it.


----------



## canthearyou

raoultrifan said:


> DT880/600 sounds great on HPA-3B. With this new balanced cable soundstage increased and details seem more focused. I really think that moving from single-end to balanced is a real upgrade for anyone, especially if DAC is really-balanced as well.
> 
> BTW, I'm already thinking in doing few "mods":
> - upgrading volume knob with a black anodized aluminium knob as *burdie* suggested (headamp will look much better)
> ...




Raul, do you have a direct link to the JB JFX poly caps?


----------



## raoultrifan

Hello,
  
 I bought my capacitors from TME (http://www.tme.eu/ro/details/jfx-4.7u_250/condensatoare-cu-polipropilena-audio/jb-capacitors/), but more details could be also found herel: http://www.jbcapacitors.com/Plastic-Film-Capacitors/JFX-Premium-Metallized-Polypropylene-Film-Capacitors-Axial.html.
  
 MKP caps made by WIMA, MIFLEX etc. should be a fine choice too, per their price/quality ratio.
  
 Regards, 
 Raul.


----------



## canthearyou

Thanks!


----------



## canthearyou

Any U.S. source for the JFX caps?


----------



## canthearyou

Here we go! Just finished modding my HPA-3B.
  
 My main reason for this mod was to lower the voltage to allow me to swap other op-amps. I went with Sparkos Labs discrete regulators in 15V.
  
 I started by removing all necessary components. 

  
 Here is the new discrete regulator mounted to the heatsink. The reg is not insulated so I used an adhesive thermal pad, some thermal paste and a nylon shoulder washer to make sure it was well insulated.

  
 I had to make room for the new regs and that meant moving the caps closest to it.

  
  
 As you can see in the above photo, the new reg interferes with the capacitor directly in front of it. To remedy this I ordered a pair of ELNA Silmic II caps. I angled the wire leads to offset the position of the cap.

  
 Here is the completed board.

  
 And here it is ready to test. I am running Sparkos Labs discrete op-amps.

  
 Here it is in its fan cooled case I did a few weeks ago.

  
 I want to thank Mr. Andrew Sparks of Sparkos Labs for his patience in answering all my questions.
  
 I will get some listening impressions in a little bit.


----------



## canthearyou

I've given the new amp a decent listening. It is powerful, clear, and revealing. It allows me to hear things I've never heard before. I can hear the artist breathing between passages, guitar picks plucking the strings, the grain/grit of a bow on a violin. It sounds like cymbals and tambourines are live. Vocals have a new life to them. 

One thing I noticed is that each sound is pronounced on its own. I can't really explain it. I guess it would be separation. And there is zero "fuzz" around each sound. The cleanest sound I've heard yet.


----------



## raoultrifan

Nice clean work, I totally love it!
  
 BTW, after lowering the voltage I believe you don't really need that fan anymore, what do you think?
  
 P.S.: In case you'll find out a scope around sometimes it would be great to measure AC ripple after Sparkos power regulators.


----------



## canthearyou

raoultrifan said:


> Nice clean work, I totally love it!
> 
> BTW, after lowering the voltage I believe you don't really need that fan anymore, what do you think?
> 
> P.S.: In case you'll find out a scope around sometimes it would be great to measure AC ripple after Sparkos power regulators.




Thank you! Like you said I probably don't need the fan anymore. But since I already drilled holes and all that, I'll keep it. I did lower the fan speed quite a lot. It is completely silent. 

I don't have a scope of my own, but the specs on the Sparkos are great.


----------



## allinhead

hi guys, look awesome !
  
 i want this amp but ther is a big but 
  
 this "heatsink" amp is so hot ? i mean can you let your hand on the top of it or it s burning you ?
 can you fell the warm at 1m away ?
  
 i live in very hot country with out air condition so it s important for me 
 (i am not DIY guy by the way)
 Thanks


----------



## raoultrifan

Hi, it is hot indeed, but that should be expected from a Class-A amplifier. All Class-A amps are getting hot after 1 hour or more of operation, so if amp heat is so important for you, then maybe you could get something "cooler" working in AB-class.
  
 Note: Theoretically a Class-A amplifier may sound better than Class-AB-or Class-D amplifiers, so this is why most audiophiles are trying to buy Class-A.


----------



## allinhead

i have a class A amp is not hot at all 
  Theore and realty may deffer some times ...
  
 and you didn t anwsered my question by the way "can you let your hand on the top"
 because hot for some one can be just warm for other 
 thanks


----------



## raoultrifan

All Class-A amplifier transistors are hot to touch, otherwise it's not Class-A anymore, right?  Now depends what the idle current would be and how the heat from the output transistors is dissipating to the case, so what Class-A headamp do you own and you're referring to, please?
  
 For HPA-3B & 3U the case itself it's part of the heatsink, so it will be quite warm to hot to the touch after a couple of hours of operation and I mean at least 50C during summer. Power required from main would be around 15W when idling and even more when headphones connected and driven.
  
 More about this here:
 http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12178996
 http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/105#post_12397517
 http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12157815
  
 As you can see, I had lowered voltage from 36V to 30V, so I can use other op-amps; this also means internal temperature decreased a bit, so now it's less than 50C (I can do a measurement tonight again if you like).


----------



## allinhead

My AMP is the nuforce udh 100 and is just gently warm .
  
 50C is to much for me so i decide to go SE withe the beresford capella .
 Yes i have seen your work that realy good but i am not a DIY guy in Electronique.
  
 Do you have a balanced dac ? If not, have you heard improvement with balanced phone ?
  
 Enjoy your listening


----------



## raoultrifan

NuForce UDH-100 is most likely a very good headamp, but temps are lower mostly because the output transistors are not directly connected to the case. Like I said, HPA-3B has a small case and this is also part of the heatsink, this is why the higher temps. HPA-3B might have a higher transistor current as well and also the no. of output transistors are probably doubled because of balanced operation.
  
 Yes, I do have a balanced DAC (ASUS Essence One DIY MUSES) and I was very please with increase in scene when going balanced with my Matrix headamp.


----------



## Ampeezy

Just put in the 2x LME49710HA on browndogs and boy has the sound become much clearer. The highs are more prominent but not in a harsh way, just more balanced and in line with the other frequencies. Overall Highs are much more detailed, which is the most significant improvement. There is also better transparency, everything is more separated, with more pin point and three-dimensional sound-staging. I know the LME49710HA may not be the ideal op-amp for rolling with the +/-18v regulators but for now I will enjoy them


----------



## serg1245

Has anyone compared the sound of the first Matrix M-stage (2012) with the new M-stage HPA-3B?

 There is a difference in the sound of the Single End Headphone Output?


----------



## gto88

gordec said:


> Anyone compared the 3B to the Liquid Carbon. I'm looking for an amp to pair with ifi micro iDSD and LCD3. This is only half the price of the Liquid Carbon seems to perform really well.
> 
> Sent from my SM-N920V using Tapatalk


 
 Any one who own both HPA-3B and LC?  They both are balanced amp, it would be good to have a comparison.


----------



## tecnos6

Thanks for your hard work, effort and time guys, really really cool what your doing to this 'little' amp. I was after a fully balanced amp to power my LCD-X's and you guys found it for me, just ordered and on its way.


----------



## Ampeezy

tecnos6 said:


> Thanks for your hard work, effort and time guys, really really cool what your doing to this 'little' amp. I was after a fully balanced amp to power my LCD-X's and you guys found it for me, just ordered and on its way.


 
 Nice, Hope you enjoy them


----------



## Carlitos

hello everyone!
  
 can you guys recommend some clear/agressive/bright opamps?
  
 btw, do i need to get the opamps with the dip adapter?
  
 =)


----------



## canthearyou

carlitos said:


> hello everyone!
> 
> can you guys recommend some clear/agressive/bright opamps?
> 
> ...




Sparkos Labs opamps.


----------



## Carlitos

=O
  
 thanks
 but, how about the cheap stuff?


----------



## Ampeezy

carlitos said:


> =O
> 
> thanks
> but, how about the cheap stuff?


 
 2x LME49710HA on adaptors. I use them, and the top end is very present and detailed. Some folks here raised concerns about the amp having +/-18v and the lme49710HA having a recommended max of +/-17V. Has worked fine in mine though for the past month and a half. I think you are fine as long as you dont use max gain very often.


----------



## Carlitos

ok thanks
  
 will get those LME


----------



## Ampeezy

carlitos said:


> ok thanks
> 
> will get those LME


 
 http://www.ebay.com/itm/141710809457?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
  
 This is the ready-made version, very convenient


----------



## raoultrifan

Hi guys, 
  
 Here http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/90#post_12390513 I wasn't able to close the upper case of my MATRIX HPA-3B headamp, because BURSON SS V5 dual op-amps are 2mm higher then it should be to properly fit inside the case. So, I did some "custom cables" to connect them and bend the wires to 90 degrees, so I can close the case properly.
  


  
 For those interested in purchasing BURSON SS V5 op-amps for MATRIX HPA-3B I strongly recommend them to purchase the special adapters with small cables and DIP8 sockets to properly bend the V5, like in the above pictures. I do not recommend you to DIY those adapting cables like I did, because there's a high chance of getting some short-circuit or the induce oscillations.    
 The sound is the same like we all know: detailed, non fatiguing, open soundstage and very transparent.
  
 Temps with case open were: 59.5C on the bottom op-amp and 61.9C on the top op-amp. Will see if I can measure the temps with case closed in the next days (I have a small temperature probe for this, just need the time to do it).    
  
 Regards, 
 Raul.
  
 P.S.: When working late and tired I might break up some things: I had inserted the top V5 into the DIP8 socket vice-versa (don't ask me how I could do this rookie mistake, please). Looks like there's some sort of protection inside the V5, because it didn't blew away like I would expect from an op-amp that is powered to the wrong pins and this is a very good thing I'd say! Also, some protection is probably installed in the MATRIX HPA-3B, because nothing wrong happened with the headamp. I only powered the HPA-3B for 1-2 seconds, then I realised the issue (one resistor or one diode got smoked a bit, but I measured both and they're within parameters). After this issue I've tested my HPA-3B with my 600 ohms DT880 at extreme volume for over 2 hours and I'm happy my headamp is still within parameters. 
  
 L.E.: Do not try to install BURSON SS V5 or V5i in MATRIX M-Stage HPA 3B if you haven't lowered the voltage from +/-18V to +/-15V by replacing the 2 power regulators! The mod is quite simple and is perfectly covered here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/90#post_12390513.


----------



## raoultrifan

canthearyou said:


> Here we go! Just finished modding my HPA-3B.
> 
> My main reason for this mod was to lower the voltage to allow me to swap other op-amps. I went with Sparkos Labs discrete regulators in 15V.
> 
> ...




I must confess that I almost forgot about this post. 
I would be interested on how does it sounds now, comparing with what it used to be before this mod. Also, if there's a scope around you, I would love if you could measure the RMS AC ripple & noise after Sparko's regulators.


----------



## canthearyou

Still no scope for me.
FYI this is on Massdrop for $350.


----------



## raoultrifan

For such a good balanced class-A headamp it totally worth the money!


----------



## wildwestgoh

Does anyone ever tried both balance and the unbalance at the same time on the HPA-3B?
 I may need this features if I am going to purchase another headphone in the future, may sometimes just swap around for A/B testing or just pure listening without the hassle to unplug the other headphone out.
  
 Thank you in advance for info.


----------



## raoultrifan

I did, but not in the same time because I can't do A/B test between 2 different plugs on the same headamp, instead I swapped headphones plug from balanced output to single-ended/balanced adapter that was connected to single-ended output (I do have a BAL to SE adapter).
  
 I've noticed a larger soundstage, no matter the headphones used (AKG K550, AKG K701, BYERDYNAMIC DT880/600ohms); also the output power was much higher in balanced mode. I do prefer balanced over single-ended.


----------



## canthearyou

Look at the different board layouts. That is weird!


----------



## raoultrifan

I'll say this again: I totally love your Sparkos! 
  
 What do you mean by different board layout? It looks exactly the same to me.


----------



## canthearyou

raoultrifan said:


> I'll say this again: I totally love your Sparkos!
> 
> What do you mean by different board layout? It looks exactly the same to me.




Look at the little black heatsinks.


----------



## raoultrifan

Sorry, PCBs look the same to me, maybe you missed some of my previous posts like http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12157815 or http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12178996 where I replaced the original black radiators with bigger ones.


----------



## canthearyou

raoultrifan said:


> Sorry, PCBs look the same to me, maybe you missed some of my previous posts like http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12157815 or http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12178996 where I replaced the original black radiators with bigger ones.




Ahhhhh..... now I see!


----------



## canthearyou

Just a heads-up I recently listed mine for sale here: http://www.head-fi.org/t/822524/m-stage-matrix-hpa-3b-modded-w-extra-op-amps


----------



## JoeDoe

Hey Matrix owners, just stumbled onto this unit and I'm curious to know if anybody has experience with the "plus" version now being offered on Massdrop?
  
 https://www.massdrop.com/buy/matrix-hpa-3u-dac-amp
  
 Looks largely the same, but if memory serves they did this drop a few months back so maybe someone can offer some insight?


----------



## canthearyou

joedoe said:


> Hey Matrix owners, just stumbled onto this unit and I'm curious to know if anybody has experience with the "plus" version now being offered on Massdrop?
> 
> https://www.massdrop.com/buy/matrix-hpa-3u-dac-amp
> 
> Looks largely the same, but if memory serves they did this drop a few months back so maybe someone can offer some insight?




That unit has a built in DAC, not balanced with less power. Can't give any insight into how it sounds though.


----------



## lugnut

Has anyone tried the  HPA-3B with the hd800 or hd800s ?


----------



## AOARoses

Has anyone tried putting 2 x LME49990 on HPA-3U+ ? I saw previous post about 2 x LME49710, and the result was better high end. Just wondering if it works with 2 x LME49990? I've no knowledge of swapping op amps, hope it does not destroy anything if I ask my friend to put LME49990 on.


----------



## raoultrifan

Also, please ask your friend to check for oscillations or strange harmonics with a decent scope, just to be sure LME49990 will not oscillate.
  
 Waiting for your findings about the sound quality with these opamps.


----------



## AOARoses

raoultrifan said:


> Also, please ask your friend to check for oscillations or strange harmonics with a decent scope, just to be sure LME49990 will not oscillate.
> 
> Waiting for your findings about the sound quality with these opamps.


 


Thanks for the suggestion 
	

	
	
		
		

		
			





  Will I be able to distinguish by ear if there are strange harmonics?


----------



## jeff7742

I want to get the HPA-3B. I will eventually get a balanced DAC, but for now I only have a single-end DAC. Will I still hear some improvement over a single-ended amp (using balanced headphones)? I have noticed that some balanced amps have something called a "phase splitter" that simulates balanced for RCA inputs. Does the HPA-3B have anything like that? -Thanks


----------



## raoultrifan

Hi, 
  
 HPA-3B is fully balanced inside, but it also has a single-ended output. I strongly recommend you to use the balanced XLR output for best results.
  
 On the RCA plugs you can only attach single-ended DAC source.
  
 P.S.: In case you don't want to balance your headphone, then aim to active ground headamps like the ones made by Meier Corda or perhaps the TEAC UD-503.


----------



## jeff7742

raoultrifan said:


> Hi,
> 
> HPA-3B is fully balanced inside, but it also has a single-ended output. I strongly recommend you to use the balanced XLR output for best results.
> 
> ...


 
  
 Thanks. I was comparing this amp to the cheaper Aune X7S. The Aune had balanced outputs, but only single-ended inputs. They use some kind of phase-splitter technology which somehow simulates a balanced input (like the Liquid Carbon). I was just wondering if the HPA-3B did the same thing with single-ended inputs.


----------



## raoultrifan

I believe Cavalli did an additional circuit after the RCA inputs that are inverting the phase for both L and R inputs and attack the internal amplifier with native balanced signal: + & - for each of the R and L inputs. I don't see such circuit inside the HPA-3B and don't see its point anyway, as long as XLR cables helps a lot in transmitting analog signal between source (DAC) and preamplifier or amplifier.
  
 If you;re thinking in upgrading to balanced and if you can purchase a Liquid Carbon then go for it, because its a great amplifier, but if not, then just forget about the RCA and jack plugs and only use the XLR ones. How analog signal is transmitting between RCA plugs and internal acitve circuit should not concern us too much; let's use balanced XLR if possible.


----------



## jeff7742

Oh yes, I definitely want to use XLR. But I need some time to shop around for a balanced DAC. I was just wondering if, in the mean time, I would notice any improvement with my single-ended DAC.


----------



## AOARoses

raoultrifan said:


> Also, please ask your friend to check for oscillations or strange harmonics with a decent scope, just to be sure LME49990 will not oscillate.
> 
> Waiting for your findings about the sound quality with these opamps.


 

My engineer friend put the double LME49990 in my HPA-U3+, and I heard more energy coming out of my TH-X00 purpleheart. It is also cleaner at higher volumes (I guess the new chip has less distortion???). The difference is very minimal but definitely better than the stock.


----------



## raoultrifan

LME49990 is a great opamp, I'm sure it may sound better than the original from HPA-U3+, just double check for oscillation.


----------



## raoultrifan

Well, you can use the single-ended RCA inputs as well and use balanced headphones, I'm pretty sure the soundstage will increase Usually, ugrading default single ended cable to a custom balanced one is considered an improvement.


----------



## canthearyou

jeff7742 said:


> I want to get the HPA-3B. I will eventually get a balanced DAC, but for now I only have a single-end DAC. Will I still hear some improvement over a single-ended amp (using balanced headphones)? I have noticed that some balanced amps have something called a "phase splitter" that simulates balanced for RCA inputs. Does the HPA-3B have anything like that? -Thanks




Be sure to check the classifieds for a great deal. Wink wink.


----------



## jeff7742

Just picked up an HPA-3B. It's 12% off for black friday. Look forward to hearing it! Some great reviews on it.


----------



## loserica

jeff7742 said:


> Just picked up an HPA-3B. It's 12% off for black friday. Look forward to hearing it! Some great reviews on it.


 

 I bought HPA-3U a few days ago from Spain. 360 Euros (20% off) and free shipping in the UE.


----------



## jeff7742

Got my HPA-3B today. I can only listen single-ended since my headphone cable isn't balanced yet. After a few hours burn-in my first impressions are that the sound is quite refined - more so than my SMSL VA2, and also much warmer than I thought it would be - almost lush. Maybe even too warm. I used to have to EQ my Beyer T1's since they were a tad bright. But no EQ with this amp. Soundstage also seems bigger. Overall I'm pleased though. Can't wait to finish my balanced cable and listen balanced.


----------



## jeff7742

Well I guess this unit is going back. Just turned it on again and smoke started coming out of it. Now it won't turn on. Not good. Don't know if I should get a replacement or refund.


----------



## canthearyou

jeff7742 said:


> Well I guess this unit is going back. Just turned it on again and smoke started coming out of it. Now it won't turn on. Not good. Don't know if I should get a replacement or refund.




Was it set to the correct supply voltage?


----------



## jeff7742

canthearyou said:


> Was it set to the correct supply voltage?


 
  
 Yeah, it was. I haven't touched it. Worked for a few hours, them smoked when I turned it on again. Bad component somewhere, I guess. I just got the lemon this time.


----------



## raoultrifan

Sorry to hear that. 
  
 Anyway, it might worth checking the voltage, on the left side, though I'm pretty sure it's not from there the smoking part.
  
 Unless you can get a Cavalli Carbon, the HPA-3B is a very good option.


----------



## jeff7742

Yes, I checked the voltage - it's at 115. It a good amp. From single-ended, the amp sounded a little more refined than than my VA2, but in A-B tests the VA2 is also quite good, just brighter. I would love to have heard it balanced, though.
  
 I've read good and bad things about the Cavalli. Is it much better than the HPA-3B? 
  
 For single-ended, I will also try the Beyerdynamic A20, which everyone seems to think is one of the best for the T1 and other Beyers (along with the A2).


----------



## raoultrifan

I'm not sure it's better, because I haven't tested, but Cavalli it's a higher grade design. Anyway, you can read all about it on it's Head-Fi forum.
  
 All I know is that I wouldn't give up my HPA-3B for anything else unless I'll test it first, no matter it's Cavalli or anything else.  Anyway, same HPA-3U design & schematic is also use in Audeze Deckard, so I really trust Matrix on HPA-3U and HPA-3B internal design, but I'm aware that improvements can be done.


----------



## burdie

jeff7742 said:


> Well I guess this unit is going back. Just turned it on again and smoke started coming out of it. Now it won't turn on. Not good. Don't know if I should get a replacement or refund.


 
 If i remembered correctly, it won't turn on if the opamps were burnt.


----------



## canthearyou

Now this is weird! I recently received the Fostex TH-X00 from Massdrop. I immediately installed SMC connectors and used my balanced cable. 

The headphones have an audible hiss as soon as they are plugged into the amp. If I touch the brass connectors near the cups the hiss disappears completely. I thought maybe because of the metal construction of the headphones it was somehow causing a grounding issue. I went ahead and fully insluated the SMC connectors from the cups. The issue is still present. The hiss is not present when I use my SE cable.

But what's even more weird is if I switch my amp to high gain the hiss is gone. Only bad thing is I can only use about 20% of available volume control.

The headphones do sound great, though!

P.S. The cable/amp works perfect with my HE-500.


----------



## raoultrifan

That's odd, I know it may sound silly, but is this happening with default opamps too?
 Also, mid gain is also affected?
  
 I had issues with V5i (though original V5 was working perfectly), but only when using low-gain and the hiss was pretty loud, I wasn't able to actually listen to the music because of that. Anyway, now I'm using MUSES02, because the V5 are so big and are also heating too much for my taste.


----------



## canthearyou

It was there in mid gain but not as loud. I am using the v5i...hmmmmmm. 
I will try the Sparkos and stock op-amps this evening.


----------



## raoultrifan

MUSES8820 is extremely low noise and is also wire with gain.
 Anyway, looking for your reply after changing the opamps.


----------



## canthearyou

Installed the Sparkos and it's completely silent. Unless I flip it to high gain, then there is a slight hiss.

So it was the V5i causing the hiss at low gain.

That is the strangest thing!

I wonder since the HE-500 are less sensitive and higher resistance I never heard the hiss?

*I still don't understand how touching the exposed metal on the SMC connectors removed the hiss, though.


----------



## raoultrifan

It's most likely related to headphones impedance more than sensitivity, that is causing sort of oscillation when using the V5i. This was happening to myself too and I've seen on the V5i review pages/thread that was happening to another head-fier into a different amplifier (see the http://www.head-fi.org/t/784790/burson-supreme-sound-audio-v5-opa-d-v5-opa-s-review/120#post_12921569 and my reply too).
  
 Anyway, the original SS-V5 sounds great inside Matrix HPA-3B, but with case closed I got opamp temps of around 70-72C (on outer plastic shell) and I'm not very pleased of this, this is why I removed them and got MUSES02 instead.
  
 P.S.: I still need to say that best buck for the bang would remain MUSES8820 for VAS, LPF and OutputBuffer in all of my tested devices (Essence One, Objective2, Matrix HPA-3B).


----------



## wildwestgoh

Spoiler








Something came in today.


----------



## raoultrifan

Looks great! I found those opamps on eBay, but I'm not sure who's the manufacturer and what's the "scene name" for these.
 In their specs the max. operating voltage would be +/-/22V, so there should be no problems to operate perfectly in HPA-3B.
  
 Can you please measure the DC-output on single & balanced output plugs (without music playing and no source connected to inputs)? Also, any change of getting some scope plots or an RMAA, if possible please?
  
 And ofc, how do they sound?


----------



## wildwestgoh

raoultrifan said:


> Looks great! I found those opamps on eBay, but I'm not sure who's the manufacturer and what's the "scene name" for these.
> In their specs the max. operating voltage would be +/-/22V, so there should be no problems to operate perfectly in HPA-3B.
> 
> Can you please measure the DC-output on single & balanced output plugs (without music playing and no source connected to inputs)? Also, any change of getting some scope plots or an RMAA, if possible please?
> ...


 
 My friend got it on Taobao, so I tempted to listen after the other said it's pretty darn clean opamp.
 I just got few quick listen and compare it against my LME49990.
 Overall, more bass and body (warm?) than LME49990, treble is a bit peaky at a certain high frequency, not all but noticeable at very high frequency, mid-high is laid back compare to LME49990, mid however remain similar throughout all the tracks I listen to.
 Some said it's colored cause I am listening to it using my T1 (gen 1), for T1 is known to lack of amount of bass, and that opamp brings out the bass like a boss, like listening to gen 2 of T1 at some point.
 Those are quick comparison, on shopping complex ambient, take it as grain of salt as 2 of my friends has different perspective of the sound.
 I also do not know what kind of chips they use... I will update once I found out from my friend.
  
 And about your request for measurement, I am sorry cannot help you because I don't own all of those stuff... haha, unless someone can sponsor me.


----------



## canthearyou

wildwestgoh said:


> Spoiler
> 
> 
> 
> ...




Does the cover for with those op-amps?


----------



## wildwestgoh

canthearyou said:


> Does the cover for with those op-amps?


 
 Erm... do you mean does the top cover able to close properly? The answer is "no".
 The opamp are much higher than we expected, and with the way it was soldered into the sockets, if only they could just solder into 1 socket only would make it a just-nice height.
 My friend did suggest to drill a hole for the opamps through the thick cover... lol.


----------



## canthearyou

wildwestgoh said:


> Erm... do you mean does the top cover able to close properly? The answer is "no".
> The opamp are much higher than we expected, and with the way it was soldered into the sockets, if only they could just solder into 1 socket only would make it a just-nice height.
> My friend did suggest to drill a hole for the opamps through the thick cover... lol.




Yes, lmao! I'm not even sure what the heck I typed.


----------



## loserica

*Happy New Year!!!*





  
 I replaced the stock Op-amp with MUSES02 (I have the HPA-3U) and as he said Raoul the sound it has got consistency (a better texture especially on highs and female voices). Is felt a better instrument separation and it increased the soundstage depth. 
 I can perceive more micro details. Absolutely zero audible hiss/noise! It is a worthy upgrade.


----------



## xenithon

Hi all. Wanted to ask if anyone has had more opportunity to listen to this amp paired with the HD800 and what their impressions were in terms of synergy. The HPA03B is meant to have some warmth to it, which can possibly offset some of the HD800's edge?


----------



## ruinedx

xenithon said:


> Hi all. Wanted to ask if anyone has had more opportunity to listen to this amp paired with the HD800 and what their impressions were in terms of synergy. The HPA03B is meant to have some warmth to it, which can possibly offset some of the HD800's edge?




The headphone guru review said it paired fantastically with HD800:
http://headphone.guru/the-impressive-m-stage-hpa-3b-balanced-headphone-amplifier/


----------



## loserica

I replaced the 6th Nichicon caps with Elna Silmic II (470uf/25V) and after a few days of listening, compared with Nichicon Muse Elna sounds better! 
	

	
	
		
		

		
		
	


	




 I notice a richer, lush texture , bass has a powerfull presentation, good impact. I love how Silmic presenting the sound. It is laid back, warmth mid-range and relaxing.


----------



## alpovs

loserica said:


> I replaced the 6th Nichicon caps with Elna Silmic II (470uf/25V) and after a few days of listening, compared with Nichicon Muse Elna sounds better!
> 
> 
> 
> ...


 

 Can anyone briefly explain how electrolytic capacitors in an amplifier can affect sound? It's probably off-topic but it came up here.


----------



## alpovs

canthearyou said:


> Here we go! Just finished modding my HPA-3B.
> 
> My main reason for this mod was to lower the voltage to allow me to swap other op-amps. I went with Sparkos Labs discrete regulators in 15V.
> 
> ...


 
 canthearyou,
  
 If you still monitor this thread... I checked the specs of the Sparko's Labs SS3602 OpAmps and they call for +/- 18 Vcc Max which is the original voltage in the HPA-3B. That means one wouldn't need to replace the voltage regulators if they wanted to use Sparko's Labs SS3602 OpAmps only. Right? I understand you wanted to "roll" different OpAmps in your HPA-3B. 
  
 And based on your one post you ran the Sparkos in unmodified HPA-3B before you modded it. Did you notice any problem? High heat? The Sparkos call for 18V max and absolute maximum of 22V.


----------



## raoultrifan

alpovs said:


> Can anyone briefly explain how electrolytic capacitors in an amplifier can affect sound? It's probably off-topic but it came up here.


 
  
 https://ez.analog.com/thread/3465, http://sound.whsites.net/articles/capacitors.htm etc. Everyone agree that capacitors, but also any other devices placed in signal path will alter the sound. This was proved, so no argue here.
  
 Well, if capacitor is not in signal path, let's say is in the power supply than all it matters is it's ESR and filtering capacity (how much amps can sustain for that voltage). most likely best sounding caps in signal path might no be the best for use inside power sources. 
  


alpovs said:


> canthearyou,
> 
> If you still monitor this thread... I checked the specs of the Sparko's Labs SS3602 OpAmps and they call for +/- 18 Vcc Max which is the original voltage in the HPA-3B. That means one wouldn't need to replace the voltage regulators if they wanted to use Sparko's Labs SS3602 OpAmps only. Right? I understand you wanted to "roll" different OpAmps in your HPA-3B.
> 
> And based on your one post you ran the Sparkos in unmodified HPA-3B before you modded it. Did you notice any problem? High heat? The Sparkos call for 18V max and absolute maximum of 22V.


 
  
 Looks like SS3602 can work to 36V indeed, so if you can give'em a try just be sure to monitor temperature and check for any possible oscillations. God luck and keep us posted!


----------



## alpovs

raoultrifan said:


> https://ez.analog.com/thread/3465, http://sound.whsites.net/articles/capacitors.htm etc. Everyone agree that capacitors, but also any other devices placed in signal path will alter the sound. This was proved, so no argue here.
> 
> Well, if capacitor is not in signal path, let's say is in the power supply than all it matters is it's ESR and filtering capacity (how much amps can sustain for that voltage). most likely best sounding caps in signal path might no be the best for use inside power sources.
> 
> ...


 
 I would be surprised if this amp had capacitors in the signal path. I am not sure what loserica meant by saying "I replaced the 6th Nichicon caps". Probably just 6, not 6th. Maybe some of them could be the shunt capacitors, given the number is not 2, 4 or 8. I doubt it could affect the sound if those capacitors were not in the signal path (if there are any). But point taken - I can see how it can matter if there are capacitors in the signal path.
  
 I don't have the amp to try the Sparkos. I am only thinking about it.


----------



## raoultrifan

He replaced power supply caps with better ones (able to sustain mode ripple current); that should decrease ripple at opamp pins.


----------



## alpovs

raoultrifan said:


> He replaced power supply caps with better ones (able to sustain mode ripple current); that should decrease ripple at opamp pins.


 

 How do you know? Wouldn't the two huge caps be the power supply ones. 470uF seems too little for power supply. I can see 6 smaller caps on pictures. I think they must be what s/he is talking about. Two of them could be the shunt ones. Don't know what the other 4 do.


----------



## raoultrifan

The 6 caps are part of the power supply, just their location is after power regulators (JRC/NJM 7815/7915). The only caps in signal path are the WIMA MKS that are replaceable too, of course: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/45#post_12120336. Anyway, it's a good thing to upgrade parts in any amplifier, especially caps, as long as specs are better...of course.


----------



## canthearyou

alpovs said:


> canthearyou,
> 
> If you still monitor this thread... I checked the specs of the Sparko's Labs SS3602 OpAmps and they call for +/- 18 Vcc Max which is the original voltage in the HPA-3B. That means one wouldn't need to replace the voltage regulators if they wanted to use Sparko's Labs SS3602 OpAmps only. Right? I understand you wanted to "roll" different OpAmps in your HPA-3B.
> 
> And based on your one post you ran the Sparkos in unmodified HPA-3B before you modded it. Did you notice any problem? High heat? The Sparkos call for 18V max and absolute maximum of 22V.




You are correct. But I wanted to lower the voltage to allow me to swap to other op-amps. The Bursons are a Max 17v and tend to run a bit hot at that number. 

Now I can try any op-amp on the market without worry of overvoltage.

Before the mod the amp ran on the warm side. I know this is due to its class-a topology, but I still wanted it a bit cooler. This led me to install the case fan, which dropped temps dramatically. After I lowered the voltage the amp runs much cooler and negates the purpose of the fan. But I already installed it so now it's gonna stay put.


----------



## alpovs

I wonder if anyone compared the HPA-3B to Schiit's Jotunheim? The prices are similar.


----------



## loserica

alpovs said:


> How do you know? Wouldn't the two huge caps be the power supply ones. 470uF seems too little for power supply. I can see 6 smaller caps on pictures. I think they must be what s/he is talking about. Two of them could be the shunt ones. Don't know what the other 4 do.


 
 It is a worth upgrade, this affect the sound. The sound is better indubitable. A better, refined texture, strooong bass!!, voices are more realistic.


----------



## loserica

alpovs said:


> I would be surprised if this amp had capacitors in the signal path. I am not sure what loserica meant by saying "I replaced the 6th Nichicon caps". Probably just 6, not 6th. Maybe some of them could be the shunt capacitors, given the number is not 2, 4 or 8. I doubt it could affect the sound if those capacitors were not in the signal path (if there are any). But point taken - I can see how it can matter if there are capacitors in the signal path.
> 
> I don't have the amp to try the Sparkos. I am only thinking about it.


 
 I replaced all 6 Nichicon capacitors.


----------



## lowrider007

Thinking of grabbing the HPA-3U, can someone assure me unlike the HPA-1 it has no problems running IEMS and low impedance headphones, humming etc?


----------



## trybeingarun

I have a HPA-3u+. I have a $5 iem & I din't hear any hiss with it when I tried it on. My lowest impedance over ear is M50x, which doesn't seem to pick up any noise either.


----------



## SRKRAM

I just bought a used HPA-3U. All works well, but I get humming on the lowest gain (5db) setting with my T5p headphones. It gets worse when I touch the input or gain selector toggle switches. The other gain settings are fine, and have no humming.

This problem is only with my T5p's, which have an impedance of 32ohms, and with the lowest gain setting. My 600ohm T1's don't have any problem, and neither do any of my other low impedance cans.

All inputs are disconnected, and I've tried swapping cables on the T5p's.

I've heard of humming issues with the HPA-3U, but this is strange. Anybody got any ideas how to fix it?

-Mark.


----------



## raoultrifan

Try using an isolation transformer to power up your HPA-3U or at least a dedicated ground-loop eliminator device (for mains outlet).
  
 You could also try to shield the inside transformer, but this means a bit of tinkering (http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/45#post_12120336).


----------



## SRKRAM

raoultrifan said:


> Try using an isolation transformer to power up your HPA-3U or at least a dedicated ground-loop eliminator device (for mains outlet).
> 
> You could also try to shield the inside transformer, but this means a bit of tinkering (http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/45#post_12120336).


 
 Hi. Thanks for the tips. I saw your earlier posts, and I like the mods you have done. I noticed that turning it upside down, can affect the hum or even make it go away completely for a while. So can putting a little pressure on the power connector or phono inputs. All of the screws seem to be tight. I wondered if it could be to do with the toroidal transformer or something being lose.


----------



## raoultrifan

PCB traces for rear audio plugs from the rear are placed on main PCB, at the bottom of the DAC, so if there's any noise getting in there then it will go straight to the input caps and then to potentiometer. If the hum is not caused by a ground-loop or a noisy earth/ground then you could probably use some sort of shielding between DAC's bottom and main PCB, then connect the shield to the ground. Though, I'm almost sure this is do to a ground-loop or some inside grounding issue that should be double-checked prior to start any DIY tasks, especially if device is still under warranty.


----------



## SRKRAM

Thanks for the pointers, raoultrifan. I tried a few things and noticed that connecting the phono, USB or headphone output ground to the chassis eliminates the buzz. I also measured that there's 100ohms between the chassis ground and signal ground, which I guess was done to prevent ground loops but in this case it might be causing one, unless there's some other root cause. I bought the amp used on ebay.


----------



## mickerru

Any impressions on matrix quattro amp vs mstage 3b? Im from the Philippines and quattro is still available here. The 3b would be purchased on aliexpress. I would be using it with the hd800. Need help


----------



## SRKRAM

I'm still trying to resolve the buzzing issue with my HPA-3U.

I noticed that removing the DAC module make the buzzing go away, so it plays a roll. Perhaps as you said, raoultrifan, adding shielding under the DAC would help.

I also noticed that there are a couple of resistors soldered on the underside of the opamp and sealed with hot glue - Ive added a photo below. Are these original, or a modification? According to the text on the top side of the PCB the revision is 1.6.


----------



## raoultrifan

If I'm not mistaken those 2 resistors are 6.04K and they're soldered between both the inverting inputs of the opamp and the V+ from those 2 caps (330uF I guess). Doesn't looks like a Matrix job, but only someone with HPA-3U can confirm that (I own HPA-3B).

O picture from above the opamp might help, just inca se someone did upgraded the default opamp with something else the original resistors from the front of the PCB got burned. We should see some smoked resistors perhaps. Also, if you can measure those 8 resistors it would be great; if you'll find 6.04Kohm on 2 of them then those are burnt (and you're actually measuring the resistors values from the back of the PCB).

Anyway, if amplifier sound great, then maybe you should just ignore those 2 resistors.

If there's a way for you use some protective shielding, without creating short-circuit, it could help in lowering the buzzing sound.

L.E.: Hope I'm right with the resistor's value: https://www.digikey.com/en/resource...version-calculator-resistor-color-code-5-band


----------



## SRKRAM

raoultrifan said:


> If I'm not mistaken those 2 resistors are 6.04K and they're soldered between both the inverting inputs of the opamp and the V+ from those 2 caps (330uF I guess). Doesn't looks like a Matrix job, but only someone with HPA-3U can confirm that (I own HPA-3B).
> 
> O picture from above the opamp might help, just inca se someone did upgraded the default opamp with something else the original resistors from the front of the PCB got burned. We should see some smoked resistors perhaps. Also, if you can measure those 8 resistors it would be great; if you'll find 6.04Kohm on 2 of them then those are burnt (and you're actually measuring the resistors values from the back of the PCB).
> 
> ...



You're right about the resistor values, and they are to pins 2 & 6, so the inverting inputs. Ive attached a photo of both sides of the pcb. I'll test the other resistors later. Could anybody confirm if this is original work, or a modification?


----------



## raoultrifan (May 7, 2017)

Hi again,

I just found https://cdn.head-fi.org/a/7514507.jpg and looks like the 6K resistor connected to pin-2 of the opamp gets to capacitor's + (plus) and the resistor coming from pin-6 gets to - (minus) of the other capacitor. I wonder if this is not the Ground? 'Cause if it's the ground there, then based on http://www.ti.com/lit/ds/symlink/lme49860.pdf we should have 2 resistors there...though their values are different, but that could be Matrix's choice, of course.

I believe these 2 resistors are the ones taking care of amplifier's gain (along with R7 and R9 I assume, but can't be sure without having the schematic); more details could also be found here: http://www.wakamatsu-net.com/biz/snas435b.pdf (or just read the LME49610 datasheet).

In case someone modified the default internal fixed gain ratio of the amplifier, then all the 3 adjustable gains have been modified too. If I'm not mistaken, the default gain selector for HPA-3U are below:
  5dB = 1.75X (3.56V RMS output with 2V input)
10dB = 3.15X (6.13V RMS output with 2V input)
20dB =    10X (20.0V RMS output with 2V input)

If you have another headphone amplifier with a well-known gain, then you could A/B test your HPA-3U against the other amplifier and you could approximate if HPA-3U's gain is the same as Matrix intended.

Also, measuring RMS output voltage with a 1KHz 2V RMS input sine-wave (audiocheck.net perhaps) could give you a good idea about the internal gain of your amplifier. A scope would be perfect for this, but also a true-RMS volt-meter will do to.

Good luck!

P.S.: I'm pretty sure those resistors should not change sound quality of how the HPA-3U sounds, so you could just ignore them and enjoy the sound.


----------



## loserica (Jan 2, 2020)

The upgraded components:
*Burson V6 *Vivid (Dual) 
Voltage regulators,
*Elna Silmic II* *(470uf) instead Nichicon Muse (330uf), 6 pieces


----------



## raoultrifan

Kind of overkill I'd say, but looks quite interesting.

If the longer wires are not adding noise/buzz than it's perfect, just hope your new MUSES will not be suffocated/overheated.

Happy listening!


----------



## loserica

No. Not adding noise/buzz in any case. But the sound is incredible, it seems it is a new DAC/amp. I have the impression that I'm listening to something much more expensive, and that sounds High-End!!


----------



## KingFiercer (May 7, 2017)

Hi guys. Interested in HPA-3U+ version with CS4398 DAC. Is it good enough, higher level than Asus Xonar D1?
I like Vivo Xplay's sound (CS4398+CS8422+OPA2604), so I look forward for this DAC/AMP with same DAC.
I want use it with 42ohm ATH ESW-11 headphones.


----------



## loserica

KingFiercer said:


> Hi guys. Interested in HPA-3U+ version with CS4398 DAC. Is it good enough, higher level than Asus Xonar D1?



Matrix HPA-3U it is comparable with Burson Soloist and Conductor. Asus Xonar D1!? Come on!


----------



## SRKRAM

Here's a thermal image of an HPA-3U in case anybody's interested


----------



## thyname

Here is a HPA-3B for sale at a great price (US seller):

https://www.head-fi.org/f/threads/f...3b-headphones-amp-like-new-price-drop.847045/


----------



## trybeingarun

I have a hpa-3u+, which i've been using for the past 6 months. I also recently purchased Aune X1s & I find Aune X1s to give a much wider soundstage & cleaner output than hpa3u+ (with coin modded hd650). When I use the aune as the dac and matrix as the amp the hpa-3u+'s the setup's performance becomes a little bit better compared to Aune. Now I am a little disappointed with my matrix setup, as it struggles to compete with a cheaper unit  . Do you guys use an external dac with the unit? If I have to upgrade 3u+ opamp, what would you all suggest?


----------



## loserica

trybeingarun said:


> I have a hpa-3u+, which i've been using for the past 6 months. I also recently purchased Aune X1s & I find Aune X1s to give a much wider soundstage & cleaner output than hpa3u+ (with coin modded hd650). When I use the aune as the dac and matrix as the amp the hpa-3u+'s the setup's performance becomes a little bit better compared to Aune. Now I am a little disappointed with my matrix setup, as it struggles to compete with a cheaper unit  . Do you guys use an external dac with the unit? If I have to upgrade 3u+ opamp, what would you all suggest?



The built-in DAC it is *quite good!* If you are able to change all 6 Nichicon Muse capacitors with Elna Silmic II and WIMA with Audyn Plus (like me) and if you have the patience for burn in (about 300/400 hours) you will touch that sound you surely want! 
It would be an inexpensive upgrade but worth every penny!!! But then you have to keep it the stock opamp or to take into account the Muses02.
Mine Matrix sounds incredibly good now. The differences are huge, trust me!


----------



## trybeingarun

loserica said:


> The built-in DAC it is *quite good!* If you are able to change all 6 Nichicon Muse capacitors with Elna Silmic II and WIMA with Audyn Plus (like me) and if you have the patience for burn in (about 300/400 hours) you will touch that sound you surely want!
> It would be an inexpensive upgrade but worth every penny!!! But then you have to keep it the stock opamp or to take into account the Muses02.
> Mine Matrix sounds incredibly good now. The differences are huge, trust me!



Sure enough, your changes are quite inspiring. I personally have no experience with soldering & have to figure out how I can get it done if I go that route. It's interesting that you find this dac good; I also liked it until I paired it with Aune. It feels like Aune's attack is much better/faster than Matrix's also the soundstage seems a lot wider. It could be that I am interested in that sound just because it's a new unit. When I use Matrix as the dac & Aune as the amp this combination sounds too warm for my liking.
Also, in my Matrix unit dsd sounds very soft. For some reason when I pick dsd (Audirvana, HQ-player doesn't matter) the left & right channels are swapped. I can perfectly live without dsd capability, but a usable one would have been nice.


----------



## loserica

trybeingarun said:


> Sure enough, your changes are quite inspiring. I personally have no experience with soldering & have to figure out how I can get it done if I go that route. It's interesting that you find this dac good; I also liked it until I paired it with Aune. It feels like Aune's attack is much better/faster than Matrix's also the soundstage seems a lot wider. It could be that I am interested in that sound just because it's a new unit. When I use Matrix as the dac & Aune as the amp this combination sounds too warm for my liking.
> Also, in my Matrix unit dsd sounds very soft. For some reason when I pick dsd (Audirvana, HQ-player doesn't matter) the left & right channels are swapped. I can perfectly live without dsd capability, but a usable one would have been nice.



Those WIMA capacitors in signal path are weak. Poor attack (as you noticed), without dynamics, poor texture, narrow sound-stage! The stock Matrix sounds mediocre compared with the big fish IMHO. Unconvincing. I was about to sell it...Now I know I'll keep it for a few years because I can not find anything better in this money. I knew how it sounded Michael Jackson - Bad Album with Stax and eXStatA. I had the impression I was there close to music. I had a source in which I spent a thousand dollars in high-end capacitors (V-Cap CuTf, Black Gates). Now I'm very close with cheap capacitors. Implementation plays an important role, and to find the key points which you can improve, also.


----------



## trybeingarun

loserica said:


> Those WIMA capacitors in signal path are weak. Poor attack (as you noticed), without dynamics, poor texture, narrow sound-stage! The stock Matrix sounds mediocre compared with the big fish IMHO. Unconvincing. I was about to sell it...Now I know I'll keep it for a few years because I can not find anything better in this money. I knew how it sounded Michael Jackson - Bad Album with Stax and eXStatA. I had the impression I was there close to music. I had a source in which I spent a thousand dollars in high-end capacitors (V-Cap CuTf, Black Gates). Now I'm very close with cheap capacitors. Implementation plays an important role, and to find the key points which you can improve, also.


This makes me really want to try your mods. I will try and find someone who can do these mods for me!


----------



## trybeingarun

loserica said:


> Those WIMA capacitors in signal path are weak. Poor attack (as you noticed), without dynamics, poor texture, narrow sound-stage! The stock Matrix sounds mediocre compared with the big fish IMHO. Unconvincing. I was about to sell it...Now I know I'll keep it for a few years because I can not find anything better in this money. I knew how it sounded Michael Jackson - Bad Album with Stax and eXStatA. I had the impression I was there close to music. I had a source in which I spent a thousand dollars in high-end capacitors (V-Cap CuTf, Black Gates). Now I'm very close with cheap capacitors. Implementation plays an important role, and to find the key points which you can improve, also.



Muses02's operating voltage +-16V vs +-22V for the stock. Hope you've taken that into consideration.


----------



## SRKRAM

trybeingarun said:


> Muses02's operating voltage +-16V vs +-22V for the stock. Hope you've taken that into consideration.


People change the voltage regulators to lower the voltage.


----------



## loserica (Jun 10, 2017)

trybeingarun said:


> Muses02's operating voltage +-16V vs +-22V for the stock. Hope you've taken that into consideration.



Yes, I replaced voltage regulators with some that work on 16V. After I put the capacitors there the case gets slighty warmer. There is not a good ventilation for opamp. The space between capacitors and opamp is about a half centimeter and it looks like there's no problem.


----------



## Strangelove424

On an early page someone asked if this amp could be used as a standalone DAC, i.e. is the output unamplified? His question was not accurately addressed. In case he is still reading, no, it cannot be used standalone. The back output is a preamp, not line level. 

A few pages ago another person asked if his amp was modified with a resistor to alter the gain, and perhaps causing the humming issue he has. Again, nobody answered. 

You’d think with all these modifications taking place the user base would know the amp inside/out, and be able to answer simple yes or no questions, but alas this is not the case. This thread is not an ideal home base for users wanting to know comparisons to previous versions or other amps, specs, revision histories, or advice on purchasing. The vast majority of posts are concerning modifications, which I respectfully think the moderators should move to a new thread entitled “Matrix M stage HPA 3 Modding Thread” (as is typically done in the headphone forums).


----------



## trybeingarun

Strangelove424 said:


> On an early page someone asked if this amp could be used as a standalone DAC, i.e. is the output unamplified? His question was not accurately addressed. In case he is still reading, no, it cannot be used standalone. The back output is a preamp, not line level.
> 
> A few pages ago another person asked if his amp was modified with a resistor to alter the gain, and perhaps causing the humming issue he has. Again, nobody answered.
> 
> You’d think with all these modifications taking place the user base would know the amp inside/out, and be able to answer simple yes or no questions, but alas this is not the case. This thread is not an ideal home base for users wanting to know comparisons to previous versions or other amps, specs, revision histories, or advice on purchasing. The vast majority of posts are concerning modifications, which I respectfully think the moderators should move to a new thread entitled “Matrix M stage HPA 3 Modding Thread” (as is typically done in the headphone forums).



This unit (hpa-3u) has line out and can be used as a standalone dac.


----------



## Strangelove424

trybeingarun said:


> This unit (hpa-3u) has line out and can be used as a standalone dac.



Thanks for the clarification. Was hoping to also use the hpa 3u as a standalone DAC for a second amp, and was (mistakenly) disappointed when I heard it was amped, that's great news.


----------



## trybeingarun

@loserica Looks like Muses03 is out. Do you know if this is compatible with hpa-3u? http://www.njr.com/MUSES/series/MUSES03.html

Inspired by what you've done with your unit I've bought a soldering iron. Still don't have those capacitors with me; might be able to do at least the capacitor mods in the next couple of months. Since I live in India I am not able to get those capacitors immediately.


----------



## loserica (Jan 2, 2020)

.


----------



## xenithon

Has anyone managed to do any extensive testing of the HPA-3B with the HD800 and, if so, what were the results like?


----------



## mickerru

Anyone compared the mstage 3b to the audio gd 1amp? Which one is better driving the hd800?


----------



## mickerru

Anyone?


----------



## raoultrifan (Nov 5, 2017)

Hello,

I finally managed to write down my thoughts on how the new Burson SS V6 Classic opamps are pairing with my Matrix M-Stage HPA-3B here: https://www.head-fi.org/threads/bur...ssion-and-reviews.854912/page-9#post-13830420.

To make the long story short I'll just post the conclusions here:

*PRO*:

I really liked the sound, especially when rock is involved; try imagining the screaming from an AC/DC songs with volume close to the max., sometimes this could make you wanting to lower the volume a little bit, but when SS V6 is used, the screaming is "upgraded" from tolerable to enjoying...it's like diminishing the 2-4KHz frequencies somehow and make it sound so pleasant...though on my scope the bandwidth was perfectly flat. 
On hip-hope/house/techno/dance music I felt the sub-bass being very "pertinent" and authoritative or perhaps the mid-bass is diminished somehow, but overall I liked the bass more than V5i.
Balanced and neutral sound, but not on the analytical side and definitely not "overwarming", it's simply: pleasant sounding to my ears. Totally not-fatiguing sound compared with other digital-like sounding opamps (NE5532 or even the LME49720 and similar ones); I could actually listen to my headphones for hours, with an average volume higher then usual and fell no need to stop the music at all.

*CONS:*

Size is a bit big, the same as the SS V5 opamp, so it may not fit properly inside some devices (though purchasing additional extender cables and 90-degrees adapters will help a lot here).
Price could create an impact, though a solid-state opamp could be reused and become helpful on future devices upgrades.
Bottom of line, sound is just perfect to my ears! On both, headphones and active studio monitors, the SS V6 Classic opamp sounds correctly and pleasant, with a wider soundstage, more details and clarity and it's definitely less fatiguing. It doesn't sounds digitally at all, it's more like hearing the vacuum tubes singing, so perhaps on the warmer side a little bit, but I totally love it! This is probably related to the even-order harmonics created by the inside hand-matched FET-transistors (read more about it on OPA604 datasheet, on pg. 12) and a bit of Burson's magic touch perhaps.


 


Of course, no oscillations occurred and the opamps are fully compatible with my HPA-3B since I installed the new power regulators here.

Best, 
Raul.


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## trybeingarun (Nov 11, 2017)

loserica said:


> Hi,
> I replaced few weeks ago WIMA caps with *Audyn Plus MKP (800VDC)* and they produced a very positive emotion. *Highly recommended upgrade.*
> I noticed,
> - clarity, openess*, transparency and good speed, rhythm and timing compared with WIMA,
> ...



Finally did Elna Silmic ( 330uF instead of 470uF ) & Audyn Plus recap that's specified. The dac/amp is phenomenally better now. I haven't gone through the extensive burn-in you've mentioned, as I received the modded unit just a couple of hours back.
I tested these changes with Cheske's Ultimate Headphone Demonstration disk - 2. Changes I notice so far

Much better sound stage: Earlier the unit had a weird dumb-bell like sound stage, where front & back were squished and there was slightly more channel for instruments played in the left and right. Now it's more spherical
Improved perception of space: I notice a lot of air around instruments, which makes things more realistic
Reduced compression in the highs, which made music a little shouty earlier, not anymore
Relaxed presentation? The amp has lost its bite a little bit, which is a -ve; i'm not entirely sure though. It could be that I'm used to a shouty sound from this unit and now it is soft. The increased sound stage could also contribute to this feeling. Also I am using a HD6xx right now, IMO which doesn't pair well with the amp.
Better, but still fuzzy imaging. Earlier, imaging was plain wrong, as explained earlier. Now it's improved a lot; still there's a bit of fuzziness
Bass: nice extension to the bass
Mids: vocals are much more real life like than it used to be and the rest of the music sound airy, relaxed and spacious. The fake visceral feeling the unit gave with shouty mids is gone now.
Highs: detailed highs, and as i said earlier, uncompressed
Overall I'm really happy I did this mod. I thought capacitor changes won't change the sound by much, but I am glad I was wrong. If the sound improves as mentioned, I'm all for it!
Finally, thanks for PM'ing about the mod and your feedback about the sound changes you experienced. If not for that I wouldn't have modded my unit.

UPDATE: Experience after 3-4 days of listening.
The sound has definitely improved and i a lot more transparent now (or I am digging that sound more and more, i won't know). Bass is slightly lower than what I used to get (by memory), but it's detailed and not overpowering. I thought the stock form had slightly elevated bass anyway. So I'm good.

I've started to appreciate the way it sounds with hd6xx. Earlier I thought this combo was bad (even when using Mac -> Aune X1s dac -> Matrix -> 6XX) as it was really warm and bassy. Now it sounds natural and layered with a pretty dark background.

Most of all, I'm digging the dac/preamp of Matrix now (stock was BS IMO). I even tried this combo Mac -> Matrix m-stage hpa3u+ dac -> Nuforce HA-200 -> 6XX. The Nuforce HA-200 is also a really nice amp; I cant hear any noise floor even at full tilt. The ha-200 has a slightly different presentation, but I like the layering and spacial representation of the matrix is better.


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## loserica (Jan 2, 2020)

trybeingarun said:


> Finally did Elna Silmic ( 330uF instead of 470uF ) & Audyn Plus recap that's specified. The dac/amp is phenomenally better now. I haven't gone through the extensive burn-in you've mentioned, as I received the modded unit just a couple of hours back.


Please, wait


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## loserica

There is a clear difference between how it sounds this unit unheated (at startup) and after letting it work _for a few hours_. At first sounds sterile, strangled after which he regains its refinement and a tube-specific heat.


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## gLer (Nov 19, 2017)

Hey guys, first post to this thread. Anyone tried the HPA-3B with the ZMF Atticus? I’m currently using it with my Audeze LCD-2F (2016) and the pairing is sublime (I like my sound warm, punchy and detailed, and both amp and headphone driver in spades).

I’ve read that the Atticus prefers tubes (or should that be many Atticus users prefer it on tubes), but since the Matrix already has a ‘tubey’ presentation I think it could be a great pairing. Currently using an ifi Micro iDSD as the dac, and liking the extension of the ifi’s warm-of-neutral and revealing dac with this amp.

All thoughts and insights welcome.

PS. Have no interest in modding headphones or amps, or going down the tube amp rabbit hole for that matter.


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## raoultrifan

Hi gLer, 

HPA-3B has a discrete output buffer made of power transistors. so it will drive anything with ease...well, maybe Hifiman HE-5 could be an issue. 
However, ZMF are based on Fostex T50RP drivers. so it will drive'em perfectly. Myself I have Fostex T50RP MKiii and sound is perfect.

Good luck!


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## gLer

raoultrifan said:


> Hi gLer,
> 
> HPA-3B has a discrete output buffer made of power transistors. so it will drive anything with ease...well, maybe Hifiman HE-5 could be an issue.
> However, ZMF are based on Fostex T50RP drivers. so it will drive'em perfectly. Myself I have Fostex T50RP MKiii and sound is perfect.
> ...


Hi, and thanks for your reply. The ZMF Atticus is actually a customer made TPE dynamic driver, not one of the Fostex mods. I’m sure the Matrix will drive it easily, just wondering about the synergy as the Atticus is said to favour tubes with its 300ohm impedance.


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## raoultrifan (Nov 19, 2017)

Hi gLer, sorry for the missinfo!
I was reading now Tyll's article about the TPE custom drivers, hence...let's wait for a headfier that actually tried these headphones on a solid-state amp.

P.S.: Don't know if it counts, but my 600-ohms Beyers DT880 are easily driven by this amp.


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## gLer

raoultrifan said:


> Hi gLer, sorry for the missinfo!
> I was reading now Tyll's article about the TPE custom drivers, hence...let's wait for a headfier that actually tried these headphones on a solid-state amp.
> 
> P.S.: Don't know if it counts, but my 600-ohms Beyers DT880 are easily driven by this amp.


No probs, ZMF's newer headphones probably aren't as well known as I assumed  Well worth a listen if you get a chance. I'll be able to give my impressions when I get mine, was just wondering if any current 3B owners have tried them out.


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## loserica (Dec 17, 2017)

trybeingarun said:


> Finally did Elna Silmic ( 330uF instead of 470uF ) & Audyn Plus recap that's specified. The dac/amp is phenomenally better now. I haven't gone through the extensive burn-in you've mentioned, as I received the modded unit just a couple of hours back.



After the complete burn-in seems to have no connection with the stock unit, except the tone that is somewhere in the same area. It is significantly improved the speed, the timing, decay, resolution and sound-stage becomes so generous *in depth!! *(excelent layering). The stock unit was so anemic and unmusical comparative to the one I propose. It is something else. Everything makes sense by the fact that the sound is airy, fleshy, reliable with a transparency and those micro-details and texture which reminds me of the electrostatic system Stax&eXStatA (keeping the proportions still: control, focused image and superior texture for electrostatics).

Slowly, slowly I have the feeling of disappearance of the headphones on my ears which brings back the emotion that frankly speaking lacking before. If you ask me if it was worth the wait for the complete burn-in (I think over 600/650 hours), my only answer is this one: it sounds incredible for the price I paid!


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## CharlesC

Is the HPA-3U+ listed on the Matrix website the same device as the HPA-3U discussed here?  My first guess is that it is a recent upgrade but I can't find any separate information on it or how it is different.  Thanks.


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## trybeingarun

CharlesC said:


> Is the HPA-3U+ listed on the Matrix website the same device as the HPA-3U discussed here?  My first guess is that it is a recent upgrade but I can't find any separate information on it or how it is different.  Thanks.


The dac chip has changed b/w the two editions. Rest of it is exactly the same.


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## CharlesC

trybeingarun said:


> The dac chip has changed b/w the two editions. Rest of it is exactly the same.



I went ahead and ordered these.  At about half the price of the Deckard ( after holiday discount ) I couldn't resist.  I've got brand new LCD2-Classic headphones.  I've been running them off my Dragonfly Red for a few days.  I figure I'll have the option of running the DfR (2.1v line level) into the analog input on these if I want to.  Still waiting for shipping confirmation though so don't let me get too excited.


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## winja

I just want to drop in and say that I like my HPA-3B and the Hd800 a lot. I can hear lots of little details and nuances such as the flicking of guitar strings, vibrations of the violin bows, etc. Instrument separation and soundstage are also very good. Vocal is clean. The HPA-3B is a touch warm, and it pairs well with the hd800 when it comes to the treble peak. I have no listening fatigue even after listening to the combo for hours.


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## trybeingarun

winja said:


> I just want to drop in and say that I like my HPA-3B and the Hd800 a lot. I can hear lots of little details and nuances such as the flicking of guitar strings, vibrations of the violin bows, etc. Instrument separation and soundstage are also very good. Vocal is clean. The HPA-3B is a touch warm, and it pairs well with the hd800 when it comes to the treble peak. I have no listening fatigue even after listening to the combo for hours.


Which dac are you using to go along with the rest of the setup?


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## winja

trybeingarun said:


> Which dac are you using to go along with the rest of the setup?


I pair the HPA-3B with my Yggdrasil. The Yggdrasil is in another league of its own, but that just to say the HPA-3B is capable of revealing details if it is fed by a good source.


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## UpTo11

Did someone listen to the MrSpeakers Aeon Flow (open or closed) with the HPA-3B amp? I would like to know about this match. Thanks!


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## raoultrifan

16 ohms headphones, right? HPA-3B has an output impedance of 0.4 ohms in single-ended operation, so the dumping ratio should be very good with Aeon.
Being a Class-A amplifier means that will drive dynamic and planar as well, with ease, so I see no issue in driving the Aeon headset.
Also, the low-gain (1st position on the knob switch) would probably be perfect for these headphones.


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## UpTo11

raoultrifan said:


> 16 ohms headphones, right? HPA-3B has an output impedance of 0.4 ohms in single-ended operation, so the dumping ratio should be very good with Aeon.
> Being a Class-A amplifier means that will drive dynamic and planar as well, with ease, so I see no issue in driving the Aeon headset.
> Also, the low-gain (1st position on the knob switch) would probably be perfect for these headphones.



13 ohms impedance, 92dB (closed) - 94dB (open) sensitivity. While these numbers are good for the HPA-3B, at least on the balanced output, I'm looking for comments on this match beyond bare numbers. Anyway thanks for the answer.


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## raoultrifan

Hope someone owing Aeon and HPA-3B will provide an answer. However, specs here: https://www.innerfidelity.com/images/MrSpeakersAeonsnACXB168.pdf.


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## raoultrifan (Mar 12, 2018)

Not much activity around here lately. 

However, after more than 2 years of service I'm still enjoying my HPA-3B headamp, especially that I did some more mods recently to increase it's performance by:

Cutting backside PCB traces from the XLR plugs to the input caps, then further to the ALPS 4-gang potentiometer and getting the audio signal through good quality copper shielded wires. This way hiss and noise decreased a little bit; after all, I'm speaking of more than 20 cm of PCB traces (on expensive amplifiers input potentiometer is positioned nearby the XLR plugs and a metallic extender from the volume knob is used to adjust the volume).
Swapped 2 x BURSON V6 Classic opamps with 2 x OPA1652 installed on DIY SOIC-DIP8 adapters to further decrease background noise (some noise was audible only when using high sensitivity cans combined with highest gain setting of +20 dB). It's not much of a difference the 2 opamps, but there's a slight barely audible improvement (it's easier do check when swapping only 1 opamp only, then left headphone will have a different hiss/noise vs. the right one).
Increased treble roll-off frequency from 20 kHz to about infinite by completely removing the Low-Pass filter. Not quite recommended because some input sources might oscillate and deliver ultrasonic sounds, but in my case I'm safe...I know what DACs I got at home.
Decreased bass roll-off frequency a little bit by replacing the 50 kOhms input XLR resistors with 150 kOhms resistors (there's a high pass filter created by resistors and input caps). Ideally would be not to touch these resistors, instead to swap the input 2.2 uF caps, but I couldn't insert bigger caps inside the HPA-3B case...maybe some other time will do that too.
There was a slight channel imbalance no matter the gain I used, so I had also resolved this from the gain stage from nearby the 2 opamps. Basically, there are 4 x resistors (around 5.4 kOhms each) that are connected between pins 2/6 and GND for each opamp, so decreasing a little bit these resistors will increase amplifier's gain. I did that by adding in parallel 4 more resistors (48 kOhms each) on the back of the PCB.
Transformer shielding plus the first 2 mods from above decreased hiss and hum to half.
The 5th mod equalized levels almost perfectly to both channels on balanced and on unbalanced too.

As for the mods 3 and 4, these only "affects" beginning and ending of the audio spectrum only, so please check below pics:


 
*The above 2 pics show a perfect sine-wave 2kHz and a perfect square-wave @1kHz*. There's nothing to improve here, perfect shape, latency, no phase issue.
Channel A (blue) is the original signal, channel B (red) is what HPA-3B is throwing on the 6.3 mm headphones plug.

 
*The 2 pics above show a 20 kHz sine signal*: left - before the low pass filter removal, right after LPF removal. On the left there's a slight latency on the red channel (the HPA-3B amplifier).

 
*Above is the representation of a 100 kHz sine-wave*: left - the original unmodified HPA-3B, right - after LPF caps have been removed. Almost perfect inline with the blue channel.


*Representation of a 20 kHz square-wave*: left - original HPA-3B, right - after LPF mod. Here difference is quite huge; I know many might say that square waves are nothing to do with audio, but we all know that with square waves manufacturers are actually testing their amplifiers for imperfections.

  
*Representation of a 20 Hz square signal*: left - the unmodified HPA-3B, middle - after the high pass filter mod, right - signal applied after the 2.2 uF input caps. Everyone knows that "best cap is no cap" when dealing with caps into the audio path, so the 3rd image proves that. However, I'll be keeping the 2.2 uF caps in my HPA-3B just in case I'll connect a DAC with high DC-voltage.


*PCB traces cut and replaced with shielded wires*. This is the audio signal path coming from the XLR plugs and is having about 20 cm!


*Input high-pass filter* created by the caps and resistor; also input impedance is done here.


*Low-pass filter caps*: C29, C30, C31, C32.


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## bunkbail

@raoultrifan May I know what analyzer did you use?


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## raoultrifan (Mar 22, 2018)

Really sorry for not mentioning this: PicoScope 2204A with built-in signal generator, but also audiocheck.net audio files.

P.S.: Just changed the 4 caps from 2.2uF/250V to 4.7uF/250V. 20Hz square-wave is kinda flat now, not that makes an audible difference, but it's good for me to know that I can rely on a perfectly flat amplifier.


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## raoultrifan (Aug 31, 2018)

For the sake of modding only, I've replaced resistors R10, R1, R13, R14 of 10kOhms with 270ohms resistors for further decrease amplifier's noise. These resistors are placed directly in signal path in series with the 50 kOhms potentiometer and for an inside temperature of 50C their noise would be *1.88881 uV RMS*, that would be *-114.5 dBV*, same as stated in Matrix's datasheet (calculated with http://www.daycounter.com/Calculators/Thermal-Noise-Calculator.phtml). However, when volume it to the maximum then potentiometer's thermal noise covers the 10 kOhms resistors noise anyway. 

The 270 ohms resistor are having only *0.310363 uV RMS* of noise, that means *-130 dBV*. Difference is audible indeed, as I only modified one channel first and in my headphones one channel was having less noise (checked with sensitive cans like Beats Solo2 and Superlux 16-ohms IEM).


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## raoultrifan (Mar 22, 2018)

The 10kOhms resistors swap I was speaking about in my previous post (also, notice the 4 missing caps C29, C30, C31, C32 from the low-pass filter that f...ed up the trebles roll-off):



The 4.7uF/250V upgrade caps from signal path:
  

...and how square waves look like with these bigger *4.7uF caps* compared with the *2.2uF caps*, but also compared with *original high-pass filter + 2.2uF caps* and with *wires instead of caps*:


*Original HPA-3B with 2.2uF input caps*


*Modified high-pass filter mod & 2.2uF caps*


*Modified high-pass filter mod with input 4.7uF caps*


*Audio signal applied after the input caps (or short-circuit input caps)*

Oh, not to forget, 20Hz sine-wave looks perfect, of course:


*Note*: Blue is the input audio signal from the generator, Red is the output audio signal from the 6.3mm jack. Only one channel was tested, the other one should be identical. Perfection means Blue superimpose with Red and become one sine.


----------



## mickerru

Anyone compared the balanced 3b vs schiit SE valhalla 2 using hd800? Deciding between the 2 if the matrix 3b is more advisable.


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## WhiskeyJacks

I tried to read through this thread all the way but I just have as much time as I would like to read everything, and I was hoping someone could give me a comparison that if the 3B balanced amp from Matrix is on par or better than the Jotunheim, now I know it is preference and opinion as far as hearing goes but I am okay with that, just so I have an idea because I get the Jotunheim for 45 dollars more or go with the Matrix 3b with burson V5i opamps


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## raoultrifan (Mar 23, 2018)

Jotunheim seems very well built with higher output power in/out plugs too, not mention the cards you can add inside (also upgradable over time with future versions). If there's a way for you to test both of them it would be perfect, but if not...perhaps https://www.head-fi.org/showcase/schiit-audio-jotunheim.21792/reviews could help. If not, then please check https://darko.audio/2017/03/schiits-jotunheim-entry-level-endgame-head-fi/ etc.


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## raoultrifan (Mar 25, 2018)

Hello,

While testing some more square-shapes a couple of nights ago I somehow managed to short-circuit the output of the left channel (single-ended) and one resistor got black and another one got brown. They were measuring fine (10 ohms), but there was a smell I didn't liked and I decided to swap them both to get rid of that nasty smell. As I had bigger heatsinks glued with Arctic Silver Alumina on top of all 16 drivers transistor (4 on each channel), I needed to remove one such heatsink to be able to unsolder the black & brown resistors...and sh..t happens...the SMD transistors got taken apart from the PCB by my brute force applied. 

So, it took me a couple of days to get some low-noise BC550/BC560 complementary transistors to replace the originals. Quite a hard work for me, especially I've used through-the-hole transistors and there are no holes drilled in the PCB.



*What I do like now:* background noise decreased even further. Basically, when the first 2 gains are used this amplifier is on pair with my Objective2 when tested with sensitive cans like Beats Solo2, AKG K550 and Superlux HD-381F (16 ohms IEM). There's virtually no noise at all in my headphones if volume's to the minim on the first 2 gains; however, when the high gain is used there's a barely audible background noise, but only with the sensitive cans from above, not with the others.

*What I don't much like:* it looks dirty and non-professional with those transistors over there (well, same applies for the previous mods I've done). Also, no heatsinks can be applied anymore, so temps are really high one those drivers transistors (>60C with case open).


----------



## raoultrifan

*Original SMD transistors and some black/brown resistors vs. the new THT components:*


*The new BC550/560 transistors installed*
  

However, I can't recommend this mod, because of its high complexity and the improvement in Signal-Noise Ratio is barely noticed (and only with the highest gain).


----------



## Devangel

I'd be happy if someone could summarize all the mods for hpa-3b and hpa-3u in a post because I'm a bit lost with all the pages being a beginner and I'd like to improve my hpa-3b. Thanks.


----------



## raoultrifan

I can only recommend the following mods, because the sound gets improved and these mods are easy to be done: 1), 2) & 4).
Also, some other improvements might be considered, though the sound don't get improved: 5), 6), 7)
Despite the sound gets improved, I'll make the mods 8), 9) and 10) optional, because of the complexity and risks of damaging electronic components or the entire amplifier. An easier and maybe better solution would be to replace the default LME49860 with OPA1652 (these op-amps can be powered from +/-18V and the amplifier will benefit of a lower background noise).
Mods from 11) to 16) are quite complicated and there's a high risk to damage the amplifier for good, so can't recommend these mods, unless you really know what you're doing and if you also have a multimeter and a scope around. If you don't have a scope and perhaps a frequencies generator you should probably not touch the low-pass and high-pass filters because you can't verify if the mods have been successfully or not.
Mod 3) is really dangerous to DIY and *electricity hazard might happen*, so *I don't recommend it*! Instead, please use a power strip with common-mode filter inside or change the inside power outlet with one containing common-mode filter within. You can also get an isolation transformer with common-mode filter inside or outside, this way you'll also remove any possible ground loops you might have in your audio chain. 

Per https://www.head-fi.org/threads/int...-review-to-follow.770610/page-4#post-12120336:
- 1) Installing G.O.S.S. (Grain Oriented Silicon Steel) to shield the toroidal transformer. This will remove a bit of existing hum from the right channel (which can only be heard with very sensitive cans and volume to the max. without input source connected).
- 2) Replacing 2.2uF WIMA MKS 4 (Metallized Polyster) with JB JFX Premium Film Cap (Polypropylene Film) or with 2.2uF Audyn Plus, preferable 4.7uF, per https://www.head-fi.org/threads/int...review-to-follow.770610/page-21#post-14121897. 
- 3) Installing EMI/RFI noise suppression filter (one stage common-mode filter) to reduce any possible noise injection from mains into the audio chain.

Per https://www.head-fi.org/threads/int...-review-to-follow.770610/page-5#post-12157815:
- 4) Adding more decoupling caps at the backside of the PCB, between op-amp's V+ & GND and V- & GND.
- 5) Adding Arctic Silver MX-4 thermal paste (overkill, I know) to the output stage transistor's heatsink.

Per https://www.head-fi.org/threads/int...-review-to-follow.770610/page-5#post-12178996:
- 6) Adding 2 heatsinks above the 2 op-amps to better dissipate the heat.
- 7) Swapping the 4 existing heatsinks from above the 16 SMD transistors with bigger ones (I've used Arctic Alumina bi-compound, but I strongly recommend thermal dual-scotch tape instead of Alumina). Also, ignore the fan I've installed in there, I don't recommend it.

Per https://www.head-fi.org/threads/int...-review-to-follow.770610/page-7#post-12390513:
- 8) Swapping the original JRC7818/7918 power regulators with NJM7815/7915 to lower the voltage from 36V to 30V, so I can install more op-amps to roll. You will loose a bit of the output power, there's enough juice left in there.
- 8') Same from above, but with very low noise regulators from Sparko.
- 9) Installing BURSON SS V5 duals to increase the soundstage, clarity and depth. Also, case needs to fit well, so some adapters could be used, preferable originals from Burson if possible.

Per https://www.head-fi.org/threads/int...review-to-follow.770610/page-19#post-13830489:
- 10) Installing BURSON SS V6 duals to increase the soundstage, clarity and depth. Also, case needs to fit well, so you could use some adapters (preferable originals from Burson if possible) or loose the warranty and remove op-amps shells to lower their height enough to close the case.

Per https://www.head-fi.org/threads/int...review-to-follow.770610/page-20#post-14100120:
- 11) Cutting backside PCB traces from the XLR plugs to the input caps, then further to the ALPS 4-gang potentiometer and getting the audio signal through good quality copper shielded wires. This way hiss and noise decreased a little bit; after all, I'm speaking of more than 20 cm of PCB traces (on expensive amplifiers input potentiometer is positioned nearby the XLR plugs and a metallic extender from the volume knob is used to adjust the volume).
- 12) Swapped 2 x BURSON V6 Classic opamps with 2 x OPA1652 installed on DIY SOIC-DIP8 adapters to further decrease background noise (some noise was audible only when using high sensitivity cans combined with highest gain setting of +20 dB). It's not much of a difference the 2 opamps, but there's a slight barely audible improvement (it's easier do check when swapping only 1 opamp only, then left headphone will have a different hiss/noise vs. the right one).
- 13) Increased treble roll-off frequency from 20 kHz to about infinite by completely removing the Low-Pass filter. Not quite recommended because some input sources might oscillate and deliver ultrasonic sounds, but in my case I'm safe...I know what DACs I got at home.
- 14) Decreased bass roll-off frequency a little bit by replacing the 50 kOhms input XLR resistors with 150 kOhms resistors (there's a high pass filter created by resistors and input caps). Ideally would be not to touch these resistors, instead to swap the input 2.2 uF caps, but I couldn't insert bigger caps inside the HPA-3B case...maybe some other time will do that too.
- 15) There was a slight channel imbalance no matter the gain I used, so I had also resolved this from the gain stage from nearby the 2 opamps. Basically, there are 4 x resistors (around 5.4 kOhms each) that are connected between pins 2/6 and GND for each opamp, so decreasing a little bit these resistors will increase amplifier's gain. I did that by adding in parallel 4 more resistors (48 kOhms each) on the back of the PCB.

Per https://www.head-fi.org/threads/int...review-to-follow.770610/page-21#post-14121815:
- 16) Replacing resistors R10, R1, R13, R14 of 10kOhms with 270ohms resistors for further decrease amplifier's noise (this might increase the existing channel imbalance, so take this mod with a grain of salt).

Per https://www.head-fi.org/threads/int...review-to-follow.770610/page-21#post-14127810:
- 17) Replacing SMD transistors with TTH BC550/BC560 lower just a little bit the background noise of the amplifier.


----------



## omegaorgun (Jul 29, 2018)

Anybody experience with the 2C Classic? I ordered up a Burson opamp based on the fact earlier revisions could work with them.

There is an OPA2134 in ti right now, slapped an NE5532 in it and it sounds less harsh to me, less top end grain so excited for the burson v6.


----------



## loserica

raoultrifan said:


> - 2) Replacing 2.2uF WIMA MKS 4 (Metallized Polyster) with JB JFX Premium Film Cap (Polypropylene Film) or with 2.2uF Audyn Plus, preferable 4.7uF, per https://www.head-fi.org/threads/int...review-to-follow.770610/page-21#post-14121897.



I took into account in the future the replace of input capacitors (Audyn Plus) with Jupiter Cooper Foil Paper&Wax!! I think Jupiter will sound great in this amplifier.
Sennheiser HD600 sounds great with Matrix, undoubtedly over Beyer DT880 (it bring a great transparency, a lot of details and superior musicality & refinement).


----------



## maxxevv

raoultrifan said:


> An easier and maybe better solution would be to replace the default LME49860 with OPA1652 (these op-amps can be powered from +/-18V and the amplifier will benefit of a lower background noise).
> .




This was from months back, was wondering if you have tried using a pair(s) of LT1128 with appropriate dual channel adaptor to replace the LME49860 ?  It takes 18V rails and I have tried it on my portable amp, it works stable. And based on it specs sheet, has probably the lowest noise ratings of any op-amp that's commonly available.


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## raoultrifan

No, but it might be a good idea. I’ll see when I’ll have some time to purchase these, thank you for the hint.


----------



## prfallon69 (Sep 2, 2018)

Could somebody please let me know if it’s possible to use the Topping D50 as the Dac with the Matrix M-Stage HPA3u.

-Paul-


----------



## raoultrifan

Yes, seems that it has RCA inputs: http://www.matrix-digi.com/uploads/product/HPA-3U/03.png.
Same conclusion after reading http://www.matrix-digi.com/pdf/HPA-3U_plus_Manual_EN.pdf, page 4.


----------



## prfallon69

raoultrifan said:


> Yes, seems that it has RCA inputs: http://www.matrix-digi.com/uploads/product/HPA-3U/03.png.
> Same conclusion after reading http://www.matrix-digi.com/pdf/HPA-3U_plus_Manual_EN.pdf, page 4.



Thank you.

-Paul-


----------



## omegaorgun (Sep 4, 2018)

I have the 2C, changed the opamp to an OP275 it's a decent amp  with more low end kick and power than my NFB.11. I was confused by the output of 110 mw @32ohms thinking it might be crap but it's a powerhouse with a very tight focused sound.


----------



## mikaelmark (Oct 1, 2018)

QUOTE="raoultrifan, post: 12458973, member: 386058"]
 I'm not sure how will you A/B test headphones with Schiit Sys, because this only has RCA plugs. Perhaps this would be a very good A/B testing tool for single-ended DACs only, but not for single-ended headphone amplifiers.

 Here's what I'm using for A/B testing, either single-ended DACs, either single-ended headphone amplifiers (6.3mm jack directly plugged into 6.3mm amplifier's output connector):


 ​
 It's completely DIY and quite easy to build and with good components quality. One PCB divided into 2 sides: the left half used for headamp testing and the right half for DAC testing.

 On the left side of PCB there are 2 x 6.3mm jacks used as source inputs that might be connected to 2 different headphone amplifiers and the blue 6.3mm connector can be connected to a good and detailed pair of headphones. The silver/red switch can be used for rapid switching between the 2 sources.

 On the right side there are 2 sets of RCA inputs that might be connected to 2 DACs and the 3'rd set of RCA plugs is used as output to a transparent headphone amplifier connected to a good detailed pair of headphones. The silver/red switch can be used for rapid switching between the 2 sources.[/QUOTE]

Hi, Raoultrifan!

Nice to read your meticulous and detailed review about the Burson Play, ealier this year!

As I now has been choosen for testing of the headphone amp Fun from Burson, it would be helpful to build something similar to your A/B-tester. I´m thinking about one with two 6,35 mm (1/4 inch) TRS male jacks that can be connected to two headphone amps out. Both are soldered to cables that comes together to a 6,35 mm TRS female socket. Between, there will be a switch to chose what amp to use at the moment.

Do you think it will be enough to switch source only with the Ground, so the Left and Right channel from both amps will always be connected to the headphones? Is that the way you have done?


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## raoultrifan

Hello, 

No, sorry...current might flow between one device into another and we don't want that to happen. Why not using something cheap and cheerful similar with one from below?
- https://www.amazon.co.uk/3-5mm-Audio-Music-B-Switch/dp/B07622SYCF
- https://www.amazon.co.uk/dp/B07836JJ2Z/
- https://www.amazon.co.uk/Way-Cd-Aux-Stereo-Switch-Black/dp/B000KVODHA/

There're also with 3.5/6.3mm jack plugs as well, just nee to dive deep a bit more on Amazon or electronics related web shops.


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## mikaelmark

Thank´s for your reply! Two of those link´s are for RCA input and the other is 3,5 mm (not in stock).

I found one at eBay, and the Product description state it´s correct: "Want to switch between 2 different 1/4" TRS audio input sources into one pair of headphones". -But hey; $100 + shipping!!
https://www.ebay.com/itm/1-4-TRS-St...977092?hash=item212adbedc4:g:U30AAOSwy79Zcot8

I think a DIY with three switches will do the job fine.


----------



## raoultrifan

I'm sure you'll find a cheap one to purchase, but you can DIY one, of course.


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## mikaelmark (Oct 4, 2018)

Yes, I´m definitely gonna DIM it (DoItMyself), as I have dozens of 6,35 mm jacks, sockets and several meters of Van Damme Tour Grade Classic XKE starquad mic Cable.

For the switches, don´t even Think I must use three, only two should be fine as only the Ground always/pemanent connected between the amps should not do any harm or have any current floating, don´t you think also?

I hope my Fun will arrive soon! Gonna start a new thread for this review, I think. 

PS; I told Charles you helped me with this, thank´s a lot raoultrifan!


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## raoultrifan

Looking further for your review and, of course, for the A/B-testing device.


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## mikaelmark (Oct 16, 2018)

Finished it some days ago, and keep in mind I did it with a broken wrist for left hand!

Soldered it directly to the female socket without any PCB.

There are five buttons, so pushing the left one in, it will activate amp 1, a slight push at any other button will release the left one and activate amp 2. And if in future, I want to use any of the other buttons, I can solder for example an A/B-testor for DACs  with RCA.


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## Filipash (Oct 29, 2018)

https://imgur.com/a/nqMmkWr




Hi everyone! 
Here I haveme some pictures of the running temperature of hpa-3b amplifier and temperature of op amps
Sparkos vs stocK
i cant upload pictures, may be i am doing something wrong...
stock op amp case temperature 38.6c, op amp temperature 65.4c
sparkos op amp case temperature 49.3c , op amp temperature 100.5c


----------



## raoultrifan

Hi there, 

Can't find any pics, sorry, please re-attach.

However, per your temps, please remove the Sparkos because they're most likely oscillating. Feel free to replace them with the original LME49860 or with something else able to opearate to 36V (e.g.: OPA1652 or similar).


----------



## Filipash

raoultrifan said:


> Hi there,
> 
> Can't find any pics, sorry, please re-attach.
> 
> However, per your temps, please remove the Sparkos because they're most likely oscillating. Feel free to replace them with the original LME49860 or with something else able to opearate to 36V (e.g.: OPA1652 or similar).



Thanks for reply , already removed them
Had one more problem with sparkos at high gain , above 60% of volume Matrix turns off , turns back on on low volume


----------



## Filipash

raoultrifan said:


> Hi there,
> 
> Can't find any pics, sorry, please re-attach.
> 
> However, per your temps, please remove the Sparkos because they're most likely oscillating. Feel free to replace them with the original LME49860 or with something else able to opearate to 36V (e.g.: OPA1652 or similar).


https://m.imgur.com/a/nqMmkWr


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## raoultrifan (Oct 30, 2018)

The laser beam may not have the same focus as the thermal cell from inside. You might get higher temps if you approach the thermal cell from below the laser beam (just point it few mm above the opamp).
However, 100C on the bottom of an opamp might be 125-150C inside, depending on its internal thermal resistance. If I see an opamp with >70C I usually check for oscillations; if no oscillation found, then I try to stick a heatsink (not sure you can do that for the SPARKOs).


----------



## raoultrifan

Can anyone please do a RMAA and ARTA tests with the HPA-3B? 1-2V RMS would be just fine, without load if you can't find a 20-30Ohms 1W resistor. Thank you!

I don't think I have RMAA or ARTA tests with my HPA-3B before the modding, so I'd like to compare the results.


----------



## BSV2007

Hello, guys! Is HPA-3B good for Denon D7200 or it has too much power for these cans?


----------



## raoultrifan

HPA-3B has gain adjust knob on the back with 3 positions: Low, Mid, High; check the datasheet for details. Given the very good sensitivity of the D7200 (Impedance 25 Ω Sensitivity 105 dB/mW Maximum power input 1.800 mW) I would say that the lowest gain should do just fine.


----------



## Thenewbie76

I am planning on buying the new edition of dac/amp which is the  hpa-3u+. For the older model was it a good dac/amp. Also can I use it with an external amp


----------



## loserica

Matrix amp/dac lacking dynamics, resolution, energy. With Muses02 Opamp things do not come out of their template, but with Burson V6 Vivid (Dual Opamp) Yes! everything in sound gets life! very convincing.


----------



## maxxevv

loserica said:


> Matrix amp/dac lacking dynamics, resolution, energy. With Muses02 Opamp things do not come out of their template, but with Burson V6 Vivid (Dual Opamp) Yes! everything in sound gets life! very convincing.



Which one are you referring to ? The 3B runs on 18V rails, I would think the 3U is the same. 

The Muse02 and most of the popular opamps out there run on 15V. You're slowly cooking them if you run them on the 3B (maybe 3U too).  Do check on the input rail values if you are running them on the 3U.


----------



## raoultrifan (Apr 19, 2019)

Both me and loserica (like many head-fiers here) did replaced the two power regulators and lowered this way the voltage from 36V to 30V (+/-15V).

Both 3U & 3B are using, by default, +/-18V, which is simply too high voltage for the internal circuitry to handle; it's simply too much power and heat generated. In all of my previous tests the resistors from nearby the output stage where all smoking and trying to melt themselves (I'm speaking about 4.5W per channel while continuously testing with pure sinewaves, so please do't try that at home!). This is why I was forced to change the output resistors with more powerful once and also the voltage gain transistors (SMD ones) with TO-92 case.

Also, the voltage of the main two capacitors is almost identical with the voltage provided by the transformer and rectifier bridge, so lowering the voltage will increase lifespan of all internal components and provide the capability of swapping more opamps (+/-18V is just too much for some opamps).

Details about the above could be found in the pages from this thread.

P.S.: The tests with sinewaves at max. power I do with all my gear and this Matrix is the only one having issues when volume gets maxed out. With Burson's (PLAY, PLAYMATE and CV2+) I never had any issues, not even when connecting CV2+ directly on speakers instead of headphones. However, please don't try that at home!  Again: lowering the voltage to HPA3U/3B is a good thing to do.


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## loserica (May 14, 2019)

After a few houndred hours of burn-in time Burson V6 Vivid (Dual Opamp) sounds airy!! The amount of detail and spatial information lets you hear the acoustics of the recording venue well. A coherent and organic presentation, detail and smoothness come hand-in-hand, a well controlled and focussed image, rich and transparent overtones, the amount of decay of notes and the acoustic reverb of the recording venue, rich textured treble, very good separation of the individual instruments, a quiet background, they are all there. The texture and timbre seems very realistic. The soundstage is produced with lots of contrast, great depth and heaps of micro detail. Long term listening sessions are very pleasent which shows that there is nothing artificial about the sound at all. You get a richer tone with more flow and air with the Burson comparing it with Muses02.


----------



## Atgm1

Hi guys. I wrote to burson audio support: " Hey. I want to buy a pair of v6 vivid for the amplifier M-stage hpa-3b. Tell me whether they fit the specified amplifier or I will definitely need to lower the voltage. because it has Supply Voltage 18V. thank"

got an answer: "
Are you sure the power supply voltage is +/-18V or just what the transformer state?
Because +/-18V from the transformer will get lower to +/-15V after the voltage regulator in most design.
Warm regards
Dennis"

What does it mean?  if not difficult, resolve the bewilderment.


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## maxxevv

The unmodified HPA-3B works on 18V rails, its the voltage regulators that are spec'd at 18V.  Not 18V transformers. 
You are correct. 

As far as the Burson V6 goes, its not supposed to go above 16V.. Unless they revised the design, else its a slow fry plugged into the HPA-3B amp.


----------



## Atgm1

maxxevv said:


> The unmodified HPA-3B works on 18V rails, its the voltage regulators that are spec'd at 18V.  Not 18V transformers.
> You are correct.
> 
> As far as the Burson V6 goes, its not supposed to go above 16V.. Unless they revised the design, else its a slow fry plugged into the HPA-3B amp.


Is there any detailed instruction for modification anywhere?


----------



## maxxevv

Atgm1 said:


> Is there any detailed instruction for modification anywhere?



This is probably way more than what you're looking for but yes, there are many out there:

https://www.audiosciencereview.com/forum/index.php?threads/matrix-m-stage-hpa-3b-mods.4344/

I would suggest looking for the newer opamps that operate on 18V rails instead. Most would need a DIP-8 adapter as a lot of them are only in the SMT form factor it seems.


----------



## Atgm1

maxxevv said:


> This is probably way more than what you're looking for but yes, there are many out there:
> 
> https://www.audiosciencereview.com/forum/index.php?threads/matrix-m-stage-hpa-3b-mods.4344/
> 
> I would suggest looking for the newer opamps that operate on 18V rails instead. Most would need a DIP-8 adapter as a lot of them are only in the SMT form factor it seems.


Don't know which sound quality is comparable to vivid?


----------



## Atgm1

How to navigate when choosing an operational amplifier for the m-stage?  what company to pay attention, except burson?


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## raoultrifan

@Atgm1, just change the two power regulator from 7818/7918 to 7815/7915. Two 1 Ohm/5 Watts resistors might get added either between transformer to the bridge rectifier, either from the bridge to the big caps (to lower a bit the input voltage to the two regulators). After this mod, double check the temps of the regulators, just to be sure everything;s fine; of course, check the voltage rails and stability too. Now you can install the Vivids and enjoy the added microdetails


----------



## Atgm1

raoultrifan said:


> @Atgm1, just change the two power regulator from 7818/7918 to 7815/7915. Two 1 Ohm/5 Watts resistors might get added either between transformer to the bridge rectifier, either from the bridge to the big caps (to lower a bit the input voltage to the two regulators). After this mod, double check the temps of the regulators, just to be sure everything;s fine; of course, check the voltage rails and stability too. Now you can install the Vivids and enjoy the added microdetails


Tell me, will it not be easier for me to install muses03?  for me it’s not so much the microdetails that matter as the realism, the width and depth of the scene.


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## raoultrifan

I don't think so, you need 4 of them (so, very expensive) and also lot of DIY works to adapt them from single SOIC to dual-DIP8.


----------



## Atgm1

raoultrifan said:


> I don't think so, you need 4 of them (so, very expensive) and also lot of DIY works to adapt them from single SOIC to dual-DIP8.


besides power regulators, is it necessary to change two resistors?  I can't even imagine where they are.  I found the power regulators, but I do not want to interfere in this technological work of art.


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## raoultrifan

There are no resistors to swap, but the voltage drop on the 2 regulators will be 3V higher. So, ideally would be to lower the dropping voltage with few volts, if possible. I was actually cutting the traces that got from transformer to the bridge, and added couple of resistors on the back of PCB.
However, if you'er not comfy with such mods, please ask somebody else to do them or simply swap the regulators and care not about the resistors anymore.


----------



## loserica

Atgm1 said:


> Tell me, will it not be easier for me to install muses03?  for me it’s not so much the microdetails that matter as the realism, the width and depth of the scene.



Burson V6 Vivid add realism, width and depth (not just microdetails). Muses 02 for example is not able to enlarge the scene so much how it does Burson.


----------



## Atgm1

raoultrifan said:


> There are no resistors to swap, but the voltage drop on the 2 regulators will be 3V higher. So, ideally would be to lower the dropping voltage with few volts, if possible. I was actually cutting the traces that got from transformer to the bridge, and added couple of resistors on the back of PCB.
> However, if you'er not comfy with such mods, please ask somebody else to do them or simply swap the regulators and care not about the resistors anymore.


and if you do not turn on the gain at maximum gain, will the opamps still have 18v?


----------



## raoultrifan

If you never used the soldering gun and you're not comfortable doing the above mods by yourself, then I do not recommend you to open up the HPA amplifier.

After all, the main difference when swapping the original LME49860 with SS V6 or MUSES02, OPA1652, MUSES8920 etc. is lowering the background noise when using very sensitive cans, especially IEMs.


----------



## mikaelmark

I have a DIY Lovely Black Cube (completely made by myself), that are mostly the same architecture. It have the V6 Vivid and I replaced the LM317 and LM337 to Sparko 7915 and 1117-15 discrete voltage regulators (+-15 Volt).

The only thing I was suggested by Sparko to do, was to remove the two 100 Ohm and shorting the 1K1 Ohm resistors. It work´s like a charm! Later, I will compare the V6 Vivid and Classic to Sparko SS3601/2, and also compare my DIY to Burson Fun.


----------



## Atgm1 (Jun 11, 2019)

friends, are these opamps suitable for our amplifier?


https://eu.mouser.com/ProductDetail...=sGAEpiMZZMtCHixnSjNA6POfvxHi7ti2NVFSnl25bd8=

https://eu.mouser.com/ProductDetail/Texas-Instruments/OPA637AP?qs=wgAEGBTxy7nfgz4EbApFvQ==


----------



## raoultrifan

Not really, you need dual opamps, not singles.


----------



## Atgm1

raoultrifan said:


> Not really, you need dual opamps, not singles.


I want to try installing two on each channel.


----------



## raoultrifan

Well, you might try the OPA637 in dual config, just be sure they are not overheating. Also, measure the output DC (headphones plug).

I still think that lowering the internal voltages to +/-15V is a good thing. I personally destroyed couple of output resistors while doing tests with sinewaves and max. volume, so definitely this headamp was not designed to run at max. volume continuously. Lowering the voltages will help with any possible overheating, while opamp swap possibilities will increase a lot (30V opamps are much more than vs. 36V opamps).


----------



## Atgm1

raoultrifan said:


> Well, you might try the OPA637 in dual config, just be sure they are not overheating. Also, measure the output DC (headphones plug).
> 
> I still think that lowering the internal voltages to +/-15V is a good thing. I personally destroyed couple of output resistors while doing tests with sinewaves and max. volume, so definitely this headamp was not designed to run at max. volume continuously. Lowering the voltages will help with any possible overheating, while opamp swap possibilities will increase a lot (30V opamps are much more than vs. 36V opamps).


I use a DAC (audinst HUD DX-1) in conjunction with the m-stage.  Does it make sense to install burson in my audinst?


----------



## raoultrifan

The first 2 opamps are from the I/V stage, but are SO8/SOIC, so you really need to troubleshoot this a bit to install SS V6 opamps. I would say that it's kinda impossible. Instead, you might want to replace the two MUSES 8920 with two OPA1612 and the LPF opamp MUSES892 (DIP8 socket) to replace it with SS V6 Classic/ or Vivid.

However, in the end I don't think there will be any audible improvements in any way, but there will be fun to do these mods for sure.


----------



## Atgm1

raoultrifan said:


> The first 2 opamps are from the I/V stage, but are SO8/SOIC, so you really need to troubleshoot this a bit to install SS V6 opamps. I would say that it's kinda impossible. Instead, you might want to replace the two MUSES 8920 with two OPA1612 and the LPF opamp MUSES892 (DIP8 socket) to replace it with SS V6 Classic/ or Vivid.
> 
> However, in the end I don't think there will be any audible improvements in any way, but there will be fun to do these mods for sure.


The fact is that after installing burson vivid, the owners of the audinst HUD DX-1 are very pleased with the improvement in sound quality - heaven and earth.  so I wondered if I should be installed directly in the DAC as well.  Do the operational amplifiers of the DAC work when pairing with an external amplifier?


----------



## raoultrifan

Yes, the two SO8/SOIC opamps are the most important ones when speaking about opamp swap and yes they both work when connected to an external amp.


----------



## mikaelmark

Atgm1 said:


> The fact is that after installing burson vivid, the owners of the audinst HUD DX-1 are very pleased with the improvement in sound quality - heaven and earth.  so I wondered if I should be installed directly in the DAC as well.  Do the operational amplifiers of the DAC work when pairing with an external amplifier?


Yes, absolutely! I have implemented a Burson V6 Vivid in my AK4490 DAC, with very good result!

The only thing you should have in my, is if you should buy single (two pieces) or dual (one piece) for the unit. Those Opamp´s will replace a a lot of different OpAmp models.


----------



## Atgm1

mikaelmark said:


> Yes, absolutely! I have implemented a Burson V6 Vivid in my AK4490 DAC, with very good result!
> 
> The only thing you should have in my, is if you should buy single (two pieces) or dual (one piece) for the unit. Those Opamp´s will replace a a lot of different OpAmp models.


thanks for the answer.  Do you use a DAC in conjunction with an amplifier?  with which, if not a secret?


----------



## raoultrifan (Jun 15, 2019)

Hi,

To my HPA-3B I have ASUS Essence One MKii connected via balanced interconnects. It is a heavily modded DAC/headamp combo, but right now it is using 4xNE5532 + 4xLME49720 + 3xLM4562: https://www.head-fi.org/threads/asu...-dac-cebit-2011.542563/page-229#post-13130247.

I had also tested it with SS V5 and SS V6 as well here: https://www.head-fi.org/threads/asu...-dac-cebit-2011.542563/page-226#post_12959422.

I'm OK with the sound, very neutral and with extremely low noise on my headphones, including on the 103dB SPL & 16 Ohms IEMs. I have absolutely no hum noise coming from the DAC and not from the HPA-3B too, especially after the mods I did inside the HPA-3B; you can find suggestions about few mods below:
- https://www.head-fi.org/threads/int...-review-to-follow.770610/page-3#post-12101227
- https://www.head-fi.org/threads/int...-review-to-follow.770610/page-7#post-12390513
- https://www.head-fi.org/threads/int...-review-to-follow.770610/page-4#post-12120336
- https://www.head-fi.org/threads/int...-review-to-follow.770610/page-5#post-12157815


----------



## loserica

Atgm1 said:


> The fact is that after installing burson vivid, the owners of the audinst HUD DX-1 are very pleased with the improvement in sound quality - heaven and earth.  so I wondered if I should be installed directly in the DAC as well.  Do the operational amplifiers of the DAC work when pairing with an external amplifier?



IMHO with Burson V6 Vivid (Dual) the sound has brought liquidity (at the opposite side it is the stock Opamp which sounds dry!!). Vivid has peace&rhythm, speed&good timing, those
important attributes for what I call musicality and high sound-resolution. With the Muses02 the passages are somewhat more crowded, dynamic is poor, less transparent compared to Burson. Everything seems dull, boring with the stock Opamp.


----------



## raoultrifan

Atgm1 said:


> friends, are these opamps suitable for our amplifier?
> 
> 
> https://eu.mouser.com/ProductDetail...=sGAEpiMZZMtCHixnSjNA6POfvxHi7ti2NVFSnl25bd8=
> ...



Perhaps OPA2228 or OPA1692 might work, but please pay attention to overheating (possible oscillations).


----------



## Atgm1

thank you guys for the warm communication and caring


----------



## mikaelmark (Jun 15, 2019)

A few days ago, I also did a comparison for JRC NE5534, Burson V6 Vivid Classic and a Sparko SS3602 installed in a Burson Fun headphone amp, every A/B-test were done with a DIY stereo switch for instantly swapping between the simultaneously powered amps and compairing with my own DIY assembled LBC amp with a V6 Vivid and Sparko discrete voltage regulators SS7815 and SS1117-15, that will replace the original LM317 and LM337. Those discrete voltage regs will give the amp a steady and clean power voltage with very low noise and a black background.

Before the test, every OpAmp were burned in with pink/white noise and sinus waves for several hours. The test were made with a pair of Sennheiser HD 800 connected with the DIY A/B-switch to both amps simultaneously powered and listening to some CD´s, for example Ani DiFranco and Laura Pausini from 2006 - playing in my Arcam CD192 CD-player. Here are my conclusion:


The standard *NE5534* was dull sounding some treble roll off and not as clear and open as all the other OpAmps.

The difference between *Burson V6 Vivid* and *Classic* was the smallest between all tested and not as big as many people stated, that the Vivid should be more open with a bigger sound stage and the Classic should be warmer and closer To me, it was almost not hearable.

The* Sparkos SS3602 *had more treble than the all the other.

And when I compaired both amps with V6 Vivid for both, the DIY amp had a more open sound with a wider sound stage. But have in mind that I have paid a bit more for the *DIY amp* in component cost than the *Burson Fun*, that will cost $399 with V6´s. I think one of the biggest improvement for the DIY are the Dale 24 step volume attenuator, while the Fun has an Alp RK27 "Blue Velvet", found in mostly every well known amp in the market. One more thing I noticed, was the raw power for the Fun, as the volume knob were at bearly 9´clock, while the DIY were at almost 12´clock, when calibrated equally with noise.

My DIY amp were connected to the CD-player with a Van Damme Twin Interconnect, while I choosed the original bundle Pailiccs for the Fun. I also tried the Fun with a thick high grade silver plated OFC Interconnect, without any noticeable improvements. Therefore, I will praise the bundle Pailiccs quite high, altough I soldered the cables screen to the connectors for best connection. Have in mind that most other equipments bundle cables are of a very low quality that should be avoided to use for HiFi!

My verdict are that the Burson Fun have a very affordable price, compared to most other amps (for example; the Grado RA1 have a price, while having a very simple schematic, base on the Pimeta that can be done as a coffe break DIY-project), and will give a sound that will satisfy most people, and beat most of it´s competitors - especially if you choose a discrete OpAmp, regardless model. I´m aware there are at least one more discrete in the market; the *NewClassD *(confusingly working in Class A) - that are priced a bit higher than the Sparko, while the Burson models are the cheapest. While I hav´nt heard the NewClassD, I do not think it´s much better and I guess it will play in the same league with those I´ve tested.

Finally, I really want to thank Charles at Burson and Andrew at SparkoS, as they equipped me with the discretes and made this test possible!


----------



## Atgm1

mikaelmark said:


> It´s a AK4490 DAC connected to a Yamaha RX-V771 Home Cinema Receiver, connected to a pair of fully modded B/W 683 S2.
> 
> Now, I also finishing a DAC 9 with AK4399 with either a pair of B6 Vivid or Sparko SS3601.
> 
> ...


there is another option
Orange Dual Discrete Op-Amp https://orangeamps.com/product/op-amp/


----------



## mikaelmark

Atgm1 said:


> thanks for the answer.  Do you use a DAC in conjunction with an amplifier?  with which, if not a secret?


The DAC are AK4490, connectod to a Yamaha RX-V771 Home Cinema Receiver, Bi amped with a pair of fully modded (recapped and rewired) B/W 683 S2. Now, I will also finish my modded DAC 9, with AK4399 paired with either V6 Vivid or Sparko SS3601.

One think to also have in mind when replacing OpAmps, is the PCB supports DIP (hole mounted pins) or if it´s SMT (with SMD = Surface Mounted Devices). If it´s DIP, then it´s easy swappable with discrete OpAmps, but if it´s SMT, it will require good soldering skills and a not easy to find socket adapter.


----------



## mikaelmark

Ok  Sonic Imagery and HDAM


Atgm1 said:


> there is another option
> Orange Dual Discrete Op-Amp https://orangeamps.com/product/op-amp/


Ok, thank´s!

A quick seach at eBay will found some more, for example Sonic Imagery and some cheaper models, such as HDAM. But for about such a low price, I doubt it´s at the same level!


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## omegaorgun

The HPA-3B is very decent! I amp op amps rolling atm.


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## omegaorgun (Aug 14, 2019)

mikaelmark said:


> Ok  Sonic Imagery and HDAM
> 
> Ok, thank´s!
> 
> A quick seach at eBay will found some more, for example Sonic Imagery and some cheaper models, such as HDAM. But for about such a low price, I doubt it´s at the same level!



I will have Sonic Scientific Oracle-02 and FOX Lab NT-D1 opamps soon, I currently have V5I-D's and OPA1656's that work very good in the HPA-3B. I might do a opamps shootout soon.

Both of these are superior to the LME48960's, I also have to try the OPA2604 which is one of my fave cheap opamps and it's slightly warmer bretheren the OPA2134.


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## omegaorgun

OPA2604's are a nogo, has distortion. OPA1656's and V5I-D's are SOOOO sweet!


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## omegaorgun

Can the OP change the title to the official 3A and 3B thread and list the specs/pics on the first post?


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## omegaorgun

OPA 1656'S are my favorite, very tight and clean. Burson's are a little looser but wider sounding.


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## staxstax

3 years ago I bought the Matrix M-Stage HPA3u
today out of the blue the right channel gives less volume
I tried different cables, headphones and players, the problem remains 
(no mods, never opened the case)
Am I the only one?
if you know what it may causes the problem please help


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## staxstax

3 years ago I bought the Matrix M-Stage HPA3u
today out of the blue the right channel gives less volume
I tried different cables, headphones and players, the problem remains
(no mods, never opened the case)
Am I the only one?
if you know what it may causes the problem please help


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## Atgm1

staxstax said:


> 3 years ago I bought the Matrix M-Stage HPA3u
> today out of the blue the right channel gives less volume
> I tried different cables, headphones and players, the problem remains
> (no mods, never opened the case)
> ...



I had something similar recently.  I just unplugged and reconnected the connecting cables and the problem disappeared.  Maybe something happened in the socket of the DAC or amplifier?


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## mikaelmark

inseconds99 said:


> Isn't m-stage a Chinese company and therefore if I purchase direct I would be purchasing from China or am I mistaken? Also tamaudio on Amazon shows the product shipping from China. Where would I buy the product where it wouldn't come from China?


Where do you live? I live in Sweden (northern/west Europe) and has built some LBC (Lovely Black Cube) - similar yours as clone to the Lehmann Black Cube Linear.

Have sold my first buid to a very satisfied head-fi:er in France a couple of years ago. And now I´ve some with very high grade components (24 step Dale volume attenuator, Holco/PRP9372 resistors, Elna Silmic 2/Panasonic FR/Mundorf/Audyn/Teflon caps and Discrete OpAmp etc...)

Have also built a portable model of this, to be carried in a back packer.


Please tell me if youre interesest!

https://www.head-fi.org/threads/bur...-opamps-discussion-and-reviews.854912/page-24


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## staxstax

Atgm1 said:


> I had something similar recently.  I just unplugged and reconnected the connecting cables and the problem disappeared.  Maybe something happened in the socket of the DAC or amplifier?



i was wrong about the model, it is the Matrix M-Stage HPA3B


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## raoultrifan

staxstax said:


> 3 years ago I bought the Matrix M-Stage HPA3u
> today out of the blue the right channel gives less volume
> I tried different cables, headphones and players, the problem remains
> (no mods, never opened the case)
> ...



You need to provide more info:
- have you tried both RCA and XLR inputs and same happens?
- what about balanced cans, same issue happens?
- have you tried mixing the two opamps between and see what happens?
- anything suspicious inside HPA-3B (maybe some macro pics would help)?


----------



## staxstax

thanks raoultrifan
i tried RCA and XLR with different players the same happens
balanced headphones or not the same,
i thought it may be the pot but when i turn the knob there is no noise or cracking
i will open it to mix the opamps and see if the problem moves to the left channel (i hope)


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## staxstax

i mixed the opamps thr problem remains at the same channel


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## raoultrifan

Then it might be the gain-adjust circuitry. Could you please adjust the backside gain switch until the volume is identical on both channels? Maybe the gain switch or relay or surrounding circuitry got mad or something.


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## staxstax

i dont see a back side gain switch, it is the matrix stage HPA-3B
i also checked inside, (I only removed the cover)
can you tell me please where this switch can be?
i attach a photo
thanks


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## staxstax

photo


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## staxstax

i can not attach the photo


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## deafenears

Bottom left is where the gain switch is at.


----------



## staxstax

Thanks again for helping me
i already tried all three positions on the gain switch, the problem stays
if i listen to an orchestra the problem is not so big but on solo instruments guitar violin etc they all move to the left
connecting the ibasso dx200,  the headphone output (only there i can change the balance) to the HPA3B, i have to correct the balance on the dx200 6 lines to bring the guitar in the middle
the same headphones direct to the dx200 headphone output sounds perfect in the middle
i also tried different cables balanced or RCA


----------



## raoultrifan

When switching the gain switch, while listening to the music, was the volume changing on both headphones with the same amount (percentage)?

BTW, please post here your testing setup:
- Single-ended DAC and headphones used
- Balanced DAC and headphones use


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## staxstax

Hi
again Thanks a lot for the help
I really appreciate
I know almost nothing about electronics, because after 3 years there is no guaranty,
if it is completely broken i will give to a friend to play with and ...never matrix again
so yesterday I opened the case and I re-soldered the connections of the pot
and everything I could,
well it works now perfect, for how long I dont know
but right now I listen to a recent guitar recording (ibasso dx200  canare cable LV-77S to chord Hugo kimbel silver cables to Matrix single ended with the transformers) the guitar is right  in the middle
the headphones I use, with balanced and single ended cables are sony z7 ,  Audeze LCD-X creator new edition
denon 2000 sennheizer HD 600  Nad HP50only single ended
the problem was always there what ever items I used
also switching the gain the problem was the same on all three positions
I will try a Nad D 1050 balanced dac to see if the problem is gone
Thanks again for helping


----------



## raoultrifan

OK, so after resoldering the big ALPS potentiometer issue seems to go away, right?


----------



## staxstax

yes for the moment the problem is solved
also the balanced output of the NAD with the same balanced cables on all headphones work perfect
I dont know what was, I just re- soldered everything I could, at the back side of the plate
sometimes (very rare) stupid reactions of ignorant people give good results, I was just lucky


----------



## omegaorgun

If anyone feels like trading for a Jotunheim hit me up.


----------



## Atgm1

Guys, do not tell me how to get to the back of the board?  What bolts do you need to twist?


----------



## Atgm1

figured out


----------



## Atgm1

Atgm1 said:


> Guys, do not tell me how to get to the back of the board?  What bolts do you need to twist?


figured out


----------



## mikaelmark

staxstax said:


> yes for the moment the problem is solved
> also the balanced output of the NAD with the same balanced cables on all headphones work perfect
> I dont know what was, I just re- soldered everything I could, at the back side of the plate
> sometimes (very rare) stupid reactions of ignorant people give good results, I was just lucky



I also had the similar issue earlier this year, when I first listened to a well known headphone amp from a big manufacturer - but for me there was a lot of background noise/crackling all the time, mostly heared when listening at silent passages.

First tried to swap the OpAmp, but the noise still remained. I then unscrewed the PCB from the enclosure and when looking at the back of the PCB (secondary side), I found the six soldering for the Alp RK75 volume pot was horrifying! I assume the manufacturer had cut the pot pins with a nipper after soldering (see below montage picture and also see the included RCA cable with unsoldered middle pin).

About connecting the HPA3B to a balanced DAC and balanced headphone, how to do that as balanced standard has 4 pin DIN-connector? This headphone amp only has RCA line in and phone 1/4 (6,35mm) phono jack out, right?


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## mikaelmark

By default, this amp are having fast recovery rectifier diodes BYV27 (not the cheaper and slower "standard" 1N400x) bypassed with 0,1 uF capacitor for each diode to eliminate unwanted high voltage peakes.

But some people say those bypass cap´s should only been used for standard slow rectifier diodes, eventually also combined with a low ohm resistor in serial. If BYV27 has bypass caps, there may be a worser result as there will be a small amount of quiscent/leakage AC current.

Maybe it will be better if removing those 0,1uF bypass caps (the four square in the power supply)? Any thoughts?


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## raoultrifan

It's been 4 years since I bought this headamp and I'm enjoying this balanced headamp since then, feel free to read the first pages from this thread.

Today I was playing PVZ1 and Grid2 with Audeze LCD-2 Fazor + HPA3B and since about 2 hours I'm listening to music. 

AFAIK there is a standard bridge rectifier inside, place vertically, between transformer and the two big caps. However, the ripple & noise measured across opamps is somewhere below 1mV RMS (try to search my scope measurements from the beginning of this thread). I don't recommend replacing this bridge, because there will be no gain, other than messing with the internals and risking to do more damage than good stuff.

The only mods I might recommend would be:
- decreasing the rails voltage (this will lower the internal temps and provide the ability to use more opamps to roll)
- shield the transformer (only if you have audible hum)
- upgrade the four coupling caps with MKP 4.7uF instead of the default MKS 2.2uF (you need to measure twice, then do the purchasing).


----------



## raoultrifan

mikaelmark said:


> About connecting the HPA3B to a balanced DAC and balanced headphone, how to do that as balanced standard has 4 pin DIN-connector? This headphone amp only has RCA line in and phone 1/4 (6,35mm) phono jack out, right?



HPA-3B is the balanced one and HPA-3U is non-balanced, the one with built-in DAC inside, right?
However, there are 3-pin XLR to RCA adapters that can be used for line level.


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## omegaorgun (Nov 17, 2019)

raoultrifan said:


> It's been 4 years since I bought this headamp and I'm enjoying this balanced headamp since then, feel free to read the first pages from this thread.
> 
> Today I was playing PVZ1 and Grid2 with Audeze LCD-2 Fazor + HPA3B and since about 2 hours I'm listening to music.
> 
> ...



Does this affect the power output and can you do a guide on how to do that. Even in the wake of THX I crave another one and might be picking one up soon. I absolutely loved the OPA1656 in this, was super tight. Bass is so visceral and superior to a Jotunheim.ans perhaps more body to the sound over THX.


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## raoultrifan

No need to lower voltage rails to use OPA1656, as these are already supporting 36V, per http://www.ti.com/lit/ds/symlink/opa1656.pdf, unless you want to lower the internal temps. Also, check for overheating on the OPA1656, in case you want to use them inside HPA-3B or 3U.
Check out the first 10 pages or so from this thread, you should find many answer, measurements as well. If I remember well, for *60 Ohms resistive load*, after lowering power rails I got 1.05W/ch. from the initial 1.45W/ch in single-ended, and in balanced I got 3.45W/ch instead of 4.5W/ch., so plenty of power left anyway (for 32 Ohms power is higher anyway).


----------



## lugnut

staxstax said:


> the headphones I use, with balanced and single ended cables are sony z7


I too have a pair of Sony Z7, I use in balanced mode. Some people think the Z7 has boomy bass, I use them with a good balanced cable and I think they sound pretty good !


FireLion said:


> If anyone feels like trading for a Jotunheim hit me up.


Funny you ask, I had the Jotunheim when I received HPA-3B, I preferred the Matrix and sold the Jot.


raoultrifan said:


> It's been 4 years since I bought this headamp and I'm enjoying this balanced headamp since then, feel free to read the first pages from this thread.


That is about how long I have had my Matrix with no issues so far. I also have the older Matrix M Stage Amp, retired it, but still works great.


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## omegaorgun (Nov 25, 2019)

Reunited with another HPA-3B, time to dust off the OPA1656's I have but the bursons are pretty good too!


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## omegaorgun (Nov 25, 2019)

lugnut said:


> I too have a pair of Sony Z7, I use in balanced mode. Some people think the Z7 has boomy bass, I use them with a good balanced cable and I think they sound pretty good !
> 
> Funny you ask, I had the Jotunheim when I received HPA-3B, I preferred the Matrix and sold the Jot.
> 
> That is about how long I have had my Matrix with no issues so far. I also have the older Matrix M Stage Amp, retired it, but still works great.



I am waiting on a balanced cable for my Z7M2, can't wait. I think the internal DAC lets the Jot down but the HPA-3B is a superior amp regardless + opamps swapping!
I liked it so much that I obtained a second after selling my first, it even has qualities that are better than the 789 IMO depending on the opamps used.


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## omegaorgun

I inherited the one with the sparkos regulators, does anyone know why this mod was done and how it affects the amp overall?

I was getting some interference on med gain on certain tracks with v5i, swapped in the opa1656's and no issues.


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## raoultrifan

So you got a unit with 2x15V instead of 2x18V, great news then. You can roll more opamps now and temps will be lower, on some expense of the output power (it still have a huge power reserve anyway).

I got same noise myself too when tested the V5i, so there's sort of incompatibility for sure.


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## mikaelmark (Dec 21, 2019)

FireLion said:


> I inherited the one with the sparkos regulators, does anyone know why this mod was done and how it affects the amp overall?
> 
> I was getting some interference on med gain on certain tracks with v5i, swapped in the opa1656's and no issues.


I suppose this amp will work at 15 Volt from start, with LM317/337.

SparkoS discrete voltage regulators should give a much cleaner voltage signal. Just notice that the 1K1 Ohm should be removed and 100 Ohm should be shorted when using discrete voltage regs LM1117-15 and LM7915 (for 15 VDC).

https://sparkoslabs.com/discrete-voltage-regulators/

However, I have´nt tried the V5 or V5i, but those voltage regs combined with either V6 Vivid or SparkoS SS3602 has not gave any noticeable noise. I must say SS3602 in this amp are will give a truly phonomenal sound!


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## raoultrifan

The original HPA-3B is powered from +/-18V (JRC7818/7918 regulators), whike FireLion's version is powered from +/-15V (Sparkos 7815/7915). There is no need to remove any resistors, please check first pages of this thread for detailed pictures.

With the original regulators, the AC ripple and noise was lower than 1mV RMS, so quite good.

V5i are not compatible with this headamp, but I suggest you to try V6 and compare the sound with SS3602.


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## mikaelmark (Dec 8, 2019)

raoultrifan said:


> The original HPA-3B is powered from +/-18V (JRC7818/7918 regulators), whike FireLion's version is powered from +/-15V (Sparkos 7815/7915). There is no need to remove any resistors, please check first pages of this thread for detailed pictures.
> 
> With the original regulators, the AC ripple and noise was lower than 1mV RMS, so quite good.
> 
> V5i are not compatible with this headamp, but I suggest you to try V6 and compare the sound with SS3602.



I have tried both the V6 Vivid, SS3602, NewClassD and Orange discretes and to me the SS3602 are the best - working at really high BIAS Class A (altogh the other competiters are not bad). I´m curious about the SS2590, but it´s a pro-version with a really high price and are really huge!

BUT, the amp I´m using are based on the Lovely Black Cube with LM317/337 (SS1117-15/SS7915) and not the HPA-3B! (I supposed they both were similar)

At this moment, I´m about to replace the four parallel 0,1uF caps for the rectifier diodes with a snubber mod, with a 0,33uF film cap and a 330 Ohm resistor in series for transformer secondary side (before the heat fuses), as this should make the a cleaner signal with less AC in the Power supply!

Below is the schematic for the LBC amp with the snubber (green and blue). Are there any other difference to the HPA-3B? (mine has BYV27-200 and not the slower 1N400x)


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## Carlitoss12345

ebay link for volume knob from post 407?


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## omegaorgun (Feb 7, 2020)

Carlitoss12345 said:


> ebay link for volume knob from post 407?



Hi I bought it like that and think it is a generic 30mm.

https://www.aliexpress.com/item/326...chweb0_0,searchweb201602_5,searchweb201603_55

https://www.amazon.com/Taiss-Aluminum-Electronic-Potentiometer-Knob，Electric/dp/B07F26WT4R/ref=sr_1_18_sspa?keywords=30mm+volume+knob&qid=1581112468&sr=8-18-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUE4STBEUElZQUQ3NVomZW5jcnlwdGVkSWQ9QTAzNjAyMjkxTVRPUTUwTjU0Nk8xJmVuY3J5cHRlZEFkSWQ9QTA5MzYwNTkzRzQ5Q01XM043T1ZXJndpZGdldE5hbWU9c3BfbXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==


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## omegaorgun

mikaelmark said:


> I have tried both the V6 Vivid, SS3602, NewClassD and Orange discretes and to me the SS3602 are the best - working at really high BIAS Class A (altogh the other competiters are not bad). I´m curious about the SS2590, but it´s a pro-version with a really high price and are really huge!
> 
> BUT, the amp I´m using are based on the Lovely Black Cube with LM317/337 (SS1117-15/SS7915) and not the HPA-3B! (I supposed they both were similar)
> 
> ...



My chips are on the opa1656 haven't had any issues, I might try the bursons again.


----------



## Dobrescu George

I have made a Youtube Video Retrospective review about Matrix HPA 3U, it is an excellent unit that I always wanted, and it still holds up to its name  

If anything would be a disadvantage for it, it tends to get pretty hot, and it tends to be a tad bright, but this also means it pairs really well with warmer headphones / IEMs


----------



## omegaorgun

Dobrescu George said:


> I have made a Youtube Video Retrospective review about Matrix HPA 3U, it is an excellent unit that I always wanted, and it still holds up to its name
> 
> If anything would be a disadvantage for it, it tends to get pretty hot, and it tends to be a tad bright, but this also means it pairs really well with warmer headphones / IEMs




Try two OPA1656 opmaps! https://www.ebay.com/itm/OPA1656-So...490556?hash=item365ca412bc:g:tJgAAOSwLIZeD4j8

Yes it gets hot, wish they made a class A/B version with similar shape to 789.


----------



## paulusek

One opamp enough for HPA 3U .


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## omegaorgun

paulusek said:


> One opamp enough for HPA 3U .



I also suggest that OPA 1656 it's one of Texas instruments lowest measuring opamps ever. It hasn't the widest sound stage but it has a very tight sound across the range.


----------



## omegaorgun

How many of you have the HPA-3B? with the opa1656 I am preferring it to my 789.


----------



## Filipash

FireLion said:


> How many of you have the HPA-3B? with the opa1656 I am preferring it to my 789.


I am running opa 1656 in my hpa 3b , was planning to lower the voltage to 16v but my hd6xx are power hungry , it's running hot , but not big differences in temperature from stock


----------



## raoultrifan

I'm still on OPA1652, because with OPA1656 the DC-output was a bit higher. With OPA1652, in HPA-3B, I get lowest DC and lowest background noise, but of course YMMV.


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## omegaorgun (Apr 14, 2020)

raoultrifan said:


> I'm still on OPA1652, because with OPA1656 the DC-output was a bit higher. With OPA1652, in HPA-3B, I get lowest DC and lowest background noise, but of course YMMV.



Interesting, both from the same family so sound is probably similar. I wasn't overly impressed with sound initially but over time it opened up or grew on me. Right now it sounds fantastic with an SU-8.

it does run warm, my unit came pre fitted with sparkos regulators. I might opamp roll this week and I remember having issues with the bursons but appear to have two different looking sets to test.


----------



## rodel808

I have an unmodified fully stock hpa-3b and want to try swapping out the op amp. Is the opa1656 simply just a swap and drop replacement? Also is there a list of op amps that I can try that will work in this amp?


----------



## raoultrifan

https://www.ti.com/product/OPA1656 - just SOIC8 package, so you need to DIY on adapters.


----------



## Filipash

rodel808 said:


> I have an unmodified fully stock hpa-3b and want to try swapping out the op amp. Is the opa1656 simply just a swap and drop replacement? Also is there a list of op amps that I can try that will work in this amp?


https://www.ebay.com/itm/124186391989


----------



## lambdastorm

raoultrifan said:


> The original HPA-3B is powered from +/-18V (JRC7818/7918 regulators), whike FireLion's version is powered from +/-15V (Sparkos 7815/7915). There is no need to remove any resistors, please check first pages of this thread for detailed pictures.
> 
> With the original regulators, the AC ripple and noise was lower than 1mV RMS, so quite good.
> 
> V5i are not compatible with this headamp, but I suggest you to try V6 and compare the sound with SS3602.


Are you suggesting that there are two revisions of this amp?


----------



## omegaorgun

lambdastorm said:


> Are you suggesting that there are two revisions of this amp?


No the one I bought is modded. I can use burson in it but it's better with opa1656 imo.


----------



## lambdastorm

FireLion said:


> No the one I bought is modded. I can use burson in it but it's better with opa1656 imo.


Oh okay. I just bought one, hope it sounds good enough


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## omegaorgun (May 13, 2021)

lambdastorm said:


> Oh okay. I just bought one, hope it sounds good enough


IMO it's fantastic, more natural sounding than a 789 and double the power @ 300/600 Ohm.

Here are my recommendation on op amp. It doesn't look fancy but it is one of Texas instruments latest and greatest and cheap.

https://www.ebay.com/itm/333850298075


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## rodel808

FireLion said:


> IMO it's fantastic, more natural sounding than a 789 and double the power @ 300/600 Ohm.
> 
> Here are my recommendation on op amp. It doesn't look fancy but it is one of Texas instruments latest and greatest and cheap.
> 
> https://www.ebay.com/itm/333850298075


Will these opamps  work with a stock amp? I currently run mines with sparkos opamps. I think they sound great but I'm open to try something different.


----------



## omegaorgun

rodel808 said:


> Will these opamps  work with a stock amp? I currently run mines with sparkos opamps. I think they sound great but I'm open to try something different.


Yes it should work fine. 

Can I see a pic of the sparkos? I wanted to get a similar looking one but not sure if it would fit.


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## rodel808

FireLion said:


> Yes it should work fine.
> 
> Can I see a pic of the sparkos? I wanted to get a similar looking one but not sure if it would fit


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## omegaorgun

rodel808 said:


>



Thanks, do you know what the dimensions are on that one?


----------

