# Audio-gd discrete op-amps reviewed: OPA-Earth, OPA-Moon, OPA-Sun v.2



## majkel

Thanks to my fellow from forum.MP3store.pl (Powered by Invision Power Board) whose personality is known to me and Kingwa, the discrete op-amps designer, I received three types of discrete op-amps from Audio-gd for review. The schematics and descriptions can be seen here: ÐÂ½¨ÍøÒ³ 1
 The modules I have tested are:
 dual OPA-Earth
 dual OPA-Moon
 dual OPA-Sun v.2
 All came with capacitor upgrade and I didn't modify them in any way for the time of the tests. Each of them spent at least 24 hours of burn-in, observing if any changes occur. When I realized nothing changed any more, I started critical listening sessions. The equipment I used were:

*Grado GS1000* headphones

 Here is not much to comment. I regard these headphones as the top class dynamic model, with extraordinary spatial presentation and timbral abilities. Their bad side is long burn-in time, making some annoyed guys sell these headphones in premature condition to people like me. 
	

	
	
		
		

		
			





*Grado RS2* headphones

 These are pretty well known to the head-fi community. I'll just point that mine were without buttons, I bought them new in February 2008 and in the last weeks, after trying some burn-in tricks working with the GS1000's these settled down on very nice sonic signature. Their role were minor in the whole test but this will be clarified later. 
	

	
	
		
		

		
		
	


	




*Creative Aurvana Live!* headphones
 For the purpose of the fellow who sent these discrete op-amps to me and chose his favorite using these headphones and the Zero DAC, IIRC. Mine are re-cabled, BTW. 

*Technics SL-PS840* CD player
 This one has been modified heavily but I used it as the digital transport only. The mods I applied were among others:
 - ultra fast MUR120 diodes in place of 1N4003 rectifying diodes (8 pieces)
 - Elna and Sanyo capacitors replaced in many sections of digital and analog power supply
 - long and thin PCB traces doubled with solid tin-plated copper wire
 - precise 5ppm gold pin OMIG quartz put in the SOAD70A mechanism servo circuit
 There were other strictly analog part related mods like capacitors and op-amps replacements which improved the Technics' sound significantly but it still was not the class of the modified...

*CS8416/CS4397 DIY DAC kit* as the DAC
 I bought the kit from _gigawork_ on ebay, choosing the SMD version which some people consider as the better choice because of short traces and separated power supply built on another printed circuit board. This DAC has been “discovered” and popularized mostly by Lukasz Fikus. What hi did to this DAC, you can read here: CD DAC Lampucera lampizator
 I'll just admit that the stock form of this kit will not catapult you in the hi-end sound realm, it's rather significant upgrade to budgetary CD players and comparable to devices like 2x OPA627 upgraded Zero DAC, based on my forum mate's opinion. However, after some mods, this DAC kit starts to compete or maybe win (last upgrades haven't been verified yet) with $1000-$3000 DACs. At least it could fight with: AudioNemesis DC-1 upgrade+Tara Labs internal wiring, the NorthStar M192 MkI or theTheta DSP Gen Va. So, here is the short list of upgrades making this DAC a reliable, I hope, test platform:
 - 20VA 2x 14V AC toroidal transformer in place of the original one (hum with OPA-Moon showed it's too weak)
 - Elna Tonerex capacitors on each voltage rail on the DAC PCB
 - shortened ground traces for the op-amp slot
 - all supply voltages of the analog section of the DAC bypassed with the Elna Silmic II capacitors
 - digital voltage supplies of the CS8416 SPDIF receiver and the CS4397 DAC chip bypassed with the Sanyo WG capacitors (better specs and sound than OSCON)
 - Toslink receiver supply supply bypassed with the 220uF tantalum capacitor
 - shorted output capacitors
 All those mods were thoroughly tested. I tried many different mods in the last months, some were unnecessary, some required testing many different parts, etc. 

*Beresford TC-3618* optical digital cable
 This is the best optical cable I have ever tried. Not distinguishable from the more expensive Profigold PGD5000, much better than some hyped “glass” optical cables having both mediocre build and sound quality. Use this one or choose a trusted manufacturer, that's my advise for today. 

*Moonlight v.8* headphone amplifier
 The name tells you nothing and I know that because it's my own design. The details I'm willing to reveal now are:
 - class A output
 - no regular op-amps in the signal path (to hear the op-amps influence in the DAC) 
	

	
	
		
		

		
		
	


	



 - DC signal path with passive offset cancellation
 - virtual ground architecture with some unique solutions
 - external regulated DC power supply
 This amp was roughly compared to the Yamamoto Soundcraft HA-02 and the RudiStor NX-33, from memory to the ASL Twin Head MkIII with upgrades (caps, DACTs, tube sockets, different tubes). For an opinion on this amp it's best to ask Piotr Ryka or fallow81 at this moment. Just in case you're not sure I could rely on the sound. 

*Analog interconnect*
 Having disassembled DAC and amp, I could get rid of this element, using a couple of centimeter long wires to connect one PCB to another. This sounds best to me. 
	

	
	
		
		

		
		
	


	




 If not, I take the Conducfil SPEAKFIL 8896 cable, the Neutrik NYS373 plugs, and make my own IC connecting wires exactly how Oyaide did in the PA-02 TR interconnect. Then I could sell the Oyaide product as being less transparent and precise than the professional Conducfil cable. 
	

	
	
		
		

		
		
	


	




*Albums*
 Ayo “Gravity at Last”
 Diana Krall “Live in Paris”
 J. S. Bach “Brandenburgian Concertos I – VI”, Czech Broadcast Recordings
 W. A. Mozart “Requiem”, Polish Cathedral Choir (forgot exact name)
 Blue Note Trip 7 – Maestro compilation
 Seal "Soul"
 Basement Jaxx "The Singles"
 Silverchair "Frogstomp"

*Other albums, headphones and amplifiers will be subject to update this thread whenever something interesting appears, so be patient if you won't find all you're looking for at the moment. *

*Technology*
 As you all know, the discrete op-amps were designed to replace generic or brand name, available for sale in electronic shops integrated op-amps. Discrete circuits are considered to be superior to integrated circuits and it's explained in several ways:
 1)The circuits are created for a specific purpose and voltage range, unlike the universal integrated op-amps. Here we have audio.
 2)Discrete passive elements are isolated from the die and manufactured in the optimal technology for a specific solution. Implementing resistances and capacitances within the op-amp silicon die is limited by the integrated circuit technology.
 3)There is no crosstalk and capacitive coupling between the circuit sections. 
 However, integrated circuits were created because of their advantages and these shall be listed below.
 1)Unmatched thermal coupling between all active elements, keeping parameters like transistor current gain or DC offset at the output well compensated in the whole temperature range.
 2)Short signal paths allowing weaker bandwidth compensation and using faster active elements for negative feedback circuits allowing higher slew rate, shorter settling time and lower phase shifts at high frequencies. Lower EMI vulnerability in general. 
 3)Minimized silicon-metal signal transitions. In the integrated circuits almost all current flow happens in the same piece of silicon. In the discrete circuit it comes from the pin to the silicon and goes to the pin-PCB trace-pin path before reaching another transistor's structure. Count the transistors in the the whole I/V or voltage gain section and see how many times the signal goes through the barriers like silicon-metal joints and solder joints. Sure, it can be done with high quality and possibly no loss to the signal, but in a continuous signal path within the same medium there is no such loss for sure.

*Conditions*
 The discrete op-amps were designed mostly as the replacement for the regular op-amps but also as circuits around which you can build your own audio equipment. On the other hand, when going discrete from the scratch, it's disputable to use global feedback loop dedicated circuits, so let's stick to the upgrade role of the Audio-gd discrete op-amps for now. In my DAC circuitry they worked as the low-pass filter and buffer circuit converting symmetrical CS4397 voltage output into unbalanced signal. The supply voltages were +-12V. I allowed each discrete op-amp to heat up before I started listening. For each discrete op-amp the additional grounding necessity was evaluated and appropriate comments will be provided. 

*Competition*
 Unfortunately I don't have Burson discrete op-amps in stock so cannot compare to these from Audio-gd but there are several things regarding popular integrated op-amps that should be pointed out. I tested lots of them, many times due to possibility of receiving free samples, many other times making trades or just buying them. I could say I know almost all of those you could use for audio, so let's categorize them somehow. 
*Category 1 – waste of time and money*
 Without further comments, I'll just tell you I put all the popular audio op-amps here, too much for listing. Instead of this I'll mention the op-amps I think are fine but couldn't use in the DAC: AD8021, AD8022, ADA4841-1/2, OPA637(?). Those I regard somehow more than Category 1 will appear later in this section with a remark. 
*Category 2 – nice but incomplete sound*
 AD823 – quite popular in voltage stages of amplifiers and CD players after upgrades, doing fine but keeping it's own timbre, not allowing for full color reproduction. 
 AD8620 – the A series is a bit harsh and aggressive, the B series is smooth but still too present in the sound. Going to the bright side and keeping sounds a bit confined. I'd appreciate more independence. 
 AD8397 – this is a smart one, really. At the first moment you think it does everything perfect, the sound is complete with no obvious flaws and predefined timbre. What it does bad is shrinking and flattening of sounds, some offensive forwardness due to the thinned sound contour.
 OPA2111KP – holly crap, this one is pretty neutral and sounds better than you could expect from the specs. Very similar to the OPA2107 in this regard but sonics just better. Truer bass with more impact, more coherent and convincing rest of the spectrum. On the bad side is a piece of mess and congestion. Sounds get mixed and interfering each other starting from higher midrange sometimes. 
 2x AD825 – man, I've liked this one for a very long time. I still could find use for these, like entry level headphone amps or budgetary DAC output stages. This one is lively, rich, fast, with long treble finish, nice midrange timbre. Sounds like a sweet spot between the AD8620 and the AD744 which gets to warm, thick and uncontrolled sometimes. The AD825's unique midrange can “save” your rig when you cannot achieve enough transparency. The overall order and separation is less than perfect but not obviously flawed. I blame the highs for being a bit accentuated and with artificially sustained decay. 
 OPA2604 – a classic audio op-amp. This one can sound really bad when supplied badly. Just see its PSRR specs. Mere 84dB. 
	

	
	
		
		

		
		
	


	




 I could confirm it. Unregulated power supply makes it sound congested, harsh, unstable, messed-up and offensive. Well regulated and filtered supply voltages keep it quite neutral, with dimmed and unfocused trebles, good pace (LOL at the 2x OPA627A here) and overall good tone. 
 LM4562 – just a lesser version of the LME49720. Its midrange is on the warm-bright side instead of neutral, overall good and rich presentation, unfortunately too obviously defined hence predictive and limited sometimes. 
*Category 3 – sound almost complete but imperfect*
 Here I guess additional comment is required... Some people say op-amps are bad. They just sound bad and sound like op-amp. Op-amps do weird things to the sound and using transparent amplification or acoustic transducers will let you hear that. People who want go higher with their equipment just abandon the op-amp realm and go full discrete – using transistors and/or tubes only. 
 The effects of op-amps are something like these:
 there is an invisible barrier in the soundstage, in front of you, or surrounding the stage
 the three-dimensional image of the sound is flat, corrupted or fixed to the soundstage like a picture to the wall
 not enough freedom, clarity, space and timbre differentiation, and other nuances making you just hear sonic spots instead of seeing and feeling the instruments and performers' breaths. 
 So let's enter the area where you can experience touch of true performance, with exceptions but we're yet on the other side. 
	

	
	
		
		

		
		
	


	



 2x LT1028CN8 – wow, with the Blue Note Trip I can say I'm between the performers. The trumpet is properly drawn, I feel the air and the presentation is convincing. There is a slight tint of nervousness in the midrange, which gets sometimes slightly dry but sure you can hide it using passive components. Regarding the dryness – these op-amps just blow away the popular LT1364 in this field. If you like the latter, use 2x LT1028 instead. 
 AD8599 – this one can do things most other op-amps cannot do, period. It's like a sport car with big supercharged engine and huge carbon brakes. It can accelerate and brake rapidly thus keeping perfect rhythm, pace and timing, proper release and decay and exact texture. It's warmer than the LT, with more delicate, thinner trebles, no nervousness but this strange direction of the soundstage. It feels like it's not completely open towards the listener. 
 OPA2228P – say, the OPA2604 killer when you can use bipolar and uncompensated op-amp. Higher midrange complexity, more coherence and focus. Sometimes laid-back and the trebles could use more hues.
*Category 4 – like a completely arranged room, not quite tidy yet*
 I'd say, the fight with the Audio-gd op-amps starts making sense here. 
	

	
	
		
		

		
		
	


	



 Did you ever know that the op-amp grade matters for audio? Yes, it does, at least for OPA2134, OPA2132, LT1028, AD797 and OPA627 which I can confirm. So, let's continue:
 2x OPA627BP – welcome to Category 4! Unlike the AP or AU series, this one is not lacking proper attack. Sure, it's not lightning fast but at least this one can keep the rhythm, it's actually pretty similar to the AD797ANZ with the advantage of JFET inputs. Lack of the last refinement and oomph makes it less than perfect. I'll get back to this later.
 2x AD797ANZ – this one I regarded for a long time as a piece of wire equivalent when used as a buffer. It lacked some level of the lowest detail but added pleasant tube-like timbre, in a delicate form of course. This one is a bit better than the AD8599, with less accentuated sonic signature. 
 2x LT1028ACN8 – the better LT1028 grade. Sure it's audible. Instead of the slight dryness you get a bit longer sustain in the mids, with a slightly higher midrange coloration, hardly perceivable when your ears get used to it. The soundstage is correct, the imaging is correct, tha PraT is correct, and what I would like from it to be perfect is a bit more independence of the events in the furthest background plans. It's sounds like it's a bit hazy there, however you can like it. 
 2x OP27GP – no kidding! Just see the prices of the OP27E from Texas. 
	

	
	
		
		

		
		
	


	




 There is a trick – this one, I mean the one from Burr-Brown I own, requires class A biasing. Otherwise it's not worth considering. I remember I liked it even more than the 2x LT1028ACN8 combo. As a side note I can write that the OPA627 was designed to have this op-amp offering JFET inputs. Same with the OP37 vs. OPA637. 
 2x OPA211 – the king of the space, I guess it's even exaggerated. In terms of overall order, clarity, timbre transparency and rhythm, this one is a direct upgrade from the OPA2228. Slight but worth it. The increased shape detail and huge soundstage is probably the result of something I'd call sound disassembling. It's like losing spatial coherence of each sound, having the tone in one place, and the harmonics just aside, not surrounding the right tone. Strange but true.
*Category 5 – complete sound traveling in the clean air*
 2x AD797BRZ – this is the op-amp truly deserving the name of the Analog Device. This one is a smoother and fuller sounding version of the AD797. Switching from the ANZ to the BRZ series is like going vinyl instead of digital. Everything is smooth to the moment your music craves for the harsh texture like aggressive violin passages, distorted guitars, or stronger double bass phrases. The readability of the furthest plans is great, without going into image sharpening effect which makes you see the details more but lose the feeling of perspective at the same time. Roughly, it's like the AD79ANZ with all advantages of the OPA627BP added. The soundstage is nowhere limited and the sound image of whatever possible shape. This is a reference integrated op-amp for me so let me know as soon as you find better, and I will verify it. 
	

	
	
		
		

		
		
	


	




*Let the show begin... first impressions*
 I started with the OPA-Earth as being the oldest and most recognized design from Audio-gd. I put it direct after AD797BRZ pair which I normally use and wow! Bigger soundstage, more saturated timbre. However, after some time I realized the sounds are too punctual, the soundstage is a bit predefined like in some op-amps and I started thinking what to improve? I used the ground wire. There are two polar opposites regarding my DAC where I can connect this wire – as close to the DAC chip as possible, or straight to the output connector. The difference was almost none, if really any, so I kept the DAC ground connected. This improved the vocals in the first place. The singers were no longer strangled, the shape of the voice got opened and not so focused, say more natural. Overall sound imaging improved, getting a bit less spectacular due to lower timbre emphasis but the exaggerated punctuality disappeared as well and the presentation became simply truer. What I still want? Give me back the smoothness and intimacy I had with my AD combo. We'll talk later as you're straight out of the box.

 The second one to try out in this impatient rush caused by hunger for knowledge was the OPA-Moon. Let's see what guys call “sentiment” and tube-like presentation. Hmm, sound is more mellow and intimate than with the OPA-Earth but it's going to create it's own world more obviously as well. There is more transparency within the soundstage but on the other hand you hear it's borders stronger. It's like inflated from the inside but limited at the borders. The sound is smoother and a bit rounded but the soundstage is slightly uncontrolled. I connected the ground wire again and it helped for the second time. The change is slight but for the better. The imaging got less spectacular again but with lighter intrusion into natural imaging as well. On the other hand I had impression that the OPA-Earth is still closer to the transparency. 

 So, finally the Sun v.2 enters the socket and from the very beginning I know I like it! What a positive sounding device! The first thing making it superior to the other two is that the headphones disappeared from my head. The presentation is so coherent and convincing that I feel no strain and necessity of additional resolving of what I hear. This one is brighter than the previous two, with denser presentation and overall thicker sounds. The timbre is rich and nice, pretty straightforward. Connecting the ground wire I found as a bad idea. The sonic presentation got flatter, less of being everywhere and the instruments got a bit confined to their localization. In case of the OPA-Sun I decided I'd choose more of the sonic freedom and joy instead of stability making the presentation more flat at the same time. Another good thing about this device is that it's sound is unique and you can forget all integrated circuits when looking for sound like this. 

*Ayo “Gravity at last” album impressions*
 Well, well, well. This CD is very well recorded and mastered. Very transparent stage, rich tonality, good presence of voices and mechanically produced sounds. This one is better mastered IMHO than the previous “Joyful” album. 

 I forgot previously to define the competitors. I decided it to be 3 against 3, so the representatives of the better class of OPA627, LT1028 and AD797 will fit the bill, I guess. Going from the best to the worst, it looks like this:
 1.AD797BRZ
 2.OPA-Moon
 3.LT1028ACN8
 4.OPA-Sun v.2
 5.OPA627BP
 6.OPA-Earth
 The winner got it right. Maximal midrange complexity,transparent ambiance, great performers' presence near you. The OPA-Moon had maybe more interesting midrange tonality at the first moment but it tried to put all the sound in it's own frames, and all in all the midrange wasn't quite complete, however rich and enjoyable. The LT was actually similar to the OPA-Sun v.2 but won due to smoother and softer presentation. I found it more true than that of the OPA-Sun because the latter felt a bit like hard wood in the texture. Both are the brighter part of the bunch. The OPA-Sun v.2 easily won with the OPA627BP pair. For this great album the demarcation line of the “op-amp smell” rose to the level of the OPA627BP. It was a bit grainy and flat in the foreground. Good tonality but sounds embraced with a barrier. The OPA-Earth got it even slightly worse. Similar problems and some congestion added. Just like the OPA627BP without the ambiance transparency. 

*Classical*
 1.AD797BRZ
 2.OPA-Sun v.2
 3.OPA-Moon
 4.OPA-Earth
 5.LT1028ACN8
 6.OPA627BP
 First two places provide pure enjoyment. The AD797BRZ won due to clean atmosphere (again), natural, not offensive tone and great instrument definition. The piano showed its supremacy and the woodwind second. With the piano you hear great string decay echoed in the wooden box. Yes, you hear it's all like that. The OPA-Sun moves everything towards the “wooden” side a bit. The trombones played tad too low, without upper finish but overall presentation was logic, coherent, powerful, enjoyable, keeping great rhythm and pace. There was no congestion or disorder. OPA-Moon sounded mellow, with lesser energy, rather nostalgic which somebody might enjoy, especially with some tracks. The sound was kind of caramel-sweet but it was a slight intrusion, not forced in every note. The soundstage wasn't completely open but on the other hand, presence of the instruments was well accentuated. The OPA-Earth presented a bit nervous and congested sound. It's like you feel there is something in the air and you can't relax. However it was still on the good side with overall correct texture, a bit flatter presentation than the top three, and surely better than the pair of the LT1028's. These showed too rounded tone, to the level it was greasy and boring. Not enough separation in this music sauce for me. The OPA627BP's were disappointing. Nice tone but corrupted piano with no piano presence. It was simply synthetic, with uncontrolled note decay and flat, “electric” timbre. Like plastic toy. No fun, no score.

*Seal “Soul” album impressions*
 1.AD797BRZ
 2.LT1028ACN8
 3.OPA627BP
 4.OPA-Moon
 5.OPA-Earth
 6.OPA-Sun v.2
 Instead of live instruments and minimal mastering, we have here Warner Bros logo at the bottom of the CD box and obvious sonic idea about this album. It sounds sentimental, smooth, with no aggression, giving impression of a big hall, with somehow distant vocal. Slight echo adds the feeling of empty audience, just the performer and the orchestra more in the background. 
 Looks like heavily engineered mastering is a domain of chip op-amps. The first two places were quite close to each other. I rate neutrality higher, so the AD is the winner. Another reason is that the AD797 reached further on the vertical axis. The LT sounded fuller and more plushy in the higher midrange, making vocals more kind and friendly. The AD was more groovy in the voices department. The OPA627BP's showed simple but coherent presentation with good transparency. Leaning towards plastic but acceptable. The OPA-Moon was more physiological but with lesser clarity. I'd say they were equally good and somebody could change the order between them in the ranking just due to preferences. The OPA-Earth was similar to the LT but with worse clarity and uneven texture. The LT1028's presented more culture and coherence. The OPA-Sun v.2 with it's specific texture preferences did not match Seal's voice and emotionality of this album at all. The sounds were kind of crude and thick, not getting smooth enough when expected. 

*Electronica*
 1.AD797BRZ
 2.OPA-Earth
 3.OPA-Moon
 4.LT1028ACN8
 5.OPA627BP
 6.OPA-Sun v.2
 Here what I care for is tonal complexity, layering, soundstage dimensions, textural abilities, merging in music - simply said. The AD provides the magic touch that makes you perceive the sounds not only with your ears. They make you imagine what other senses could project in coherence with hearing. The OPA-Earth provided some positively edgy fun, with complete tonality and precise texture, however not that transcendent you'd expect from good electronic music composers. This one is correct and enjoyable without entering the fourth dimension. 
	

	
	
		
		

		
		
	


	




 The OPA-Moon is more emerging in the whole music ocean, and if you care more for this instead of every possible timbre delivered, this one, with its caramel presentation will fit your expectations. The soundstage is perceivably huge, especially wide, and you're in the center of the music event. The LT1028ACN8's were smoother but sometimes distant, making sounds escape a bit from you. The tonality was complete but the texture too rounded, and the haze in the background. You can like it but it's added value so I rate it as a disadvantage. The OPA627BP's made it simple. If you don't know your recordings well, you think it's the clear picture of them, with plain notes, correct, nice tones, not so big soundstage and kind of disappointing simplicity. The OPA-Sun v.2 tried to paint a rainbow using roughly five crayons when seven is required, and the hand was shaking when the picture was born. The footprint of this shaking is this repetitive texture, not differentiated enough, and limited tonality due to missing paints. Using nice colors only is moderately fun. The forward presentation doesn't feet electronica, either. 

*Silverchair “Frogstomp”* album impressions
 I'd say it is the rock/metal capabilites test. This album was their first and best, with it's young spirit and garage studio feeling. I like it all, some harshness, some anger, true acoustics, nicely distorted guitars. So, the score goes like this:
 1.AD797ARZ
 2.LT1028ACN8
 3.OPA-Earth
 4.OPA-Sun v.2
 5.OPA-Moon
 6.OPA627BP
 The winner is in another league, magic of reality and presence, with no further excuse. Places 2 to 4 is roughly the same, a bit lower league where the OPA-Earth added some nice harshness to the vocals, emphasized the distortion of guitar strings and kept great rhythm and timing. The LT1028ACN8's scored a bit higher due to more present vocal and richer guitar tone, making each pluck perceived like a wind blow. The OPA-Sun v.2 kept the vocalist “sane” and effortlessly singing each phrase, the scene was broad and open, everything was happening like on the stage close to you, with nice tonality and texture. The sound was believable, with no issues. The OPA-Moon got too mellow and too dark, making music sentimental but sometimes absent, not his music genre, definitely. The OPA627BP's showed all the legendary chip op-amp excellence, not even worth describing it. It's an exceptional album and want to hear that. I didn't.

*Final assumptions*
 Well, I feel I know much enough. 
	

	
	
		
		

		
		
	


	




 There should have been jazz impressions added but actually the jazz instruments appeared in classical and rock sections, with the female vocal on Ayo album evaluated, so I think I can summarize my thoughts on the discrete Audio-gd op-amps. 

 First, guys from Audio-gd achieved what they planned, really! They delivered a worthy chip op-amp replacement, presenting three different sonic signatures. For the studio and hi-end purposes they are probably not good enough, but for most DIY aware audiophiles they are an interesting and enjoyable upgrade, in the league that mid-end equipment will benefit from them. If you can assure the conditions below are possible to fulfill, then go ahead and try one or more of them, considering their sonic tendencies:
 - efficient power supply for both rails, I guess 200mA reserve per voltage is the minimum
 - enough space around the socket or near it, when the extension cable is required, you have to provide mounting of the OPA
 - easy access to the ground on the original PCB, as the OPA ground wire might bring advantage when connected

*OPA-Earth*
 This one feels best in electrical and electronic music, where raw power and aggression is an advantage. This one has got the ability to present some of the sounds live, like from your surroundings, not headphones, even on lesser models like Creative Aurvana Live! or Grado SR325i (thanks to my friend for loaning them). The bass is shaking and precise, the mids are colorful but slightly on the flat and thin side, however tonally the most complex of the three discrete op-amps. _This one is doing better with the ground wire connected as you get rid of nervousness and the vocals melt in the air more naturally._

*OPA-Moon*
 The sweetest and the most romantic one. Slightly darker than the other two, a natural step-up from the AD825 pair as I know there are lots of their fans. This one has got big but defined soundstage, the listener becomes a part of the spectacle. You feel emerged in the music flow however the musical fluid is not completely spiced for me. I don't want things to be sweet or salty all the time, I need a tiny sip of sour or bitter flavor sometimes, making the dish more refined. In other words, the music does not have to be sentimental all the time, I'd like it to be intriguing and surprising sometimes. 
_This one better leave ungrounded. _

*OPA-Sun v.2*
 The best first impression, losing a bit when thoroughly discovered. It simplifies the harmonic content the most. There are some tonal nuances the OPA-Sun does not deliver. The musical presentation is straightforward, positive, joyous, like a sunny day. I liked classical quite a lot with it and some people will enjoy rock because its ambiance is clear and fitting headphones well. The OPA-Sun removes the headphones from your head on most albums I tried and if you don't know, or don't think about some tonal particles missing or hidden, you'll enjoy this one. The texture is wooden thick, the midrange is on the rich side, all is brought to the listener without further excuse, honestly and friendly. 
_For more precise imaging, leave it ungrounded, for smoother and more airy presentation, connect the ground wire._

 My favorite? OPA-Earth. Delivers the most of what was recorded but not in the best form each time. Then comes OPA-Moon and the OPA-Sun v.2. The OPA-Moon is missing something sometimes but it sounds like a young man who fell in love just forgot about something, forgivable and natural. The OPA-Sun v.2 is kind of a cottage musician. He's got a lot of willing to play and positive energy. He plays notes the only way he can do but he never forgets to smile to you, and you smile with him. Pure, simple joy.

*UPDATE 11 Jan 2009*
 I rebuilt the power supply so that the digital and analogue section of the DAC chip gets double regulated +5V supply. I find the OPA-Moon more complete tonally and it looks like it's at least equal in terms of SQ to the OPA-Earth. All discrete op-amps improved a bit with this modified PSU but so the AD797BRZ's did. The chip op-amps got better in terms of acoustical correctness and transparency.


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## Bleemv1

good review. I'm very interested as I'm about to upgrade my op-amps. 

 Do you reckon you could put up the costs of each of the op-amps your comparing. That way we could see some kind of price to performance comparison too.


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## Ron.id

Very nice review majkel... i'm waiting for your full review 
	

	
	
		
		

		
		
	


	




 Btw, recently I bought OPA Sun v2 from my friend. I put it on my SOUL v1 headamp (designed by my fellow friend). Here's a little spec of this headamp:
 - 3 channel + buffer architecture
 - class A bias for voltage-gain stage
 - precision virtual ground
 - Jung multiloop

 Since I have only one SUN v2 (dual version), I put it on ground channel at buffer stage. For my lack of english & ability to review 
	

	
	
		
		

		
		
	


	




, I could only say that the first thing I noticed is a significant wider soundstage and fuller sound compared to my previous opamps (AD8397, 2x AD825, AD8066, OPA2134). Btw, I supplied only 19V to this headamp, so it's 9.5V rail-to-rail(?).

 Next time I want to put more discrete opamps to replace my L/R channel too. Maybe I need to modify my amps power supply stage to deliver more current to feed ups these HDAMs.

 Here's a photos when I tested it with DIYmod iPod, custom made LOD with 22uF BG NX Hi-Q inside, Grado SR125000 (modded like Alessandro MS1000):


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## TzeYang

^Nice! Is that sum OPA + BUFFER Three channel amplifier? Needs more details on the self etching.

 @majkel,

 I've been too absorbed by the AD825 that I did not even bother to try the AD797. If you ranked it two ranks below the AD797, that I MUST TRY. 

 (though i'm pretty lazy about balancing input bias).


----------



## majkel

It's easier to make the AD825 sound right than the AD797, mainly in regards of supply. As I said, the AD825 is playing its own melody but this melody is one of the best available. However, sometimes the original beauty is nicer and you'd like to hear it.


----------



## Bleemv1

Which one would you recommend majkel? sounds like the discrete opamps aren't heaps good. Is the AD825 expensive? 

 when's the rest of the review coming up? too much suspense haha：Ｐ


----------



## majkel

Quote:


  Originally Posted by *Bleemv1* /img/forum/go_quote.gif 
_Which one would you recommend majkel? sounds like the discrete opamps aren't heaps good. Is the AD825 expensive? _

 

They are very good but not perfect. They win with most chip op-amps. Maybe higher supply voltages will make them better.
  Quote:


 when's the rest of the review coming up? too much suspense haha：Ｐ 
 

Probably today in the evening. I need to comment other albums and music genres, add a word regarding the RS2 and final conclusions.


----------



## Pricklely Peete

Excellent job on the review man !!! 

 I hate to break this to you but all the audio-gd modules need at least 250+ hours to settle completely. They will all improve dramatically once you get past 175 hours with incremental further improvements to 300 hours. They take a long time to form for some reason. The original module (that LC and Burson Audio sell...also an audio-gd design) took in excess of 175 hours when I reviewed it for the Zero last spring ( I now have all the versions of HDAM both V1 and V2)...it was maddening since I was trying to get the piece completed and the dang sonic goal posts kept moving on me.....

 Again...a simply outstanding review !!!!

 Peete.

 PS Your assumption about a stiffer PSU for these is right on the money....these modules love a good PSU (best case is around + - 15-17V at 500 mV min which includes current needs for surrounding output stage of course).


----------



## Bleemv1

250+ hours!!! that's heaps. did you find the HDAM modules sounded better than opamps after 250+ hours?


----------



## Ron.id

Quote:


  Originally Posted by *Bleemv1* /img/forum/go_quote.gif 
_250+ hours!!! that's heaps. did you find the HDAM modules sounded better than opamps after 250+ hours?_

 

For me... Sun v.2 HDAM definitely sounded better than AD8397, 2x AD825, 2x AD8065, AD8066, OPA2134, OP270 (this is all that I own) even though burn-in time is less than 10 hours (I bought it from my friend and he use it no more than 1 hour just to test if it's worked). The sound is much wider and "full" than these ICs.


----------



## 00940

Quote:


  Originally Posted by *Bleemv1* /img/forum/go_quote.gif 
_250+ hours!!! that's heaps. did you find the HDAM modules sounded better than opamps after 250+ hours?_

 

I wouldnt' worry too much... transistors or opamps "burn-in" is mostly related to someone's memory being unable to remember how it sounded 250 hours earlier. Not to any actual changes in the semi conductors


----------



## majkel

I haven't noticed any changes so far but this thread will be updated with my impressions. The aforementioned AD825's which I compared yesterday with the OPA-Moon got one strong kick from the discrete op-amp and went to the box ashamed. It's another league. The OPA2134 or the OPA2132 are interesting in the P series only, the PA can sound different from one production date to another. The PA series and the AD8066 is no competition for the discrete op-amps. 
 There is oncoming opinion on rock, electronica to add to the review in the evening.


----------



## Pricklely Peete

Quote:


  Originally Posted by *Bleemv1* /img/forum/go_quote.gif 
_250+ hours!!! that's heaps. did you find the HDAM modules sounded better than opamps after 250+ hours?_

 

To my ears without a doubt. I do prefer the Earth and Moon modules though over the SUN (V1 at least, I have a pair of V2's cooking now).

 The dynamics, texture and full freq spectrum take time to fall into place.....it's the damndest thing to think they require this time but after going through this process now for 10 HDAMs it's predictable and repeatable each time.

 New ones I get automatically get a pass until at least 150 hours have passed then I get into the process from there noting the last major changes over the next 100+ hours.

 Peete.


----------



## majkel

OK, I will let them stay in the socket but it's only one per round possible, so this will take same time. Will I get much improvement replacing the regulators for +-15V range, or would it be just slight? I don't want to do it aimlessly as I will lose possibility of using some chips.

 Peete, you can try a pair of the AD797BRZ eventually. If you don't like them, I'll take them. 
	

	
	
		
		

		
		
	


	




 Maximum supply voltage is +-15V.


----------



## Pricklely Peete

Quote:


  Originally Posted by *00940* /img/forum/go_quote.gif 
_I wouldnt' worry too much... transistors or opamps "burn-in" is mostly related to someone's memory being unable to remember how it sounded 250 hours earlier. Not to any actual changes in the semi conductors 
	

	
	
		
		

		
		
	


	


_

 

How many of these modules (if any) do you have in your possession ? 
	

	
	
		
		

		
		
	


	




 My memory is fantastic !!! An easy test is to have 2 of the same type of HDAM, burn in one fully and then swap it for a fresh one...the differences are obvious and immediate.....you'd have to be deaf not to hear the difference....(sideways jab back at ya 
	

	
	
		
		

		
		
	


	




).


 Peete.


----------



## Pricklely Peete

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_OK, I will let them stay in the socket but it's only one per round possible, so this will take same time. Will I get much improvement replacing the regulators for +-15V range, or would it be just slight? I don't want to do it aimlessly as I will lose possibility of using some chips._

 

Depends on the circuit. Email Kingwa and ask him a few questions, he may be able to give some other options I don't yet know about that will fit the bill without boosting the V.

 Peete.


----------



## majkel

OK, so the first one dedicated for prolonged burn-in will be the OPA-Earth as this one is the worst at the moment.


----------



## Pricklely Peete

It's funny that's what everyone says about the Earth HDAM at first, including myself...the SUN is the fav (out of the gate) but the Earth once formed supplants the (unnatural IMO anyway) SUN V1& V2 rather quickly.....check the Zero thread for many such observations (between pages 500-650 I think). I have to add that I much prefer a neutral OPA in a DAC and Moon module in an analog circuit although I also like the Earth in that position for some music. 

 I have a review of the original module from last March in that thread. It took me ages to complete it (2 sections to it 3 weeks apart, due to the long burn in ) and was mentioned in this thread already (not specifically).....

 I think you'll be surprised by the changes to come..by far the biggest drawback to these is burn in time....although in my mind that really isn't a drawback at all just SOP for these modules.

 Peete.


----------



## Ron.id

Quote:


  Originally Posted by *TzeYang* /img/forum/go_quote.gif 
_^Nice! Is that sum OPA + BUFFER Three channel amplifier? Needs more details on the self etching._

 

I don't know about the amp that you referred. Mine is designed and self-etched by my friend, I only bought all the parts and soldered it all. It's a 3-channel active ground topology, buffer architecture, precision virtual ground reference, Class-A bias at voltage gain stage, Jung multiloop headamp. All opamps is dual channel version:







 My friend made another version of this headamp (ver.2) with input caps, single opamps at buffer stage, bass-boost control and dual layer PCB. It's professionally etched but I still prefer his v.1 design. 
	

	
	
		
		

		
		
	


	




 Here's the photos:


----------



## Currawong

Fantastic write-up, even if it isn't complete yet. Please do give the HDAMs 350 hours and have another listen. I had a weird moment somewhere around that mark with one of Audio-gd's amps, where one week I was listening as usual, then the next week, with no changes, suddenly all the music sounded better.


----------



## TzeYang

Quote:


  Originally Posted by *Ron.id* /img/forum/go_quote.gif 
_I don't know about the amp that you referred. Mine is designed and self-etched by my friend, I only bought all the parts and soldered it all. It's a 3-channel active ground topology, buffer architecture, precision virtual ground reference, Class-A bias at voltage gain stage, Jung multiloop headamp. All opamps is dual channel version:




_

 

That's freaking cool. It's like a Smaller PPA V1. 

 Do you think I can have snapshots of the bottom of the self etched single layer board?

 I was going to etch something similar with discrete buffers. I just want to know how clean it looked and add some confidence into self etching solutions.


----------



## majkel

OK, so let me report the review is finished at this time. Shocking news will be delivered ASAP when appear.


----------



## Bleemv1

So where does one get the AD797BRZ ?

 Is it directly swappable with something like the LM4562?

 edit: ok so it seems they are a single op-amp, so for my DAC which needs two dual opamps, I would need to get 4 AD797BRZ and 2 dual adaptors?


----------



## majkel

Correct, they are single and you should install them onto the adaptor as they're SOIC only. You can get them from Farnell or DigiKey I suppose. If the LM4562 worked in the circuit, the AD797BRZ x2 would do as well.


----------



## Pricklely Peete

You need to put an asterisk beside that conclusion stating the results are based upon modules that are no where near burned in.

 It's misleading as it now stands.

 I hope you plan to give these the required time because I can guarentee you they will change quite a bit from where they are now.

 Peete.


----------



## majkel

Quote:


  Originally Posted by *Pricklely Peete* /img/forum/go_quote.gif 
_You need to put an asterisk beside that conclusion stating the results are based upon modules that are no where near burned in._

 

I will report changes if appear. They had to be a better option for chip op-amps and they are. I'm sorry for taking to comparison not so popular types from better series but the only way to discuss my observations is to use exactly the same chips, especially AD797BRZ, and confirm I'm right or wrong. The LT1028ACN8 is another outstanding op-amp and I don't expect anything to change. Kingwa mentioned on his website 48 hours of burn-in and this condition has been fulfilled. I will try +-15V supply rails probably next week and tell you how it works. Until now, I didn't observe any changes due to burn-in.


----------



## Currawong

The interesting thing was the reports that the SOIC versus PDIP versions of some of the different opamps sound different, something I was wondering about.


----------



## majkel

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_The interesting thing was the reports that the SOIC versus PDIP versions of some of the different opamps sound different, something I was wondering about._

 


 The higher grade B series of the AD797 in the DIP package does not exist. The LT1028 CN and ACN series are both DIP, the ACN series has got tighter specs and does sound different. I guess it's another factory with "cleaner" production technology for the higher grade parts.


----------



## NelsonVandal

Majkel, would you like to try any of my discrete amps, AD797-clone or AD829-clone? AD829 is invisible in RMAA tests, limited by the E-mu 0404 sound card. AD797 measures excellent at 15V but not with 9.6V battery supply. It actually sounds better than it measures, and the harmonics are what's considered perfect with a nice falling pattern from 2nd to 7th. I use a weird ground, TLE2426 for the small signal returns and Sanyo WX caps and a discrete rail splitter for the headphones returns. This gives a much better channel separation and lower distortion at low Z loads compared to passive ground.

 My FET/CFP input JLH-clone is so messy, I'm ashamed of showing it to anyone. The le Classe A clone is also messy, and in this one I use the too bright sounding Toshiba transistors. I also have an 18V (not battery operated) version of the AD829-clone with larger voltage drop to the cascode transistors and current mirror.


----------



## majkel

Sun v.2 at +-15V is the only complete discrete op-amp, with a touch of wooly-woody-something added. The OPA Earth is like a cleaner AD8397 but tonality is not 100% complete. The OPA-Moon is sweet but tonally even less complete. 

 Regarding the my "top three" - yes, the OPA211 is great. After listening with the RS1's I borrowed from my friend I have to admit LT1028ACN8 is the best in imaging and smoothness. Best for both GS1000 and RS1. 

 AD797ANZ is as worse as the BRZ series, as the LT1028CN8 is worse than ACN8 series. Both suffer slight dryness, while the ACN8 is British rich and smooth. I have to say that after further modifications of my DAC - BG added to power supply and analog multiplexer bypass, now it looks like this. The most analog sounding are LME49710NA but they exaggerrate in this to the level imaging is blurry, and soundstage slightly congested. The LT1028AN8 is perfect but with its own, very delicate timbre, less present than in other op-amps like OPA2228 or LM4562. 

 Regarding measurements - I can't do that and I don't care for their results actually. I am of course curious of listening to some new toys/ 
	

	
	
		
		

		
		
	


	




 NelsonVandal, you're welcome. 
	

	
	
		
		

		
		
	


	




 Regarding IC's - I have to try out the LME49722, it's like decompensated LME49720. Sounds delicious. 
	

	
	
		
		

		
		
	


	




 My current recommendation list:

 1. 2x LT1028ACN8
 2. 2x OPA211ID (issues like in the review)
 3. 2x AD797BRZ (finally I found slight imaging issues and timbral imbalance)
 4. LME49720MA / 2x LME49710NA (I guess I like the former a bit more)
 5. OPA-Sun v.2 (thick, flawless, likeable sound)

 No more unconditial recommedations at the moment.


----------



## majkel

Try Elna Silmic II at all analog supplies of the DAC chip. I had the Sanyo WG previously in those places but ATM they remain at digital supplies only. BTW my DAC is based on the CS4397 chip and if you look at the Evaluation Board datasheet, there is the LT1028 proposed as the unbalancing filter op-amp. They knew what they suggested.


----------



## majkel

What headphones are you using? The OPA211 has got somewhat corrupted "instrument drawing structure". 
	

	
	
		
		

		
		
	


	




 For me the LME49710 is too blurry. It is great in my friend's headphone amp preamp section to compensate for somewhat edgy sound from the TI's NE5532 used in the first stage. I left the Sanyo WG in my CDP near the DAC together with the Panasonic PX's but I'm using it as the digital source only nowadays. Sometimes as a comparison when there is a doubt I did something wrong to the DIY DAC.


----------



## majkel

syllabus, I understand your preference but don't agree that looking for exact playback is audiophile related. I'd rather say audiophiles are looking for sepcial effect and that's why they dissect what they hear to evaluate if certain effect is sufficiently present. It might turn out that in another circuit I will prefer LME49710 or another op-amp. As I realised yesterday, the AD797BRZ and the OPA211ID, the *grounded OPA Sun v.2* are still serious contenders for the ultimate op-amp.


----------



## majkel

@syllabus, it looks like TI stopped sending free samples to Poland, at least they refused to send them the last time explaining I already had ordered those parts which wasn't true. I see no source of these op-amps to buy them. The OPA827 is not yet available at European vendors, either. I went back to the OPA211ID pair in the meanwhile, due to capacitors changes mainly. As a general rule I would say that any low distortion op-amp might be your favorite dependng on the surroundings from the power supply to the electroacoustic transducers, so I defer from telling anybody the LME49720, the OPA211, the Sun v.2 or the LT1028 is the best.


----------



## majkel

These won't work for my DAC - too low voltage supplies. Including the topic of this thread - we're drifting aside. These THS40.. probably won't work, either. They have pretty high input currents. When I tried the AD8022 or a pair of the AD8021's, I heard noise only. They were high input current op-amps, too. The Audio-gd discrete op-amps have the advantage of JFET inputs which is very low input current.


----------



## majkel

AD826 worked well besides it's nothing special, AD8022 was noisy, and yes, I have decoupling capacitors on all op-amp inputs. Might be these were oscillations because the AD8019 produced no noise, neither did the AD8397.


----------



## majkel

Our experiences differ a lot. I never liked the LT1364 and for me it's roughly the AD826 class, the AD8022 is one of the best for output buffers. I installed them there in my CDP, many guys did it in their Audiotrak Prodigy HD2 soundcards and confirmed that it was better than any other popular op-amp besides maybe AD8599 which is slightly different, much easier to use and very likeable.


----------



## majkel

I evaluated the AD8022 once as sounding pretty similar to the AD797ANZ, maybe a bit more tubey.


----------



## NelsonVandal

This thread has already gone astray, so I might just as well ask you, syllabus and majkel, how are you using AD797? What resistor values etc. Are you using the 47 pF decompensation (distortion cancelling) cap? I find AD797 to sound darker and more neutral with it, but when simulating it this way in LTSpice, it looks like hell.

 Majkel, I'll send you a PM regarding the discrete amps.


----------



## direcow

Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_This thread has already gone astray_

 


 yeah... it has.


----------



## Currawong

Out of interest, I tried the OP27GP in my test Compass as they were in my local electronics shop and they give a very good first impression, better than the 627s do, managing to be seductive with the music in the mid range, reminding me somewhat of the Moon, but with some of the punch you get from the Earth in the upper ranges. Quite interesting.


----------



## back

hi guys.
 anybody knows why audio gd don`t answer emails?


----------



## theBigD

remember audio-gd is in china. they are not there to answer email till 4pm pst. i did encounter a delay with them and then emailed again usually around 4pm pst and they got back to me quickly.


----------



## Currawong

I get very prompt replies from Kingwa whenever I email, but my timezone isn't a lot different from his. 

 Back: The time of your post would have been about 5 or 6am his time or thereabouts.


----------



## back

guys i have sent him emails before and he responded very fast.

 this time it`s 4 days and still no answer.


----------



## csroc

Quote:


  Originally Posted by *back* /img/forum/go_quote.gif 
_guys i have sent him emails before and he responded very fast.

 this time it`s 4 days and still no answer._

 

Did you get the confirmation email that Audio-gd received it? If so maybe it just got lost in their queue of emails to answer or the response was emailed to you but never made it. If you never got that confirmation then it's likely they never got the email. You could try sending it again.


----------



## back

Quote:


  Originally Posted by *csroc* /img/forum/go_quote.gif 
_Did you get the confirmation email that Audio-gd received it? If so maybe it just got lost in their queue of emails to answer or the response was emailed to you but never made it. If you never got that confirmation then it's likely they never got the email. You could try sending it again._

 


 no i didn`t and i have sent two times.


----------



## csroc

Try another email address if you haven't. I've always gotten their confirmation email instantly.


----------



## Currawong

It's probably ended up in your spam folder.


----------



## Ron.id

Because this thread has already gone astray, allow me to keep it on track with my latest headamp set ups: two OPA Moon and one OPA Sun v2.

 To get a higher current, I changed the precision rail splitter IC's with Sijosae's discrete rail splitter module (thanks to my friend, he made it for me) 
	

	
	
		
		

		
			





 The original rail-splitter ICs who provide less currents actually worked fine with 3 HDAMs plus 3 op-amps, but this discrete rail-splitter module seems to "widen" the sound...
















 It sound..... just wonderful....


----------



## majkel

Thanks, Ron. What are these SOIC chips?


----------



## Ron.id

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_What are these SOIC chips?_

 

All these SOIC chips biased to Class-A, part of gain stage for L/R/GND channels, it's a combination of AD8066 / OPA2134 / AD8397 or OP270.


----------



## majkel

Isn't it too many opamps to have great sound? The fewer of them, the better. Also, try removing the tantalum capacitors from analog circuits wherever they are and replace them for some decent electrolytic caps. They pollute analog supplies badly while they rock for some digital supply bypassing - not everywhere of course. 

*Blog style review update - 2/9/2009*

 I upgraded a bit my digital source yesterday because of what I learnt on the meeting with my friend owning the Accuphase DP800/DC801 combo. I tried the DP800 as the CD transport for my DAC and realized it was significantly better. However my actual preferences regarding parts in my DAC remained unchanged. Regarding the integrated op-amps as well but the classification needs to be revised. 
	

	
	
		
		

		
		
	


	




 I know I change my mind pretty often due to new lessons learned each time but for today...
*Absolute number one: LME49860*
*Absolute number two: Audio-gd Sun v.2*
 They are both pretty similar sounding, with the LME being a bit richer harmonically and the Sun v.2 being slightly more analytical and showing very slight instability on vocals only. Actually with a better digital source (it wasn't that bad anyway) it increased the distance to the OPA Earth and the OPA Moon, not to mention I prefer it to pairs of the OPA211 and the AD797BRZ now.


----------



## Bleemv1

so the LME49860 is your favourite at the moment? should I look for the MDIP or the SOIC version? are these Dual op amps?

 Are these swappable with say an lm4562?

 thanks


----------



## majkel

Quote:


  Originally Posted by *Bleemv1* /img/forum/go_quote.gif 
_so the LME49860 is your favourite at the moment? should I look for the MDIP or the SOIC version?_

 

I tested DIP version.
  Quote:


 are these Dual op amps? 
 

yes
  Quote:


 Are these swappable with say an lm4562? 
 

yes


----------



## NelsonVandal

One of the guys involved in the development of the LME-opamps are active at diyaudio.com. He claims the metal can versions sound significantly better. Have you tried one of those? Do you know where to get them?


----------



## majkel

farnell.com if any but there is a lot of metal can versions of op-amps like OP27, OPA627, OPA111, LM4562 but they are damn expensive. I'm not sure on the other hand if the LME49860 exists in the can package.


----------



## haloxt

Copying and pasting from http://www.head-fi.org/forums/f5/des...ml#post5412359

  Quote:


  Originally Posted by *jjlucas76* /img/forum/go_quote.gif 
_I have tried the OPA627BP on my headamp to replace a couple of AD797AN and the difference was quiet stunning in terms of speed and quality, but the bass and the sound coming from dark were missing. lucky for me I have ordered together with them a couple of AD797BRZ and 2 nice SOIC to DIP converters. 

 The results? uhm I need to say that who was saying that the AD797BRZ are better then the OPA627BP was right and I can only confirm that they actually have both qualities from the OPA627BP and the AD797AN. Excellent choice for your preamp or DAC.

 Cheers._

 

My feelings about the 3 hdams' characteristics are quite similar with your review, so I am thinking about trying out the LME49860.


----------



## Bleemv1

I thought I read somewhere that the LME49860 is the same as the LM4562 but with slightly better tolerances or something? are these people wrong?


----------



## NelsonVandal

I thought it was a well known fact that LME49720 is a renamed LM4562. Isn't it so? A former National employee, active at Diyaudio.com, claims that LME49860 also is _exactly_ the same opamp as LM4562. The only difference is that they're tested to assure they withstand a slighly higher voltage supply, and if you don't need this higher voltage rating you could just as well use LM4562.

 So threre's really no reason to believe LME49860 is a superior chip, and if we like the sound of them and want to make the most of it we should go for LM4562, LME49720 or LME49710 metal can version.

 Here's the discussion at Diyaudio
diyAudio Forums - National opamp inflation - Page 1


----------



## Bleemv1

Yeh I might have read that thread. Although I remember seeing some graphs comparing both the op amps and they were very slightly different...?


----------



## Currawong

There are two versions of the AD797BRZ on farnell.com, one new one which is a low-noise version. Which version is the one to get or doesn't it matter?


----------



## majkel

I guess it doesn't matter. It's just a mess in their database. Beware of Newark option which costs much outside of North America. BTW, order the LME49860 for yourself. This one looks best to me and I didn't have it in the review time.

*NelsonVandal*, the LME49720 sounds different than the LM4562, and the LME49860 is better than both. BTW, you can perform a test: supply the LME49720 or LM4562 with +-22V rails and see if it's blown. 
	

	
	
		
		

		
			





 If so, then it sure is a different circuit than the LME49860. BTW, some specs are a bit different. 
 Thanks for loaning the "AD797 clone" BTW. 
	

	
	
		
		

		
		
	


	




 I have some impressions and will let you know later. Very nice job and sound.


----------



## NelsonVandal

Quote:


  Originally Posted by *Bleemv1* /img/forum/go_quote.gif 
_Yeh I might have read that thread. Although I remember seeing some graphs comparing both the op amps and they were very slightly different...?_

 

You have to take the supplied voltage in consideration. The specs for LM4562 are measured at +/- 17V and LME49860 at +/- 18V and 22V. If they were measured at the same supply voltage they'd probably look exactly the same.


----------



## majkel

I compared specs for +-15V.


----------



## NelsonVandal

I took a look at the graphs in the data sheets, and most of them are identical. They must have used the same graphs for both LM4562 and LME49860, and if they did they must think that the amps are absolutely the same.


----------



## majkel

I think it's a bit of laziness. The datasheets are for the most part written by students being on internship. I remember many simple mistakes in datasheets from different brands. There is no reason to rely on them. What I think is that all three have the same schematic but are produced on different production lines with use of different silicon compound, giving higher acceptable voltage supplies and just different sound. It's like TLE2072 against TLE2082 - specs are identical, sound quite different.


----------



## NelsonVandal

"1. Yes the 4562 and LME49720 are identical. National changed the numbering system to go from 4 to 5 digits and since they would not give us a new name for the high performance series of parts we just changed the LM to LME (E for excellence). Also the High voltage parts are identical but tested and guaranteed to higher standards. Testing always costs more...can anyone say MIL Spec!"

diyAudio Forums - National opamp inflation - Page 3


----------



## majkel

I care for sounds, not specs. There is more difference between the LM4562MA and the LME49720MA than between any of these and the LME49860 while the latter is more refined than the other two.


----------



## theBigD

so marjkel, are you now saying LME49720MA is better than the ad797brz? what are the characteristics of LME49720MA?


----------



## majkel

Quote:


  Originally Posted by *theBigD* /img/forum/go_quote.gif 
_so marjkel, are you now saying LME49720MA is better than the ad797brz? what are the characteristics of LME49720MA?_

 

No, I wouldn't say that but I like the OPA211 and the LME49860 a bit more than the AD797BRZ's but you know, these all are contenders to be the best depending on your tastes and the rest of the audio gear, as well as the OPA Sun v.2.


----------



## theBigD

so what do you find so appealing about the lme49860? i might get a sample and try in my ef1. i am still waiting for earth and moor to arrive, came from china to LA going to oregon via NJ??? maybe i will get tomarro.


----------



## majkel

Timbre, transparency and resolution on fast, complex instrumental passages. This made even the AD797BRZ to suffocate slightly, the OPA211 was better in this field together with the NI product but the LME49860 is sounding more effortless.


----------



## Bleemv1

just got my LME49680s. How long burn in did you put through it?

 I don't really know if there's a difference. But maybe it is less bright than the LM4562. That's the feeling I'm getting at the moment. Maybe positioning is more defined as well. Can't be bothered A/B ing the chips


----------



## majkel

Maybe your equipment is not resolving enough? For me these are subtelties that matter. Also, I cannot tell how they differ both the LM4562 and the LME49860 from one piece to another within the type.


----------



## linuxworks

Quote:


  Originally Posted by *00940* /img/forum/go_quote.gif 
_I wouldnt' worry too much... transistors or opamps "burn-in" is mostly related to someone's memory being unable to remember how it sounded 250 hours earlier. Not to any actual changes in the semi conductors 
	

	
	
		
		

		
			



_

 

lol 
	

	
	
		
		

		
		
	


	




 I always like a refreshing bit of honesty in this sea of high-end audio.

 cheers.


----------



## majkel

Thanks buddy. I forgot to mention I realized no burn in effect on any integrated op-amp. This applies to the LME49860 as well.


----------



## Bleemv1

ok 
	

	
	
		
		

		
		
	


	




 I do feel overall that my system is more enjoyable to listen to. Even if changing the op amps have not done anything, it will have a placebo effect since you have recommended it highly haha


----------



## Shoreman

Quote:


  Originally Posted by *Bleemv1* /img/forum/go_quote.gif 
_ok 
	

	
	
		
		

		
		
	


	




 I do feel overall that my system is more enjoyable to listen to. Even if changing the op amps have not done anything, it will have a placebo effect since you have recommended it highly haha_

 

What a refreshingly honest sentiment...


----------



## linuxworks

see, everyone KNOWS op-amps don't need burn-in.

 now, cases and screws, that's a *whole* other ballgame! my case is still breaking in and I expect better sound in the next week or two, once the sheetmetal and screws have all 'settled' in their magic positions.

 (lol!)


----------



## sum1

If i like the vocals to be tonally full and bought upfront so that it becomes the main focus of the music would that sound more like Sunv2 or moon?


----------



## majkel

Sun v.2, always Sun v.2.


----------



## sum1

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Sun v.2, always Sun v.2. 
	

	
	
		
		

		
		
	


	


_

 

Sun v.2 huh. I would've thought the so called tube-like moon would sound more like it. Heck i might just get them both if my wallet agrees 
	

	
	
		
		

		
		
	


	



 Thanks for the info and for your great review as well.


----------



## majkel

The Moon is not tube-like. Tubes are more accurate in terms of timbre reproduction. Smoothness is not enough.


----------



## theBigD

majkel, you seem to be liking the sun more and more. your description on the first page of sun doesnt seem to endorse your current enthusiasm. what has changed? is it not as woody sounding as you thought? i am going to try LME49860MA and see how it does in my ef1. i wouldnt mind trying the ad797 brz but its kinda a pain when you have to get a 2:1 adapter and mount for dual. the earth and moon i had on order went from china to LA to NJ back to LA and now it is going back to china i think???? i am working on getting a refund now. im pretty bummed i never got to try them, but it kinda seemd op amps might be better anyway.


----------



## majkel

This is due to coinciding development of my DAC in the time I try new op-amps. I hear more qualities of some devices, and more flaws of some other but don't find it best to update the first post eacj time. The idea is to read the whole thread. The LME49860 is a safe purchase - no supply, stability or input currents issues as for a bipolar op-amp. 

 Regarding the Sun v.2 - it is a bit woody but it does not interfere with other qualities of this device. *Please also notice that I switched from the +-12V to the +-15V supply some time after ending the review, and this improved the Sun v.2 against the other discrete op-amps.*


----------



## fzman

Quote:


  Originally Posted by *linuxworks* /img/forum/go_quote.gif 
_see, everyone KNOWS op-amps don't need burn-in.

 now, cases and screws, that's a *whole* other ballgame! my case is still breaking in and I expect better sound in the next week or two, once the sheetmetal and screws have all 'settled' in their magic positions.

 (lol!) 
	

	
	
		
		

		
		
	


	


_

 

not to mention when your nuts warm up too


----------



## theBigD

what exactly does +- voltage mean compared with max voltage? for instance the max voltage on my ef1 is 16volts but head direct gives no +- voltage rating.


----------



## fzman

i am in the midst of testing opamps for both my new xonar essence stx and prodigy hd-2 sound cards which use 3 dual 8-dip opamps:

 two for I/V conversion after the analog devices d-a (xonar) akm (prodigy), and 
 one dual balanced to single ended for output

 i've ordered a bunch of brown dog adapters which will allow me to do soic to dip-8 either dual-dual, or 2 singles to dual and also some 2 single dip-8 to single dual dip-8s.

 here's the questions:

 anyone know if the browndogs will even fit in these cards?

 do soics sound better than dips?
 do pairs of singles outperform duals?

 do the metal can to-99-8's sound better than their dip or soic counterparts?

 are there specific recommendations for either or both positions, for either or both cards?, e.g., fet inputs for the I/V... bipolars for output, etc...?

 i know than nothing replaces pesonal listening, but the essence card has an emi shield, which takes time to remove-reinstall, plus the shutdown-reboot times which makes it really tedious to do the swap-outs.

 tia,

 Mark


----------



## Ron.id

Another modifications of my (modified) headamp... went full discrete. 
	

	
	
		
		

		
		
	


	








 Two OPA Moon and one OPA Sun v2










 Discrete Diamond Buffer modules upgrade





 Base headamp PCBs

 Sound is so good, powerful, dynamics, tight, wide.... in short, I love it!


----------



## NelsonVandal

Quote:


  Originally Posted by *Ron.id* /img/forum/go_quote.gif 
_Base headamp PCBs_

 

One schematic tells more than a thousand pictures! Open loop/closed loop? Resistor values? Grounding?

  Quote:


 Sound is so good, powerful, dynamics, tight, wide.... in short, I love it! 
	

	
	
		
		

		
			




 

It would be nice if you could develop this a bit, like compared to what etc.


----------



## Ron.id

Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_One schematic tells more than a thousand pictures! Open loop/closed loop? Resistor values? Grounding?_

 

It's a 3 channel headamp with buffers, class-A bias at gain stage, Jung multiloop.














  Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_It would be nice if you could develop this a bit, like compared to what etc._

 

Hmmm... i didn't compared it head-to-head with other headamps yet, so I based my statement only with this headamp previous settings, and my memory when i have a chance to compare it with others in the past. In the past I have compared this headamp with this (mine is third from the bottom):






 My friend has version 2 of this headamp (slight modification in the schematic), as you can see it on top of Lisa III, which use a better parts than me (mostly the opamps), ranked the second best below Lisa III.

 And... going to full discrete - if my memory served me well - this headamp jump much higher than that v2.

 I don't know how good is this discrete against Lisa III coz my experienced is too short with this headamp. As i remember, one thing that definitely makes Lisa III stay ahead of all headamps at that photograph is the soundstage. I hope at our local meet at the end of this month someone will bring Lisa III so I can compare it.


----------



## majkel

This schematic is not optimal. First - it is designed the way that the L/R channels have two stages and it makes no sense as the second stage is nowhere more efficient in terms of current. Just op-amps again. Second thing is that parallel connections of outputs decrease detail a bit - just due to some very slight but existing phase shifts between the two parallel stages. All in all, the amp is not very current efficient - just like INA134 by half. I saw the LISA III schematic and it makes much more sense but NelsonVandal's discrete amp makes even more IMHO.


----------



## psychaudio

Hi all...

 Since Ron.Id has posted the schematics here, I might as well explain it a bit...

 Yes, probably it's not optimal, but given the purpose of the design is:

_"To build a multiloop amp, with parts available only on local stores around me"_

 Now, if you live in my country, well, to get a good op-amp is really difficult, the same also with buffer chip like the popular BUF634 is almost impossible to get in local stores around, the best I can find is only LM4562 and OPA2134...

 Yes we can get parts from internet, but I usually just use what available around me...

 So why does the L/R have two stages, with the 2nd stage just acting as follower and yes, it's nowhere more efficient in terms of current...

 Because to use the multiloop topology we need buffer (or in this case follower), and since I need bigger current output to drive low impedance headphones, so a quick hack is just to parallel the 2nd stage L/R (the follower) with another op-amp 
	

	
	
		
		

		
		
	


	




 ~ a l a A47

 So why don't I just use single op-amp and follow it with discrete diamond buffer? Since it's easy to get general purpose BJTs around?

 Simple, because I want it to be able to swap buffer (as long as it works inside the feedback loop)

 first the use of dual op-amp (for both stage) on the L/R makes it easy for me to just use the U1 DIP8 socket as an "expansion" socket, just like Ron.Id do with his Diamond buffer module which is plugged in directly to the U1 socket

 and second, because the U2 op-amp is in parallel, whenever there's an "expansion" module inserted to U1 socket, I can just ignore it completely by not plugging any op-amp on the U2 socket...

 And the last, the use of INA134 as rail splitter, it's just simply because I can't get TLE2426 around, and this is the only chip I found that states inside the application note that it can be use as a virtual ground...

 I hope it explains well about the schematics 
	

	
	
		
		

		
		
	


	




 Regards...


----------



## Ron.id

Thanks for the explanation psychaudio 
	

	
	
		
		

		
		
	


	




 Now, as we're talking about discrete op-amps, specifically Audio-gd OPA's, yesterday I have an opportunity to compare it with several headamps as I received an invitation to test a brand new IE Series from Sennheiser (IE6, IE7, IE8).

 This is the humble headamp setups for these HDAMs:






 Two OPA Moon and one OPA Sun v2 at the gain stage, followed by discrete diamond buffers. No ICs at all in this headamp, all discrete.






 The result is: discrete op-amps easily beats down all his rivals, to name it: virtually all iBasso series, The Hornet, TTVJ Millet, as well as version 2 of this headamp with expensive components and ICs. The huge dynamics is a wow factor here with discrete op-amps, among the other things.


----------



## Currawong

Nice work Ron.id. Pity it's too big to go in one's pocket. 
	

	
	
		
		

		
		
	


	




 What made you decide to choose the Moon and Sun respectively?


----------



## mbd2884

They are quite a bargain in comparison to the Burson 100 dollar OpAmps eh?

 Ron that is one of the most interesting Amps I've seen, very cool looking. For casing, I think be awesome, what someone did for the DAC-100, have holes in the top casing to so the HDAMs can be seen.


----------



## theBigD

I finally got my earth and moon that i ordered over 2 weeks ago and installed the moon in my ef1 on fri. everything seemed to be working ok. I used 2 8pin socked adapters stacked on top of original op amp socket. ive been burning in moon since then. then this morning i went to try earth becuase i thought it might synergize better with denons d5000 i had on loan. I was sorely dissapointed there was horendous distortion in right channell with certain higher frequency. I checked the sockets and they were tight and still worked fine with moon. then i discovered if i touched one side with my finger distortion went away. and here comes the weired part, if i just put my finger by the otherside without touching it the distortion would get worse! its like my finger is passing through a magnetic field or something.

 Have you guys ever run across this before? any way to fix? I am hoping i dont have to send back. these almost got lost by the post office getting here, dont know if i trust it to get back in one piece.

 thanks for the help.


----------



## Ron.id

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_Nice work Ron.id. Pity it's too big to go in one's pocket. 
	

	
	
		
		

		
		
	


	




 What made you decide to choose the Moon and Sun respectively?_

 

Thanks Currawong. Yeah this headamp surely too big to put into the pocket, but still portable enough, coz i run it with a portable NiMH external battery 
	

	
	
		
		

		
		
	


	




 I choose the Moon just to know how it sound, because I already have 1 piece of SUN v2 before bought the Moons.

  Quote:


  Originally Posted by *mbd2884* /img/forum/go_quote.gif 
_They are quite a bargain in comparison to the Burson 100 dollar OpAmps eh?

 Ron that is one of the most interesting Amps I've seen, very cool looking. For casing, I think be awesome, what someone did for the DAC-100, have holes in the top casing to so the HDAMs can be seen._

 

Yes it is.... the price is good.

 Thanks for your compliments. I thought the same thing with casing, with a hole on top of it to show these HDAMs. 
	

	
	
		
		

		
		
	


	




 But after some considerations, I prefer a closed one because I want to put another casing on top of it that contains capacitors since I use this headamp with modified iPod (DIYmod). 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *theBigD* /img/forum/go_quote.gif 
_then i discovered if i touched one side with my finger distortion went away._

 

Have you ground the Earth? LOL ...how to ground the earth anyway LOL 
	

	
	
		
		

		
		
	


	




 I mean, have you connect the ground lead of OPA Earth to the ground of your PCBs? Hope this could help... although I'm not so sure about it.


----------



## majkel

Connecting the ground helps all OPA's IMHO. Do it as close to the output as possible for best results. I connect the ground to the ground pin of the socket for wiring the RCA outputs.


----------



## theBigD

yes i grounded to the rca ground in back. this was kingwas suggestion. unfortunenetly didnt fix the earth. but i have moon grounded there now and it may be responsible for the much improved attack and speed of it, although sennsay says it is part of burn in. I have around 56 hours on it now and plan to get at least 200. 

 audio-gd is sending a new earth as replacement and hopefully this will fix the issue. kingwa is very good to do bussness with. he has responded very quickly to help me with this problem.

 if you guys can think of any other thing i could be doing i sure appreciate it. the contacts seem to be well connected and work better than the extension lead i was using before.

 and the moon is working great right now. in the same arrraingement.

 here are some pics before i moved ground to proper spot.


----------



## Currawong

The effect I noticed from grounding the HDAMs to the RCA output in the Zero DAC I could best describe as sounding like the power circuit had been upgraded and had better control, if that makes any sense.


----------



## fzman

Quote:


  Originally Posted by *theBigD* /img/forum/go_quote.gif 
_I finally got my earth and moon that i ordered over 2 weeks ago and installed the moon in my ef1 on fri. everything seemed to be working ok. I used 2 8pin socked adapters stacked on top of original op amp socket. ive been burning in moon since then. then this morning i went to try earth becuase i thought it might synergize better with denons d5000 i had on loan. I was sorely dissapointed there was horendous distortion in right channell with certain higher frequency. I checked the sockets and they were tight and still worked fine with moon. then i discovered if i touched one side with my finger distortion went away. and here comes the weired part, if i just put my finger by the otherside without touching it the distortion would get worse! its like my finger is passing through a magnetic field or something.

 Have you guys ever run across this before? any way to fix? I am hoping i dont have to send back. these almost got lost by the post office getting here, dont know if i trust it to get back in one piece.

 thanks for the help._

 

i've been opamp rolling in an asus xonar essence sound card which uses 3 dual dip-8s. at the suggestion of a former national semiconductor engineerwho was on the team which came out with the 497xx series of opamps, i put in 3 49720s, in the to-99-8 metal can version, i first put them in sockets to preform the leads, then put them, socketed, into the sockets on the cards.

 this lead to some of the same kind of distortion you mention, so i pulled them, and put them directly into the card's sockets. distortion went away.

 more recently, i put a pair of 49710s (the single version of the 49720) also metal cans, into the output position, using a browndog adaptor which converts a pair of single dip-8s to one dual dip-8.

 the small box-shaped caps surrounding the opamp socket prevent the adaptor from going al the way in, and there is a hint of that same distortion, unless i push it in as far as it will go.

 lead-length seems crucial in these applications, and that may be what you are running into.

 hope that helps,

 best,

 Mark


----------



## NelsonVandal

I can't see how the gd-opamps could function properly unless you connect them to ground where it's specified.


----------



## theBigD

yeah with the hdams the connection has to be absolutely solid. i did get the earth to finally work in my ef1. I really like the wide involving soundstage of the earth and moon. I have yet to hear an op amp that sounds this natural and dynamic. but then i havent yet tried the ad797brz or the other opamps that markl likes better yet. i do plan on trying them soon. 

 my ef1 is on the fritz right now. so i went back to by go vibe v5s with 24volt elpac. didnt like the sterility of the op627 i had in it so. i plugged the earth into it and wow! huge spacial improvement not to mention a more extended bass response better tonal representation. 

 i have to say the hdams seem like a step in soundstage between the op amp and tube like sound.


----------



## haloxt

I just got the LME49860NA's, they are much better than the LME498710's on browndogs (maybe because incompetent me soldered it heh heh). How long do you guys think I should burn it in before comparing it with the hdams?


----------



## les_garten

Quote:


  Originally Posted by *haloxt* /img/forum/go_quote.gif 
_I just got the LME49860NA's, they are much better than the LME498710's on browndogs (maybe because incompetent me soldered it heh heh). How long do you guys think I should burn it in before comparing it with the hdams?_

 

You believe there is burn in on an IC?

 .


----------



## haloxt

I don't know, I got two LME49860's so I'll compare a new one to one at 50 hours. I just want people's opinion on if burn-in is required since I've heard some experts suggest it. If burn-in is not required then my initial impression is that the LME49860's are much better than the LM4562 and LME49710's. I'll become familiar with the LME49860's before I compare it with the earth and moon hdam's.


----------



## les_garten

Quote:


  Originally Posted by *haloxt* /img/forum/go_quote.gif 
_I don't know, I got two LME49860's so I'll compare a new one to one at 50 hours. I just want people's opinion on if burn-in is required since I've heard some experts suggest it. If burn-in is not required then my initial impression is that the LME49860's are much better than the LM4562 and LME49710's. I'll become familiar with the LME49860's before I compare it with the earth and moon hdam's._

 

Interested to hear what you think about the LME49860. I have some of those also, haven't put them in yet.

 .


----------



## Bleemv1

I did the same upgrade, from LM4562 to LME49860.

 I found the sound to be a bit more detailed and more enjoyable at the same time. Bass impact seemed a bit better too. the LME49860 seems more refined compared to the LM4562.


----------



## les_garten

Quote:


  Originally Posted by *Bleemv1* /img/forum/go_quote.gif 
_I did the same upgrade, from LM4562 to LME49860.

 I found the sound to be a bit more detailed and more enjoyable at the same time. Bass impact seemed a bit better too. the LME49860 seems more refined compared to the LM4562._

 

Note to self:
 Change out those OPAs tomorrow!

 .


----------



## NelsonVandal

If it's possible for you, let someone else roll the opamps and then try to tell which is which. Have it done a number of times and see if you get it right more than half of the times
	

	
	
		
		

		
			





. Placebo is a strong medicine. LM4562 = LME49720 = LME49860. There's no reason to believe any of them should be better than the others, but maybe different batches sound different.


----------



## majkel

So let's assume one batch is named LME49720, another is LME49860 and the third one say LM4562. I recommend the LME49860 batch. You can also say there is no difference between Siemens and Tesla because it's always E88CC just from another factory. 

 After some more experiments with upgrading my headphone amp and its PSU I find again the AD797BRZ to be the best, in terms of overall transparency. 

 I sold the Earth so I cannot say how it helps but my Sun v2 improved when I removed the capacitor upgrade. The ones I use in my DAC are better and those from Evox just were making the sound worse. So, I strongly recommend to anybody removing the cap upgrade or placing there some decent electrolytics, i.e. Black Gate STD.


----------



## les_garten

Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_If it's possible for you, let someone else roll the opamps and then try to tell which is which. Have it done a number of times and see if you get it right more than half of the times
	

	
	
		
		

		
		
	


	




. Placebo is a strong medicine. LM4562 = LME49720 = LME49860. There's no reason to believe any of them should be better than the others, but maybe different batches sound different._

 

They are different Opas, ehhh? Also what you are discussing will get you censored here, ehhh?

 .


----------



## haloxt

Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_If it's possible for you, let someone else roll the opamps and then try to tell which is which. Have it done a number of times and see if you get it right more than half of the times
	

	
	
		
		

		
		
	


	




. Placebo is a strong medicine. LM4562 = LME49720 = LME49860. There's no reason to believe any of them should be better than the others, but maybe different batches sound different._

 

Sorry it won't be possible because I have no friends in real life. My method of testing is just extended listening to see if anything changes and switching back and forth to verify. Placebo is a strong medicine, and it can become far more effective than actual medicine once firmly believed in 
	

	
	
		
		

		
		
	


	




 so in a sense I value my placebo-prone tests to DBT. But if I had friends yeah I'd do DBT 
	

	
	
		
		

		
		
	


	




.

 I'm very much impressed by the LME49860's, it gives a very complete and neutral sound but it sounds flat and 2-D compared to the earth hdam. That's my feeling after 15 hours of burn-in. I'll see again how it compares after 50 and 100 hours just to be sure.

 I'll take out my sound card and do A/B of lm4562's and lme49860's later, right now I've only compared with my lme49710's, but my memory tells me lm4562's and lme49860's sound similar.


----------



## majkel

Even if they have the same schematic, this means nothing. The LME49860 accepts higher voltages so it's another technology or different silicone compound used. In my DAC it is not 2-D. The holography is very good. And yes, the LME49860 is somewhere in between the LM4562 and the LME49720. The former is smooth, rich and slightly colored, the latter a bit dry.

 I forgot to add: there is no burn-in regarding chip op amps. Verified many times.


----------



## les_garten

Quote:


  Originally Posted by *haloxt* /img/forum/go_quote.gif 
_Sorry it won't be possible because I have no friends in real life. My method of testing is just extended listening to see if anything changes and switching back and forth to verify. Placebo is a strong medicine, and it can become far more effective than actual medicine once firmly believed in 
	

	
	
		
		

		
		
	


	




 so in a sense I value my placebo-prone tests to DBT. But if I had friends yeah I'd do DBT 
	

	
	
		
		

		
		
	


	




.

 I'm very much impressed by the LME49860's, it gives a very complete and neutral sound but it sounds flat and 2-D compared to the earth hdam. That's my feeling after 15 hours of burn-in. I'll see again how it compares after 50 and 100 hours just to be sure.

 I'll take out my sound card and do A/B of lm4562's and lme49860's later, right now I've only compared with my lme49710's, but my memory tells me lm4562's and lme49860's sound similar._

 

When you change these do you change all 4 or just the Headamp OPAs?

 .


----------



## haloxt

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_When you change these do you change all 4 or just the Headamp OPAs?

 ._

 

I won't use the sound card to test lme49860 because I don't have 4 of them, and I need 4 because they all affect sound quality.

  Quote:


 The each polarity signal produced by AK4396 goes to 2 dual opamps (U8 for left, U10 for right) In those dual opamps, each opamp handles only one polarity, either positive signal or negative. Then both exclusively amplified positive and negative signals are re-assembled and goes to another opamps (U9 for left, U11 for right) for second amplification. In the second dual opamp, U9, The one opamp is for left headphone and the other is for left RCA output. In U11, one opamp is for right headphone and the other is for right RCA output.


----------



## les_garten

Quote:


  Originally Posted by *haloxt* /img/forum/go_quote.gif 
_I won't use the sound card to test lme49860 because I don't have 4 of them, and I need 4 because they all affect sound quality._

 


 Hi,
 I understand all 4 effect SQ. But to throw out another variable here, it's possible/probable someone would like one set of OPAs in the Front end and another set of OPAs in the Headamp.

 .


----------



## guilders0

is there a place to buy AD797BRZ mounted on DIP8 socket ?

 I haven't been that positively surprised by the LME49860. Of course it all depends on the player (in my case a shanling scd-t200c).
 Currently I run with LT1028 SOIC on DIP8 socket, more open, more natural, more bass power than the LME. And it seems to be the standard version of 1028.
 I'd like to give a try to the AD797BRZ...


----------



## PPkiller

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_So let's assume one batch is named LME49720, another is LME49860 and the third one say LM4562. I recommend the LME49860 batch. You can also say there is no difference between Siemens and Tesla because it's always E88CC just from another factory. 

 After some more experiments with upgrading my headphone amp and its PSU I find again the AD797BRZ to be the best, in terms of overall transparency. 

 I sold the Earth so I cannot say how it helps but my Sun v2 improved when I removed the capacitor upgrade. The ones I use in my DAC are better and those from Evox just were making the sound worse. So, I strongly recommend to anybody removing the cap upgrade or placing there some decent electrolytics, i.e. Black Gate STD._

 


 Hi there,

 able to test ad743? my last impression of this opamp is it does better then ad797A version. not that sure how it fares when compared to ad797B...


----------



## theBigD

I just got my replacement ef1. And put the earth in it. Forgot how muddy and compressed the ef1 sounds before burn in. 

 On the bright side (no pun intended), i got the Sun today. So i poped that into my amp and it picked it right up. Brighter more dynamic presentation and nice aggresive midrange with great percussion. I am listening with d7000, and of course this is all pre-burn in, i expect there will be some changes especially after 50 hours.

 I really like the sun right now and it will be great to burn in the amp with this.


----------



## les_garten

Quote:


  Originally Posted by *theBigD* /img/forum/go_quote.gif 
_I just got my replacement ef1. And put the earth in it. Forgot how muddy and compressed the ef1 sounds before burn in. 

 On the bright side (no pun intended), i got the Sun today. So i poped that into my amp and it picked it right up. Brighter more dynamic presentation and nice aggresive midrange with great percussion. I am listening with d7000, and of course this is all pre-burn in, i expect there will be some changes especially after 50 hours.

 I really like the sun right now and it will be great to burn in the amp with this._

 

It will be interesting to se if you like the SUN in the Long run. Some guys put it in, liked it and then got tired of it and went back to the Earth. kinda like too much Cotton Candy. Let us know.

 .


----------



## theBigD

Well with over 75 hours on it the SUN and my amp have opened up. Its all a bit brighter and forceful. I love the energy and dynamics of the SUN. It seems like its almost a bit eager in its presentation. While the earth sounds pretty nuetral and a bit smoother the sun is puncy dynamic and fun. The sun lacks a bit of mid bass warmth that the earth has, I am hoping to find a bit of warmth in the sun, maybe more burn in is required.

 I just switched the tube to a mullard from the sylvania i typically use, and that certainly helps. i kinda want to try a long plate mullard because they are known to have a larger soundstage. I find the short plate mullard i have, to be a bit smaller in the soundstage than i like. But man it sure sounds good right now, nice bass and warmth, rockin out to some Boston right now and its pretty freakin nice.


----------



## haloxt

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_It will be interesting to se if you like the SUN in the Long run. Some guys put it in, liked it and then got tired of it and went back to the Earth. kinda like too much Cotton Candy. Let us know._

 

Kingwa suggested not to get the sun in the compass because he thought it might have bad synergy, something about the compass itself sounds neutral. Have you heard people other than compass owners say they didn't like the sun as much as the moon and earth? Personally I think all three hdam's would be equally enjoyable in applications other than headphone listening, headphone listening just relies too much on minor differences.

 I've been comparing the LME49860's and the hdam's in the compass and although the LME49860's are balanced and detailed, it isn't as 3-d or real as the hdam's. Maybe audio-gd simply knows how best to synergize its own products lol. But the LME49860 is certainly better than LM4562, and I think it would be a preferable opamp in certain situations, just not for the compass.


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## les_garten

Quote:


  Originally Posted by *haloxt* /img/forum/go_quote.gif 
_Kingwa suggested not to get the sun in the compass because he thought it might have bad synergy, something about the compass itself sounds neutral. Have you heard people other than compass owners say they didn't like the sun as much as the moon and earth? Personally I think all three hdam's would be equally enjoyable in applications other than headphone listening, headphone listening just relies too much on minor differences.

 I've been comparing the LME49860's and the hdam's in the compass and although the LME49860's are balanced and detailed, it isn't as 3-d or real as the hdam's. Maybe audio-gd simply knows how best to synergize its own products lol. But the LME49860 is certainly better than LM4562, and I think it would be a preferable opamp in certain situations, just not for the compass._

 

There were a few folks in the Zero thread who jumped on the SUN bandwagon. Listened for a few weeks and felt it was too "Fun" and Punchy" for them. ScottieB would be a good one to ask. Since I wanted to hear a good difference, I got the Earth and SUN for my Compass. The Compass seems like a good platform for OPA rolling! It's a Pian to pull the card from my Box to do the Halo. You tell me which ones to go with and that's it. I won't really use it as a Headamp after I get the New Gear. Basically a backup.

 .


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## les_garten

Quote:


  Originally Posted by *haloxt* /img/forum/go_quote.gif 
_Kingwa suggested not to get the sun in the compass because he thought it might have bad synergy, something about the compass itself sounds neutral. ._

 

I had not heard this before, about kingwa mentioning this.

 .


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## theBigD

My room mate likes the SUN in his compass so far. He has only had it a few days though. And I noticed when I listened to the sun in his compass at first it sounded a bit bright and sterile (but very enjoyable) compared with the ef1 which i can tune with the tube. But this was the first night. I get to babysit his amp while he in on vacation this week, so I will definetly be doing some reviewing of the hdams and comparing compass to ef1.

 I just plugged my ety er6s into my ef1 and listening to some Madelein Peryoux, and the piano is just steller! Everything sounds just right, nice and clean detail with excellent soundstaging especially for the iem. Very nice indeed! Percussion is very punchy and dynamic.


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## les_garten

Quote:


  Originally Posted by *theBigD* /img/forum/go_quote.gif 
_My room mate likes the SUN in his compass so far. He has only had it a few days though. And I noticed when I listened to the sun in his compass at first it sounded a bit bright and sterile (but very enjoyable) compared with the ef1 which i can tune with the tube. But this was the first night. I get to babysit his amp while he in on vacation this week, so I will definetly be doing some reviewing of the hdams and comparing compass to ef1.

 I just plugged my ety er6s into my ef1 and listening to some Madelein Peryoux, and the piano is just steller! Everything sounds just right, nice and clean detail with excellent soundstaging especially for the iem. Very nice indeed! Percussion is very punchy and dynamic._

 

Gettin' to play with your roomate's NEW gear, PRICELESS!

 .


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## B00MERS00NER

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_Gettin' to play with your roomate's NEW gear, PRICELESS!

 ._

 

HEHEHE, hopefully he won't be soldering on it when he gets back. Sorry D, couldn't resist.

 I am using the Sun in the Compass, neutral setting and have about 100 hours on it. At this stage I like it, at first it was pretty bright, seems that there has been improvement and for now it works, can already see that it will work better for types of music and not so well for others.

 Can't wait to experiment with all the combo's possible with 3 different hdams and jumper settings on the Compass.


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## les_garten

Quote:


  Originally Posted by *B00MERS00NER* /img/forum/go_quote.gif 
_HEHEHE, hopefully he won't be soldering on it when he gets back. Sorry D, couldn't resist.

That's a Good one!

 I am using the Sun in the Compass, neutral setting and have about 100 hours on it. At this stage I like it, at first it was pretty bright, seems that there has been improvement and for now it works, can already see that it will work better for types of music and not so well for others.

Let us know if you feel the Change, and I mean Change we can believe in!

 Can't wait to experiment with all the combo's possible with 3 different hdams and jumper settings on the Compass.

Good Clean Fun There!
_

 

My desoldering iron shipped today!

 .


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## B00MERS00NER

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_My desoldering iron shipped today!

 ._

 


 Now when you get it you can look for stuff to break, I mean fix.

 The difference between using that and wick/hand pumps will be phenomenal, you'll be very happy.


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## les_garten

Quote:


  Originally Posted by *B00MERS00NER* /img/forum/go_quote.gif 
_Now when you get it you can look for stuff to break, I mean fix.

 The difference between using that and wick/hand pumps will be phenomenal, you'll be very happy._

 

I got some serious wood watching those Video links you posted. I think that qualifies me as serious DIY potential!

 .


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## B00MERS00NER

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_I got some serious wood watching those Video links you posted. I think that qualifies me as serious DIY potential!
 ._

 

Ha, that also officially qualifies you for being dangerous to inanimate objects in working and non-working condition.


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## haloxt

Let's not derail this thread with compass burn-in impressions, post it in the compass thread. As for Kingwa discouraging the sun in the compass, it was up for only like a week or so on his compass webpage advising prototype compass buyers to choose between moon or earth only, which leads me to suspect he designed the compass to compliment those two in which case it would make it difficult to find out if there is the recessed mids majkel mentions by using the compass as the only test bed. I do find the sun and the LME49860 quite similar in the compass (but I prefer the sun overall), which leads me to believe the sun will be equally liked as the other hdam's outside of the compass.


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## theBigD

Ive had a week with the SUN. And still prefer to anything ive heard. Lots of energy, bass has excellent impact, makes the d7000 SING. Also like the earth, just doesnt have the punch the sun has. I keep feeling like the moon is too smooth not enough edge for me.


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## gregdee

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Thanks to my fellow from forum.MP3store.pl (Powered by Invision Power Board) whose personality is known to me and Kingwa, the discrete op-amps designer, I received three types of discrete op-amps from Audio-gd for review. The schematics and descriptions can be seen here: ÐÂ½¨ÍøÒ³ 1
 The modules I have tested are:
 dual OPA-Earth
 dual OPA-Moon
 dual OPA-Sun v.2
 All came with capacitor upgrade and I didn't modify them in any way for the time of the tests. Each of them spent at least 24 hours of burn-in, observing if any changes occur. When I realized nothing changed any more, I started critical listening sessions. The equipment I used were:

*Grado GS1000* headphones

 Here is not much to comment. I regard these headphones as the top class dynamic model, with extraordinary spatial presentation and timbral abilities. Their bad side is long burn-in time, making some annoyed guys sell these headphones in premature condition to people like me. 
	

	
	
		
		

		
			





*Grado RS2* headphones

 These are pretty well known to the head-fi community. I'll just point that mine were without buttons, I bought them new in February 2008 and in the last weeks, after trying some burn-in tricks working with the GS1000's these settled down on very nice sonic signature. Their role were minor in the whole test but this will be clarified later. 
	

	
	
		
		

		
		
	


	




*Creative Aurvana Live!* headphones
 For the purpose of the fellow who sent these discrete op-amps to me and chose his favorite using these headphones and the Zero DAC, IIRC. Mine are re-cabled, BTW. 

*Technics SL-PS840* CD player
 This one has been modified heavily but I used it as the digital transport only. The mods I applied were among others:
 - ultra fast MUR120 diodes in place of 1N4003 rectifying diodes (8 pieces)
 - Elna and Sanyo capacitors replaced in many sections of digital and analog power supply
 - long and thin PCB traces doubled with solid tin-plated copper wire
 - precise 5ppm gold pin OMIG quartz put in the SOAD70A mechanism servo circuit
 There were other strictly analog part related mods like capacitors and op-amps replacements which improved the Technics' sound significantly but it still was not the class of the modified...

*CS8416/CS4397 DIY DAC kit* as the DAC
 I bought the kit from gigawork on ebay, choosing the SMD version which some people consider as the better choice because of short traces and separated power supply built on another printed circuit board. This DAC has been “discovered” and popularized mostly by Lukasz Fikus. What hi did to this DAC, you can read here: CD DAC Lampucera lampizator
 I'll just admit that the stock form of this kit will not catapult you in the hi-end sound realm, it's rather significant upgrade to budgetary CD players and comparable to devices like 2x OPA627 upgraded Zero DAC, based on my forum mate's opinion. However, after some mods, this DAC kit starts to compete or maybe win (last upgrades haven't been verified yet) with $1000-$3000 DACs. At least it could fight with: AudioNemesis DC-1 upgrade+Tara Labs internal wiring, the NorthStar M192 MkI or theTheta DSP Gen Va. So, here is the short list of upgrades making this DAC a reliable, I hope, test platform:
 - 20VA 2x 14V AC toroidal transformer in place of the original one (hum with OPA-Moon showed it's too weak)
 - Elna Tonerex capacitors on each voltage rail on the DAC PCB
 - shortened ground traces for the op-amp slot
 - all supply voltages of the analog section of the DAC bypassed with the Elna Silmic II capacitors
 - digital voltage supplies of the CS8416 SPDIF receiver and the CS4397 DAC chip bypassed with the Sanyo WG capacitors (better specs and sound than OSCON)
 - Toslink receiver supply supply bypassed with the 220uF tantalum capacitor
 - shorted output capacitors
 All those mods were thoroughly tested. I tried many different mods in the last months, some were unnecessary, some required testing many different parts, etc. 

*Beresford TC-3618* optical digital cable
 This is the best optical cable I have ever tried. Not distinguishable from the more expensive Profigold PGD5000, much better than some hyped “glass” optical cables having both mediocre build and sound quality. Use this one or choose a trusted manufacturer, that's my advise for today. 

*Moonlight v.8* headphone amplifier
 The name tells you nothing and I know that because it's my own design. The details I'm willing to reveal now are:
 - class A output
 - no regular op-amps in the signal path (to hear the op-amps influence in the DAC) 
	

	
	
		
		

		
		
	


	



 - DC signal path with passive offset cancellation
 - virtual ground architecture with some unique solutions
 - external regulated DC power supply
 This amp was roughly compared to the Yamamoto Soundcraft HA-02 and the RudiStor NX-33, from memory to the ASL Twin Head MkIII with upgrades (caps, DACTs, tube sockets, different tubes). For an opinion on this amp it's best to ask Piotr Ryka or fallow81 at this moment. Just in case you're not sure I could rely on the sound. 

*Analog interconnect*
 Having disassembled DAC and amp, I could get rid of this element, using a couple of centimeter long wires to connect one PCB to another. This sounds best to me. 
	

	
	
		
		

		
		
	


	




 If not, I take the Conducfil SPEAKFIL 8896 cable, the Neutrik NYS373 plugs, and make my own IC connecting wires exactly how Oyaide did in the PA-02 TR interconnect. Then I could sell the Oyaide product as being less transparent and precise than the professional Conducfil cable. 
	

	
	
		
		

		
		
	


	




*Albums*
 Ayo “Gravity at Last”
 Diana Krall “Live in Paris”
 J. S. Bach “Brandenburgian Concertos I – VI”, Czech Broadcast Recordings
 W. A. Mozart “Requiem”, Polish Cathedral Choir (forgot exact name)
 Blue Note Trip 7 – Maestro compilation
 Seal "Soul"
 Basement Jaxx "The Singles"
 Silverchair "Frogstomp"

*Other albums, headphones and amplifiers will be subject to update this thread whenever something interesting appears, so be patient if you won't find all you're looking for at the moment. *

*Technology*
 As you all know, the discrete op-amps were designed to replace generic or brand name, available for sale in electronic shops integrated op-amps. Discrete circuits are considered to be superior to integrated circuits and it's explained in several ways:
 1)The circuits are created for a specific purpose and voltage range, unlike the universal integrated op-amps. Here we have audio.
 2)Discrete passive elements are isolated from the die and manufactured in the optimal technology for a specific solution. Implementing resistances and capacitances within the op-amp silicon die is limited by the integrated circuit technology.
 3)There is no crosstalk and capacitive coupling between the circuit sections. 
 However, integrated circuits were created because of their advantages and these shall be listed below.
 1)Unmatched thermal coupling between all active elements, keeping parameters like transistor current gain or DC offset at the output well compensated in the whole temperature range.
 2)Short signal paths allowing weaker bandwidth compensation and using faster active elements for negative feedback circuits allowing higher slew rate, shorter settling time and lower phase shifts at high frequencies. Lower EMI vulnerability in general. 
 3)Minimized silicon-metal signal transitions. In the integrated circuits almost all current flow happens in the same piece of silicon. In the discrete circuit it comes from the pin to the silicon and goes to the pin-PCB trace-pin path before reaching another transistor's structure. Count the transistors in the the whole I/V or voltage gain section and see how many times the signal goes through the barriers like silicon-metal joints and solder joints. Sure, it can be done with high quality and possibly no loss to the signal, but in a continuous signal path within the same medium there is no such loss for sure.

*Conditions*
 The discrete op-amps were designed mostly as the replacement for the regular op-amps but also as circuits around which you can build your own audio equipment. On the other hand, when going discrete from the scratch, it's disputable to use global feedback loop dedicated circuits, so let's stick to the upgrade role of the Audio-gd discrete op-amps for now. In my DAC circuitry they worked as the low-pass filter and buffer circuit converting symmetrical CS4397 voltage output into unbalanced signal. The supply voltages were +-12V. I allowed each discrete op-amp to heat up before I started listening. For each discrete op-amp the additional grounding necessity was evaluated and appropriate comments will be provided. 

*Competition*
 Unfortunately I don't have Burson discrete op-amps in stock so cannot compare to these from Audio-gd but there are several things regarding popular integrated op-amps that should be pointed out. I tested lots of them, many times due to possibility of receiving free samples, many other times making trades or just buying them. I could say I know almost all of those you could use for audio, so let's categorize them somehow. 
*Category 1 – waste of time and money*
 Without further comments, I'll just tell you I put all the popular audio op-amps here, too much for listing. Instead of this I'll mention the op-amps I think are fine but couldn't use in the DAC: AD8021, AD8022, ADA4841-1/2, OPA637(?). Those I regard somehow more than Category 1 will appear later in this section with a remark. 
*Category 2 – nice but incomplete sound*
 AD823 – quite popular in voltage stages of amplifiers and CD players after upgrades, doing fine but keeping it's own timbre, not allowing for full color reproduction. 
 AD8620 – the A series is a bit harsh and aggressive, the B series is smooth but still too present in the sound. Going to the bright side and keeping sounds a bit confined. I'd appreciate more independence. 
 AD8397 – this is a smart one, really. At the first moment you think it does everything perfect, the sound is complete with no obvious flaws and predefined timbre. What it does bad is shrinking and flattening of sounds, some offensive forwardness due to the thinned sound contour.
 OPA2111KP – holly crap, this one is pretty neutral and sounds better than you could expect from the specs. Very similar to the OPA2107 in this regard but sonics just better. Truer bass with more impact, more coherent and convincing rest of the spectrum. On the bad side is a piece of mess and congestion. Sounds get mixed and interfering each other starting from higher midrange sometimes. 
 2x AD825 – man, I've liked this one for a very long time. I still could find use for these, like entry level headphone amps or budgetary DAC output stages. This one is lively, rich, fast, with long treble finish, nice midrange timbre. Sounds like a sweet spot between the AD8620 and the AD744 which gets to warm, thick and uncontrolled sometimes. The AD825's unique midrange can “save” your rig when you cannot achieve enough transparency. The overall order and separation is less than perfect but not obviously flawed. I blame the highs for being a bit accentuated and with artificially sustained decay. 
 OPA2604 – a classic audio op-amp. This one can sound really bad when supplied badly. Just see its PSRR specs. Mere 84dB. 
	

	
	
		
		

		
		
	


	




 I could confirm it. Unregulated power supply makes it sound congested, harsh, unstable, messed-up and offensive. Well regulated and filtered supply voltages keep it quite neutral, with dimmed and unfocused trebles, good pace (LOL at the 2x OPA627A here) and overall good tone. 
 LM4562 – just a lesser version of the LME49720. Its midrange is on the warm-bright side instead of neutral, overall good and rich presentation, unfortunately too obviously defined hence predictive and limited sometimes. 
*Category 3 – sound almost complete but imperfect*
 Here I guess additional comment is required... Some people say op-amps are bad. They just sound bad and sound like op-amp. Op-amps do weird things to the sound and using transparent amplification or acoustic transducers will let you hear that. People who want go higher with their equipment just abandon the op-amp realm and go full discrete – using transistors and/or tubes only. 
 The effects of op-amps are something like these:
 there is an invisible barrier in the soundstage, in front of you, or surrounding the stage
 the three-dimensional image of the sound is flat, corrupted or fixed to the soundstage like a picture to the wall
 not enough freedom, clarity, space and timbre differentiation, and other nuances making you just hear sonic spots instead of seeing and feeling the instruments and performers' breaths. 
 So let's enter the area where you can experience touch of true performance, with exceptions but we're yet on the other side. 
	

	
	
		
		

		
		
	


	



 2x LT1028CN8 – wow, with the Blue Note Trip I can say I'm between the performers. The trumpet is properly drawn, I feel the air and the presentation is convincing. There is a slight tint of nervousness in the midrange, which gets sometimes slightly dry but sure you can hide it using passive components. Regarding the dryness – these op-amps just blow away the popular LT1364 in this field. If you like the latter, use 2x LT1028 instead. 
 AD8599 – this one can do things most other op-amps cannot do, period. It's like a sport car with big supercharged engine and huge carbon brakes. It can accelerate and brake rapidly thus keeping perfect rhythm, pace and timing, proper release and decay and exact texture. It's warmer than the LT, with more delicate, thinner trebles, no nervousness but this strange direction of the soundstage. It feels like it's not completely open towards the listener. 
 OPA2228P – say, the OPA2604 killer when you can use bipolar and uncompensated op-amp. Higher midrange complexity, more coherence and focus. Sometimes laid-back and the trebles could use more hues.
*Category 4 – like a completely arranged room, not quite tidy yet*
 I'd say, the fight with the Audio-gd op-amps starts making sense here. 
	

	
	
		
		

		
		
	


	



 Did you ever know that the op-amp grade matters for audio? Yes, it does, at least for OPA2134, OPA2132, LT1028, AD797 and OPA627 which I can confirm. So, let's continue:
 2x OPA627BP – welcome to Category 4! Unlike the AP or AU series, this one is not lacking proper attack. Sure, it's not lightning fast but at least this one can keep the rhythm, it's actually pretty similar to the AD797ANZ with the advantage of JFET inputs. Lack of the last refinement and oomph makes it less than perfect. I'll get back to this later.
 2x AD797ANZ – this one I regarded for a long time as a piece of wire equivalent when used as a buffer. It lacked some level of the lowest detail but added pleasant tube-like timbre, in a delicate form of course. This one is a bit better than the AD8599, with less accentuated sonic signature. 
 2x LT1028ACN8 – the better LT1028 grade. Sure it's audible. Instead of the slight dryness you get a bit longer sustain in the mids, with a slightly higher midrange coloration, hardly perceivable when your ears get used to it. The soundstage is correct, the imaging is correct, tha PraT is correct, and what I would like from it to be perfect is a bit more independence of the events in the furthest background plans. It's sounds like it's a bit hazy there, however you can like it. 
 2x OP27GP – no kidding! Just see the prices of the OP27E from Texas. 
	

	
	
		
		

		
		
	


	




 There is a trick – this one, I mean the one from Burr-Brown I own, requires class A biasing. Otherwise it's not worth considering. I remember I liked it even more than the 2x LT1028ACN8 combo. As a side note I can write that the OPA627 was designed to have this op-amp offering JFET inputs. Same with the OP37 vs. OPA637. 
 2x OPA211 – the king of the space, I guess it's even exaggerated. In terms of overall order, clarity, timbre transparency and rhythm, this one is a direct upgrade from the OPA2228. Slight but worth it. The increased shape detail and huge soundstage is probably the result of something I'd call sound disassembling. It's like losing spatial coherence of each sound, having the tone in one place, and the harmonics just aside, not surrounding the right tone. Strange but true.
*Category 5 – complete sound traveling in the clean air*
 2x AD797BRZ – this is the op-amp truly deserving the name of the Analog Device. This one is a smoother and fuller sounding version of the AD797. Switching from the ANZ to the BRZ series is like going vinyl instead of digital. Everything is smooth to the moment your music craves for the harsh texture like aggressive violin passages, distorted guitars, or stronger double bass phrases. The readability of the furthest plans is great, without going into image sharpening effect which makes you see the details more but lose the feeling of perspective at the same time. Roughly, it's like the AD79ANZ with all advantages of the OPA627BP added. The soundstage is nowhere limited and the sound image of whatever possible shape. This is a reference integrated op-amp for me so let me know as soon as you find better, and I will verify it. 
	

	
	
		
		

		
		
	


	




*Let the show begin... first impressions*
 I started with the OPA-Earth as being the oldest and most recognized design from Audio-gd. I put it direct after AD797BRZ pair which I normally use and wow! Bigger soundstage, more saturated timbre. However, after some time I realized the sounds are too punctual, the soundstage is a bit predefined like in some op-amps and I started thinking what to improve? I used the ground wire. There are two polar opposites regarding my DAC where I can connect this wire – as close to the DAC chip as possible, or straight to the output connector. The difference was almost none, if really any, so I kept the DAC ground connected. This improved the vocals in the first place. The singers were no longer strangled, the shape of the voice got opened and not so focused, say more natural. Overall sound imaging improved, getting a bit less spectacular due to lower timbre emphasis but the exaggerated punctuality disappeared as well and the presentation became simply truer. What I still want? Give me back the smoothness and intimacy I had with my AD combo. We'll talk later as you're straight out of the box.

 The second one to try out in this impatient rush caused by hunger for knowledge was the OPA-Moon. Let's see what guys call “sentiment” and tube-like presentation. Hmm, sound is more mellow and intimate than with the OPA-Earth but it's going to create it's own world more obviously as well. There is more transparency within the soundstage but on the other hand you hear it's borders stronger. It's like inflated from the inside but limited at the borders. The sound is smoother and a bit rounded but the soundstage is slightly uncontrolled. I connected the ground wire again and it helped for the second time. The change is slight but for the better. The imaging got less spectacular again but with lighter intrusion into natural imaging as well. On the other hand I had impression that the OPA-Earth is still closer to the transparency. 

 So, finally the Sun v.2 enters the socket and from the very beginning I know I like it! What a positive sounding device! The first thing making it superior to the other two is that the headphones disappeared from my head. The presentation is so coherent and convincing that I feel no strain and necessity of additional resolving of what I hear. This one is brighter than the previous two, with denser presentation and overall thicker sounds. The timbre is rich and nice, pretty straightforward. Connecting the ground wire I found as a bad idea. The sonic presentation got flatter, less of being everywhere and the instruments got a bit confined to their localization. In case of the OPA-Sun I decided I'd choose more of the sonic freedom and joy instead of stability making the presentation more flat at the same time. Another good thing about this device is that it's sound is unique and you can forget all integrated circuits when looking for sound like this. 

*Ayo “Gravity at last” album impressions*
 Well, well, well. This CD is very well recorded and mastered. Very transparent stage, rich tonality, good presence of voices and mechanically produced sounds. This one is better mastered IMHO than the previous “Joyful” album. 

 I forgot previously to define the competitors. I decided it to be 3 against 3, so the representatives of the better class of OPA627, LT1028 and AD797 will fit the bill, I guess. Going from the best to the worst, it looks like this:
 1.AD797BRZ
 2.OPA-Moon
 3.LT1028ACN8
 4.OPA-Sun v.2
 5.OPA627BP
 6.OPA-Earth
 The winner got it right. Maximal midrange complexity,transparent ambiance, great performers' presence near you. The OPA-Moon had maybe more interesting midrange tonality at the first moment but it tried to put all the sound in it's own frames, and all in all the midrange wasn't quite complete, however rich and enjoyable. The LT was actually similar to the OPA-Sun v.2 but won due to smoother and softer presentation. I found it more true than that of the OPA-Sun because the latter felt a bit like hard wood in the texture. Both are the brighter part of the bunch. The OPA-Sun v.2 easily won with the OPA627BP pair. For this great album the demarcation line of the “op-amp smell” rose to the level of the OPA627BP. It was a bit grainy and flat in the foreground. Good tonality but sounds embraced with a barrier. The OPA-Earth got it even slightly worse. Similar problems and some congestion added. Just like the OPA627BP without the ambiance transparency. 

*Classical*
 1.AD797BRZ
 2.OPA-Sun v.2
 3.OPA-Moon
 4.OPA-Earth
 5.LT1028ACN8
 6.OPA627BP
 First two places provide pure enjoyment. The AD797BRZ won due to clean atmosphere (again), natural, not offensive tone and great instrument definition. The piano showed its supremacy and the woodwind second. With the piano you hear great string decay echoed in the wooden box. Yes, you hear it's all like that. The OPA-Sun moves everything towards the “wooden” side a bit. The trombones played tad too low, without upper finish but overall presentation was logic, coherent, powerful, enjoyable, keeping great rhythm and pace. There was no congestion or disorder. OPA-Moon sounded mellow, with lesser energy, rather nostalgic which somebody might enjoy, especially with some tracks. The sound was kind of caramel-sweet but it was a slight intrusion, not forced in every note. The soundstage wasn't completely open but on the other hand, presence of the instruments was well accentuated. The OPA-Earth presented a bit nervous and congested sound. It's like you feel there is something in the air and you can't relax. However it was still on the good side with overall correct texture, a bit flatter presentation than the top three, and surely better than the pair of the LT1028's. These showed too rounded tone, to the level it was greasy and boring. Not enough separation in this music sauce for me. The OPA627BP's were disappointing. Nice tone but corrupted piano with no piano presence. It was simply synthetic, with uncontrolled note decay and flat, “electric” timbre. Like plastic toy. No fun, no score.

*Seal “Soul” album impressions*
 1.AD797BRZ
 2.LT1028ACN8
 3.OPA627BP
 4.OPA-Moon
 5.OPA-Earth
 6.OPA-Sun v.2
 Instead of live instruments and minimal mastering, we have here Warner Bros logo at the bottom of the CD box and obvious sonic idea about this album. It sounds sentimental, smooth, with no aggression, giving impression of a big hall, with somehow distant vocal. Slight echo adds the feeling of empty audience, just the performer and the orchestra more in the background. 
 Looks like heavily engineered mastering is a domain of chip op-amps. The first two places were quite close to each other. I rate neutrality higher, so the AD is the winner. Another reason is that the AD797 reached further on the vertical axis. The LT sounded fuller and more plushy in the higher midrange, making vocals more kind and friendly. The AD was more groovy in the voices department. The OPA627BP's showed simple but coherent presentation with good transparency. Leaning towards plastic but acceptable. The OPA-Moon was more physiological but with lesser clarity. I'd say they were equally good and somebody could change the order between them in the ranking just due to preferences. The OPA-Earth was similar to the LT but with worse clarity and uneven texture. The LT1028's presented more culture and coherence. The OPA-Sun v.2 with it's specific texture preferences did not match Seal's voice and emotionality of this album at all. The sounds were kind of crude and thick, not getting smooth enough when expected. 

*Electronica*
 1.AD797BRZ
 2.OPA-Earth
 3.OPA-Moon
 4.LT1028ACN8
 5.OPA627BP
 6.OPA-Sun v.2
 Here what I care for is tonal complexity, layering, soundstage dimensions, textural abilities, merging in music - simply said. The AD provides the magic touch that makes you perceive the sounds not only with your ears. They make you imagine what other senses could project in coherence with hearing. The OPA-Earth provided some positively edgy fun, with complete tonality and precise texture, however not that transcendent you'd expect from good electronic music composers. This one is correct and enjoyable without entering the fourth dimension. 
	

	
	
		
		

		
		
	


	




 The OPA-Moon is more emerging in the whole music ocean, and if you care more for this instead of every possible timbre delivered, this one, with its caramel presentation will fit your expectations. The soundstage is perceivably huge, especially wide, and you're in the center of the music event. The LT1028ACN8's were smoother but sometimes distant, making sounds escape a bit from you. The tonality was complete but the texture too rounded, and the haze in the background. You can like it but it's added value so I rate it as a disadvantage. The OPA627BP's made it simple. If you don't know your recordings well, you think it's the clear picture of them, with plain notes, correct, nice tones, not so big soundstage and kind of disappointing simplicity. The OPA-Sun v.2 tried to paint a rainbow using roughly five crayons when seven is required, and the hand was shaking when the picture was born. The footprint of this shaking is this repetitive texture, not differentiated enough, and limited tonality due to missing paints. Using nice colors only is moderately fun. The forward presentation doesn't feet electronica, either. 

*Silverchair “Frogstomp”* album impressions
 I'd say it is the rock/metal capabilites test. This album was their first and best, with it's young spirit and garage studio feeling. I like it all, some harshness, some anger, true acoustics, nicely distorted guitars. So, the score goes like this:
 1.AD797ARZ
 2.LT1028ACN8
 3.OPA-Earth
 4.OPA-Sun v.2
 5.OPA-Moon
 6.OPA627BP
 The winner is in another league, magic of reality and presence, with no further excuse. Places 2 to 4 is roughly the same, a bit lower league where the OPA-Earth added some nice harshness to the vocals, emphasized the distortion of guitar strings and kept great rhythm and timing. The LT1028ACN8's scored a bit higher due to more present vocal and richer guitar tone, making each pluck perceived like a wind blow. The OPA-Sun v.2 kept the vocalist “sane” and effortlessly singing each phrase, the scene was broad and open, everything was happening like on the stage close to you, with nice tonality and texture. The sound was believable, with no issues. The OPA-Moon got too mellow and too dark, making music sentimental but sometimes absent, not his music genre, definitely. The OPA627BP's showed all the legendary chip op-amp excellence, not even worth describing it. It's an exceptional album and want to hear that. I didn't.

*Final assumptions*
 Well, I feel I know much enough. 
	

	
	
		
		

		
		
	


	




 There should have been jazz impressions added but actually the jazz instruments appeared in classical and rock sections, with the female vocal on Ayo album evaluated, so I think I can summarize my thoughts on the discrete Audio-gd op-amps. 

 First, guys from Audio-gd achieved what they planned, really! They delivered a worthy chip op-amp replacement, presenting three different sonic signatures. For the studio and hi-end purposes they are probably not good enough, but for most DIY aware audiophiles they are an interesting and enjoyable upgrade, in the league that mid-end equipment will benefit from them. If you can assure the conditions below are possible to fulfill, then go ahead and try one or more of them, considering their sonic tendencies:
 - efficient power supply for both rails, I guess 200mA reserve per voltage is the minimum
 - enough space around the socket or near it, when the extension cable is required, you have to provide mounting of the OPA
 - easy access to the ground on the original PCB, as the OPA ground wire might bring advantage when connected

*OPA-Earth*
 This one feels best in electrical and electronic music, where raw power and aggression is an advantage. This one has got the ability to present some of the sounds live, like from your surroundings, not headphones, even on lesser models like Creative Aurvana Live! or Grado SR325i (thanks to my friend for loaning them). The bass is shaking and precise, the mids are colorful but slightly on the flat and thin side, however tonally the most complex of the three discrete op-amps. This one is doing better with the ground wire connected as you get rid of nervousness and the vocals melt in the air more naturally.

*OPA-Moon*
 The sweetest and the most romantic one. Slightly darker than the other two, a natural step-up from the AD825 pair as I know there are lots of their fans. This one has got big but defined soundstage, the listener becomes a part of the spectacle. You feel emerged in the music flow however the musical fluid is not completely spiced for me. I don't want things to be sweet or salty all the time, I need a tiny sip of sour or bitter flavor sometimes, making the dish more refined. In other words, the music does not have to be sentimental all the time, I'd like it to be intriguing and surprising sometimes. 
This one better leave ungrounded. 

*OPA-Sun v.2*
 The best first impression, losing a bit when thoroughly discovered. It simplifies the harmonic content the most. There are some tonal nuances the OPA-Sun does not deliver. The musical presentation is straightforward, positive, joyous, like a sunny day. I liked classical quite a lot with it and some people will enjoy rock because its ambiance is clear and fitting headphones well. The OPA-Sun removes the headphones from your head on most albums I tried and if you don't know, or don't think about some tonal particles missing or hidden, you'll enjoy this one. The texture is wooden thick, the midrange is on the rich side, all is brought to the listener without further excuse, honestly and friendly. 
For more precise imaging, leave it ungrounded, for smoother and more airy presentation, connect the ground wire.

 My favorite? OPA-Earth. Delivers the most of what was recorded but not in the best form each time. Then comes OPA-Moon and the OPA-Sun v.2. The OPA-Moon is missing something sometimes but it sounds like a young man who fell in love just forgot about something, forgivable and natural. The OPA-Sun v.2 is kind of a cottage musician. He's got a lot of willing to play and positive energy. He plays notes the only way he can do but he never forgets to smile to you, and you smile with him. Pure, simple joy.

*UPDATE 11 Jan 2009*
 I rebuilt the power supply so that the digital and analogue section of the DAC chip gets double regulated +5V supply. I find the OPA-Moon more complete tonally and it looks like it's at least equal in terms of SQ to the OPA-Earth. All discrete op-amps improved a bit with this modified PSU but so the AD797BRZ's did. The chip op-amps got better in terms of acoustical correctness and transparency._

 

hallo Majkel

 this review is an outstanding job mate.
 it makes most professional reviewers 
 looking like a flock of teddy bears on
 the crowded shelf of audio industry !!! 

 thanks a lot for that 
 Greg

 ps.I love your avatar mate ,we were grown 
 with the same cartoons ,always at 7pm each Tuesday 
 na dobranoc

 ps.cause we 're both polish I'd like to stay closer
 to confirm things.


----------



## fault151

I also tried the HDAM modules in my friends Jaycar KC5417 Headphone amp (modified). I posted a review on how i found them on my blog, click here if your interested.


----------



## anoobis

So there are all these posts here and on the Compass thread giving impressions of the sound of the HDAM modules. However, nowhere have I seen the intention behind each module.

 AFAIKT,

 Earth: supposed to be neutral
 Moon: supposed to be smoother and darker than Earth
 Sun: supposed to be brighter and more detailed than Earth, effectively a V-shaped EQ.

 IMO, more detail is often artificial, due to the over enhancement of higher frequencies. Once you've heard them, you notice that they were anyway with the 'less detailed' (darker) setup.

 Please correct me if I'm wrong.


----------



## theBigD

Quote:


  Originally Posted by *anoobis* /img/forum/go_quote.gif 
_So there are all these posts here and on the Compass thread giving impressions of the sound of the HDAM modules. However, nowhere have I seen the intention behind each module.

 AFAIKT,

 Earth: supposed to be neutral
 Moon: supposed to be smoother and darker than Earth
 Sun: supposed to be brighter and more detailed than Earth, effectively a V-shaped EQ.

 IMO, more detail is often artificial, due to the over enhancement of higher frequencies. Once you've heard them, you notice that they were anyway with the 'less detailed' (darker) setup.

 Please correct me if I'm wrong._

 

Yes I think youve pretty much summed up the individual characteristics of the hdams. I think I like the sun becuase it emphasizes the strengths of my d7000 bass slam and dynamics, it does lack a bit of the midrange that the earth brings out. The moon is a bit too smooth for my taste but might just suit yours very well. I would recommend you get the earth and moon, you cant really go wrong they both sound very good.


----------



## Hot Pixel

Is there a way to tell the HDAMs apart visually? The stickers have come off and are on the floor right now. The sun has LED's, but the earth and moon look alot like eachother if you don't know where to look.
 As far as I can tell the earth has more of those black thingies.
 ...
 yeah. black thingies. I'm really into this technical stuff


----------



## les_garten

Quote:


  Originally Posted by *Hot Pixel* /img/forum/go_quote.gif 
_Is there a way to tell the HDAMs apart visually? The stickers have come off and are on the floor right now. The sun has LED's, but the earth and moon look alot like eachother if you don't know where to look.
 As far as I can tell the earth has more of those black thingies.
 ...
 yeah. black thingies. I'm really into this technical stuff 
	

	
	
		
		

		
		
	


	


_

 

Go to A-GD and look at the circuit traces carefully, you should be able to ID them, get your Sharpie out and Label them. A-GD needs to quit investing in stickers in my Opinion. You should see how many you are treated to on the REF1. 

 .


----------



## theBigD

Quote:


  Originally Posted by *Hot Pixel* /img/forum/go_quote.gif 
_Is there a way to tell the HDAMs apart visually? The stickers have come off and are on the floor right now. The sun has LED's, but the earth and moon look alot like eachother if you don't know where to look.
 As far as I can tell the earth has more of those black thingies.
 ...
 yeah. black thingies. I'm really into this technical stuff 
	

	
	
		
		

		
		
	


	


_

 

The earth is chocked full of goodies! Moon has two large brown discs in front and looks a little hollow compared to earth.


----------



## majkel

Quote:


  Originally Posted by *Hot Pixel* /img/forum/go_quote.gif 
_Is there a way to tell the HDAMs apart visually? The stickers have come off and are on the floor right now. The sun has LED's, but the earth and moon look alot like eachother if you don't know where to look.
 As far as I can tell the earth has more of those black thingies.
 ...
 yeah. black thingies. I'm really into this technical stuff 
	

	
	
		
		

		
		
	


	


_

 

The Earth is more filled inside. 
	

	
	
		
		

		
		
	


	




 Regarding the V-shaped Sun sound - I don't agree. The sound is thicker and heavier than the Earth but IMO the Earth is a bit dry, the Sun v.2 is more accurate. The Moon is smooth and sweet but a bit lacking resolution and timbral complexity, kind of the same flavor all the time.


----------



## anoobis

Majkel, is this assessment with specific HP or across the board?


----------



## majkel

Across my board. 
	

	
	
		
		

		
		
	


	




 Grado GS1000, Creative Aurvana Live!


----------



## Currawong

Earth, Sun and Moon respectively:






 The Sun is easy to spot because of the glowing diodes. The Moon has 4 transistors sticking up at the top, whereas the Earth only has two.


----------



## anoobis

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Regarding the V-shaped Sun sound - I don't agree. The sound is thicker and heavier than the Earth but IMO the Earth is a bit dry, the Sun v.2 is more accurate. The Moon is smooth and sweet but a bit lacking resolution and timbral complexity, kind of the same flavor all the time._

 

Okay, it seems I misunderstood your review. I took less harmonic content to mean more hollow, maybe airer (coupled with my expectation of V-shaped). If you mean the higher harmonics are less prominent, I suppose that will make the sound biased towards the heavier side.


----------



## LaidBack

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_Earth, Sun and Moon respectively:






 The Sun is easy to spot because of the glowing diodes...._

 

Do you know if the Sun V2 has changed? The OPA I just received with my Compass that is supposed to be a Sun V2 looks similar to your pic, but it does not have the glowing diodes in the middle. The diodes look more block "C" shaped with wire legs...


----------



## les_garten

Quote:


  Originally Posted by *Horse* /img/forum/go_quote.gif 
_May I ask why the review doesn't include details about the LME49710, LME49720 and LME49860 ?


 Also I'd like to say that the AD744 is the coldest sounding opamp I've ever heard, nothing like "warm" unless you mean purely for balance and not chromatically (tonally it's very cold-blue in its sound). The LME opamps I find to have a similar character too, though it can be corrected with proper power supply bypassing._

 

I smell a RAT!

 .


----------



## Currawong

Andrea, to your credit, the LME49710 is very good, about the same as the Earth, if marginally less detailed. To your discredit, being right about something doesn't change that you've been banned and are about to be again.


----------



## majkel

I didn't own the aforementioned LME op-amps in the time of the review but added some remarks later in the thread. The LME49860 is great, something between the thickness of the LM4562 and the cold neutrality of the LME49720. However a pair of the AD797BRZ is slightly better, just slightly. On top of this I would place the decompensated op-amps, when you fine tune their feedback and/or custom compensation loops, they outperform even the AD797BRZ pair. These are OPA228, OPA2228 and AD8021 - no joke. Especially fine-tuning the AD8021 is kind of surprising. I had best results with no compensation capacitance between pins 4 and 5 and about 200 ohms Rf.

 Regarding the AD744 - it's cold when supplied with low voltages, thicker sounding when supplied closer to the maximum voltage rating, i.e. +-15V.


----------



## majkel

OPA2227 is terrible, worse than the OPA2134. I don't understand using the Panasonic FC series for audio, either. For digital the Sanyo WG seems the best, for analog - here you have quite a big choice - BG, Elna Tonerex, Elna Silmic II, Panasonic PX. When using the OPA2228 the compensation must be added for gains lower than 5. In the DAC I'm using it's just plug and play, no oscillations. The AD8021 won't work in it without circuit ingerence but I tried it in a headphone amp in the VGND section after the voltage divider, and it worked best, better than the AD797BRZ or some other high grade single op-amps.


----------



## jamato8

I have used the FC series and have heard it as the only cap in a portable and frankly I found the cap to perform well.


----------



## majkel

The LT1364 plays simplified and a bit colored music. In unresolving setups it's helpful, starting from some level of quality, it is annoying and killing nuances. This op-amp sounds nothing more than a bit defective LT1028 pair. 

 Regarding the Panasonic caps - the FG series is more pleasant sounding than the FC, the same applies to the FA and the PX series, where the latter is truly audio dedicated, AKA Pureism.


----------



## majkel

Quote:


  Originally Posted by *Horse* /img/forum/go_quote.gif 
_You keep showing me that you only or mostly listen to detail and the "formal" side of sound._

 

You are wrong, period. I care for real presentation, full of dynamics, timbre, touch, air, intimacy, just everything. 
  Quote:


 For me tonality is vital, and _there_ lies much of the emotion. And BTW the LT1364 does NOT sound like a less resolving LT1028, since it doesn't have the dryish and slightly lightweight mids, and slightly skeletal bass, of the LT1028. The LT1028 on the other hand doesn't have what I call the "warm luminosity" of the LT1364. 
 

Leave the CN8 series and try the LT1028ACN8, it's more lush than the LT1364 which has colored trebles and a kind of imaging instability causing bluriness. Try the AD8599 if you haven't so far. Up to your preferences IMHO.


----------



## majkel

I don't agree, the statements about the LM6172 mean the guy has got not good enough equipment. The LM4562 is audibly, obviously better for audio than the LM6172. However, it might be true both your impressions for the Xenos ans his impressions for the DIYEDEN. If you tweak the DAC totally (caps, rectifiers, transformer?, Toslink supply?, digital parts decoupling, power supply section rebuild) you can compare the op-amps again - on another quality level this time. The same applies to Mr Jim. Have fun!


----------



## majkel

Quote:


  Originally Posted by *Horse* /img/forum/go_quote.gif 
_P.S. The guy also says that the OPA2604 is "dirty sounding" and prefers the OPA2134 
	

	
	
		
		

		
			



_

 

OPA2134 has got pumped up bass and nasal coloration. I still prefer the OPA2604 while both aren't interesting for me. 

 I compare, also side by side, to more sophisticated DACs than you've mentioned - more like AudioNemesis DC-1, CEC TL51, NorthStar M192, Theta DSP Pro Va, Accuphase DC801. So, save me that drama about a $50 DAC. Regarding the buffers - I won't tell you what buffers I use, they just keep me laughing at the BUF634, but it's another story.

 One more word about the dryness present everywhere - try good, audio grade capacitors. Leave the Pana FC. You have a choice of black gate's polar and non-polar, different flavors of Elna, Nippon Chemicon (LXG or LXY maybe), Rubycon (YXF?), some plyester film caps for decoupling the 'lytics, some bipolar to decouple bigger electrolytics, etc. Try it. See for yourself why controlled avalanche diodes are sonically different than soft recovery diodes, why both are better than standard rectifier diodes. See how the DAC chip reacts to more stabilized analog voltage. When you have it verified and chosen, start listening. The end of it will be - compensated op-amps are the bottleneck, no matter which one you choose. Uncompensated op-amps properly used are in a different league. Make it audible. I made several turns around the OPA2228 until my circuit got so transparent that all the rest fell off. In it's sound is just more freedom.


----------



## majkel

My DAC went through many more upgrades since the review time. I have double stabilized 5V, one regulator after another. No Silmic caps, Rubycon YXF + film cap, then Elna + film cap before another regulator, then Rubycon BG STD on the supply, and lots of different caps near the DAC chip. Silmic II is there as well. 

 I have no clock onboard as I have precise clocking in my digital transport, based on a 5ppm gold pin quartz, so the DAC works synchronously (which I find the best way to design digital electronics - keep it synchronous where possible is what I was taught during the studies). 

 My modified Technics SL-PS840 sounds 1-2 levels inferior to my DAC while being comparable to the DAC devices I mentioned previously. I prefered my DAC to the Northstar before many later upgrades, with the standard EI transformer, normal diodes, poorer supply decoupling, don't remember what else. 

 I ordered the LT1358 just for fun and will let you know what I think about it. 

 What I think about coaxial cables is that they suck when you have no isolation transformer at least on one side of the path as you create a ground loop between devices. The Toslink keeps them electrically separated. For higher transfer and powerful, isolated transports like the gorgeous Accuphase DP800, I'd go with a generic 75 ohm digital TV cable which is all this transport needs. It's powerful enough to squeeze the bits thru a normal cable - confirmed.


----------



## majkel

Quote:


  Originally Posted by *Horse* /img/forum/go_quote.gif 
_No with the coaxial you don't create a feedback loop (if the transport is just that), at most you create a ground chain and that's no bad thing. 
	

	
	
		
		

		
		
	


	


_

 

Should have been a _ground _loop, just a typo. It's a bad thing. One ground connection sometimes is a good thing. I tried several optical cables. I agree that some are crap. On the other hand, a good transport will work well with a generic coaxial cable, and I could live with that but ATM I am using a transport which I like very much due to magnetic laser mechanism (no tooth wheels) and there was just the Toslink as the digital output. I am to lazy, and see no reason, to install the coaxial output. My another transport will be something reading denser formats than the RBCD but no sooner than when my current CDP fails. 
 The matter with the Toslink is that both transmitter and receiver need supply tweaking just like other parts of the CD player or the DAC when you want to improve it. After that you can see what a decent optical cable is capable of. The simplest trick is to add a roughly 100uF tantalum capacitor to the Toslink transmitter and receiver supply, between the GND and +5V pins respectively.


----------



## Pluto2

>To sum it up - even if you were able to identify an individual "best opamp", cascading a few of them will always produce flawed and worse sound than more imperfect individual opamps sensibly and competently combined both for sound and specific electrical virtues. 

 Hi Horse, this combination (LME49860 + LT1358) sounds interesting, have you ever tried it?

 I am thinking of upgrading my 2-way active crossover that contains six LM4562s per channel with those perhaps....instead of the discretes which I had in mind....suggestions?


----------



## Pluto2

Thanks Horse, will be interested in hearing the report from majkel on the LT1358 as well


----------



## majkel

The THS4032 is a bit dry and colorless. Regarding the LME49860 - in my setup it's a sweet spot between the LM4562 and the LME49720 but I still prefer the AD797BRZ pair. On fast, acoustic music with lots of classic guitars playing at the same time the AD maintains the resolution and instrument separation better. On the other hand, there is still one music dimension missing due to overcompensation. When you compare the AD797BRZ to the AD8021 with matched feedback loop, the latter is better. Possibly, do it without caps, just the Rf matching (see datasheet). However, when compensated op-amps are in the further signal path, it's obviously impossible to hear what I'm talking about.


----------



## Pluto2

Excellent gentlemen. Soon will order some LME49710s, LME49860s (mainly), and LT1358s, together with several discretes I already have for mix and match fun : )


----------



## majkel

Quote:


  Originally Posted by *Horse* /img/forum/go_quote.gif 
_The THS4031 is luminous sounding, more so than the blueish and a bit sad LME49xxx & LM4562. It is a bit colorless if not properly matched with the rest of the active parts (DACs, opamps...).

 Anyway my complaints with the LME's don't lie in the dimensions of the stage (pretty secondary aspect for me). 
	

	
	
		
		

		
		
	


	




 BTW for tonal quality my favorite in the series seems to be the LME49710.


 BTW there's the THS4051 that's warmer (due to the "5" in its name 
	

	
	
		
		

		
		
	


	




 ) than the THS4031. I prefer the THS4051. It's more stable as well.


 Then again, the LT1358 has both the 3 and the 5 in its sonics so for any lone opamp application it's my favorite of the bunch. 
	

	
	
		
		

		
		
	


	





 Haven't tried the AD8021, anyway its numbers anticipate that it's close to the LT1028 for tonal quality, so realistically not quite a favorite for me.

 While the AD8022 had too much "2" (greenish sound), so it's even worse._

 

Cool! Op amp numerology. 
	

	
	
		
		

		
		
	


	




 Could you provide us some rules how to resolve the sound from the numbers? Hearing is so subjective, numbers are so scientific...

 OK, I acquired the LT1358. This one is better than the LME flavors, indeed but in my current diode/cap/transformer/other stuff a pair of the LT1028ACN8 sounds a bit more liquid and natural. The LT1358 sound is a bit sweeter but also a tad sticky and confined. Actually there is something common between the LT1358 ant the LT1364 in low treble region which is overemphasised and smoothed at the same time. The OPA2228 is still another league with its independent source imaging and acoustics. So, there was no surprise when I tried the OPA228P which I received as well, that I liked them even more due to bigger soudnstage and more stable imaging.


----------



## majkel

I will try the OPA2727 in the MxM some day when I've got enough time to assemble the amp. There is two of them lying in my desk's drawer.


----------



## NelsonVandal

Horse, good thing for you opamps aren't made by IKEA. Then they'd have a name instead of a number.

 Your condition is called synesthesia. Some people have it others don't. Colors can be associated with a lot of things like sounds, shapes, numbers and letters. No wonder we perceive sound differently.


----------



## majkel

I also suffer from _chromaesthesia_ (relating sound timbre with a color) but I don't relate the colors with the numbers. The rules of numbering are different an depend on the manufacturer and its policies regarding the op-amp architecture, the application an the parameters.


----------



## majkel

Sure it's no suffering. Another sense communication is that I recognize the taste of the sound - it might be sweet, sour... I haven't experienced bitter.


----------



## WindowsX

I compared new Burson opamp with Sun V2. Burson's tonal balance is more like Earth rather than Sun V2 but it provides better resolution (even better than Sun V2 itself). I suggest to upgrade to Burson opamp if possible because they're making a sale in ebay now.


----------



## les_garten

Quote:


  Originally Posted by *WindowsX* /img/forum/go_quote.gif 
_I compared new Burson opamp with Sun V2. Burson's tonal balance is more like Earth rather than Sun V2 but it provides better resolution (even better than Sun V2 itself). I suggest to upgrade to Burson opamp if possible because they're making a sale in ebay now._

 

Audio-GD makes Burson's HDAMs.

 .


----------



## WindowsX

And burson upgrades it few months ago. If it was old burson like year ago, Sun is better. Now, it's burson's.


----------



## zeroibis

Sorry to hijack but this seems like a thread with a lot of knowledge on opamps in general. Does any one know ok a good opamp that has a wider sound stage then the LT1364 and that I can find in 8pin somewhere. I have been digging all over the place and so far this thread seems like the place to ask.


----------



## les_garten

This is the thread to look at, have you read it?

 *************************************
 *************************************
 On another note, I can't believe it took this long to get the Equine Scat out of this thread! At least Majkel had a blast...

 .


----------



## majkel

@zeroibis, buy yourself the LME49860, just a better op-amp. You could be lucky with the OPA2228P as well but I can't guarantee a decompensated op-amp will work in your circuit.


----------



## peranders

Anybody been at http://audio-gd.com lately? Closed down?


----------



## peranders

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_OPA2227 is terrible, worse than the OPA2134._

 

Just wondering, do you have a tailored working environment for each opamp do you use a socket only and push in different types in the same circuit? If that is the case I think it's a bit unfair to rule out some good opamp just because it isn't professionally designed in, only replaced. It would have been OK if the test criteria was how does the opamp sound in a standard circuit. Somehow I have interpreted this "how good is opamp in an optimal environment".


----------



## peranders

Quote:


  Originally Posted by *NelsonVandal* /img/forum/go_quote.gif 
_I took a look at the graphs in the data sheets, and most of them are identical. They must have used the same graphs for both LM4562 and LME49860, and if they did they must think that the amps are absolutely the same._

 

It's confirmed that those types are the same. A National guy has confirmed this and the reason was marketing. LME is the new series where the "E" stands for enhanced (performance). The reason for having LM4562 available is (my guess) that customers don't want to change thier product documentation.


----------



## majkel

Quote:


  Originally Posted by *peranders* /img/forum/go_quote.gif 
_Just wondering, do you have a tailored working environment for each opamp do you use a socket only and push in different types in the same circuit?_

 

Do you find the environment posted at the beginning as unfair or suboptimal? Please tell me what places of the circuit make the comparison unfair. You can visit Lukasz Fikus' website to review the schematic. It's stated explicitly what the environment was and your remark is just a reminder, isn't it?
 The application where the OPA2227 was really bad was the Cmoy with passive, transistor based current mirror virtual ground. And it was more than two years ago. I just repeated the comparison to confirm this one sounds bad. It's easily explainable - the uncompensated version OPA2228 isn't very fast as for today's op-amps, so the compensation needs high capacitance to work fine. Capacitors implemented in a silicon die aren't the best available. 

 Regarding the LME - they might have the same schematic but be produced on different technology lines, so this makes a difference in terms of parameters or sonic behavior. When you qoute "a guy from NI" please give his name and position, otherwise it's unauthorized statement to be considered like a rumor.


----------



## peranders

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Regarding the LME - they might have the same schematic but be produced on different technology lines, so this makes a difference in terms of parameters or sonic behavior. When you qoute "a guy from NI" please give his name and position, otherwise it's unauthorized statement to be considered like a rumor._

 

The National guy is member at diyaudio but right know I haven't the thread.


----------



## peranders

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_This one is a smoother and fuller sounding version of the AD797. Switching from the ANZ to the BRZ series is like going vinyl instead of digital. Everything is smooth to the moment your music craves for the harsh texture like aggressive violin passages, distorted guitars, or stronger double bass phrases._

 

The difference between these two is only the offset voltage, otherwise the same performance. How can you recognize a DC parameter? I know that the "better" selection has a higher price. Can it be that?


----------



## les_garten

Quote:


  Originally Posted by *peranders* /img/forum/go_quote.gif 
_Anybody been at http://audio-gd.com lately? Closed down?_

 

They are up. It does not take much to slam them down. I'm sure some Post-Canjam traffic will do them in.

 .


----------



## peranders

Really, not for me.


----------



## peranders

Quote:


  Originally Posted by *zeroibis* /img/forum/go_quote.gif 
_Sorry to hijack but this seems like a thread with a lot of knowledge on opamps in general. Does any one know ok a good opamp that has a wider sound stage then the LT1364 and that I can find in 8pin somewhere. I have been digging all over the place and so far this thread seems like the place to ask._

 

In which circuit have you used the LT1364?


----------



## les_garten

Quote:


  Originally Posted by *peranders* /img/forum/go_quote.gif 
_Really, not for me._

 

I've been reading it all morning, just checked it. Sounds like your issue. Actually responding faster than usual. Click on one of the Links in my sig

 .


----------



## les_garten

Quote:


  Originally Posted by *peranders* /img/forum/go_quote.gif 
_In which circuit have you used the LT1364?_

 

Common Zero Headamp chip.

 .


----------



## majkel

Quote:


  Originally Posted by *peranders* /img/forum/go_quote.gif 
_The difference between these two is only the offset voltage, otherwise the same performance. How can you recognize a DC parameter? I know that the "better" selection has a higher price. Can it be that?_

 

You should read the datasheets more carefully to realize it is not the whole truth. They sound obviously different and there is at least one more person in this forum who confirmed this.

 Regarding the Audio-gd website, it is slow to load due to probably inefficient server. All you need is to increase timeouts for your internet connection in the OS, router, whatever concerned and be patient.


----------



## peranders

Quote:


  Originally Posted by *peranders* /img/forum/go_quote.gif 
_Really, not for me._

 

The website needs "www" also. Rather unsusual these days.


----------



## peranders

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_You should read the datasheets more carefully to realize it is not the whole truth. They sound obviously different and there is at least one more person in this forum who confirmed this._

 

It's the input bias currents also, only DC parameters as I can see it. If it really was a difference it could also be a difference between two specimens, not to types. It may be a small number with only one piece to give a statistical opinion.


----------



## majkel

There are some more restrictions, not sure it's for the Analog op-amps as well but probably for all - most first page parameters in bold are guaranteed for the better series, it's sometimes stated in the middle of the document. As well as some more explanation to the MIN TYP MAX columns which one applies to which series.
 As this is an audiophile forum, I don't discuss parameters and measurements here. If there is no difference in sound, I don't report any such.


----------



## peranders

If we have the parameter "it sounds better" it's hard to argue about this, nevertheless, I notice the tweaks on CD DAC Lampucera lampizator In the industrial world it's a big no-no to have excessive leads on parts. Caps with leads more than necessary will have their resonance frequency lowered which means less effective decoupling at high frequencies. Besides it forms also antennas which radiates unwanted energy (very important in digital circuits). When you connect a good ceramics cap with a "bad" polyester you will get a parallel resonance which increases the impedance. The true tweak here is to solder a bigger ceramic cap on top of the original, possible use a surface mounted plastic cap with no leads.






 Compare the PPS cap I have used at the right in the picture.
http://en.wikipedia.org/wiki/Poly(p-phenylene_sulfide)


----------



## majkel

Sorry, neither I solder with long wires, nor I use the crappy Vishay caps seen above. I keep the SMD ceramic caps to let them work and add different types of capacitors or replace electrolytics. Regarding the second picture - I have no idea what you're trying to show. Two transformers very close to each other, four mediocre electrolytics and a capacitor desert around the rest of the components.


----------



## peranders

I wanted to show the PPS caps at the right in the picture.

 (Just wondering: How do you know that the electrolytics are mediocre?)


----------



## majkel

By the brand - I can't read it, and look. The higher are supposed to be Rubycon, YXF, YXG (well, OK but nothing special) or YK, ZL (blah!). The smaller - violet means low temperature range, until 85 C and standard use. No idea about the manufacturer.


----------



## peranders

I'm afraid, lot's of speculations. Both types or not general purpose types and the brands are....? You can read the brand on one cap but the other one knows only I. I have dug quite much how electrolytic caps are made, material, chemistry and technology. So much I can say, they are more alike than you think when it comes to similar basic properties. You can't tell from the colour of the sleeve which properties the cap has.

 I had a professional problem in reliability of a certain brand.
diyAudio Forums - Failure in a huge capacitor board - Page 1

 I can say that much that Rubycon has a good quality when it comes to lifetime.


----------



## peranders

Quote:


  Originally Posted by *packman* /img/forum/go_quote.gif 
_majkel, how do you say that the Rubycon ZL are "blah!" ?_

 

I was thinking the same thing. I noticed also that both YXF and YK were "good". YK is a cheap general purpose type with normal lifetime. I think that the reason for that some brands are "good" is simply because they are mentioned often. At work we used Lelon which I'll guess you never have heard of. Still the company is huge. The same goes for Arcotronics or Electronic Concept which makes probably the best caps in the world when it comes to performance. Check out their slew rate limits!


----------



## majkel

ZL sound dry and unpleasant. I can't comment the ZLH series, though. ZL is a typical mobo cap, use it where recommended. Regarding the Arcotronics - I like their film caps and use them. Very good supply decoupling cap when put in a right place. Besides BG's, Panasonic PX, Elna Tonerex and other capacitors in my headphone amp, the Arcotronics acts like the icing on a cake, adding clarity and treble focus without going nasty.


----------



## peranders

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_ZL sound dry and unpleasant. I can't comment the ZLH series, though. ZL is a typical mobo cap, use it where recommended. Regarding the Arcotronics - I like their film caps and use them. Very good supply decoupling cap when put in a right place. Besides BG's, Panasonic PX, Elna Tonerex and other capacitors in my headphone amp, the Arcotronics acts like the icing on a cake, adding clarity and treble focus with going nasty._

 

Have you ever laid your hands on an Electronic Concept? Check out the wire size!
diyAudio Forums - Cap from Electronic Concept - The best in the world? - Page 1


----------



## majkel

Holly crap, these look like suitable for loudspeakers or tube amp coupling. 400VDC is far beyond my current needs. However thanks for the info, the company looks nice.
 Re: ZL - in power supply, I have only one cap per channel in my signal chain - between the DAC chip and the analog filter stage. There is no place for the Rubycon ZL. The rest is DC coupled.


----------



## peranders

Quote:


 Metallized Polypropylene and Military Styles CFR13 and CFR14."Hi-Rel" replacement for electrolytics for a broad range of commercial and military switching power supplies. 
 

As you see strictly for heavy duty industrial use. It's a mystery that you guys never have seen this Brand especially when they are good AND very expensive.

 I noticed that I spelled it wrong, it's Electronic Concepts with a "s" at the end.


----------



## peranders

The cap can handle 3795 A!!!! and a fantastic continuous ripple current of 30 A up to 100 kHz!

 These caps feel expensive when you hold them in the hand. They are real massive and heavy.


----------



## laobrasuca

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_Common Zero Headamp chip.

 ._

 

talking about zero, have any of you guys tested the LME49860 everywhere in the zero (dac and head/pre amp) all together? Even in case not tested, would you recommend the LME49860 for both dac buffer and head/pre amp I/V all together (jointly, at the same time)?

 thx, lao


----------



## les_garten

I smell Dead Fish...

 .


----------



## peranders

... meaning what for us non-native english members?


----------



## les_garten

Fish was fried...

 .


----------



## laobrasuca

where's the comments of sap???

















 I still don't understand it les_garten, what you mean. For me, when you say "I smell Dead Fish..." I would say "So, go take a shower"


----------



## les_garten

Quote:


  Originally Posted by *laobrasuca* /img/forum/go_quote.gif 
_
















 where's the comments of sap???

















 I still don't understand it les_garten, what you mean. For me, when you say "I smell Dead Fish..." I would say "So, go take a shower" 
	

	
	
		
		

		
		
	


	


_

 

SAP is gone, he stinks, get it...

 He was Horse, He was Andrea........
 .


----------



## laobrasuca

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_SAP is gone, he stinks, get it...

 He was Horse, He was Andrea........
 ._

 

hhhhhhhuuuuuuuuuuuuuuuuummmmmmmmmmmmmmmmmmmmm got it now 
	

	
	
		
		

		
		
	


	




 this guys is still around? 
	

	
	
		
		

		
		
	


	




 go get a life dude 
	

	
	
		
		

		
		
	


	




 anyway, what about the LME49860?
  Quote:


  Originally Posted by *laobrasuca* /img/forum/go_quote.gif 
_talking about zero, have any of you guys tested the LME49860 everywhere in the zero (dac and head/pre amp) all together? Even in case not tested, would you recommend the LME49860 for both dac buffer and head/pre amp I/V all together (jointly, at the same time)?

 thx, lao_


----------



## Bonthouse

how the fudge did this thread derail to being about caps? It's about op-amps!


----------



## laobrasuca

who's talking about caps?
	

	
	
		
		

		
		
	


	




 anyway.

 Well, can you at least say if I put 3 LME49860 in my zero will burn it or something? Or it should work good? (not too hot like the LT1364 in the DAC sectio). I'd like to try this upgrade before jumping to a hdam.

 thx, lao


----------



## les_garten

Here we go again with the Dead Fish smell...

 .


----------



## majkel

Quote:


  Originally Posted by *rufuss* /img/forum/go_quote.gif 
_Well I can tell you that the ZLH is the most natural sounding low ESR cap I've tried, in the power supply of a 2 channel headphone amp. I have Sanyo WG in another amp, and I had them in another C&C BOX too, but I don't recall them sounding quite as natural as the Rubycon ZLH is sounding (though my newly discovered OPA2376 opamps play a part here, too).

 Maybe the ZL were to low ESR for your DAC's regulators._

 

It probably depends what's the definition of neutrality. I don't say the WG's are transparent, neither I use them in any analog circuits. Digital supply, and that's it. For the analog sections I just take different kinds of those "for audio" electrolytic capacitors which are not expected to have extremely low ESR rather than low THD at 10kHz.

 For the I/V stage I'd use a pair of OPA827, the JFET inputs will suck out less current from the DAC.


----------



## majkel

Regarding the Zero - I didn't pay attention what kind of DAC output it utilizes but as I said, the OPA827 might be nice for the I/V stage in general. 

 I read this document roughly a week ago or something and didn't find it bringing any revolution. There is too much concern about the CMRR which is not a frequent issue in today's audio, so looking at the sine graphs might lead to wrong choices. The THD elaboration is a good point, then there are some very valuable chips missing like the OPA228 or the AD8021. 

 I tried the LME49722 and I think the LME49720 is slightly better. I expected the opposite as there is probably less compensation in the LME49722. However, as I said before, decompensated op-amps like the OPA228 or the AD8021 are in their own league.


----------



## laobrasuca

yo majkel, do you think that one can use 3 LME49860 (1 DAC + 2 HP/pre amp) in the ZERO safely? I'm mean, Peete said that the LT1364 can go really hot if used in the DAC, is it the same for the LME49860?

  Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_Here we go again with the Dead Fish smell..._

 

I hope it's not me who's smelling fish, since everyone seems to ignore me! Or it's just because my questions are non sense or boring?

 lao


----------



## les_garten

Quote:


  Originally Posted by *laobrasuca* /img/forum/go_quote.gif 
_yo majkel, do you think that one can use 3 LME49860 (1 DAC + 2 HP/pre amp) in the ZERO safely? I'm mean, Peete said that the LT1364 can go really hot if used in the DAC, is it the same for the LME49860?



 I hope it's not me who's smelling fish, since everyone seems to ignore me! Or it's just because my questions are non sense or boring?

 lao_

 

It's not you. We have a certified Nut case named Andrea that is constantly IN/Out here. He's like a Moth to a flame with this thread. I reported him last night. Then I see this AM he's already back and playing his games. Once you get used to patterns, he's easy to spot.

 He won't be able to avoid this thread. He's an Opamp FREAKster.

 .


----------



## majkel

@laobrasuca, you can try the LME49860, there is a voltage out DAC chip in the Zero. The LT1364 probably goes unstable in the circuit that's why it gets hot. Just see the document already two guys linked here - how did such high distortion appear in this op-amp? It sounds like unstable and it is unstable, that's why it gets hot. There are some fans of the LT1364 in this forum but it is a wrong chip for audio, period. You can try the LT1358, it is very close sonically and not getting hot. Last time I thought I even prefered it slightly to the LME49860.


----------



## laobrasuca

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_@laobrasuca, you can try the LME49860, there is a voltage out DAC chip in the Zero. The LT1364 probably goes unstable in the circuit that's why it gets hot. Just see the document already two guys linked here - how did such high distortion appear in this op-amp? It sounds like unstable and it is unstable, that's why it gets hot. There are some fans of the LT1364 in this forum but it is a wrong chip for audio, period. You can try the LT1358, it is very close sonically and not getting hot. Last time I thought I even prefered it slightly to the LME49860._

 

thx majkel, i'll put all three LME49860 together so since they seem to be very good at DAC as well as in the amp 
	

	
	
		
		

		
			





 thx for the advices.

 EDIT: BTW, I will also try the LT1358 in the amp section to see if it pleases more my ears 
	

	
	
		
		

		
		
	


	




 @les_garten: y, i've already read about him, i'm aware of it (SAP, les_garden, or whatever), thx.

 lao


----------



## wdoerr

OP amps ordered.
 I will do an independent evaluation with the Compass.
 Even thou it probably won't be allowed.


----------



## les_garten

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_@laobrasuca, you can try the LME49860, there is a voltage out DAC chip in the Zero. The LT1364 probably goes unstable in the circuit that's why it gets hot. Just see the document already two guys linked here - how did such high distortion appear in this op-amp? It sounds like unstable and it is unstable, that's why it gets hot. There are some fans of the LT1364 in this forum but it is a wrong chip for audio, period. You can try the LT1358, it is very close sonically and not getting hot. Last time I thought I even prefered it slightly to the LME49860._

 

The 1364 does run a bit hot in the Zero.

 .


----------



## robjrock

Sorry to be slightly off topic, but I just found this thread and figured better to post here than start a new thread...
 Anyway, I recently swapped LM4562 for a LME49860 and to my ears they sound very different! yet many people swear they are the same... I noticed a lot of people discussing them here, was there ever any consensus that they are in fact different?


----------



## haloxt

I think they are different sounding. LME49860 is better but LM4562 presents things very 2D which makes it good for analytical detail.


----------



## hopeless

Quote:


  Originally Posted by *robjrock* /img/forum/go_quote.gif 
_Sorry to be slightly off topic, but I just found this thread and figured better to post here than start a new thread...
 Anyway, I recently swapped LM4562 for a LME49860 and to my ears they sound very different! yet many people swear they are the same... I noticed a lot of people discussing them here, was there ever any consensus that they are in fact different?_

 

Different how?


 BTW, I've been using the LME49860 inside the Super Pro 707, and it was very nice. However, I find the LT1469 to sound better (just as precise, but smoother in the mid-treble and more meaty in the bass) so that's the opamp of choice for the older Super Pro. 

 While for the newer, it's the TLE2142 (preferred to LM4562, LT1364 etc.). 
	

	
	
		
		

		
		
	


	





 Unless the OPA2211 dethrones it as soon as the proper adapter arrives.


----------



## robjrock

LM4562- loads of detail, aggressive, fast, intense. Very involving and the detail is amazing, but a little harsh, especially in the treble.
 LME49860 - like a 'polite' version of the LM4562 - sweet and neutral with nice treble but lacks the detail and intensity of the LM4562 

 I like em both, but I keep coming back to the LM4562, I guess I'm a sucker for detail - this may change when I get my Grado's though (I'm willing to guess they don't make the best match)

 I will hopefully be getting LT1028 soon, which the original reviewer rated higher than the LM4562, so that'll be interesting...


----------



## hopeless

I like the TLE2142 better than the LM4562. It sounds more natural, more solid, and has similar detail.


 Try the LT1358 as well. The LT1028 is very nice, quite transparent though a little bit drier/harder than the former.


----------



## ROBSCIX

The LM4562 and LME49720 are also said to be the same and share the same spec sheet but many swear they hear differences.

LM4562 Spec sheet

LME49720 Spec sheet


----------



## hopeless

What is most certain is that the LM/LME's sound much more the same than different 
	

	
	
		
		

		
			





 I mean, you instantly hear that they all belong to the same family. (kind of like between the LT1355/13358/1361/1364, but the LM/LME's are closer to each other than that)


----------



## majkel

Quote:


  Originally Posted by *hopeless* /img/forum/go_quote.gif 
_I like the TLE2142 better than the LM4562. It sounds more natural, more solid, and has similar detail.


 Try the LT1358 as well. The LT1028 is very nice, quite transparent though a little bit drier/harder than the former._

 

The TLE2142 is an old chip, good for Cmoy's while I prefered the TLE2082 there. In higher tier equipment it shows its limited capabilities and is not even a "middle class", below the LME49860. It's true the latter is not very resolving but it sounds nice. The OPA2211 might be a contender - I tried both the OPA211ID and the OPA211AID pairs. On the other hand, it confirms that Burr Brown single pairs fare better than their dual equivalent, i.e. the OPA228 against the OPA2228. The latter is the king of op-amps for me but you have to own the signal chain with no compensated op-amps on the track. Otherwise, the comparisons are limited by some inabilities of compensated op-amps. Compared to the well supplied and fed back OPA228 other op-amps sound confined. There is lack of freedom in the sound and instruments play like driven from the same engine. Probably that's why some people swear by op-amps. The AD8021 is an exception when you read throughly its datasheet and understand its compensation techniques however this one is nasty due to high input bias current.


----------



## hopeless

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_The TLE2142 is an old chip, good for Cmoy's while I prefered the TLE2082 there. In higher tier equipment it shows its limited capabilities and is not even a "middle class", below the LME49860. It's true the latter is not very resolving but it sounds nice. The OPA2211 might be a contender - I tried both the OPA211ID and the OPA211AID pairs. On the other hand, it confirms that Burr Brown single pairs fare better than their dual equivalent, i.e. the OPA228 against the OPA2228. The latter is the king of op-amps for me but you have to own the signal chain with no compensated op-amps on the track. Otherwise, the comparisons are limited by some inabilities of compensated op-amps. Compared to the well supplied and fed back OPA228 other op-amps sound confined. There is lack of freedom in the sound and instruments play like driven from the same engine. Probably that's why some people swear by op-amps. The AD8021 is an exception when you read throughly its datasheet and understand its compensation techniques however this one is nasty due to high input bias current._

 

I'm sorry for your classifications, but I like the TLE2142 more than the TLE2082 (that is for sure!) and I like its tonality, body, and bass quality, more than that of your "middle class" chips.


 Regarding the OPA2211, I surely consider it as a better alternative to the LME's, considering how good I found the OPA211 to be (clearly better than the LT1028 too). I will use it as soon as possible (adapters are travelling).



 There's a 4300 euro Acoustic Arts DAC that uses 8x TLE2142 in its output stage and I realize why -- it sounds good. That DAC was reviewed in 2007 as one of the very best available (surely it's better than your $50 chinese little ebay board).

 Consider that in my DAC the supply voltage is 12V and the TLE2142 has good output swing and good performance at that voltage.


----------



## majkel

Another Accustic Arts DAC is based on 10x OPA627 and I am very sorry for future users. However IMHO it's still a better idea than 8x TLE2142. 

 I strongly encourage you to go +-15V instead of 12V. You can't do the justice to the best op-amps with such a voltage. There are some great 12v op-amps but of limited usability. Actually, I know just one - stable at gains >= 4.


----------



## hopeless

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Another Accustic Arts DAC is based on 10x OPA627 and I am very sorry for future users. However IMHO it's still a better idea than 8x TLE2142. 

 I strongly encourage you to go +-15V instead of 12V. You can't do the justice to the best op-amps with such a voltage. There are some great 12v op-amps but of limited usability. Actually, I know just one - stable at gains >= 4._

 

I don't like the OPA627, but I do like the TLE2142 (maybe because it's bipolar and I like that).

 What exactly is wrong with the TLE2142 for you?


 Regarding supply voltage, I don't recall the LT1028CS8 sounding worse at 12V than the LT1028ACN8 did at +/-15.3V (almost the opposite) ... So be careful with generalisations. There are even opamps that sound better at that voltage.

 For instance, the LT1364 (than 2x LT1363 @ +/- 15.3V).


 BTW one opamp that works excellent at 12V is the OPA2727, almost better than the LME49720HA at the same voltage (which is better than the DIP at any voltage). Then I must try the OPA2822, unless you can enlighten me on it and save my time 
	

	
	
		
		

		
		
	


	





 Oh and I could dig out an old post of yours where you said to someone that the TLE2142 sounded "quite good" - or those posts where you said that the LM4562 and siblings are awful, that they kill midrange color... (which is partly true, BTW).


----------



## hopeless

BTW, speaking of single BB opamps... have you ever tried the OPA132UA ? On another forum (Audio Asylum) it was said to sound quite good, very dynamic among the other things, and with the same soundstage retrieval or the OPA627.

 I had really liked the OPA2132 for its bold and right sound, though its definition isn't the best ever heard. The OPA132UA is said to be an enhanced single version of the original OPA2132. Must try it (I have them).



 Oh, BTW... speaking of equipment, I doubt you can reach an universal judgment of audio opamps using _headphones_. I listen with speakers (prefer so), except while I'm on bed when I use my little headphone system.


----------



## hopeless

Really, the TLE2142 sounds good. Comparing side to side with my other DAC (the Super Pro with TLE2142 @12V with the DIYEDEN with 2x LME49710, both modified), you can barely hear a difference in quick A/B, but if you do you hear a slightly better tonality and more solid sound from the Super Pro thanks to the TLE2142. The only thing where the TLE2142 lacks just a little bit is treble openness (but it retains the detail).


 Be very careful with generalisations, BTW, since every circuit is different... (I know it sounds trivial 
	

	
	
		
		

		
		
	


	




 )


----------



## majkel

TLE2142 is a bit colorless, dark and loses tiny details. I can agree the trebles lack openness, and air I think. I'm not saying it's wrong, it's OK but no miracles. This is possible in some applications it is optimal. I don't like the OPA627 either, just see the review again. 
	

	
	
		
		

		
		
	


	




 Op-ampish op-amp, luxurious kind of op-amp sound, kind of this.


----------



## linuxworks

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I strongly encourage you to go +-15V instead of 12V. You can't do the justice to the best op-amps with such a voltage. There are some great 12v op-amps but of limited usability. Actually, I know just one - stable at gains >= 4._

 

I find this hard to believe - that anything appreciable (other than more heat!) happens from a dual 12 to a dual 15.

 (or, did I misread: are you comparing a dual15 to a single12 ??? that was not clear.)


----------



## hopeless

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_TLE2142 is a bit colorless, dark and loses tiny details. I can agree the trebles lack openness, and air I think. I'm not saying it's wrong, it's OK but no miracles. This is possible in some applications it is optimal. I don't like the OPA627 either, just see the review again. 
	

	
	
		
		

		
		
	


	




 Op-ampish op-amp, luxurious kind of op-amp sound, kind of this. 
	

	
	
		
		

		
		
	


	


_

 

I will say I just connected my other Super Pro, that with the LT1469 inside (again at a single supply voltage of 12V), and that's a different story. 
	

	
	
		
		

		
		
	


	





 I hadn't listened to the newer Super Pro with the TLE2142 enough. It just has that red-ish kind of sound which I tend to like better among the various possible colorations (in fact also my favorite the LT1358 has it). It indeed loses the tiny details and is dark.


 If only there was an opamp like the LT1469 with just a tad of added red to its sound... that would be perfection? 
	

	
	
		
		

		
		
	


	




 Anyway the LT1469 at 12V does wonders, it even improves on the LM4562 and LME49860 (the former opamp in the Super Pro I'm listening to).



 BTW it seems that the OPA2727 will be my 1st candidate as soon as the soic-dip adapters arrive, even before the OPA2211 due to it working optimally at 12V.

 I could always highten the supply voltage to 24V, nothing wrong with that except that the LM317's going from 24V to 5V do get hotter


----------



## majkel

Quote:


  Originally Posted by *linuxworks* /img/forum/go_quote.gif 
_I find this hard to believe - that anything appreciable (other than more heat!) happens from a dual 12 to a dual 15.

 (or, did I misread: are you comparing a dual15 to a single12 ??? that was not clear.)_

 

Single 12V against dual 15V. It is obvious when you follow the older posts. @hopless makes judgements in his portable (?) DAC and amp while I use desktop devices for comparisons. Good example for the low against high voltage is the OPA228 or 2228 - it sounds different at 9V and another way at 30V.


----------



## hopeless

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Single 12V against dual 15V. It is obvious when you follow the older posts. @hopless makes judgements in his portable (?) DAC and amp while I use desktop devices for comparisons. Good example for the low against high voltage is the OPA228 or 2228 - it sounds different at 9V and another way at 30V._

 

My DAC is not portable, and I use it in a home hi-fi system.


 Why do people always associate 12V (or so) with portable...
	

	
	
		
		

		
		
	


	






 Anyway, the little Super Pro 707 @ 12V sounds as good as the big DIYEDEN SVDAC05 brother with its multiple power supply lines and +/-15.3V for the opamps.



 P.S. For the opamps (Super Pro) I'll choose among OPA2211, LM4562, OPA2727, OPA132UA.


----------



## hopeless

Hmm, later today or tomorrow I will give a try to the OPA2132P as well. I've got a feeling? Anyway, we'll see. 


 The reason for my searches is that I was not happy with the tonal qualities of LME49860 and LM4562. They just made the Super Pro sound less natural and immediate than it did sound with the stock LT1364. So let's see if the OPA2132 manages to be at midway or something.


----------



## hopeless

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_ On the other hand, it confirms that Burr Brown single pairs fare better than their dual equivalent, i.e. the OPA228 against the OPA2228. The latter is the king of op-amps for me but you have to own the signal chain with no compensated op-amps on the track. Otherwise, the comparisons are limited by some inabilities of compensated op-amps. Compared to the well supplied and fed back OPA228 other op-amps sound confined. There is lack of freedom in the sound and instruments play like driven from the same engine. Probably that's why some people swear by op-amps._

 

I guess you're a fan of exaggerated separation of instruments 
	

	
	
		
		

		
		
	


	




 I prefer sounds to appear as a compact whole. I like monitor-like presence.

 By the way, have you tried the EL2227, another decompensated + fast opamp, with very low distortion? I tried to try it in my new Super Pro, but it wouldn't work well (at least not plug and play, as it obviously distorted, like the THS4031 did; strangely, the THS4031 worked just fine in my older Super Pro).


----------



## majkel

The OPA2228 is not so tricky like i.e. the OPA637. It does not require a gain of 5 or more. It just doesn't accept capacitive loads at low gains. It's said in the datasheet. You can still compensate it externally, though. 
  Quote:


 I guess you're a fan of exaggerated separation of instruments 
 

Bad guess. First you need to hear what I am talking about but you choose to stay in the low voltage, stable op-amps prison instead. It's your choice, I decided not to waste my time and money for this group of op-amps anymore. It's not about the separation, it's about playing independently. Easier to hear than to explain, sorry.


----------



## hopeless

OK, I might try the OPA2228, or 2x OPA228, later on. For now I'll enjoy the OPA2727 (do try it maybe) etc.


----------



## hopeless

Hey majkel,

 You should hear how the LT1469 is performing in my older Super Pro & @ 12V. It's true that I had to remove the muting circuit (strangely not using the dedicated pins of the CS4398) to use it, because for some reason it interfered with (or let's say it was defeated by) the LT1469 and not with the other opamps.

 But now I realize that it was totally worth it 
	

	
	
		
		

		
		
	


	




 Because I've just listened to PJ Harvey's latest (and quite beautiful) "A Woman a Man Walked By", and... I've fallen in love with this album. Guess why? 
	

	
	
		
		

		
		
	


	




 I hadn't yet heard it reproduced this amazingly good. I totally stand by my former statement that the LT1469 is outstanding (when stable, at least). Now I'd have to hear if that OPA2228 sounds better... But, sooner than that, I wanna try OPA2727 (which was great) and OPA2822 (previously used as a headphone amp buffer and worked great).



 Meanwhile, the new Super Pro just took an OPA2132P and is ready to go. Will see if it stands the comparison...


----------



## hopeless

Notice that according to the datasheet the LT1469 has exactly the same THD at +/-5V and at +/-15V.


 Anyway I'm listening to the OPA2132P in the new (also modified) Super Pro... Sounds quite good. It's a bit less assertive and "fast", perhaps, than the other one with the LT1469, but in change you're greeted with a seductively mellow sound (not that the other wasn't, just that this one is more).

 Also (well, at least with the crickets singing their concert at full volume outside) interesting is the fact that with the OPA2132P in the Super Pro, I can barely hear any slight difference between it and the DIYEDEN (modified with better parts + LME49710'ed + DC coupled).

 The OPA2132P'ed Super Pro has the same treble clarity, the same soundstage, but it noticeably has a slightly more "feelable" bass (something I love and that the LT1469 has too). I think that the Super Pro with the OPA2132 has an oustandingly transparent and smooth midrange, without any lack of meatiness. 

 Sounds like doing 2x OPA132UA on adapter should not be a bad idea. 
	

	
	
		
		

		
		
	


	







 In conclusion, having considered the minor differences of character, I equally like the three DAC's (with their respective opamps). 
	

	
	
		
		

		
		
	


	




 Call me simple minded. 
	

	
	
		
		

		
		
	


	




 Now I'm curious to see how the new Super Pro fares with OPA2211 and OPA2727 (on the two Browndogs I'm waiting for). Anyway after a brief first listen the OPA2132P might very well stay (and surely the LT1469 will stay in the older DAC). But we're suuuuch maaaaniaccs...




 Edit- I'm not at all surprised that the OPA2132 fared well (like the LT1469) in the "big measurement shootout" ...http://www.sg-acoustics.ch/analogue_...distortion.pdf


----------



## maddman79

Greetings!

 I'm new to this forum. But, this I've been captivated by this particular thread. I now know that I'm not the only crazy person out there 
	

	
	
		
		

		
		
	


	




 I'm looking at things from the other perspective. I've been researching suitable components for an ADC project.

 Long story short, I've developed an affinity to the AD8066 for the input/preamp stage. And, up until now, I've been rather set on using the OPA2211 for the ADC driver. However, this thread has now made me a bit more respectful to the LME49860.

 As such, I have two questions:

 1. What are your thoughts for pairing the AD8066 (input) with the LME49860 (driver)?

 2. How does the OPA2211 compare with with LME49860; particularly, in this use-case?

 Thanks!

 -Brian


----------



## hopeless

Welcome!


 I'm not familiar with AD conversion, but for me the OPA2211 must be superior to the LME49860, especially for tonal naturalness. Try it, you won't be disappointed...


 I would try the LT1469 too.


----------



## majkel

For the ADC input you need low input currents, good linearity and fast settling time. So the JFET op-amp choice is correct. It's up to the required speed whether you need the AD8066 or might be something slower but more accurate. I like the OPA827 a bit more than the OPA211, is just a bit warmer and more coherent through the whole frequency range. So, with a pair of the OPA827 you probably get the optimal option for the ADC input. I don't understand using another buffer, the LME49860 in this case. It doesn't increase the output current capability at all, so it's just another source of noise and distortions.


----------



## hopeless

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_For the ADC input you need low input currents, good linearity and fast settling time. So the JFET op-amp choice is correct. It's up to the required speed whether you need the AD8066 or might be something slower but more accurate. I like the OPA827 a bit more than the OPA211, is just a bit warmer and more coherent through the whole frequency range. So, with a pair of the OPA827 you probably get the optimal option for the ADC input. I don't understand using another buffer, the LME49860 in this case. It doesn't increase the output current capability at all, so it's just another source of noise and distortions._

 

To me (inside the DIYEDEN DAC, so at +/-15V) the OPA827 was more rough sounding and especially more _colorless_ than the OPA211. It probably was a bit more coherent, though. Overall I didn't prefer it to the OPA211. Also I remember how more satisfactory was the LT1357 I put in just after the OPA827, smoother and more intense though a bit less resolving.


 BTW, low input currents are what you get with the OPA2211 and the LT1469 (and LME49860).


----------



## majkel

Quote:


  Originally Posted by *hopeless* /img/forum/go_quote.gif 
_BTW, low input currents are what you get with the OPA2211 and the LT1469 (and LME49860)._

 

For the OPA827 it's more than 1000 times smaller. Actually the color saturation of the OPA827 is OK in my DAC. The OPA228 goes further with the timbre than the OPA211 IMHO and doesn't add any stupid op-amp related sound effects.


----------



## maddman79

True, the FET opamps tend to have less current-related noise compared to their CMOS brethren. However, CMOS tends to have a little less voltage-related noise. The OPA827 and AD8065 are measured in the magnitude of pA, compared to nA in the OPA2211 and even the LME49860.

 I got the impression that the LME49860 seemed more CMOS than FET. Am I alone in this thinking?

 I suppose the use of a second stage is a personal preference. In my mind, I like having low current noise in the input stage and low voltage noise in the ADC driver.

 -Brian


----------



## hopeless

Quote:


  Originally Posted by *maddman79* /img/forum/go_quote.gif 
_True, the FET opamps tend to have less current-related noise compared to their CMOS brethren. However, CMOS tends to have a little less voltage-related noise. The OPA827 and AD8065 are measured in the magnitude of pA, compared to nA in the OPA2211 and even the LME49860.

 I got the impression that the LME49860 seemed more CMOS than FET. Am I alone in this thinking?

 I suppose the use of a second stage is a personal preference. In my mind, I like having low current noise in the input stage and low voltage noise in the ADC driver.

 -Brian_

 

The opamps I've suggested are fine for voltage noise.

 BTW if your supply voltage is no more than 12V try the excellent (indeed) OPA2727, that is CMOS. Not the lowest voltage noise maybe, but it has sound quality and transparency that few opamps manage. Input current is in the pA range..


 Although I don't think 10 nA or such could do any damage even in AD conversion, but then again what do I know about it? 
	

	
	
		
		

		
		
	


	







 The OPA2211 has its colorations majkel, but the OPA827 was just a bit flat sounding. There are much more colorful opamps. I may try it again though, who knows, maybe it were the interconnects or digital cable 
	

	
	
		
		

		
		
	


	






 Anyway, I've just done a little thing... changed the main power supply cap of the new Super Pro (which powers the opamp directly, apart from the total 430nF of bypass Wima film caps I've added) from Rubycon YXH (470uF 25V) to Rubycon ZL (same physical size but 680uF 16V).

 Well, there's been an unexcpected improvement! This is the first time I try the ZL's, and the first impression is...impressive. There's been the classical veil lifted from the sonic presentation (currently I'm using the LM4562 as the output stage opamp, which I'd already tried before), bringing a sense of greater transparency, more black between sounds... Much appreciated. 
	

	
	
		
		

		
		
	


	




 Later I'll listen better. At any rate the YXH are a higher ripple current variant of YXF and YXG.


----------



## robjrock

Quote:


  Originally Posted by *hopeless* /img/forum/go_quote.gif 
_What is most certain is that the LM/LME's sound much more the same than different 
	

	
	
		
		

		
		
	


	




 I mean, you instantly hear that they all belong to the same family. (kind of like between the LT1355/13358/1361/1364, but the LM/LME's are closer to each other than that)_

 

While I generally agree with that, the differences are obvious enough to warrant attention / discussion. From what I've read, most people who insist they are the same chips haven't actually heard them side by side. 
 Incidentally, the LME49860 is great for vocals / voices... Its growing on me a lot, but I miss the detail of the 4562. The 4562 is a ferocious chip, takes no prisoners thats for sure. 
 In a week or two I should have the LME49720 so I'll do a comparison 'tween all 3...


----------



## hopeless

Quote:


  Originally Posted by *robjrock* /img/forum/go_quote.gif 
_While I generally agree with that, the differences are obvious enough to warrant attention / discussion. From what I've read, most people who insist they are the same chips haven't actually heard them side by side. 
 Incidentally, the LME49860 is great for vocals / voices... Its growing on me a lot, but I miss the detail of the 4562. The 4562 is a ferocious chip, takes no prisoners thats for sure. 
 In a week or two I should have the LME49720 so I'll do a comparison 'tween all 3..._

 

Well I'm loving the LM4562 @ 12V. My other DAC has the LME49710 @ 30V and I prefer how the 12V DAC sounds.


 Maybe thanks to the new Rubycon ZL, which really has brought an improvement in dynamics, detail, while keeping the midrange smooth.

 Maybe it's also that the LM4562 @ 12V sounds less aggressive?


----------



## hopeless

I should receive samples of OPA228UA and OPA228P. I will try the former in the Super Pro. I'm also awaiting the OPA2822 (had finished them) to try in the Super Pro as well.

 The OPA2822 is said in its datasheet to have "vanishingly low distortion in the audio range", and below 50 KHz anyway.




 BTW the OPA2132 also sounded really good. I feel that it's a highly underrated opamp around here (unlike @ diyaudio, IIRC). I may try it again.



 P.S.: Regarding what I said in the previous post... Actually it's that the DIYEDEN has a bit variable sound quality with the attenuator setting, and to level the output with that of the Super Pro I have to keep it at -7 (goes from 0 to -127 in .5 dB steps), which is not my favorite setting. My favorite is -11, as the SVDAC05 sounds a little more tonally luminous at that setting. 
	

	
	
		
		

		
		
	


	




 The two DACs both sound excellent to my ears -- the DIYEDEN (with two LME49710) a bit more airy and rigorous, the Super Pro (with LM4562) a bit more meaty and warm.


----------



## robjrock

Quote:


  Originally Posted by *hopeless* /img/forum/go_quote.gif 
_ BTW the OPA2132 also sounded really good. I feel that it's a highly underrated opamp around here (unlike @ diyaudio, IIRC). I may try it again._

 

I think its quite a pleasant sounding IC, and easy to work with, IMHO the soundstage sucks. It sounds practically mono IMHO. And to me one of the biggest advantages to upgrading your equipment (whatever that may be!) is getting better soundstage, which is the best way to increase overall clarity... IMO, o'course...


----------



## hopeless

Quote:


  Originally Posted by *robjrock* /img/forum/go_quote.gif 
_I think its quite a pleasant sounding IC, and easy to work with, IMHO the soundstage sucks. It sounds practically mono IMHO. And to me one of the biggest advantages to upgrading your equipment (whatever that may be!) is getting better soundstage, which is the best way to increase overall clarity... IMO, o'course... 
	

	
	
		
		

		
		
	


	


_

 

Maybe you think its soundstage sucks because it has good midrange presence. Its crosstalk is very good, so there's no particular reason for it to sound "mono". There was a mention of "thermal effects", which may cause thermal crosstalk, in the big measurement shootout, though.


 I will try two OPA132UA on adapter: should give the genuine sound of it with the ambience and clarity the OPA2132 does not reach


----------



## robjrock

Quote:


  Originally Posted by *hopeless* /img/forum/go_quote.gif 
_Maybe you think its soundstage sucks because it has good midrange presence. Its crosstalk is very good, so there's no particular reason for it to sound "mono"._

 

Perhaps. 
 To me other op amps provided 'eye opening' soundstage, while the OPA2132PA felt very narrow and 'pushed together' - but a lot of people love the 2132, so you know, YMMV and all that. 
 Could also have something to do with what circuit / equipment one has it in!


----------



## hopeless

Quote:


  Originally Posted by *robjrock* /img/forum/go_quote.gif 
_Perhaps. 
 To me other op amps provided 'eye opening' soundstage, while the OPA2132PA felt very narrow and 'pushed together' - but a lot of people love the 2132, so you know, YMMV and all that. 
 Could also have something to do with what circuit / equipment one has it in!_

 

Yeah, sure. I know that it doesn't like too much high input impedances. I guess you did not use it in a DAC output stage.


 Maybe it's not as good as the LM4562 I'm listening to right now, but it's good. The 2x OPA132UA should be even better.

 BTW as a dual opamp I do love the LT1469... I will say I miss it a bit, but it had some little problem with the Super Pro's muting circuitry. If only they sent me those LT1632 and LT1678 to try...


----------



## hopeless

Given my satisfaction with the LM4562 (it's an opamp for all seasons - i.e. for all records), the LME49720HA will be the next (and logical) step. It worked very well before; I'm just curious to hear if it sounds as warm as the LM4562 inside this DAC, or more transparent but more sterile tonally? We'll see.


----------



## Pluto2

Hi majkel,

 Have you ever compared LME49710 x2 on a Brown Dog with LME49860? I know you had pointed out LME49720 had some colder characters relatively. Wondered if 49710 x2 is same as 49720....anyone tried?

 BTW, thanks guys for the advice I swapped the 12 LM4562s in my active 2-way crossover with eight LME49860s and four LT1358s (as the last opamp in each channel), and the results are great with improvement in every area - clarity, focus, spatial resolution, etc. Now voical is much sweeter and string instruments seemed more realistic : )


----------



## hopeless

Proving that no single opamp is "transparent", but paradoxically putting more & different opamps together in the signal path _can_ yield a subjectively much better sound. 
	

	
	
		
		

		
			






 I say this for those who would blame a player or DAC for having an OPA627 in the signal path, when it may be the ideal solution when paired with other opamps with opposite/complementary sonic peculiarities, as often happens. That of matching different opamps is a delicate art. 
	

	
	
		
		

		
		
	


	






 BTW glad you like the LT1358 as I do. I'm sorry I've finished them, otherwise one would be inside my DAC in place of the LM4562 (which is good, but doesn't quite make me fall in love with the sound as happened with LT1358 and LT1469, and previously with the OPA211).


 BTW of course LME49710 x2 must be a little better than a single LME49720, but they must be placed on individual sockets for single opamps, separately power supply bypassed, in order to make the most of them. I have two LME49710 working like that inside my SVDAC05.

 On the other hand, if you use the LME49720HA, i.e. the T099 ...


----------



## hopeless

Think I will first try replacing the LM4562 with a LME49860. Last time I thought that the the LME49860 had a more 'saturated' sound especially in the mids.

 What I don't entirely like is the "digital" sounding treble of the LME49860 especially. Here definitely the OPA2211 is going to be better 
	

	
	
		
		

		
		
	


	




 since the OPA211 was.


----------



## Pluto2

Hi hopless,

 I thought you also liked LME49860 before, no?
 Would you say LM49710 x 2 or LME49720HA or opa2211 could be a better match to LT1358 then?


----------



## hopeless

Quote:


  Originally Posted by *Pluto2* /img/forum/go_quote.gif 
_Hi hopless,

 I thought you also liked LME49860 before, no?
 Would you say LM49710 x 2 or LME49720HA or opa2211 could be a better match to LT1358 then?_

 

Sure and I still like it. I think that you can't like one of the LM/LME's and then dislike the rest of the family. 
	

	
	
		
		

		
		
	


	




 They're sooo close to each other... (compared to how all the other different opamps are to each other)



 Having said that, perhaps it's the LM4562 that's the better match for the LT1358. Why not try putting back the LM4562 where you have put the LME49860's and seeing how things change? I'd be curious to know the outcome...


 Anyway the OPA2211 will also be a great match to the LT1358. Try and decide what you prefer. For me, I think that the sound of the OPA2211 (well, OPA211) is better than that of the National counterparts. I'm awaiting the adapters to use mine.




 Later I might try the LME49860 again (as I said before) and if so I will tell you what I prefer for my DAC, though after all I'm still enjoying the LM4562 and not finding particular faults to it..


 Wish I had another LT1469...
	

	
	
		
		

		
		
	


	




 Oh... why don't you try to pair the LT1358 with the LT1469? It will work for sure...


----------



## hopeless

BTW also try the THS4052 (single: THS4051). It's a great sounding opamp, more natural than the THS4032, to use wherever 2.5 uA of Ib is not a problem.


----------



## diditmyself

Quote:


  Originally Posted by *hopeless* /img/forum/go_quote.gif 
_Sure and I still like it. I think that you can't like one of the LM/LME's and then dislike the rest of the family. 
	

	
	
		
		

		
		
	


	




 They're sooo close to each other... (compared to how all the other different opamps are to each other)_

 

LM4562=LME49720=LME49860... as said before


----------



## Pluto2

Thanks hopeless : )

 Will try swapping the LM4562s back and see.

 LT1469? How about LT1364 with LT1358?


----------



## hopeless

The LT1469 has the same low bias current of the various LM & LME, and also has great distortion specifications. It could be a great alternative (for me it is).



 But...

 I'm listening to the DAC with a *LT1355* inside. This is the slowest of the LT13xx series (12 MHz and 400 V/us), and I feel that it possibly is the best 
	

	
	
		
		

		
		
	


	




 No matter the 1 mA of quiescent current... it sounds more "analog" than the LM4562 yet with an even nicer transient response. Leonard Cohen's Recent Songs just turned sweeter and more fascinating.


 I remember that when I first tried it, in between 2x THS4031 and LT1358, I found the LT1355 to be more natural and "right" than the former, and also a bit less protagonist than the latter. In short... why did I overlook it? I guess I was fooled by it being "too slow" or "too low quiescent current", LOL. 
	

	
	
		
		

		
		
	


	





 Not that it's going to stay forever... probably. Too restless.


----------



## hopeless

Yeah, the LT1355 is fine sounding. Sounds warm yet open, sweet yet precise. 

 I think that the better capacitive load drive (less overshoot) might be its advantage over the even quicker brothers.


----------



## hopeless

While the SVDAC05 with its LME49710's is a bit more cozy in the upper midrange (typical of this opamp), the Super Pro now is a bit more open and direct. Small difference, and I like them to not sound identical. They both sound great.


----------



## hopeless

Has majkel fleed in shame? We did love his comments


----------



## hopeless

Anyway, for how good is the LT1355, I still miss the LT1469. That can really sound impressive.


----------



## hopeless

Love the LT1355 though. It's an all-round good sounding opamp (something not easy to find). I love its tonality too.


 The way it plays Jason Lytle, "Yours truly, the commuter", is irresistible.


----------



## ROBSCIX

I started a opamp topic as I figured it would help keep all the oapmps dicussions where people could find them.


----------



## hopeless

The LT1355 exhibits a very clear and impactful bass, liquid mids, and very clear transients. Tonally it seems about neutral (bit differently from the more enthusiastic LT1358).


----------



## hopeless

Still finding the LT1355 to be transparent and unobtrusive - very important for me. I remember the OPA211 (in the other DAC, at +/- 15V) sounding a bit "peculiar", with a certain (often interesting BTW) coloration in the midbass, for instance.


----------



## hopeless

Hey majkel,


 I've just put two OPA228P inside my evolved CMOY and it's working (sounding) great. Thanks for the suggestion. 
	

	
	
		
		

		
			






 It's a little bit better than the AD845KN -- slightly smoother and heavier mids, slightly more neutral tonality. On the other hand, the AD843 was perhaps the best sounding (I'd like to compare but I have them no more). That's at 24V, G= 4, and a 30 ohm isolation resistor (inside the feedback) on the outputs. Altogether I think it's my "definitive" CMOY opamp.



 Interestingly the OPA228 looks (sounds) like perfectly stable, also because its current draw apparently is low compared to that of the AD845 judging by the time the led stays on when power is turned down. While the OPA552 (also stable from G= 5 on paper) made a slight distortion, only at a certain volume level, indicating that it was not quite stable.


----------



## majkel

Thanks for the info. I'll try the OPA552 probably tomorrow. When playing with Cmoy's, I was also able to make the OPA2228 stable at lower gains than 5 but at 2.7 it definitely needed additional compensation which made the sound worse so I just increased the gain.

 Regarding the AD843 - it's artificially harsh to me with a kind of ugly timbre. You need a lot of nice coloration elsewhere in the signal chain to really enjoy it but it doesn't make overall sense IMHO.


----------



## hopeless

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_Thanks for the info. I'll try the OPA552 probably tomorrow. When playing with Cmoy's, I was also able to make the OPA2228 stable at lower gains than 5 but at 2.7 it definitely needed additional compensation which made the sound worse so I just increased the gain.

 Regarding the AD843 - it's artificially harsh to me with a kind of ugly timbre. You need a lot of nice coloration elsewhere in the signal chain to really enjoy it but it doesn't make overall sense IMHO._

 

I disagree about the AD843. When my DIYEDEN DAC still had sockets 
	

	
	
		
		

		
		
	


	




 I tried it briefly and definitely found it good sounding, smooth, open and pleasing. This is with respect to the LT1028 that I've always liked, or the OPA211. Certainly it did sound different tonally. Don't think my system is so colored...

 Even in the headphone system (Kenwood DP-X337 PCDP's line out - silver/copper cable - evolved CMOY - Senn HD238 and HD485) the AD843 sounded quite promising when I briefly tried it; maybe just a bit too dark, but in a CMOY that's not a bad thing (too many opamps sound too lightweight).

 Anyway the OPA228P is good enough for it for me to call it definitive 
	

	
	
		
		

		
		
	


	




 though later on I may want to compare with LT1361 and LT1364 (some of the best inside my CMOY).



 The OPA552 sounded very good except for that slight distortion only at a specific volume level - must have had to do with input resistance (no caps in the signal path). I would rather use the OPA551 than increase the gain, which only a couple of opamps would benefit by; moreover, the resistors are SMD so it's just a bit more complicated (I would have to replace them with non-SMD ones).


----------



## maddman79

Just wanted you guys to know that I am very pleased with the results of pairing the AD8066 with the OPA2211. The recorded signal sounded very clear and natural.

 Also, I'm currently taking a stab at my own rendition of the OPA-Earth discrete opamp. Only difference: I opted for a surface mount design, as opposed to through-hole. Board layout has already been completed. PCBs should be in later this week.

 For this project, I used thin film resistors, tolerant to 0.1%. I plan to use my LCZ for tighter pairing of passive components. Also, I had to do a bit of part substitution for the surface mount transistors.

 I'll post pictures and share with you my results. If I'm not completely embarrassed by how the final result sounds, I may lend out a couple for review...

 -Brian


----------



## maddman79

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_I started a opamp topic as I figured it would help keep all the oapmps dicussions where people could find them._

 

Link?


----------



## Bonthouse

Quote:


  Originally Posted by *maddman79* /img/forum/go_quote.gif 
_Link?_

 

It's called "The Opamp thread" (orly? *YARLY! IT MAKES SENSE!*) and it's on the first page of the DIY section..
 Go look it up...


----------



## maddman79

Quote:


  Originally Posted by *Bonthouse* /img/forum/go_quote.gif 
_It's called "The Opamp thread" (orly? *YARLY! IT MAKES SENSE!*) and it's on the first page of the DIY section..
 Go look it up..._

 

Wouldn't it have just been easier to post the link? 
	

	
	
		
		

		
		
	


	




http://www.head-fi.org/forums/f6/opamp-thread-432749/


----------



## Bonthouse

You're a big boy now
	

	
	
		
		

		
		
	


	




 You must learn to take your own steps!


----------



## ROBSCIX

Quote:


  Originally Posted by *maddman79* /img/forum/go_quote.gif 
_AI'm currently taking a stab at my own rendition of the OPA-Earth discrete opamp. Only difference: I opted for a surface mount design, as opposed to through-hole. Board layout has already been completed. PCBs should be in later this week.

 For this project, I used thin film resistors, tolerant to 0.1%. I plan to use my LCZ for tighter pairing of passive components. Also, I had to do a bit of part substitution for the surface mount transistors.

 I'll post pictures and share with you my results. If I'm not completely embarrassed by how the final result sounds, I may lend out a couple for review...

 -Brian_

 

Can I speak for one of these test units?


----------



## maddman79

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Can I speak for one of these test units?_

 

Sure, you're welcome to test one. I'll pay for your shipping each way.

 Keep in mind, this prototype is meant to be a drop-in replacement for a dual opamp in SIP-8 package. The driving force behind this project is to upgrade my turntable 
	

	
	
		
		

		
		
	


	




 Down the road, I may build a 4 or 6 layer version in DIP-8 package...

 majkel and hopeless, would either of you have any interest in testing one? I have enough parts for four.

 -Brian


----------



## hopeless

Quote:


  Originally Posted by *maddman79* /img/forum/go_quote.gif 
_Sure, you're welcome to test one. I'll pay for your shipping each way.

 Keep in mind, this prototype is meant to be a drop-in replacement for a dual opamp in SIP-8 package. The driving force behind this project is to upgrade my turntable 
	

	
	
		
		

		
			





 Down the road, I may build a 4 or 6 layer version in DIP-8 package...

 majkel and hopeless, would either of you have any interest in testing one? I have enough parts for four.

 -Brian_

 

That's interesting. Unfortunately the Super Pro has a very small enclosure and at the moment it's the only place where I could try it (aside from my CMOYs).


----------



## majkel

Yes, sounds very promising but it's unstable in my circuit. Unfortunately it might be compensated for lower gains in inverting configuration only. So I'll try it as a headphone amp with a decent DIY PSU and we'll see. 
	

	
	
		
		

		
		
	


	




 On the other hand OPA211ID gained lots of points in my DAC after rebuilding the headphone amp a bit. It's a tough choice between the OPA228P and the OPA211ID. Probably the latter is more linear and the first unity gain stable op-amp without more or less corrupted imaging. What I mean is that on all compensated op-amps I know there is an effect that correct imaging happens in limited area only. On the extremes, or in the middle, things get flat, or there is an impression of a barrier limiting the soundstage. In the OPA211ID there is none. On a pair of AD797BRZ it is very slight. The OPA Sun v.2 seems to work on it's own rules, bringing something new to the op-amp world - fluent transition between sound sources and feeling of free music flow. I'm not sure it's realistic but at least interesting.


----------



## maddman79

Well, I've successfully built-out my first prototype OPA-E, using surface mount parts. I did a quick test with it in my Auzen X-Fi Prelude 7.1, and it does seem to be working!

 I ran it without the ground plane attached, and it seems to exhibit strangled mids and an annoying over-emphasis in the timbre with the highs. I don't have any other discrete opamps to compare this with. But, it seems consistent with majkel's description of the ungrounded OPA-E.

 I want to run some more tests with the thing grounded. I also want to throw some caps in there for decoupling.

 Pics soon to come...

 -Brian


----------



## fzman

Brian,

 I've done some DIY stuff recently where the grounding made enormous sonic differences, not just i terms of noise, rf, hum type stuff. Having continuity between all of the ground points in the circuit is not enough.

 before you mess with other things, experiment with where things are grounded-- and make sure they are really good connections. star ground wherever possible!!!!!

 Prps to you for the surface mouont diy!!!!


 Mark


  Quote:


  Originally Posted by *maddman79* /img/forum/go_quote.gif 
_Well, I've successfully built-out my first prototype OPA-E, using surface mount parts. I did a quick test with it in my Auzen X-Fi Prelude 7.1, and it does seem to be working!

 I ran it without the ground plane attached, and it seems to exhibit strangled mids and an annoying over-emphasis in the timbre with the highs. I don't have any other discrete opamps to compare this with. But, it seems consistent with majkel's description of the ungrounded OPA-E.

 I want to run some more tests with the thing grounded. I also want to throw some caps in there for decoupling.

 Pics soon to come...

 -Brian_


----------



## maddman79

Thumbnail:





 Full size:
http://img199.imageshack.us/img199/431/opamp027.jpg


----------



## maddman79

Vias make star contact with ground plane. However, positive and negative supplies only have traces at the moment. It's only a 2-layer board after all 
	

	
	
		
		

		
		
	


	




 After I get all the gremlins out, I'll use either a 4 or 6-layer PCB. That way, my supplies can each have their own plane. I also plan on using 0603 passives, as opposed to the 1206 in the first version. I'm thinking that next time around, I can reduce board size by 50%.

 Today, I'll try attaching the ground plane and see if that impacts audio quality.

 -Brian


----------



## exhausted

The look of it is great. 
	

	
	
		
		

		
		
	


	





 Does it sound exactly like the Earth once grounded?


----------



## ROBSCIX

Quote:


  Originally Posted by *maddman79* /img/forum/go_quote.gif 
_Vias make star contact with ground plane. However, positive and negative supplies only have traces at the moment. It's only a 2-layer board after all 
	

	
	
		
		

		
		
	


	




 After I get all the gremlins out, I'll use either a 4 or 6-layer PCB. That way, my supplies can each have their own plane. I also plan on using 0603 passives, as opposed to the 1206 in the first version. I'm thinking that next time around, I can reduce board size by 50%.

 Today, I'll try attaching the ground plane and see if that impacts audio quality.

 -Brian_

 

Wow. I am very impressed. That is some fine work.


----------



## maddman79

I did some quick tests with grounding; and so far, it seems to be helping with that annoying distortion in the high-end timbre.

 -Brian


----------



## ROBSCIX

Are you considering turning this into a commerical product?


----------



## maddman79

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Are you considering turning this into a commerical product?_

 

It wasn't my original intent to make this into a commercial product. But, if people are interested, I'll make extras.

 Since I'm planning to make the next revision a 4-layer PCB, it would help me a great deal with reducing costs if I was making more than just what I needed. Plus, it would give me more purchasing power in sourcing parts. Some of these components are really hard to find.

 FYI, next version will be DIP-8...

 -Brian


----------



## ROBSCIX

Great, well if the test goes good I will take a few off you.

 The DIP8 socket seems to still be the most common among a great deal of audio gear.

 Given the tools and prices avialable now it is easy to make your own PCB's when you need them.
 I can still remembe etching my own PCB's in the basment.


----------



## maddman79

Grounding made a significant difference. I'm anxious for you to review a prototype.

 -Brian


----------



## ROBSCIX

Send it over and I will give you my impressions.


----------



## n_maher

maddman, please check your PM's.


----------



## maddman79

Mark -

 I used to work across the street from the Thompson Center. Sometime, I'll have to stop-by and poke around in your shop 
	

	
	
		
		

		
			





 -Brian


----------



## maddman79

I've been in touch with Nate, and we've reached an agreement on an acceptable way the surface mount discrete opamp can be sold here.

 Since I'm unable able to charge for any sort of labor costs associated with assembly, per rules and regulations here at Head-Fi, I will be offering these for sale only in kit format.

 -Brian


----------



## maddman79

Quote:


  Originally Posted by *ROBSCIX* /img/forum/go_quote.gif 
_Send it over and I will give you my impressions._

 

Steve -

 I shipped you one this morning.

 -Brian


----------



## ROBSCIX

Great. I am looking forward to testing. I will let you know when it arrives and my impressions after I have had a chance to lsiten to it for ahwhile.


----------



## fzman

Brian,

 We can always use another madman visiting our shop. 
	

	
	
		
		

		
		
	


	




 give me a heads-up when you might stop by-- bring the opamp!!!

  Quote:


  Originally Posted by *maddman79* /img/forum/go_quote.gif 
_Mark -

 I used to work across the street from the Thompson Center. Sometime, I'll have to stop-by and poke around in your shop 
	

	
	
		
		

		
		
	


	




 -Brian_


----------



## maddman79

Hey Guys -

 I've a quick update...

 I installed two of these things into my Denon DP-52F. I know that it's not the greatest turntable around... but, it's got a Zyx Airy cart in it 
	

	
	
		
		

		
		
	


	




 Anywho... It does sound better. Then again, that's not saying much... considering that it originally had Mitsubishi M5218 opamps.

 Since I have only two discrete opamps on-hand at the moment, I was able to upgrade only one channel. For comparison, I put OPA2211's in the other channel. From there, I was able to directly compare the two using headphones.

 Here's some pics of the project:
Pictures by maddman79 - Photobucket

 I can honestly say that the discrete opamp sounded more transparent than the OPA2211. However, the use of a discrete opamp seems to disrupt the functionality of the tonearm. It caused a few haywire moments. To confirm this, I reconfigured the opamps so that I had an OPA2211 and a discrete in each channel. From there, the tonearm was even more misbehaved.

 From my experience, I don't think a discrete opamp can be a drop-in replacement in the Denon DP-52F... at least, not without some tweaking.

 -Brian


----------



## les_garten

Quote:


  Originally Posted by *maddman79* /img/forum/go_quote.gif 
_Hey Guys -

 I've a quick update...

 I installed two of these things into my Denon DP-52F. I know that it's not the greatest turntable around... but, it's got a Zyx Airy cart in it 
	

	
	
		
		

		
		
	


	




 Anywho... It does sound better. Then again, that's not saying much... considering that it originally had Mitsubishi M5218 opamps.

 Since I have only two discrete opamps on-hand at the moment, I was able to upgrade only one channel. For comparison, I put OPA2211's in the other channel. From there, I was able to directly compare the two using headphones.

 Here's some pics of the project:
Pictures by maddman79 - Photobucket

 I can honestly say that the discrete opamp sounded more transparent than the OPA2211. However, the use of a discrete opamp seems to disrupt the functionality of the tonearm. It caused a few haywire moments. To confirm this, I reconfigured the opamps so that I had an OPA2211 and a discrete in each channel. From there, the tonearm was even more misbehaved.

 From my experience, I don't think a discrete opamp can be a drop-in replacement in the Denon DP-52F... at least, not without some tweaking.

 -Brian_

 

I had a Denon Turn Table Eons ago. Don't remember which one. Does the signal go thru the op amps off the Tonearm?? I'm sure it didn't with my SOTA or Oracle. I'm confused about this one. Neat PIX, never seen inside a DENON. Obviously a lot more going on there as opposed to your average TT.

 .

 .


----------



## majkel

For the turntable the discrete op-amp was better due to FET inputs! The pitch coil is a high impedance source and it requires low current draw which the OPA2211 cannot provide. Just see the specs. The OPA827 pair or even the OPA2228 will be better.


----------



## majkel

I'd add the headphones. On the Grado PS1000 it's damn obvious there is no competition for the OPA228p pair. Just another level of... everything.


----------



## Currawong

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_I'd add the headphones. On the Grado PS1000 it's damn obvious there is no competition for the OPA228p pair. Just another level of... everything. 
	

	
	
		
		

		
		
	


	


_

 

How about the 2228?


----------



## majkel

It gives better results with 2x single but you get the idea when trying the OPA2228. Just the channel separation is not so good due to some common circuits in the die.


----------



## maddman79

Quote:


  Originally Posted by *majkel* /img/forum/go_quote.gif 
_For the turntable the discrete op-amp was better due to FET inputs! The pitch coil is a high impedance source and it requires low current draw which the OPA2211 cannot provide. Just see the specs. The OPA827 pair or even the OPA2228 will be better._

 

Very good points. I will experiment some more 
	

	
	
		
		

		
		
	


	




 -Brian


----------



## NotoriousBIG_PJ

edit: found the diagram posted on the website. my faceplate is from the first batch so it doesn't have the info

 Is it possible someone could point me to a diagram or picture of the correct way to orrient a regular opamp on the compass?

 Thanks,

 Biggie.


----------



## LuciferX

Diferences in bass/mediums/highs , quality, "type of sound" etc of this?:

 OPA2132P

 LME49860

 LM4562

 LME49720NA

 LT1361CN8

 LT1355CN8

 Im planning use them in this soundcard: HT Omega - Claro halo XT Factory installed opamps are 4580 (JRC). Claro halo use 12V for power supply voltage to opamp.

 And read this please, is the "design" of the Claro Halo: HT Omega

 And in a "combo configuration", what do you suggest ?

 The soundcard use 4 dual opamps: 






*The each polarity signal produced by AK4396 goes to 2 dual opamps (U8 for left, U10 for right) In those dual opamps, each opamp handles only one polarity, either positive signal or negative. Then both exclusively amplified positive and negative signals are re-assembled and goes to another opamps (U9 for left, U11 for right) for second amplification. In the second dual opamp, U9, The one opamp is for left headphone and the other is for left RCA output. In U11, one opamp is for right headphone and the other is for right RCA output.


 This design maximizes the feature of AK4396DAC and it also dramatically improves stereo-talk.

 It is recommended to swap all four opamps for your preferred analog sound
 color. Factory installed opamps are 4580 (JRC).

 If you choose to swap only two, they must be U8 & U10 ( They are marked on PCB of Claro halo)*


----------



## ROBSCIX

Just get some opamps and start doing some testing...


----------



## Superfrag

I just dont get one thing, pardon me if its a noob question, the AD797BRZ and the others are so small in comparison to the Audio GD's Earth, Moon and Sun. Why so, and how does such a small device compete with the bigger one's..


----------



## Superfrag

Quote:


  Originally Posted by *Superfrag* /img/forum/go_quote.gif 
_I just dont get one thing, pardon me if its a noob question, the AD797BRZ and the others are so small in comparison to the Audio GD's Earth, Moon and Sun. Why so, and how does such a small device compete with the bigger one's.._

 

anyone?


----------



## haloxt

There's some kinds of technical limitations with IC opamps but that doesn't necessarily mean they are inferior to discrete opamps. And you only have a handful of discrete opamps to choose from, whereas with opamps you have many many to try and find a sound signature you like. Since there's a wide variety of applications, and variety of preferences, I think they both can be better than the other in the right scenario.


----------



## Superfrag

hmm..
 im ordering the AD797BRZ for my compass then.. wanna try those out..


----------



## haloxt

Before you order it, you know that BRZ is packaged in SOIC and is single-channel? You'll need an adapter, like this one: Single-to-dual Op-Amp Adapter (p/n 020302)

 If you want to try IC's in the compass, I recommend trying out some free samples too (make sure they are dip-8 and dual-channel). It's fun to try out different opamps especially when it's free.


----------



## Superfrag

oh ok.. wats that exactly supposed to mean?
 Ill need two of the AD797's or just one and the adapter?
 I dont think Analog Devices will send free samples to India.


----------



## haloxt

You'll need two AD797BRZ with that two single channel SOIC-8 to single dual channel DIP-8 adapter.

 As for samples, I think they likely will give it to you with free shipping to boot, just make a gmail account and ask for samples. But they only have samples of cheaper opamps, I recommend looking for some dual channel audio opamps that can work at 16 volt because that's what the compass works at.

 Actually if you've never played with opamps before, I recommend you don't even try IC opamps in the compass because I think there's a good chance you'll much prefer the hdam's anyway. I recently blew up a soundcard because I'm stupid with opamps and you don't want to do the same with the compass.


----------



## Superfrag

Hmm..
 when Im in the US next year then I'll think about the opamps..
 for now, I think I might order the Moon and the Sun, just got the Earth for now..


----------



## PatricCoverman

The other manufacturers have also moved to larger netbooks, so choices are limited to either surplus supplies where you can find them netbooks, like MSI Wind or Acer Aspire, or UMPC's from Viliv. 
perverted jokes


----------



## PatricCoverman

THANKS!!! 
funny bedtime stories


----------



## cha_indian

After burn in of HDAMs and after getting the sound improvemnet, can they go back to their original state if not used for long time ???


----------



## leeperry

majkel, did you ever try LT1357? Jim Williams is always raving about it


----------



## les_garten

Quote:


  Originally Posted by *cha_indian* /img/forum/go_quote.gif 
_After burn in of HDAMs and after getting the sound improvemnet, can they go back to their original state if not used for long time ???_

 

Also, is the phase different in the Southern Hemisphere?


----------



## leeperry

so opams can actually un-burn themselves, that sounds scary!

  Quote:


  Originally Posted by *majkel* 
_The LT1028ACN8 make it happen, the AD797BRZ [..] do it in a lesser degree_

 

I just compared them (again 
	

	
	
		
		

		
		
	


	




), and I'll pick 797B as PCM1793 LPF: http://www.head-fi.org/forums/f5/fir...ml#post6475571

 thanks for the tip BTW, this chip is just 
	

	
	
		
		

		
		
	


	




 I don't think I'll bother trying LT1357.


----------



## luvdunhill

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_Also, is the phase different in the Southern Hemisphere?




_

 

I'd be more interested in which direction that audio-gd crap would swirl upon being flushed.


----------



## Currawong

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_I'd be more interested in which direction that audio-gd crap would swirl upon being flushed._

 

Have you experience with them?


----------



## leeperry

Quote:


  Originally Posted by *Currawong* /img/forum/go_quote.gif 
_Have you experience with them?_

 

don't pay attention to this guy, he's just a troll...he threadcrapped one of my threads w/ dumb comments like this already.

 I really think it's time for you to try AD797B anyway


----------



## haloxt

lol leeperry, sometimes you sound as crazy as the guy in your avatar looks.

 How do you think the AD797B compares to audio-gd's HDAM's?


----------



## Pacha

Quote:


  Originally Posted by *haloxt* /img/forum/go_quote.gif 
_lol leeperry, sometimes you sound as crazy as the guy in your avatar looks.

 How do you think the AD797B compares to audio-gd's HDAM's?_

 

Read this in case you didn't know anything about him :
Serge Gainsbourg - Wikipedia, the free encyclopedia


----------



## leeperry

I've A/B'ed AD797BR/LT1028ACN8 again...well, it's a knock out! AD797B has a much more versatile SS on the Z axis, but LT1028A has a much thicker sound, much wider X SS, w/ a very impressive percussive and deep low end bass response, a huge triangular SS(no need for crossfeed to get a front channel on headphones!) and slightly rolled off trebles, allowing to avoid EQ to kill middle ear resonances altogether.

 I can only +10000 what RS said about it: http://www.head-fi.org/forums/6402627-post77.html

 this thing is what PRaT is all about, they should have called it LT627-31337ACN8 and sold it for $80 a pop 
	

	
	
		
		

		
		
	


	




 also, AD797B likes to annoy you w/ tiny details noone cares about..

 I wish I could try Burson V2 in my Firestone Spitfire, but the damn thing needs 38mA and its discrete linear PSU cannot feed more than 200mA...the manufacturer advised me to forget about it 
	

	
	
		
		

		
		
	


	




 LT1122A is also nice, possibly a good option to feed a "dirty" external amp..


----------



## diditmyself

Do you know if the Audio-gd people read this thread? Are they open to creative criticism and ready to improve their modules?


----------



## leeperry

BTW, I understand why AD797 is strongly frowned upon in CMoy's! 
	

	
	
		
		

		
		
	


	




 on a cheapo soundcard(Auzen X-Raider 7.1), 2*LT1028CS8 output 0-1mVDC...but 2*AD797BR 100mVDC!!! lesson learned


----------



## haloxt

Quote:


  Originally Posted by *diditmyself* /img/forum/go_quote.gif 
_Do you know if the Audio-gd people read this thread? Are they open to creative criticism and ready to improve their modules?_

 

I've read several times that audio-gd tries to read all threads about their products to gather user feedback and ideas for improvements. If you have some ideas, share and they might use it. Some versions of the hdam's have been updated to reflect user preference and might be updated even more if enough people ask for some change. I like how the three hdam's are right now, three totally different sound signatures and fun to play with.


----------



## diditmyself

My experience is limited to folded cascode circuits like Earth. I have less experience from standard opamps like Moon or complementary amps such as Sun.

 Improvements on Earth will make it an AD797-clone.

 The simple SK170 input stage sounds warm and fuzzy and nice in a way but not clean. It's not obvious everyone would like "improvements" here, but cascoding improves details and soundstage. The sound is leaner with a more forward presentation. CFP is an alternative and also improves details and make it leaner. 

 SA970/SC2240 sound hard, typical solid state. To my ears SA1016/SC2362 are better.

 A bipolar input stage might sound better but introduces problematic bias currents that has to be dealt with. My favourite input stage at the moment is bipolar CFP.

 Applying a floating current mirror and shunt transistor to the folded cascode stage as in AD797 make it sound much better without compromises. Just cleaner and more enjoyable. I think many would describe it as "space around instruments" or "blacker background".

 It's a couple of more transistors, but I think it's worth it. I don't think the basic folded cascode circuit can compete with the best monolithic opamps, and why do discrete opamps that sounds worse when they're larger and more expensive, often draw more current and have worse output swing.

 To be discovered: if cascoding the folded cascode improves things, if the combination of cascode and CFP is as good as I hope, how a cascoded bipolar input stage sounds


----------



## haloxt

I forgot to say, Kingwa, the owner of audio-gd and the one reading the forums, doesn't have very good English 
	

	
	
		
		

		
		
	


	




 there's a chance he won't fully understand your informative post.

 Did you ever get a chance to listen to the earth btw?


----------



## leeperry

yay, I just compared LT1028ACN8 Vs LT1028CS8 in the Firestone Spitfire(fed w/ ±12V)...huh, headshot! 
	

	
	
		
		

		
		
	


	




 OTOH, AD797BR only outputs 3/4 mVDC


----------



## Currawong

diditmyself: When the Sun first appeared, Kingwa asked a few people who had bought the Earth to try it out. The response was a bit negative (IIRC it was too bright), so he changed the circuit. I'm sure he'd be interested in your comments if you emailed them to him.


----------



## les_garten

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_BTW, I understand why AD797 is strongly frowned upon in CMoy's! 
	

	
	
		
		

		
		
	


	




 on a cheapo soundcard(Auzen X-Raider 7.1), 2*LT1028CS8 output 0-1mVDC...but 2*AD797BR 100mVDC!!! lesson learned 
	

	
	
		
		

		
		
	


	


_

 

If you wanted to put a Few 797's on a BrownDog to substitute in place of an Earth, which ones wold you use?


----------



## leeperry

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_If you wanted to put a Few 797's on a BrownDog to substitute in place of an Earth, which ones wold you use?_

 

there's a dual AD797BR chinese seller on ebay, I wouldn't look any further...cheap and ready to use right away.


----------



## les_garten

Quote:


  Originally Posted by *leeperry* /img/forum/go_quote.gif 
_there's a dual AD797BR chinese seller on ebay, I wouldn't look any further...cheap and ready to use right away._

 


 So anyplace you might use an Earth Dual OPA, you could substitute one of these? No worries about Voltages or outputs?


----------



## leeperry

oooh, Earth is slow and can be used on extension leads...AD797 can output nasty DC offset in an improper design, and can be pesky stability-wise. AD797 is not a drop-in replacement to everything like OPA-Earth can be.

 same goes for LT1028, as it's not unity gain stable...so it can act REALLY funky in wrong designs, like outputting nothing but ultrasonics or oscillating to death outputting white noise.


----------



## digger945

I have 3 HDAM modules that I want to sell, and I'm pretty sure one is a Sun because it has a sticker on it, but the other two are not marked and I want to make absolutely sure I have the right ones before listing them. I think they may be Earths but want to make sure if they are single or dual or what. 

 Is there a quick way to identify these?


----------



## les_garten

Quote:


  Originally Posted by *digger945* /img/forum/go_quote.gif 
_I have 3 HDAM modules that I want to sell, and I'm pretty sure one is a Sun because it has a sticker on it, but the other two are not marked and I want to make absolutely sure I have the right ones before listing them. I think they may be Earths but want to make sure if they are single or dual or what. 

 Is there a quick way to identify these?_

 


 A-GD has pix on their website that if you fool around with you can figure out what you have.


----------



## coolfungadget

Quote:


  Originally Posted by *les_garten* /img/forum/go_quote.gif 
_A-GD has pix on their website that if you fool around with you can figure out what you have._

 

ÐÂ½¨ÍøÒ³ 1


----------



## WaveRider69

So for Pop/Electrontica/Dance am I better off getting AD797's or Op-Earth's with my Xonar Essense STX to use with my ATH-AD700's or am I better off getting a new pair of cans?
   
  What I have now just isn't hitting the sweet spot.


----------



## les_garten

Quote: 





waverider69 said:


> So for Pop/Electrontica/Dance am I better off getting AD797's or Op-Earth's with my Xonar Essense STX to use with my ATH-AD700's or am I better off getting a new pair of cans?
> 
> What I have now just isn't hitting the sweet spot.


 
  I would say if you are looking for something Tangable as far as change is concerned.  NEW CANZ!
   
  Once you Love your Canz, then roll opa's
   
  You can change OPA's at anytime, but they can't fix your Canz, IMO.
   
  Don't get me wrong, there's pretty serious differences between OPA's.  I just think if you are questioning your Canz, then Jump Froggy Jump!


----------



## leeperry

waverider69 said:


> am I better off getting AD797's or Op-Earth's with my Xonar Essense STX


 
   
  Try to PM ManuLM, I think AD797BR was oscillating like hell as I/V on his STX


----------



## WaveRider69

Quote: 





les_garten said:


> I would say if you are looking for something Tangable as far as change is concerned.  NEW CANZ!
> 
> Once you Love your Canz, then roll opa's
> 
> ...


 

 Cool that's exactly what I needed to hear.  Wasn't sure how much they might or might not fix my cans. So I'm gonna find a pair of good cans that I like then take the tweaking from there, bc it looks like this is a whole nother game on it's own with getting loads of different opamps and playing with them all


----------



## Mad Max

Quote: 





waverider69 said:


> So for Pop/Electrontica/Dance am I better off getting AD797's or Op-Earth's with my Xonar Essense STX to use with my ATH-AD700's or am I better off getting a new pair of cans?
> 
> What I have now just isn't hitting the sweet spot.


 

 AD700 has very good speed; not sure about those genres, though.
  You might love 4627-1's energetic presentation for your music.
   
  Edit: or 8597


----------



## AmarokCZ

Anyone tried some of these: *LT1122*, AD8672, ADA4637-1, LT1807, AD8028, ADA4898-2 or ADA4627-1 ??


----------



## leeperry

ah, LT1028ACN8....such a surreal sounding chip, it always leaves me out of speech 
	

	
	
		
		

		
			




   
  too bad it oscillates in the MHz range(checked w/ an analog oscilloscope) in my Firestone Spitfire DAC, and makes static noises when my neon bathroom is turned off or my fridge motor turns on. I really wish I could make it stable...and LT1128ACN8 isn't part of their sample program, besides I didn't like LT1128CN8(but I also don't like LT1028CN8).....I don't think 1128AC will sound exactly like 1028AC


----------



## leeperry

alright, LT1128ACN8 is $8 a pop on linear.com, I'll bite...hopefully it'll sound as good as LT1028ACN8


----------



## leeperry

on diyaudio.com, they say that OPA1641 lets you hear what's on the record...quite true, LT1363 and LT1028AC are colored to death...that nasty euphonic hifi sound


----------



## majkel

I ordered two pieces of the OPA1642 to upgrade the Audionet Art v2 for my fellow coleague. I'm planning to try the OPA2228 one for each channel first but in case of oscillation I decided to stay at unity gain stability and JFET inputs as in the original OPA2134PA, so the OPA1642 have the chance.


----------



## Mad Max

4637-1A is very nice, but I like 4627-1B better.  I have not tried 4637-1B yet.  I still say ADA4627-1B is the very best so far.
  OPA1641 is very nice too, like a lesser 4627 but a bit softer and not as lively and unforgiving.
   
  ADA4898 is supposed to be good.


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## leeperry

the bass of 1641 is very deep and tight, but it sounds really dry...trying to get used to it.


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## Mad Max

ISL28127 has the best bass, OPA1611 too in some circuits.
  ADA4841 also has great bass.  A bit forward compared to others.


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## leeperry

it's hard to know whether it's missing stuff or if that's the other opamps that add their own coloration...it doesn't sound thin, just really not hifi, more like hardcore flat. SS is great, though.


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## Mad Max

Flat?


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## leeperry

in the sense of "uncolored", like the hardcore monitoring gear(Yamaha NS10M / Sony MDR-CD900ST)...it doesn't entertain me, but it sounds very detailed...yet, not too boring.


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## leeperry

Ah well, I've polished the signal quality fed to OPA1641, and it's really a great sounding IC 
	

	
	
		
		

		
			




   
  I fully agree w/ the ppl on diyaudio who said that it lets you hear what's on the record...it's very impressive as PCM1793 LPF, feed it poorly and it'll shred yours eardrums....most of my other chips sound utterly colored in comparison. It'll let you hear any weak link in your rig loud and clear 
	

	
	
		
		

		
		
	


	



   
  Putting those in a mixing console must really be something!


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## peranders

Quote: 





leeperry said:


> ...more like hardcore flat.


 
  What is "hardcore flat" for a us coming from non-english countries?
  
  A flat frequency response, can it be more than flat?


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## Mad Max

It's concave bass!!!
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
  I'm joking.


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## leeperry

yeah, it really sound very little colored to my ears and does everything well...it's a keeper for sure.
   
  I'll run a shoutout against ADA4627-1B next week or so


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## leeperry

humm, ADA4627-1B is business
	

	
	
		
		

		
		
	


	



   
  but I really had to improve the signal fed to it, this thing will spit back a crappy signal right back to your face.


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## .Sup

Hey guys. I would just like to know if I can ground both left and right channel opa with the same screw.


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## qusp

sure, only reason not to would be if you are running dual mono


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## .Sup

Quote: 





qusp said:


> sure, only reason not to would be if you are running dual mono


 


  Thanks qusp, very much appreciated. I have 2x single OPA, one for each channel. Is that okay?


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## leeperry

This chip really rocks! It doesn't sound as good as a killer discrete design(it clearly doesn't retrieve as much ambience and sound cues), but you get 75% of the goodness for a few bucks....the last percents will cost ya


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## .Sup

Quote: 





leeperry said:


> This chip really rocks! It doesn't sound as good as a killer discrete design(it clearly doesn't retrieve as much ambience and sound cues), but you get 75% of the goodness for a few bucks....the last percents will cost ya


 
  Nice! Where can one purchase them? And also the adaptor looks nice. Where can that be obtained? Thanks


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## leeperry

I got the adapter on ebay: http://www.ebay.com/sch/sorch_audio/m.html?_trkparms=65%253A12%257C66%253A2%257C39%253A6%257C72%253A5698&rt=nc&_dmd=2&_trksid=p3911.c0.m14&_vc=1&_sop=15&_sc=1
   
  I've tried a few of his adapters, they're all 2oz, they have a very thick PCB and pins that provide an excellent contact within DIP8 sockets and all around they sound far better than those 1oz and very thin browndogs to my ears. This guy knows how to design adapters 
	

	
	
		
		

		
			




   
  About the AD797BNZ, I got them off a chinese broker....these are hard to source, and I believe he ran out but I could ask him if you needed a few.


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## .Sup

Quote: 





leeperry said:


> I got the adapter on ebay: http://www.ebay.com/sch/sorch_audio/m.html?_trkparms=65%253A12%257C66%253A2%257C39%253A6%257C72%253A5698&rt=nc&_dmd=2&_trksid=p3911.c0.m14&_vc=1&_sop=15&_sc=1
> 
> I've tried a few of his adapters, they're all 2oz, they have a very thick PCB and pins that provide an excellent contact within DIP8 sockets and all around they sound far better than those 1oz and very thin browndogs to my ears. This guy knows how to design adapters
> 
> ...


 


  Thanks leeperry for all the info. If you could that would be great as I trust you they are good but if you can't that is fine too and I will seek elsewhere.


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## leeperry

.sup said:


> If you could that would be great


 
   
  YGPM 
	

	
	
		
		

		
		
	


	



   


leeperry said:


> I got the adapter on ebay: http://www.ebay.com/sch/sorch_audio/m.html?_trkparms=65%253A12%257C66%253A2%257C39%253A6%257C72%253A5698&rt=nc&_dmd=2&_trksid=p3911.c0.m14&_vc=1&_sop=15&_sc=1


 

 Hah, he makes them w/ white PCB now, they look so deliciiiious


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## leeperry

Another great chip is OPA1641, it doesn't try to impress you like 797B...it just sounds very musical and detailed, and those thick 2oz thai adapters manage to extract the best out of it: 


   
  The pins are so thick that I'm always afraid to break my DAC board, talk about good contact! The SQ improvement over 1oz browndogs is dead obvious, they sound shrill and bright in comparison..I even had to reduce my ears resonances EQ


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## mikael83

I'm kind of noob when it comes to opas so I need some advices. I ordered  this Dual Opamp Adaptor little too hastily without knowing what kind of AD797BRZ I should order for it. So I found this single AD797BRZ from ebay and I would need to buy 2 of those for the adaptor, right? Then there is this dual AD797BRZ that do not need any adapter? So should I get 2 single opas for the adapter  and are there any differences with those two AD797BRZs? Lastly I do not have any extra power source for my Audio-gd FUN and I read somewhere that opas get better with extra power, so can I drive dual AD797BRZ without the extra power source?


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## kiteki

This is a very extensive review in the first post.
   
   
  I haven't read all 26 pages but has anyone blind tested any of these op-amps?


----------



## AmarokCZ

Three days ago I recieved ZERO DAC with Audio-GD MOON in it for upgradind to version "Amarok". After upgrading it I quickly "blind-compared" OPA MOON to my 2xOPA627 and the difference between them was impossible for me to tell when listening to AKG K270 or K300. But the difference was obvious when listening to STAX SR-3N because with MOON there was something wrong with highs.


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## kiteki

amarokcz said:


> Three days ago I recieved ZERO DAC with Audio-GD MOON in it for upgradind to version "Amarok". After upgrading it I quickly "blind-compared" OPA MOON to my 2xOPA627 and the difference between them was impossible for me to tell when listening to AKG K270 or K300. But the difference was obvious when listening to STAX SR-3N because with MOON there was something wrong with highs.


 
   
  The source is only as transparent as the transducer.  You can't watch blu-ray on a DVD.  I have no idea how transparent STAX really are in reality or if their amplifier section just filters out the signal or the transducers instill stax-ness all over the place.
   
   
  It seems like AD797BRZ is popular in this thread, is it much different from the AR which I already have?


----------



## ryanjun

Quote: 





majkel said:


> *Category 4 – like a completely arranged room, not quite tidy yet*
> I'd say, the fight with the Audio-gd op-amps starts making sense here.
> 
> 
> ...


 
   
   
  Hello, majkel
   
  I have a question regarding the review : you categorized OP27GP as "category 4" under one condition that they have to be class-A biased. 
   
  Do you remember* how much mA* did you biased those OP27GPs? (I am planning to use a constant current source for biasing - lm317 current regulator or BJT with a voltage reference perhaps.)
   
  I am tweaking my DIY DAC for its I-V & filter stage by trying different op amps in different ways.
   
  Pls check out the link below for the DAC. It is a collaboration project by South Korean DIYers, a.k.a. "HAS", and we used asynchronous DDC module with XMOS, ground isolator between DDC and DDC's I2S output, separate linear power supplies to DDC, digital part of DAC, analog part of DAC, and I-V & Filter stages :
   

http://www.headphoneamp.co.kr/337673
   
  I happen to have 5 of OPA27GPs from 8 years ago and never used these, but just realized the potential they have thanks to your review.
   
  I would very much appreciate it if you can share some data you had from your past experience. Otherwise, I will simply bias them 12mA each at +-15Vdc with sufficient heatsinking.


----------



## majkel

My memory tells me it was 5mA but you can try the rule that you need just a bit less than a half of output short to ground current - see data sheet.


----------



## ryanjun

Quote: 





majkel said:


> My memory tells me it was 5mA but you can try the rule that you need just a bit less than a half of output short to ground current - see data sheet.


 
   
  Thank you majkel,
   
http://www.ti.com/lit/ds/symlink/op27.pdf
  I checked Figure 22 on page 13 in the datasheet.
   
  A half of output short to ground current is 15mA, and 12mA seems good number.


----------



## kiteki

amarokcz said:


> Three days ago I recieved ZERO DAC with Audio-GD MOON in it for upgradind to version "Amarok". After upgrading it I quickly "blind-compared" OPA MOON to my 2xOPA627 and the difference between them was impossible for me to tell when listening to AKG K270 or K300. But the difference was obvious when listening to STAX SR-3N because with MOON there was something wrong with highs.


 
   
  So they both sound nice and analog?  Like silky?  Stuff like JRC4556AD sounds a bit more thin and digital to me, even the MUSES ...
   
  Perhaps my DAC is "thin and digital" and the MUSES is more transparent, the OPA627 / MOON have the colouration of liquid water?  Difficult to know for sure right ...


----------



## AmarokCZ

It was just quick listen, but both were quite neutral, not thin, with the STAXes the highs of MOON was odd - less realistic (especially cymbals and acoustic guitar), maybe little harsh and little rolled off. Also MOON has high IMD and THD at higher frequencies.


----------



## kiteki

majkel said:


> 2x AD797BRZ – this is the op-amp truly deserving the name of the Analog Device. This one is a smoother and fuller sounding version of the AD797. Switching from the ANZ to the BRZ series is like going vinyl instead of digital. Everything is smooth to the moment your music craves for the harsh texture like aggressive violin passages, distorted guitars, or stronger double bass phrases. The readability of the furthest plans is great, without going into image sharpening effect which makes you see the details more but lose the feeling of perspective at the same time. Roughly, it's like the AD79ANZ with all advantages of the OPA627BP added.


 
   
  I just noticed this, thanks, now I will definitely have to try the BRZ...


----------



## kiteki

amarokcz said:


> It was just quick listen, but both were quite neutral, not thin, with the STAXes the highs of MOON was odd - less realistic (especially cymbals and acoustic guitar), maybe little harsh and little rolled off. Also MOON has high IMD and THD at higher frequencies.


 
   
  Thanks, EARTH seems like the safest choice right...


----------



## dedemouse

Deleted


----------



## Timodeus

Based on your review I put in opa-sun in my Audio-gd 5.2 and it makes listening to classical music indeed a far bettter experience than without. 
So thanks a lot for your review.


----------



## here7423

majkel,2xAD825 is great at 10V for my soundcard's R/L,thank you!
 +-10 voltage, also has another betters recommendation? trust your feeling


----------



## Apoq

I contacted Audio-gd today because I wanted to buy a set of Audio-gd Sun opamps... and received the following disappointing reply:
 "
 Dear XXXXX,
  
 I am sorry , our all OPAs had discontinued.
 Kingwa"


 I'm a sad panda now.


----------



## Mad Max

You didn't miss anything _that_ special.
  
 Good chip opamps can't be beat in the end.


----------



## Foxer

Hello everyone.
  
 I'm reposting here, as this thread may get more attention, and maybe someone can help.
  
  
 I want to replace the (1x) NJM2114 and the (3x) NJM2068 on my _CREATIVE X-Fi Elite Pro_ sound card.
  
 -- I'm looking for a good clean accurate and precise sound (but not boringly flat) --
  
 I have in mind the *OPA1602AID* as i heard very good things about it ..but i also read that *AD8599*ARZ is a pretty good candidate!
  
  
 According to @majkel, this would be the top 5 list:
 1. LT1028ACN8 *mono*
 2. OPA211ID (issues like in the review) *mono*
 3. AD797BRZ (finally I found slight imaging issues and timbral imbalance) *mono*
 4. LME49720MA *stereo* / LME49710NA (I guess I like the former a bit more) *mono*
 5. OPA-Sun v.2 (thick, flawless, likeable sound) *stereo*
  
 but as you can see, most of these are mono.. and i need stereo. And i don't know how they fair against the opa1602aid & ad8599
  
 I would be willing to try 2 mono LT1028ACN8 with an adapter, if they're THAT good.. although it would cost me an arm & a leg. 
 But still, i don't know how they fair against the (waaaaay more cheaper) OPA1602AID
  
 Can you guys please help me out with some opinions/suggestions??
 Any advice is appreciated!
 Thanks!
  
 P.S. This sound card delivers +/-12V to the opamps.


----------

