# iBasso P3 Opamp Rolling Thread *Let the rolling begin!



## HiFlight

I copied this thread title from the "Full-size Amps" forum, as it probably more correctly belongs here. Thanks to Lucifix for beginning this thread, which undoubtedly will grow to some great length! 

 I spent considerable time tonite running thru part of my opamp supply, namely the ones that I thought would most likely show promise in the P3. I was comparing each to the D3 as many folks really like the presentation of that amp. 

 Phones used were my JVC DX-1000s and recabled RS1s. 
 Source was iRiver H140 line out. 
 P3 gain was set to 10 (high) as I wanted to check max driving ability. 
 Music was high bitrate MP3 both vocal and classical. Sorry, no rock tonite!

 I will list the different combinations with a few comments I made as I ran thru the changes. 

 I found that, indeed, the P3 has great potential and is capable of matching the sound quality and soundstage of the D3. 

 I also should mention that a number of different combinations sounded very similar, and it would probably take better ears than mine to detect the very subtle differences, if any. 

 To cut to the chase, I will first list my top 2 favorites. 
 1. LME49720 in LR, iBasso buffers, and THS4032 in ground. 
 This combination just sounds really right, soundstage, tonal 
 accuracy...it has it all. Probably not real great on battery 
 life, but, hey...that's what AC adapters are for, right??

 2. ADA4841-2 in LR, iBasso buffers, ADA4841-2 in ground. 
 This is about an exact replication of the D3. So far, it is as 
 close as I have been able to come. I doubt I could reliably 
 tell the difference. Battery life should be excellent. 

 Additional combinations, in no specific ranking, are as follows: 

 OPA2111 LR, bypassed buffers, ADA4841-2 ground: large soundstage, a bit bright. 

 ADA4841-2 in both LR & ground...bypassed buffers
 A little brighter than the D3, lively & detailed. Expect very long battery life.

 THS4032 LR, buffers bypassed, OPA2134 ground...dynamic and punchy..probably very good rock combo. 

 OPA2134 LR, buffers bypassed, THS4032 ground...better balanced than above. 

 AD746 LR, bypassed buffers, ADA4841-2 ground...nice soundstage, highs a bit recessed. 

 ADA4841-2 LR, bypassed buffers, LMH6643 ground...rather narrow soundstage that is back aways from the listener. Similar to that heard with crossfeed. 

 LT1028 LR (x2) sibilant with anything I tried with them. 

 Good ground opamps: 

 The THS4032 is very low noise, and can output a lot of current and is stable at a gain of 1, which makes it an ideal ground opamp. It lives up to its specs, IMO. 
 AD8599, neutral, nice balance. 
 AD8066 wide soundstage, detailed bass. 
 OPA2134..nice allaround performer. 
 LMH6643...works very well with ADA4841 & AD8066
 Generally speaking, the iBasso buffers add some body and warmth as well as more output current. I did try the BUF634, a very much-used buffer, but preferred the sound of the iBasso-supplied buffers in most cases. 

 I tried several combinations using the AD8599 and OPA2134 in LR, in addition to using them in the ground channel socket. They both sound quite similar and work well, sounding very well-mannered with all types of music, especially with buffers and the THS4032 in the ground channel. 


 I think that the P3 is capable of driving any dynamic phones that currently on the market, as I never even began to approach the limits of the P3 output while running the tests. 

 I have more combinations to try, but I was reaching the point where everything was beginning to sound alike, so I knew it was time to hang it up for the evening, and just listen. 

 I will keep the LME49720/buffer/THS4032 combo in my P3 for awhile and see how it wears on me for several days.

 All of the above comments are my opinions only. YMMV!!!!


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## gooky

Thanks for the information HiFlight, it's really good information for people who don't know what the different opamps will do. It's funny how you say these are only your opinions, but I think that most people who are just starting out (like me) will read them like they were the gospel truth. Looking forward to more impressions/ information, and thanks again.


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## lucifix

Sorry for the duplication of posts, I've decided to move the P3 hissing issue to the opamp rolling thread because it is more relevant to opamps.

  Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_ Quote:


  Originally Posted by *lucifix* /img/forum/go_quote.gif 
Ok I was running the Heron in its stock opamp configuration with the Transister Buffer being used, and encountered a serious problem and was wondering if any other P3 owners experience the same problem.






 I have the P3 in low gain setting, and had my UM2's on with no music playing.

 Adjusting the volume pot within the range of the first two dots as shown in the diagram where the red arrow indicates the range of volume pot adjustment, I heard lots of unwanted noise.

 I will try to describe it to the best of my ability but have included a direct-download link to the .WMA file which I have tried to record the sound with success by attaching my voice recoreder input to the output of the Heron.

http://rapidshare.com/files/152895478/DS300076.WMA

 What I heard was a shrill whistling sound that was never before heard in my Viper. This sound was very persistent and there was lots of white noise also, and only untill I move the volume pot past the second dot, where it would be pitch black and then noisy again, with lots of white noise.

 Whilst recording I first turned on the unit with music playing and turned it to the second dot, where I then stopped playing music and turned the knob back down again.

 Please let me know if anyone else has been experiencing this and if I should return this to iBasso.

 Btw, I have given the P3 a good 24 hour burn in period with the buffers as I thought the problem will go away after that.

 Thanks.

 

I have tried to duplicate this with my Heron and UM2s but I get normal sound, albeit at extremely low volume position due to the extremely sensitive UM2s. Your recording sounds like it has some 60hz hum in it. Running on batteries, there should be none. I would first try unplugging the DC adapter, if you are using it. Then try a different source using different interconnect cables. 

 If the problem persists, try changing the LR opamp and putting in the bypass buffers. 

 If problem persists, back to Dr iBasso for them to fix. 

 That sound is usually due to an opamp artifact, but can be mimiced by cables, etc. 

 FWIW, my Heron is running the LTC6241HV, iBasso-supplied transistor buffers, and an OPA2134 opamp in the ground channel. 

 Good luck, and post your results of the above trials. 

 HiFlight_

 

I swapped the opamp combination to the LMH6655MA LR with the 6241HV 3/4 with transistor buffers and the whistling sound is gone.

 This isolates the problem and I think it is caused by the AD797's.

 HiFlight, do you have similar whistling and hissing sounds with dual AD797's? (in its stock configuration)
 I may have to get iBasso to send replacement opamps 
	

	
	
		
		

		
		
	


	




 The most amazing thing about swapping opamps is how much difference it can make! When I tried again with the 6655 and 6241's, it was totally pitch black, even quieter than my stock viper which was considered relatively silent with absolutely no hissing at the first four notches of volume.

 Furthermore, with this combination it just made my music come alive with every singer coming forward.

 I read on the Viper opamp rolling thread that you had lots of praise for the 6655's, in your opinion, how do they sound in the Heron?

 This opamp rolling thread is really interesting and I can't wait to order more samples to fill the empty browndogs. Oh and just for fun, I even created a little opamp farm L@@K


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## HiFlight

HiFlight;4849223 said:
			
		

> ........................snip....................
> 
> To cut to the chase, I will first list my top 2 favorites.
> 1. LME49720 in LR, iBasso buffers, and THS4032 in ground.
> ...


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## jamato8

I have tried the 49720 over and over and even in my LD Micro tube amp but it and the 4572 just don't sound musical after a while. To me they are plastic sounding. So many choices and so much soldering to do. :^)


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## HiFlight

Quote:


  Originally Posted by *jamato8* /img/forum/go_quote.gif 
_I have tried the 49720 over and over and even in my LD Micro tube amp but it and the 4572 just don't sound musical after a while. To me they are plastic sounding. So many choices and so much soldering to do. :^)_

 


 John...
 That has been my experience also, many like the 49720, but many times I have found it unstable. This time I thought it would work, but with anything less than top line components and source, it doesn't sound very good. It is one opamp that I am ready to give up on. Too bad I have quite a few of them. 

 Ron


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## HiFlight

I tried 2 more opamp combinations, both of which sounded very good. First: LR AD8397, bypassed buffers, THS4032 in ground. Very dynamic sound with excellent detail. Treble a bit on the bright side so this would suit darker phones such as the Sennheisers. 

 Second combination, which I like even better with my phones and personal musical preferences is: 

 LR: ADA4841-2, iBasso buffers, OPA2134 in ground. Sound is nicely detail and soundstage is further back than the AD8397 combination. This is a very natural sounding combination for IEMs.
 and also works very well with my RS1s.

 FWIW, I still have not been able to match the expansive soundstage and openness of the D3.


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## lucifix

HiFlight, 

 Was just wondering if you have similar whistling and hissing sounds with dual AD797's in the P3? (in its stock configuration)


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## HiFlight

Quote:


  Originally Posted by *lucifix* /img/forum/go_quote.gif 
_HiFlight, 

 Was just wondering if you have similar whistling and hissing sounds with dual AD797's in the P3? (in its stock configuration)_

 

IIRC, I had some sonic artifacts that caused me to no longer consider the AD797s for the P3, but I don't recall exactly what they were. When I get a chance, I will retry them and see what happens. They are usually a really good choice for LR in most amps. They are Analogs answer to the OPA627. 

 Sometimes, for a variety of circuit-related reasons, an opamp just doesn't work out in practice the way the data sheets would indicate that they should. The ears are better guides than any test equipment!


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## HiFlight

Finally after a lot of time spent comparing the P3 to the D3 and trying to get the soundstage, imaging and tonal accuracy of the Heron to match that of the Python, I think I happened across a combination that is probably about as close to the same as is possible to get, considering circuit differences, etc. 

 The setup is: AD8066 in LR, buffers bypassed with iBassos supplied dummy opamps, and an LMH6643 in the ground channel. Gain is set to 10. (Jumpers set to opposing sides of the 2 sets of connectors)

 The sound of this P3 configuration presents an effortlessly wide soundstage, and is well-balanced across the audio spectrum. Instruments sound real, not like they have been recorded. Vocals are especially pleasing. 

 Try it, you'll like it!!


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## HiFlight

After further testing and trials, I have yet to find a better sounding P3 combination than that mentioned in the previous post. AD8066/LMH6643!


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## lucifix

Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_After further testing and trials, I have yet to find a better sounding P3 combination than that mentioned in the previous post. AD8066/LMH6643!_

 

Ron,

 After reading the specs of the 6643 on the company's website at LMH6643 - Low Power, 130MHz, 75mA Rail-to-Rail Output Amplifiers
 there are so many variants that I do not know which one to get.

 Is the 6643 you use LMH6643MA, or LMH6643MAX?

 Its confusing! Same thing goes for the AD8066


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## littletree76

Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_After further testing and trials, I have yet to find a better sounding P3 combination than that mentioned in the previous post. AD8066/LMH6643!_

 

I have tried the exact configuration with good result, thank you for the recommendation. With recommended dummy opamps, P3 can even drive AKG K601 reasonably well without current output of transistor buffers. This combination really benefit from burn-in as initial impression was not really good. I will let it break in for at least 100 hours and see how it go.

 I purchased AD8066ARZ (dual/SOIC8) and LMH6643MA (dual/SOIC8) from local Farnell store. I suppose alphabets after part numbers of opamps denote only working temperature, packaging and other parameters which should not affect sound quality. The basic parameters of opamps with same part number should remain the same.

 I notice one channel is slightly louder than the other channel. Wonder whether the slight imbalance is caused by overheating when trying to clear solder short between pins with 23W soldering iron. I though dual opamp should have better balance than individual single opamps. After restored back to stock opamp configuration (single AD797 x2 in L/R, dummy x2 in buffer and dual LM6172 x1 in 3/4) and burned in for short period, the imbalance still exist thus I suppose it has nothing to do with opamp rolling.

 Does single opamp usually provide better specification and performance than equavalent dual opamp ? Will there be any improvement if I switch a dual LMH6643 with a pair of single LMH6642 and dual AD8066 with a pair of single AD8065 ? Beauty of P3 design is it allows dual or single packaging with the same SOIC-to-DIP adapter (always one opamp unit on a adapter).


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## HiFlight

I have not noticed differences between the dual and single versions of the same opamp. 

 It is possible but not likely that the imbalance was caused by overheating. That will usually kill an opamp rather than affect its sound. You might make sure it is seated completely and that the pins all make good contact. You might try cleaning the pins and re-installing.


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## shadowmoses

Am currently using ADA-4841-2/THS4032. Bass is very strong, although overall it's pretty balanced. is there a combination that's tailored toward IEMs?


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## WindowsX

Here's mine

 L/R: AD797AN (Not ones from stock but ones mostly used in model like HR-2 and Apache)
 Buffer: Transistor buffer (Still looking for BUF634)
 3/4: OPA627BP (Yeah...BP...superb power opamp with magic)

 Sound.....What should I expect from ones of the best for preamp plus ones from output power combo?


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## Angsila

WindowsX

 Where in Thailand did you buy the opamps?


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## apple

Suggestions...


 Sorry that you didn't like the LT1028 - it seems like the amp didn't put it at ease. One of its best traits should be silkiness. Very low gain might be the reason. From LT try to hear the LT1357 too, that's easier to use than the LT1028 and easily sounds mellower.

 The OPA2132 is better than the OPA2134, and the LT1357 sounds better than both.

 The OPA211 is a wonderful new audio opamp from TI. Try it! It's even rail to rail, which in low voltage applications will be precious.

 From Linear Technology it is also worth trying the very musical LT1122.


 The LME49710 has disappointed me. It destroys the original tonality of records, no matter where I've tried it. Very unmusical. Also the AD8066 sounded tonally unnatural to me, and rough in the upper mids.


 Finally, purely from hearsay - the AD825 should e quite musical.


 BTW, I like the THS4031/2 a lot too.


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## jamato8

Yep, at first the 49710 can sound ok to pretty good but it doesn't hold up to further listening. Too bad as it was supposed to be the next best thing.


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## HeadphoneAddict

So, is the working theory that "apple" was "shopper"? I ask because his writing style has changed.


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## WindowsX

After getting BUF634, here's my new settings.

 1/2: OPA627BP
 Buffer: BUF634
 3/4: OPA637BP

 637BP has more details and sounds brighter. I've tried combination with AD797, AD744, AD8620, AD4841-2 and such but this seems to be only one acceptable for harshness with vocals.


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## arvee

My P3 setting primarly with DT880 03...i decided to play a little with 3/4 amp...3/4 amp i think it GND and VGND and it's related to input ground and output ground, so there's so much more configuration could be with different single op amp at 3/4 amp...for now i like :

 1/2 chnl : OPA2604
 Buffer : By Pass
 3 chnl : NE5534
 4 chnl : AD797

 this setting for DT make a good separation, has good low end, nice vocal, and could makes DT880 03 become an allround genre cans


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## HiFlight

I have had a chance to try out a few different opamp combinations in the P3. Some of the better trials are listed below: 

 1. LT1358 LR, iBasso buffers, THS4032 ground: 
 Powerful, lots of impact. Upfront soundstage. Should work well 
 with hard-to-drive phones. Linear makes some nice-sounding opamps. 

 2. TI 2211 LR, iBasso buffers, TI2211 ground:
 Very neutral, open-air sound. Lots of detail, somewhat distant soundstage. Should provide very good battery life. 

 3. TI2211 LR, iBasso buffers, LM6655 ground:
 Bright, lots of detail, very nice soundstage. 

 THS4032 LR, iBasso buffers, LMH6643 ground:
 Very nicely balanced, and detailed, Very nice imaging. 

 The TI 2211 is quite similar in its specs and power requirements to the ADA4841-2. Not surprisingly, it sounds very similar. It is also a very inexpensive opamp.

 I will later try some combinations using the LT1358 as a buffer. It has characteristics that should make it a good performer in that position, maybe better than in LR.


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## shadowmoses

I have a problem with the P3 Heron. It is quite susceptible to external EMF radiation, specifically from handphones. I will hear that irritating beeping sound through my earphones whenever a handphone nearby is active! This is a HUGE problem when listening to my rig on the go given that Singapore has more handphones than people and when we're all tightly clustered in a packed subway.

 Does anyone know a mod to block out the handphone radiation?

 On a side-note, the ADA 4841-2(LR)/THS4032(GD) combi wasn't too good. The 4841/6643 combi was a winner when paired with the TripleFi 10Ps. Hoping to get more Gd opamps to try with the 4841-2.


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## HiFlight

Quote:


  Originally Posted by *shadowmoses* /img/forum/go_quote.gif 
_I have a problem with the P3 Heron. It is quite susceptible to external EMF radiation, specifically from handphones. I will hear that irritating beeping sound through my earphones whenever a handphone nearby is active! This is a HUGE problem when listening to my rig on the go given that Singapore has more handphones than people and when we're all tightly clustered in a packed subway.

 Does anyone know a mod to block out the handphone radiation?

 On a side-note, the ADA 4841-2(LR)/THS4032(GD) combi wasn't too good. The 4841/6643 combi was a winner when paired with the TripleFi 10Ps. Hoping to get more Gd opamps to try with the 4841-2._

 

I have noticed the RF interference in all of my portables to some degree or another. Separating the amp/cables from the telephone is about the only way...as power decreases with the square of the distance, it doesn't take much, like just on the other side of the seat. 

 FWIW, the ADA4841-2 is more suseptable to RF than any of the other opamps I have tried. 

 Some other good opamps to try: 

 AD8599, LMH6622, LTC6241HV, ISL55002, AD8066, OPA2111 OPA2604, AD746, LM6172 LT1358. Don't overlook some oldies, like the OPA2227. The best sounding opamp I have ever used is the AD743. It draws quite a bit of quiescent current, but if you are using external power, this is a moot point. 

 Believe it or not, the LMH6643 sounds good in LR also. 

 Lowest current draw opamps are: ADA4841 and TI2211.


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## berniebennybernard

A little offtopic, but I just ordered a P3 off iBasso.com with PayPal, but after I paid and I clicked on return to iBasso.com, it sent me to http://www.ibasso.com/us/thankyou.as...rn+to+Merchant

 And that gives me an error: HTTP/1.1 404 Not Found

 Just wondering if it happened to you guys and it's all fine.


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## littletree76

Quote:


  Originally Posted by *shadowmoses* /img/forum/go_quote.gif 
_I have a problem with the P3 Heron. It is quite susceptible to external EMF radiation, specifically from handphones. I will hear that irritating beeping sound through my earphones whenever a handphone nearby is active! This is a HUGE problem when listening to my rig on the go given that Singapore has more handphones than people and when we're all tightly clustered in a packed subway._

 

I tested my P3 with Nokia N81 for the EMI issue. Music was played on iPod nano with P3 connected to it through LOD and ESW9 portable headphone was used for monitoring.

 When the handphone was stacked on top of P3 and a phone call was made to the mobile phone, loud peeping noise could be head. But when the handphone was transferred from top of P3 to the side of P3, the noise disappeared completely. Radio wave and hence EMI definitely susceptible to orientation and distance between devices. Even in a packed subway, orientation and distance must be right (unlikely unless handphone is with your girl friend) to cause interference.

 Running out of empty opamp adapter (SOIC8 to DIP8) for opamp rolling. Any idea which online store selling cheap adapter ? Does iBasso offer empty adapter for purchase ? iBasso should have offered various customer recommended opamps for online purchase instead of bundling some free ones with P3. Customer should be allowed to pick a set of opamps on purchasing P3 at iBasso online store, thus no unused opamp is wasted and price of P3 can be lowered (remove unreliable power adapter and pouch from P3 bundle as well).


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## HiFlight

Quote:


  Originally Posted by *littletree76* /img/forum/go_quote.gif 
_Running out of empty opamp adapter (SOIC8 to DIP8) for opamp rolling. Any idea which online store selling cheap adapter ? Does iBasso offer empty adapter for purchase ? iBasso should have offered various customer recommended opamps for online purchase instead of bundling some free ones with P3. Customer should be allowed to pick a set of opamps on purchasing P3 at iBasso online store, thus no unused opamp is wasted and price of P3 can be lowered (remove unreliable power adapter and pouch from P3 bundle as well)._

 

It would be extremely costly for iBasso to stock the dozens of opamps that can be used successfully in the P3. They included a very nice assortment of free opamps. Thats more than any other manufacturer provides with their amps. 

 If you want some special opamps, you can PM me for information. 

 You can buy adapters here: SO8 to 8-pin DIP Adapter (p/n 970601)


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## HiFlight

I spent some more hours tonight testing some different combinations of opamps in the P3. 

 Phones used for testing were my recabled RS-1s and ATH-ESW10s and the source was my iRiver CF32. 

 1. LT1358 LR, iBasso Buffers, LT1358 Ground:
 Laidback, smooth highs, good soundstage. 
 Without buffers, more upfront, wider soundstage.

 2. LMH6622 LR, bypassed buffers, LT1358 Ground:
 Forward mids, detailed. Good for vocals, acoustics, etc. 

 3: LMH6622, bypassed buffers, LMH6643 ground:
 Nice overall balance and detail. Could live with this one. 

 4: Pick of the night! 
 LMH6655 LR, bypassed buffers, LMH6643 ground: 
 Warm, tubey sound. Very smooth, good soundstage. 
 Tamed highs that tend to be prominent in Grados. 

 Added iBasso buffer: Smoother highs. Volume about the same with or without buffers. 

 This is a combination that one would likely not pick based on datasheet specs, but it sounds better than expected. 

 I find that the iBasso-supplied transistor buffers sound markedly better than BUF634.


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## knights

my p3 is yet to arrive on thursday.... so, what opamp is used by default (new p3), and how's the SQ? do i need some soldering iron or other stuff in changing the op-amps?


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## knights

tok tok tok!!!!


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## HiFlight

Quote:


  Originally Posted by *knights* /img/forum/go_quote.gif 
_my p3 is yet to arrive on thursday.... so, what opamp is used by default (new p3), and how's the SQ? do i need some soldering iron or other stuff in changing the op-amps?_

 

You need the T-6 torx bit, (one is now included, IIRC) and something to hold the opamp adapter with, such as tweezers, hemostat, etc. No soldering required. You MUST be very careful to observe correct polarity, or goodby opamp. iBasso has included very detailed diagrams to prevent such boo-boos. 

 Mine came with the AD797s installed and the dummy buffers installed, as I recall. 

 Many different opamps will work well in the P3, all of which very slightly change the response and soundstage. 

 I would suggest listening to the stock setup for awhile to familiarize yourself with the sound prior to changing opamps. 
 Write down each combo and your impressions, as you will be unable to remember all of them.


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## knights

*HiFlight*

 Thanks.... of all the combos with the *included op-amps*, what do you prefer and what headphone are you using with the said combo? i have no plan of buying any other op-amps thats why im asking... and if there's a combo (included op-amps) suited for IEM in general (low gain+longer battery+good soundstage-to compnsate IEM's natural weakness)what it will be?


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## berniebennybernard

Does anyone have a Tomahawk and can compare?


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## berniebennybernard

Oh snap, I ordered my P3 on Friday, and it arrived this afternoon. Seems that DHL shipping from China to Vancouver only takes a couple days (from previous experience as well).


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## knights

*berniebennybernard*

 i still dont have mine.... hope its gonna be here this afternoon or tomorrow


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## berniebennybernard

Just wondering, but when you guys say gain, is it like a switch somewhere in the board or do you mean the volume? 

 EDIT: Nevermind, looked closer and there's a jumper for it.


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## knights

i was also to ask same question but im still waitin for my unit to come to see if theres a knob, buton, or lever switch for this like most of portable amp...


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## berniebennybernard

Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_After further testing and trials, I have yet to find a better sounding P3 combination than that mentioned in the previous post. AD8066/LMH6643!_

 

Those are aftermarket OPAMPs I assume? May I ask where you got them?


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## HiFlight

After countless hours of opamp rolling and testing various and sundry combinations, I finally happened across a combination that , at least to my ears, surpasses the overall SQ of the D3. 

 The soundstage is a bit wider and the overall sound a little warmer, but very lifelike with all genres of music I tried. Vocals and solo instruments are very 3-dimensional, a trait that many felt the D3 excelled in. 

 The good news is that this combination sounds better than anything else I have tried...the bad news is that the new combo includes the nearly extinct AD743JN and battery life will likely be reduced. 

 For this latest and best combo, I am using the AD743 in LR sockets (it is a single-channel opamp) the iBasso dummy opamps in the buffer sockets, and the LMH6655 in ground socket. 

 Cost of the AD743 is now right up there with that of the OPA627, but at least it can be made available. 

 Now for a looonnng rest from playing with tiny chips!


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## berniebennybernard

Is the ground socket everyone talks about the 3/4 amplifier socket in the manual? (I'm new to rolling opamps (I did only get my P3 this afternoon, used a Penguin Caffeine Ultra prior)). And may I ask what the buffer sockets do? I asked a friend who's into sound stuff and he has never heard of it.

 Also, what version of the LMH6655 do you have? I'm looking online and there seems to be several versions of them.

 EDIT: Lastly, when I get my op-amps, will they be ready to be inserted or do I have to solder them to the dummy ones that come with the amp?


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## HiFlight

Quote:


  Originally Posted by *berniebennybernard* /img/forum/go_quote.gif 
_Is the ground socket everyone talks about the 3/4 amplifier socket in the manual? (I'm new to rolling opamps (I did only get my P3 this afternoon, used a Penguin Caffeine Ultra prior)). And may I ask what the buffer sockets do? I asked a friend who's into sound stuff and he has never heard of it.

 Also, what version of the LMH6655 do you have? I'm looking online and there seems to be several versions of them.

 EDIT: Lastly, when I get my op-amps, will they be ready to be inserted or do I have to solder them to the dummy ones that come with the amp?_

 

Yes, the ground channel is the 3/4 channel mentioned in the instruction sheet. This opamp used in this location effectively separates the ground channels from one another. 

 A buffer referred to in amplifiers is a device such as an opamp or transistor that matches impedances from one amp stage to another. They can be unity gain but usually are capable of producing additional current than the preceding stage alone can provide. 

 Sometimes, buffers are not required as the various circuit impedances match satisfactorily without the necessity for a buffer amp. In many cases, fewer components in the signal path can result in less coloration of the sound resulting from phase changes, capacitances, inductances, etc that are inherent in nearly all electrical components. Sometimes the changes are subtle, sometimes undectable, sometimes very noticeable. 

 Generally, if one uses low-impedance phones, the additional current provided by a buffer stage can be advantageous if one listens at high volume levels. 

 It doesn't make any difference what version of LMH6655 you choose, as long as it has an SOIC case style. Usually the last letters refer to packaging and this often determines the minimum order number. In DIP style opamps, the last letters often refer to temperature ranges in which the opamp can meet its design specs. I use LMH6655MA-ND.

 The opamps that are provided by iBasso are already mounted on adapters and are "Plug & Play" They also include one set of dummy opamps for the buffers and one set of empty adapters that you can solder your own opamps on, if you like. 

 If you order your own opamps, you will need to also purchase SOIC to DIP adapters and solder the opamps to the adapter. 
 To give you an idea of the size of the soldering, it is like soldering the legs of a lady-bug to a circuit board, the opamps are about that size. 

 Any opamps I provide are mounted and ready to insert.


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## berniebennybernard

Thanks for the information Ron, I appreciate it.

 Lastly, does anyone have trouble fitting 6AAA batteries into their P3? I just got all of my AAA and they don't fit. I can fit max of 5.

 EDIT: Nevermind, inserted the ends wrong!


----------



## denging

Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_After countless hours of opamp rolling and testing various and sundry combinations, I finally happened across a combination that , at least to my ears, surpasses the overall SQ of the D3. 

 The soundstage is a bit wider and the overall sound a little warmer, but very lifelike with all genres of music I tried. Vocals and solo instruments are very 3-dimensional, a trait that many felt the D3 excelled in. 

 The good news is that this combination sounds better than anything else I have tried...the bad news is that the new combo includes the nearly extinct AD743JN and battery life will likely be reduced. 

 For this latest and best combo, I am using the AD743 in LR sockets (it is a single-channel opamp) the iBasso dummy opamps in the buffer sockets, and the LMH6655 in ground socket. 

 Cost of the AD743 is now right up there with that of the OPA627, but at least it can be made available. 

 Now for a looonnng rest from playing with tiny chips!_

 

hi ron, i'm kinda new here... i wonder what gain-set do you use in your magnificent combo there? is it 3 or 10 ? and since the AD743 seems to be long gone here in indonesia, what substitute opamp do you recommend to -at least- reaching out the same star.... LOL... thx ron..


----------



## HiFlight

Quote:


  Originally Posted by *denging* /img/forum/go_quote.gif 
_hi ron, i'm kinda new here... i wonder what gain-set do you use in your magnificent combo there? is it 3 or 10 ? and since the AD743 seems to be long gone here in indonesia, what substitute opamp do you recommend to -at least- reaching out the same star.... LOL... thx ron.. 
	

	
	
		
		

		
		
	


	


_

 

I use a gain of 10 with the P3 "Topkit" 

 Yes, unfortunately the AD743JN is very difficult to find, as it has been discontinued and I have not been able to find a substitute. Fortunately, I acquired some of them when they were still in production. 

 For Head-Fi members who do not wish to solder, I can make the Topkit (2x AD743, 2x sockets, and (1) LMH6655)
 available at essentially what it costs me to make them up. 

 I do not intend this to be a business enterprise, but rather a service to those members who wish to upgrade their P3 via "plug & play"

 For additional information, please PM me.


----------



## shadowmoses

I couldn't resist trying the AD743 and LMH6655 combo after hearing your comments HiFlight, it works beautifully! As you said, it's pretty warm, but very engaging and sounds more organic. The AD797s in comparisons sounds more analytical and cold, though the details really came through.

 Unfortunately, i only have one AD743JN, and my other one is a AD743JNZ. Will the mixing cause any problems?


----------



## HiFlight

Quote:


  Originally Posted by *shadowmoses* /img/forum/go_quote.gif 
_I couldn't resist trying the AD743 and LMH6655 combo after hearing your comments HiFlight, it works beautifully! As you said, it's pretty warm, but very engaging and sounds more organic. The AD797s in comparisons sounds more analytical and cold, though the details really came through.

 Unfortunately, i only have one AD743JN, and my other one is a AD743JNZ. Will the mixing cause any problems?_

 

They will mix just fine. No functional differences at all between the 2.


----------



## berniebennybernard

Quote:


  Originally Posted by *shadowmoses* /img/forum/go_quote.gif 
_I couldn't resist trying the AD743 and LMH6655 combo after hearing your comments HiFlight, it works beautifully! As you said, it's pretty warm, but very engaging and sounds more organic. The AD797s in comparisons sounds more analytical and cold, though the details really came through.

 Unfortunately, i only have one AD743JN, and my other one is a AD743JNZ. Will the mixing cause any problems?_

 

So do you mean by using the AD797, you were able to hear more details? I was always wondering what the term "warm" meant, I always assumed it was smooth, and cold meant somewhat of a rougher/more treble sound. Please correct me if I am wrong.


----------



## HiFlight

Quote:


  Originally Posted by *berniebennybernard* /img/forum/go_quote.gif 
_So do you mean by using the AD797, you were able to hear more details? I was always wondering what the term "warm" meant, I always assumed it was smooth, and cold meant somewhat of a rougher/more treble sound. Please correct me if I am wrong._

 

When I refer to "warm" I mean it has a full, liquid sort of sound. Maybe a little richer bass, not necessarily more bass. This is unrelated to detail. An amp or phones can sound "warm" while still having lots of detail...ie: Sennheiser HD650.


----------



## HiFlight

I continue to receive PMs and emails regarding my method of testing and selection of opamps, and the criteria that I use, so I will again explain the process that I use: 

 I first check the opamp datasheet for several specs- squarewave response, especially looking for peaking due to capacitances which can result in harsh or sibilant highs. I also check for slew rate, which is a measure of the "speed" of the opamp. Important for good transient response. 

 I then check for THD, voltage and current noise, and whether or not they are unity-gain stable and quiescent current draw. 

 If all these specs look promising, I then try them in a particular amp, using several known musical sources, interconnects, player, and phones. Several types of phones are always tried, both high and low impedance and high and low sensitivity. 

 In theory, all opamps suitable for our use should sound the same, as the audio bandwidth is a very small part of their total frequency bandwidth, and typically, distortion and noise are below the threshold that the human ear can detect, but we all know that this is not the case. 

 There are too many interacting factors inherent in the amp circuitry for the "theoretical" perfect opamp to actually sound "perfect" when installed in the amp, so it is a trial and error game to find that elusive sound quality that resembles a live performance. As an example, the LME49720 has about as close to perfect specs as one can find, yet many find the amp "overly analytical", "cold", "sterile", "tiring". So much for choosing by specifications alone!

 It is important to mention here that NONE of the combinations I have tried sound really bad! I am simply evaluating them according to my tastes and preferences. I look for a weighty impact of fundamental bass, without smearing; for this, I use some recordings that include peals of thunder, recorded live. This is extremely hard for an amp (and phones) to reproduce in a lifelike manner. A sense of air around each voice or instrument is very important for good imaging, and highs that sound realistic, not harsh or sibilant. I listen to recordings that have applause in them, as that it a difficult thing to reproduce in a lifelike manner. Cymbals and snares tones are also a very good measure of transient ability and accurate high frequency reproduction. The voices of female vocalists are also a good measure of midrange ability, along with bassoon, oboe, cello, etc. 

 All amps are colored to some degree or another, even neutrality is a form of coloration. Very few live performances could be considered as "neutral" due to the surroundings, hall acoustics, etc. 

 One simply must pick the coloration that sounds best to ones individual tastes. I, myself, prefer the sense of realism that I hear when listening to a live performance while seated some ways back. I cannot ever recall sitting in the middle of the performance stage during a concert, unless, of course, I was performing, so I don't care for this feeling when listening to an amp. 

 The "perfect" amp will always sound like no amp at all. As they say, simply a straight wire with gain! Of course there will never be that "perfect" amp, but we are getting closer to the mountaintop all the time. 

 Bottom line is that my suggestions are based on my personal preferences in genre, musical setting, and most of all, that elusive, unmeasurable quality of realism.


----------



## HiFlight

In the FWIW department, the following excerpt is from a recent email I received from iBasso:
 ........................................snip...... .......................................
 By the way, the P3 has the best specs among our products. The S/N is 109dB, and this is the true specs. Surely, the P3 has the potential to surpass any of our products. We did not do any experiment on the P3 recently. We are busy about the T4 and the development of the D10. We are trying very hard to release the D10 before Christmas.
 ...................................snip........... ......................................


----------



## jamato8

Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_In the FWIW department, the following excerpt is from a recent email I received from iBasso:
 ........................................snip...... .......................................
 By the way, the P3 has the best specs among our products. The S/N is 109dB, and this is the true specs. Surely, the P3 has the potential to surpass any of our products. We did not do any experiment on the P3 recently. We are busy about the T4 and the development of the D10. We are trying very hard to release the D10 before Christmas.
 ...................................snip........... ......................................_

 

I look forward to the D10. 

 As we all know, it ain't always about the numbers.


----------



## littletree76

For anyone with AKG K601 headphone (120 ohm / 101 dB), try following combination with opamps already bundled with P3 Heron:

 L/R - NE5534N (single) x2
 Buffer - iBasso transistor buffer (single) x2
 3/4 - LM6172IM (dual) x1

 Take note of difference in placement on socket between single and dual channel opamps in case you have not read manual yet.

 Finally I have a decent portable headphone amplifier to drive K601 relatively well with neutral sound to my liking. This combination also work well with portable ATH-ESW9 headphone (42 ohm / 103 dB). Feel free to confirm this combination with your findings.

 According to iBasso support, the bundled transistor buffer can be replaced with BUF634 for even higher current output. I suppose NE5532 is dual channel equivalence of NE5534 hence the two NE5534 can be replaced by one NE5532 (not sure what others received from iBasso for bundled opamps).

 I have been ignoring bundled opamps so far. Look like these opamps are not bundled with P3 Heron just for marketing gimmick. iBasso indeed has selected them carefully.


----------



## shadowmoses

After another night of rolling, my favourite of the night is the LMH6655 in L/R and THS4032 in ground with bypassed buffers.

 I describe the sound as very musical, it caught my attention immediately and demanded me to pay attention to it. Bass is strong and the mids are quite warm, vocals were presented in a very live manner. It also manages to cover up the "weakness" of the source (ipod 5.5g at the moment) nicely compared to using the iBasso D1 as source. 

 The LT6241 came in a very close second in the ground section. I would have been happy with either one.


----------



## denging

is it now the time for us to.... caps roll the P3 ?


----------



## 4sound

I got HiFlights "P3 Topkit" this afternoon. Popped them in and it is unreal how good it sounds! I've tried a variety of phones (Denon D2k w/ MarkL mod, UE5 pro, Klipsch X10, Senn 650, Senn 555, AKG K414p)

 I used a variety of music:
 One Time - King Crimson
 Funk A Hall Licks - Bernie Worrell
 Blue Monk - Marcus Roberts
 Metamorphosen - R. Strauss
 Switchblade 327 - Brian Setzer Orch.

 Everything sounds good. Soundstage is wide, very warm & great definition. 

 For certain types of classical I sometimes like a more analitical sound but for overall flexability this opamp combo sounds awsome.


----------



## littletree76

Quote:


  Originally Posted by *4sound* /img/forum/go_quote.gif 
_I got HiFlights "P3 Topkit" this afternoon. Popped them in and it is unreal how good it sounds! I've tried a variety of phones (Denon D2k w/ MarkL mod, UE5 pro, Klipsch X10, Senn 650, Senn 555, AKG K414p)_

 

I suppose "P3 Topkit" come with following configuration:

 L/R - AD743JN (single/DIP8) x2
 Buffer - iBasso dummy/bypass adapter (single/DIP8) x2
 3/4 - LMH6655MA (dual/SOIC8) x1
 Gain - 10 dB (high)

 I like the exceptional clarity and detail of high frequency response as well as the soundstage. It can drive sensitive IEM (V-Modal Vibe at 2/10 volume level) and hard-to-drive full-size can (AKG K701 at 5/10 volume level) equally well when tested with 3G iPod nano and alloy LOD interconnect.

 Transistor buffer is not needed to drive the AKG K701. Other opamp combinations require volume level to be set near maximum most of the time. With IEM, hissing can be head when volume is set beyond 8/10 position, but no one can hear at such high volume with sensitive IEM. No channel imbalance is detected at low volume setting. I suspect low gain setting (3 dB) can be used for sensitive IEM to lower noise floor. Volume adjustment range up to 2/10 level with high gain is too narrow for fine setting anyway.

 I notice that if the opamp for 3/4 channel (ground channel) LMH6655MA is swapped for iBasso bundled opamp LM6172IM (dual/SOIC8 x1), bass response become tighter. Though I like deep and impactful bass, but I can't stand slightest loose bass. This change work for me relatively well.

 Only shortfall is battery drain is rather high. With above setup (3G nano, AKG K701, 5/10 volume settting) and Sanyo Eneloop AAA 800 mAH rechargable batteries during burn-in, it lasted about 20 hours. Two set of the rechargable batteries are needed in case you are heavy user. Use of akaline batteries is too wastful/polluting and unecessary to me (no matter how cheap they are).


----------



## berniebennybernard

If anyone wants, I can sell them my P3 topkit for $40. The only thing is that either me or the buyer will need to exchange the LMH6655 with HiFlight as it is broken.


----------



## ditoy

tok..tok..tok...anybody there...


----------



## denging

since i couldnt afford the 'Top Kit' yet, for now i'm quite happy with my combo : OPA2604 + Transistor Buff + 3(AD797 stock) , 4 (OPA627)... it gives me very nice impression.... huge soundstage, nice timbre, thick vocal (lively presentation) and detailed high... all come in very nice balance, oh i forgot to mention that i've caps-rolled my P3... for PSU, i now use panasonic [ M ] matsu****a X-pro 3300uf 16v and substitute the red caps with BG NX HiQ 0.1uf


----------



## denging

just received my 'TopKit' from Ron, wow the AD743 combo rock! Ow, by the way, i've modded my P3 with Rubycon ZL 3900uf (replacing the 3300uf Nichicons) and Blackgate NX HiQ 0.1uf (replacing the red film caps)...


----------



## Navyblue

Between stock P3, D3 and P3 with 'top kit', is the performance difference huge? Would they be considered in the same league?

 I don't need a DAC, and SQ is the only concern. If I am getting either of P3 or D3, I'm wondering which one should I go for.


----------



## wsatia

what are you guys' opinions on the best combination of the opamps provided! cause I'm not buying any opamps yet still playing around with the ones provided.


----------



## 4sound

Navyblue, if you don't need a DAC. I'd go for the P3 Heron and get the Topkit. Sound quality is in the ear of the beholder but IMO it was a huge difference with the Topkit from HiFlight. The only downside was the battery life was less but not so short that it was a problem on even long flights.


----------



## Navyblue

Quote:


  Originally Posted by *4sound* /img/forum/go_quote.gif 
_Navyblue, if you don't need a DAC. I'd go for the P3 Heron and get the Topkit. Sound quality is in the ear of the beholder but IMO it was a huge difference with the Topkit from HiFlight. The only downside was the battery life was less but not so short that it was a problem on even long flights._

 

Thanks. 
	

	
	
		
		

		
			





 I've actually auditioned the stock P3 and the D3, along with the T4. Among them I preferred the D3, but probably I'm getting neither. They all changed the and colour the sound of my setup, but IMHO neither of them actually offer any objective improvement, if not worsen it. That's likely because I am using easy to drive IEMs and Zune which has the best headphone out among DAPs I have tried. But if my itch come again 
	

	
	
		
		

		
		
	


	




, I'd probably get the P3 and play with the opamps, or going for other amps like Headsix or the Tomahawk.


----------



## wsatia

Quote:


  Originally Posted by *WindowsX* /img/forum/go_quote.gif 
_After getting BUF634, here's my new settings.

 1/2: OPA627BP
 Buffer: BUF634
 3/4: OPA637BP

 637BP has more details and sounds brighter. I've tried combination with AD797, AD744, AD8620, AD4841-2 and such but this seems to be only one acceptable for harshness with vocals._

 

has anyone else tried the OPA627? is it anywhere near worth it's price? anyway, can anyone recommend a DIP only configuration? cause I totally can't solder the SOIC ones ):


----------



## jamato8

So Ron, what are your latest thoughts on the configuration and sound?


----------



## Navyblue

The last time Ron PMed me he talk about liking the OPA2107.

 John, have you experimented with various opamps?

 I am thinking of getting the P3 tomorrow, someone stop me if I should get the D10 or the Headsix instead before it's too late. 
	

	
	
		
		

		
		
	


	




 I heard the stock P3 and not thrilled by it. I heard the Headsix and I really like it. Haven't heard the D10 and don't need the DAC, but wouldn't mind paying more for it if the amp section sounds better than P3.

 Btw, anyone can answer how does the P3 compares to the D10 when the same opamps combination are used?


----------



## HeadphoneAddict

HiFlight once said the opamp rolled P3 is slightly better than D3 or D10, but then later e posted that the opamp rolled D10 beats his iQube.


----------



## Navyblue

Just as I thought that I made up my mind after months...

 When is it going to end?


----------



## littletree76

Quote:


  Originally Posted by *Navyblue* /img/forum/go_quote.gif 
_Btw, anyone can answer how does the P3 compares to the D10 when the same opamps combination are used?_

 

P3 and D10 have quite different amplifier architectures and supply voltages. P3 is built with 4-channel architecture where opamps for main amplifier, buffer and ground channels (6 sockets all together for single-channel opamp package) can be changed with wide variety of opamps (they may have different minimum voltage requirements). Whereas in D10, only main amplifier and buffer can be changed with more restriction on minimum voltage requirement and room for opamp adaptor.

 Thus it is unlikely that you can use same opamp configuration in both P3 and D10 for comparison purpose. If you want to roll opamp to your heart content to match characteristic of your headphone and never need DAC, then go for P3. Otherwise if there is a need for DAC in foreseeable future, go for D10 instead. In other words, see opamp rolling as optimization instead of necessity.


----------



## SpudHarris

I just ordered my P3 4 days ago, got my tracking no today so it should be with me soon 
	

	
	
		
		

		
		
	


	




 I am slightly confused, probably because I haven't yet seen the internals of the P3 but you guys are quoting single and dual opamps....how does the P3 deal with that? or are the singles you speak of on SOIC adapters?

 I know it comes with a few opamps but I have my favourites and wanted to know what I will or wont be able to use? Now remember what we hear is subjective so no slagging off my choices 
	

	
	
		
		

		
		
	


	




 Favourites are:
 LM6172 (dual)
 AD823 (dual)
 OPA627 (dual /2 on SOIC Adapter)
 OPA627 (single)
 OPA637 (single)
 AD8610 (single)
 LME49710 (single)
 LME49860 (dual)
 AD744 (single)
 AD843 (single)

 As I make a few Cmoys here and there so I also keep a supply of the cheaper BB chips 2227, 2132, 2134.

 I guess what I'm asking in essence is will I be able to use my singles? I have more of these as I roll them in my PPAv2 (although L/R 637 G 627 combo hasn't changed for months).

 Thanks


----------



## SpudHarris

Doh......should have read the whole thread. think I've answered nearly all my own questions. One thing I haven't picked up yet - What is a ''Topkit'' I assume it is a set of opamps proven to sound good? What are the opamps in a Topkit?


----------



## Navyblue

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Doh......should have read the whole thread. think I've answered nearly all my own questions. One thing I haven't picked up yet - What is a ''Topkit'' I assume it is a set of opamps proven to sound good? What are the opamps in a Topkit?_

 

It's in the thread too.


----------



## littletree76

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I am slightly confused, probably because I haven't yet seen the internals of the P3 but you guys are quoting single and dual opamps....how does the P3 deal with that? or are the singles you speak of on SOIC adapters?_

 

The beauty of P3 is that it cater to both single and dual packagings for all opamps. There are three group of sockets labelled as: L/R Amplifier, Buffer and 3/4 Amplifier. Within each group, two DIP8 sockets are laid side by side on PCB. For single opamp in a IC package (quoted as single opamp), two ICs are inserted into the two DIP8 sockets. Whereas for dual opamps in a IC package (quoted as dual opamp), one IC is inserted in between the two DIP8 sockets. Thus no adaptor is required regardless of single/dual IC packaging.






 The only adaptor required is when there is only SOIC package (surface mount technology) for required opamp and it must be inserted into DIP8 socket (conventional technology) on PCB of P3. Just solder the opamp in SOIC package onto Brown Dog SOIC-to-DIP8 adaptor before inserting the adaptor into DIP8 socket in P3.

 Clear opamp rolling instruction is given in manual sheet and there are two empty SOIC-to-DIP8 adaptors provided together with few opamps in rolling kit delivered together with P3 amplifier. Send an email to iBasso support to request for the manual in Microsoft Word format and your doubts will be cleared.


----------



## Navyblue

Ok guys, I am officially in the club.

 I am listening to OPA2111 in both L/R and 3/4 with iBasso buffer.

 It sounds somewhat laidback, somewhat warm. I kind of wish that it has more treble sparkle, not sure if it is the treble extension or I just prefer a brighter sound signature. Overall pretty ok, btw it isn't burned in yet.

 How long does it take to burn in?

 I guess by removing the buffer it would sound brighter? But I intentionally installed it to burn it in, assuming if buffer does burn in.


----------



## SpudHarris

Littletree - Many thanks for your HELPFULL reply, much appreciated


----------



## Navyblue

Questions:

 - How long does it take to burn in the P3?
 - When AC adapter is used, would the battery stop draining?
 - Does low and high gain sound any different? I notice that most of you guys are using high gain mode. But for me even in low gain with IEMs I can't go past 9 o'clock, and 12 o'clock is loud enough for the very inefficient K501.

 Thanks.


----------



## SpudHarris

Do the batteries need to be a specific mAh? I've got a few 250mAh lying around but thought I ought to buy some new/better quality ones Like Vapextech 1100mAh.


----------



## HiFlight

I haven't noticed a great deal of difference in the sound of my P3 since new and now. I am not sure that "burn-in" is a real issue with the P3. 

 When the AC adapter is used, the batteries are not draining. 

 I have never tried high gain, as, like you, I find that low gain powers all of my headphone to far greater volume than I can ever use. 

 There are several opamps that will provide more high-end detail and sparkle. The ADA4841 is one of them. Very open and airy with excellent detail. I think you will also find that the OPA2107 will provide more detail in the high frequencies also. 

 The P3 Heron is, IMO, one of the best portable amps available. 



  Quote:


  Originally Posted by *Navyblue* /img/forum/go_quote.gif 
_Questions:

 - How long does it take to burn in the P3?
 - When AC adapter is used, would the battery stop draining?
 - Does low and high gain sound any different? I notice that most of you guys are using high gain mode. But for me even in low gain with IEMs I can't go past 9 o'clock, and 12 o'clock is loud enough for the very inefficient K501.

 Thanks. 
	

	
	
		
		

		
		
	


	


_


----------



## HiFlight

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_Do the batteries need to be a specific mAh? I've got a few 250mAh lying around but thought I ought to buy some new/better quality ones Like Vapextech 1100mAh._

 

How long the 250 MA cells will play depends upon your choice of opamps and phones. I would suggest investing in a set of Eneloops. They self-discharge very little, and perform way above their Ma rating. 

 Whatever you decide, make sure the capacity of all 6 cells are the same, otherwise the lowest one will be your weak link and result in poorer performance.


----------



## Navyblue

Thanks Ron.


----------



## SpudHarris

P3 is on the truck for delivery today!! + just got a call from my Audiologist and my Custom Sleeves for my IE8's are ready for collection!!

 Today is a good day


----------



## Navyblue

Played around with the opamps that comes with the P3 and also OPA2107, OPA2111, OPA2132, LT1028, LT1358, LT1364, LT1469. Most of them are ok sounding. My favorite is the OPA2111 and OPA2107. The former being warm sounding, has a wide soundstage, laidback but detailed. The later being comparatively brighter sounding and bring the details to your face.

 I started out with OPA2111 in the L/R/3/4 and the iBasso buffer in place, and went back to the same combo. For now I imagine that I'd go back and forth between this combo and OPA2107 in L/R while keeping the rest the same.

 Next would be waiting for the "Topkit" to arrive from Ron. 
	

	
	
		
		

		
		
	


	




 I am curious about the LMH6321 buffer, it replaces the BUF634 in the PIMETA v2 as the default buffer. Does anyone have these to try it on your P3?


----------



## wsatia

Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_The P3 Heron is, IMO, one of the best portable amps available._

 

You know, before I bought the amp I wouldn't have thought it possible. But after using my P3 for a month and a half, I tried out the Xin Reference, Voyager, and one other amp I can't remember and I preferred my P3 over them. Well but YMMV seeing that I only briefly tried them like around 5mins listening time each and it might be due to component matching or my ears simply not used to those amps.

 and fyi I'm using a L/R 2x AD845 and Ground OPA2132 combination.


----------



## SpudHarris

I got mine yesterday and even the stock Opamp combo to my ears was real good, I thought I'd listen for a while before I start changing. I'm not too technically minded so can anyone tell me is there a 'rule of thumb' for Opamps that require buffers or is it just a case of trial and error as to what sounds good with and without.


----------



## HiFlight

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I got mine yesterday and even the stock Opamp combo to my ears was real good, I thought I'd listen for a while before I start changing. I'm not too technically minded so can anyone tell me is there a 'rule of thumb' for Opamps that require buffers or is it just a case of trial and error as to what sounds good with and without._

 

Generally, I find that opamps that output a lot of current can be used without buffers and still supply plenty of headroom and punch. Such opamps might include: THS4032, AD8397, AD797, LMH6643, AD8656 (6v only!). Output current can be found in the .pdf datasheets for each opamp. 

 Even opamps with average output still greatly exceed the current supplied by most unamped players, so unless your phones are extremely inefficient, most opamps will perform adequately without buffers. 

 Buffers also act as impedance matching devices, so some opamps may need buffers to deliver their full potential performance with some phones. 

 All things being equal, I feel that the fewer devices that are in the signal path, the less chance there is for stray inductance and capacitance artifacts and phase differences being introduced into the amplified signal. 

 Despite all the info in datasheets and theoretical mumbo-jumbo, it is still all about what sounds best to your ears. Just pick your favorite opamps and try them with and without buffers and go with what sounds the best to your ears.


----------



## SpudHarris

^ Thanks Ron


----------



## SpudHarris

I already said I was impressed by the SQ of this little amp even with the stock Opamps. I've been playing around and have come to the conclusion that yes, there are a few combinations that sound fairly, even very good with most music genre. As I mostly listen to various electronica, psy-chillout/dub, IDM, downtempo stuff (Shen, Shpongle, Ott, Slackbaba, Kuba, Pitch Black, Vibrasphere etc.....you get the picture) I've been experimenting trying to find a signature that suits this best, I think I've found it.

 OPA637 L/R
 Ibasso Buffers
 AD8610 3/4

 If you like the above genre (s) and have these Opamps try the combo. I'm blown away by this amp and then some.


----------



## HiFlight

Addictive, eh???


----------



## LionPlushie

How will a THS4032 LR, buffers bypassed, AD8066 ground sounds like?

 and is THS4032 LR, buffers bypassed, OPA2134 ground punchy and aggressive but better balanced than the reversed?

 and how will the buffers help if not bypassed?


----------



## HiFlight

The THS4032 with bypassed buffers sounds excellent. The LR opamp has more influence on the sound that 3/4. I would just go with whichever 3/4 sounds best to your ears. I also like the LMH6655 very much as a 3/4 choice. 

 My personal P3 has the AD743JN single-channel opamps in LR, bypassed buffers, and THS4032 in 3/4. I would match the sound to any amp costing hundreds of dollars more.


----------



## jamato8

Yep, you are right, that is a good combination. I just plugged it in.


----------



## LionPlushie

Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_The THS4032 with bypassed buffers sounds excellent. The LR opamp has more influence on the sound that 3/4. I would just go with whichever 3/4 sounds best to your ears. I also like the LMH6655 very much as a 3/4 choice. 

 My personal P3 has the AD743JN single-channel opamps in LR, bypassed buffers, and THS4032 in 3/4. I would match the sound to any amp costing hundreds of dollars more._

 

Is there a need to use an adapter?


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## SpudHarris

I've just ordered THS4032CD - I assume the CD suffix is not important?


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## HiFlight

Quote:


  Originally Posted by *LionPlushie* /img/forum/go_quote.gif 
_Is there a need to use an adapter?_

 

With the AD743JNs...No: (2) single DIP JN743s are used. 
 With THS4032...Yes
 With LMH6655...Yes
 With OPA2134...Yes


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## littletree76

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I've just ordered THS4032CD - I assume the CD suffix is not important?_

 

Today I purchased THS4032CD dual opamp from Farnell Netwark local store, soldered it onto SOIC-to-DIP adaptor and inserted it into 3/4 channel socket of P3 Heron. Everything work fine with no channel imbalance even at low volume and hissing only happen with sensitive IEM (V-Modal Vibe) when volume is set pass 3 o'clock and connected iPod in pause state. Thus the CD suffix does not matter.

 According to TI data sheet downloaded from Farnell website, minimum supply voltage of THS4032CD is rated at 9V, but there are only 6 Sanyo Eneloop rechargeable batteries in P3 Heron which make up to 6 x 1.2 = 7.2V. How come THS4032CD still working according to specifications when there is shortfall of supply voltage by 1.8V ? Perhaps the supply voltage provided by batteries has been increased beyond 7.2V through voltage doubler circuit in P3 ? If this is true then P3 should be able to drive most high impedance headphones relatively well.

 Does anyone has any idea how does the THS4032 in 3/4 channel socket affect battery life ? I am currently burning in the newly rolled P3 with 6 fully charged Sanyo Eneloop rechargeable batteries until they are completely depleted (let see how long the batteries will last).


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## HiFlight

The supply voltage for the THS4032, like many opamps, is a *recommended* value that will allow the opamp to meet the minimum specifications as established by the manufacturer. Some opamps can function with less voltage, but may not be able to meet stated bandwidth, output voltage and other specifications. 

 Using the opamp as an audio device is much less demanding than many other industrial uses, hence we are, in some cases, able to use the opamp successfully with less than recommended supply voltage. 

 If one were to try to re-measure the published specifications of the opamp with this lower supply voltage, one would likely find a number of parameters that would be adversely affected, but not particularly detrimental to our rather undemanding use in a basic amplifier audio circuit.

 FWIW, although most supply voltages specifications are listed as double-ended, IE: +/- values, I find that usually a single-ended supply of the same value will allow the opamp to function satisfactorily. The P3 supply voltage to the buffers, for example, is 8 vdc, so an opamp with a supply spec. of +/-5 volts should work just fine, even though theoretically, the single-end supply voltage should be 10 volts.


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## littletree76

Thank you for the explanation on minimum supply voltage. Thank you for recommending THS4032 as well.

 It has given my AKG K701 a second life as lately I find K701 a bit dull/boring and considering to replace it with Denon D2000 for much better bass response. Improvement in bass response of the bass-shy K701 after installation of THS4032 opamp is rather profound. In fact right now I prefer combination of AKG K701 with rolled P3 over my usual portable rig which make up of Ultrasone HFI-780 and rolled P3.

 After replacing bundled opamp LM6172IM (neutral/transparent) with THS4032CD (warmer) in 3/4 socket, battery life is about 20 hours with Sanyo Eneloop batteries (1.2V,800mAH) and HFI-780 headphone. Driving capability has increased with volume setting reduced from 2 o'clock to 12 o'clock for same sound level with AKG K701 headphone.


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## HiFlight

I am going to be doing some more research with different buffers and different LR. Hopefully, the new combos will be improved even over the THS4032. Will post my impressions of the results. Will probably take about a week to work thru everything.


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## SpudHarris

I am using OPA637's L/R + Ibasso Buffers + OPA627's 3/4 and I can honestly say I never thought portable listening could ever sound so good. This combination makes this amp sound llike something that costs several hundred £'s more than it does (although the Opamps do add about £50).

 I do have one issue though which I'm sure is normal but thought I'd run it by you guys. I get quite a loud thud and crackle/hiss when turning it of is this right? I use my IE8's with my P3 and am worried they could be damaged by this, it is quite loud! I use this combination minus the transister buffers in my PPAv2 without issue so am assuming it is to do with the buffers. Thanks.....


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## jamato8

Ok, I put some BUF634's in, which I hadn't used with the P3 before. So I have some Ad743's in the opamp, 634 buffers and something else, but can't remember what, maybe 4032. 

 Sounds excellent. I am also running it from my Tekkeon external battery at 9 volts. Pure DC.


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## HiFlight

Quote:


  Originally Posted by *SpudHarris* /img/forum/go_quote.gif 
_I am using OPA637's L/R + Ibasso Buffers + OPA627's 3/4 and I can honestly say I never thought portable listening could ever sound so good. This combination makes this amp sound llike something that costs several hundred £'s more than it does (although the Opamps do add about £50).

 I do have one issue though which I'm sure is normal but thought I'd run it by you guys. I get quite a loud thud and crackle/hiss when turning it of is this right? I use my IE8's with my P3 and am worried they could be damaged by this, it is quite loud! I use this combination minus the transister buffers in my PPAv2 without issue so am assuming it is to do with the buffers. Thanks....._

 

The loud sound you hear when turning off your amp is the perfectly normal sound of the opamp dying from lack of voltage. Nearly all opamps make some sort of sound when supply voltage is removed. It will not harm your IE8s. Just turn down the volume before turning off the amp.


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## SpudHarris

Thanks Ron,

 I'm still rolling and last night after one too many sherberts I inserted my AD8620 in ground the wrong way round, which resulted in a very unpleasant smell and a completely dead chip 
	

	
	
		
		

		
			





 I'm still experimenting but have yet to find anything that comes close to the 637's....


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## SpudHarris

^ Until Now.........

 Anyone still rolling? this thread doesn't seem to be getting many posts recently, maybe you are all happy with your chip set up??

 Well I've finally found a set up that sounds so good I'm putting in the proper screws on the back panel instead of the thumb screws. Anyone who owns either a Graham Slee Solo or a C&C XO will know that the AD823 in the proper circuit is an absolute stunner in every respect. The AD823 with bypassed buffers and AD797's in 3/4 positions is the chipset that I believe can't be bettered...........

 The good thing about this set up also is that the AD823 won't break the bank and the others were included in the P3 package.

 Can anyone else with the AD823 try this and tell me what you think.

 Nigel


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## qusp

nice one, the AD823 sounds almost as good as the AD825 IMO and 797's rule so i'm not surprised you like this combo


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## chesterqw

i like my opa2111 very much. some how lol.
 any good 3/4 opamp to use?
 hopefully DIP as i damaged 3 opa827(yes 827) while soldering them.


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## SpudHarris

I'm not familiar with the OPA827 but you do have to be real careful soldering those damn things. I've found that the 2 x 797's that came with the P3 complement many chip set ups. I tend to leave them in situe and roll 1/2 and buffers.

 Are the 827's any good? (not yours of course)

 Edit: Man I just checked out the price of those things (£16 each), sorry about you killing them you must be well angry.....


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## RAQemUP

The Ibasso P3+ seems to be up on the Ibasso website and it seems to come with some different opamps too.

 I wonder if anyone can tell me what's different from the P3+ over the P3. And also what kind of battery life people are getting with their prefered opamp setups in the P3 and on what gain.

 I'll probably end up purchasing a P3+ in a week or 2.


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## SpudHarris

Looking at it I can't see any immediate difference apart from the bundled OpAmps. With the standard P3 you didn't get AD827, AD712, AD8066, LMH6655, LMH6643 or the BUF634 buffer chips. It may be that the original didn't have Nichicon or Dale components but I can't say for sure, maybe someone else knows more?

 I'm getting about 16-20 hours with my favourite chipset - AD823 in 1/2 / Ibasso Transistor Buffers / AD797's in 3/4. Although this is my favorite chipset, it shines best with my W3's. The best chipset I've found for the IE8's is the same apart from AD843's in 1/2.

 I've ordered the AD827, 712 and 8066 from Farnell so will be rolling them tomorrow night all being well.


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## chesterqw

i nearly fainted lol.

 P3+ is out... i wonder...


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## denging

has anyone here tried AD829 in L/R or 3/4? this chip is (supposedly) for hi-res video application, nevertheless i did pair it with OPA627AU (soic) with this combo : AD829 + bypass + OPA627AU... to my ears, this combo delivers certain degree of Ron's TopKit quality with much forward (thicker) mid register.... prior to this, AD829 oscillates like hell with my other combo...


----------



## diditmyself

Quote:


  Originally Posted by *denging* /img/forum/go_quote.gif 
_has anyone here tried AD829 in L/R or 3/4? this chip is (supposedly) for hi-res video application, nevertheless i did pair it with OPA627AU (soic) with this combo : AD829 + bypass + OPA627AU... to my ears, this combo delivers certain degree of Ron's TopKit quality with much forward (thicker) mid register.... prior to this, AD829 oscillates like hell with my other combo... 
	

	
	
		
		

		
		
	


	


_

 

AD829 is a cranky opamp. It often needs external compensation (a cap from pin 5 to ground), especially if used as a unity gain voltage follower. Besides the input bias current is huge resulting in a massive DC offset if the bias currents aren't balanced.


----------



## HiFlight

Quote:


  Originally Posted by *RAQemUP* /img/forum/go_quote.gif 
_The Ibasso P3+ seems to be up on the Ibasso website and it seems to come with some different opamps too.

 I wonder if anyone can tell me what's different from the P3+ over the P3. And also what kind of battery life people are getting with their prefered opamp setups in the P3 and on what gain.

 I'll probably end up purchasing a P3+ in a week or 2._

 

The P3+ has many updated internal components plus gold-plated circuit boards and battery contacts. There are more possiblities for opamp rolling and one can select from virtual ground or 4-channel ground or even bypass the ground sockets. 

 It also allows for some different opamps to be used in the grounds. 

 The sound of the P3+ is improved beyond my best efforts with the P3 Topkit. iBasso just raised the bar a little higher. They took a very good amp and just made it better. 

 The major differences I hear between the two are most apparent in the more open spatial soundstage and depth of imaging, not so much tonally. The sound is much less confined to the inside of the head.


----------



## acvtre

Any set up to suggest? So far I tried only the stocked buffers and opamps and I think the amp it's not bad but nothing exceptional. In particular with my in-ear sennheiser ie6 I hardly ear an improvement.
 Now I also got an enormous problem because I ear a strange buzz while the amp is powered by the batteries, on the contrary if it is powered by the power adapter everything's ok.

 Can anybody help me? Any suggestions?

 P.S.: already read the first pages. Maybe I only need some "training"?


----------



## HiFlight

Quote:


  Originally Posted by *acvtre* /img/forum/go_quote.gif 
_Any set up to suggest? So far I tried only the stocked buffers and opamps and I think the amp it's not bad but nothing exceptional. In particular with my in-ear sennheiser ie6 I hardly ear an improvement.
 Now I also got an enormous problem because I ear a strange buzz while the amp is powered by the batteries, on the contrary if it is powered by the power adapter everything's ok.

 Can anybody help me? Any suggestions?

 P.S.: already read the first pages. Maybe I only need some "training"?_

 

First thing to try is to replace the batteries with a fresh set of good rechargeables ( Eneloops) or alkalines. Keep in mind that the power adapter does NOT recharge batteries.


----------



## acvtre

Quote:


  Originally Posted by *HiFlight* /img/forum/go_quote.gif 
_First thing to try is to replace the batteries with a fresh set of good rechargeables ( Eneloops) or alkalines. Keep in mind that the power adapter does NOT recharge batteries._

 

Already done and doesn't work.


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## acvtre

What kind of setup would you suggest, in order to hear a big improvement with my cowon D2 and akg k240 MKII? Don't bother 'bout the cost or what else.
 I was wondering how do you test the set ups. Do you use it for days or can you hear immediately the difference? Do you use particular songs?


----------



## blackmondy

Hi, everyone

 I'm new to this opamp-rolling thing but I just want to make my P3 as neutral as possible to "neutralize" (pun intended) the coloration of the amp in order to enjoy the warmness of the ESW9.

 In short, I'll like to iQubelize the P3. 
	

	
	
		
		

		
		
	


	




 What sort of opamp combo should I be looking at ?

 Cheers !


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## beamthegreat

to OP
  What stock opamp combo do you think is the best?


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## MusicalChillies

Quote: 





hiflight said:


> Quote:
> 
> 
> Originally Posted by *acvtre* /img/forum/go_quote.gif
> ...


 


 x2 on the battery, only use eneloop for every source, wii etc.


----------



## yooss




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