Jon L
For him, f/1.2 is a prime number
- Joined
- May 20, 2003
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I finally had some time to compare the op-amps in my SM3. 4G iPod with apple lossless->Sik Din->Xin mini adapter->SM3->Ety4P. Most comparisons done with 4P->4S switch on, bass boost on, gain to low, and crossfeed off.
Sorry, no AD8610. I do have some but did not want to use up the few Browndogs left in my possession.
THS4061MJG
Some people really like this op-amp, and it is good, but compared to OPA627/637, it just sounded a bit veiled and less transparent. Triangles, Cymbals didn't sparkle and decay like 637, and instruments/vocals didn't have that "open" quality many people talk about with 627/637. Bass was pretty neutral sounding but didn't have quite as much Oomp of 627/637. Music also sounded a few rows more laid-back compared to others, contributing to less immediacy. The upside is that it's very forgiving of bad recordings, but it gives up too much transparency IMO. Still, you wouldn't notice much of these "shortcomings" unless directly A-B'd with songs familiar to you.
AD797
I really like this op-amp. General tonality/flavor is somewhat more similar to THS4061 than to OPA627/637, but with few important differences. Compared to THS4061, instruments/vocals "project" more with more texture, verve, and character. More exciting and engaging sound. It also is more forgiving than 627/637, sounding a bit more liquid and smooth throughout the low-treble/upper-midrange area. Sibilance in poor recordings are more tolerable and less grating. Bass is not as thick and round as OPA627/637 but barely so. Well-balanced sound without any offensive flaws with enough detail/texture to prevent boredom. If you find your setup with 627/637 a bit too intolerant of poorer recordings, definitely give 797 a listen.
OPA627
The "King" is in the house. Very detailed, textured, robust throughout mid-treble to low bass range. VERY involving and engaging sound, very much reminiscent of a very high-end 300B push-pull tube amp, for example. Bass is slamming (with SM3 bass boost on) and rich, upper-midrange/low-treble is very open and seductively breathy, which is what sets 627 apart from other op-amps. Very hard to give up this quality once you're used to it. Loved my SM v.1 with 627 and love my SM v.3 with it as well. What's not to like? Well, it is pretty unforgiving of those heavily processed rock/pop albums that have boosted treble/upper-mids. But those same albums sound just as annoying over $100K super high-end speaker systems as well.
OPA637
Basically my choice with one caveat. You must use use good bass boost, like SM3's switch. 637 is a little more extrended in high treble compared to 627 and sound a bit faster as well. On naturally-miked female focals, for example, the voice sounds more even and continuous through the entire treble range(including high treble) than 627, which seems a wee bit rolled off/darker in extreme treble, which in turn makes voices a bit thicker/richer. So it'll be a preference thing. 637 does sound a bit more pellucid and crystalline, but without some bass boost, all that transparency can sound a little too "naked" with many CD's. Throw on the SM3 bass boost, and the rich bass balances out the clarity resulting in truly stunning high-end sound. But I can see others preferring 627 over 637. Once again, it's a preference/synergy thing. I suppose 637 can be called even a little less forgiving than 627, but when I do run into those really nasty recordings, I just throw in the crossfeed switch, which softens the treble a bit.
Well, this is about all I can stand to do in one day, but soon I hope to do the comparison again when I can make up the 4-pin XLR adapter for my AKG K1000, which Xin keeps saying should be OK with SM v.3.
ADDENDUM:
AD744
Perhaps my favorite, but then again, there are so many opamps that sound great in SM v.3 that perhaps "favorite" is pointless. AD744 does not "wow" you at first, but more you listen, the more you like its combination of neutrality AND detail AND musicality. Nothing stands out as emphasized or recesed, yet there is rich tonality and focus through midranges. There's also this pleasing texture to instruments and vocals, which is not 'quite' as present in something like OPA637. OPA637 does seem to have a bit more extended and translucent high treble, but that's OPA637's strength over all others.
Oh, did I mention the bass is simply Perfect? At least for Ety4S w/ bass boost on? The right amount of slam, tautness, extension, and warmth. Oooh, yeah.
AD744 Class A biased -- "AD744A"
Improvements are across the board over AD744, as hard it is to imagine. Class A biasing tends to burn off haze and veil mostly, which you didn't think was present until it was gone. More transparency, detail, immediacy, and delicacy come right through. This is High Fidelity and High Resolution with capital letters. It really sounds amazing, and it pulls off the trick of "wow'ing" you WITHOUT emphasizing certain parts, which is indeed a tough trick. It's even more detailed and resolving through the ranges than OPA637, yet it gives more body and 3-D density to vocals/instruments. What's the catch? Alas, there is a catch after all. Even though bass quality is probably better, bass quantity decreases a bit over AD744. With a lot of full-sized cans, this is going to be interpreted as tighter, more controlled bass. But with Ety4S, even with bass boost on, AD744A bass to my ears is 'just' shy of my imagined perfection. Oh, well. The other downside is that combined with increased detail and a bit less bass quantity, AD744A is less forgiving of poorly recorded material than AD744. Such is life..
NE5534
The cheap prior "default" opamp Xin used to ship SM v.3 with. Frankly, I didn't even try it before now due to my low expectation of this $1 opamp. But even in stock form, there are some pleasing aspects of this opamp. First off, you get very round, harmonic, forgiving, rich, musical presentation. Voices sound bigger and more robust. It's near impossible to hear irritating sibilants, "digititus" through this opamp. But there is obvious shortcomings in transparency and detail department in midranges. Treble is rolled off and soft, and bass is a bit ill-defined.
NE5534 Class A biased-- "NE5534A"
Once again, class A biasing seems to burn away a good amount of veil and haze. Transparency improves as well as detail. Treble becomes less soft and bass more tight and slamming. All this while retaining the pleasing roundness, richness, and KILLER tone and texture. With Ety4S, this might be the ideal match for many folks b/c while there is good amount of detail in class A mode, just enough becomes forgiving that those poor recordings with screechy highs and irritating sibilants become a lot more listenable. This is most obvious when you crank up the volume with Ety4S, something you can't do very much with something like OPA637 or AD744 class A. After a certain loudness level (pretty loud actually), a lot of recordings, even of decent average quality, become too grating. With NE5534A, you can crank up the volume all you want and grin
In fact, I was able to crank up tracks like Bela and Fleckstones "Flight of Hippo" to hearing-damaging levels and Physically "FEEL" the bass in my intestines. Even a few minutes later, I can feel my skulls vibrating. Ety4S may have thin bass unamped and un-bassboosted, but when SMv.3 w/ NE5534A gives it the bassboost, Ety's can take it without a blink without distortions.
Downside is that AD744A still has more detail and resolution, especially at low to moderate volume levels.
Perhaps Xin could do his magic thing and provide 2 sets of different op-amps on his board with a switch to easily go back and forth?
ADDENDUM
SA5534AN class A
Biased to class A, SA5534AN sounds very good. A word of warning for class A biasing fans. SA5534AN pins are the most brittle of all the op-amps I've tried. I was unable to bend the pin away without it breaking off, no matter what. No such problems with opamps like AD744 and even NE5534, so just different manufacturing technique/material it seems. I haven't directly A-B'd SA5534 class A to NE5534 class A, but SA5534 does seem a bit clearer. What is surprising is how close SA5534 A sounds to OPA627 in A-B comparison. Before class A, NE/SA5534 sounds significantly less transparent and less detailed than OPA627, but it catches up with OPA627 after class A biasing. Both SA5534 and OPA627 have rich, detailed, open sound with a sense of fullness across the ranges. Both are great choices with Ety's.
AD744 class A Revisited
I've finally done some comparisons with AKG K340 and AKG k1000. Yes, you read that correctly. K1000 was driven by SM v.3 via my DIY 4-pin XLR to mini adapter. Both are punishing load, K340 being 400 Ohm! load and K1000 being 120 Ohm load with sensitivity in 70's. SM v.3 drove both to moderate levels pretty well, actually, but beyond that distortions set in.
Anyway, with these other phones, I've now decided AD744 class A is my favorite. Even compared to OPA627 or SA5534 class A, there's just more resolution and clarity. There's sense of "freshness" and the feeling that you can infinitely zoom in on instruments or parts of music and see everything. The small issue of diminished bass quantity with Ety's when AD744 is biased class A is not an issue b/c these full-size cans interpret that as even more solid, agile bass. That sense of fullness with OPA627, SA5534 now seems to me like artificial fluffyness overlaid on music.
As long as I don't betray the volume knob with these phones, I'm getting some real serious high-end sound quality out of these phones. Stay tuned for AD829, etc.
Addendum
AD743
A nice surprise as I wasn't expecting that much. There's a rightness about the sound that gets the basics right, leading to immediate connection to music. Generous, full tonality with nice textured details without brightness or peakiness. Not one of those thin, midrange-recessed sounds, which I hate. Detail resolution is on par with something like OPA627 but not at the level of AD744 in class A. AD744 A remains the king of resolution with surgical scalpel precision and insight into microdynamics and subtle intonations, texture in vocals/instruments.
Bass definition of AD744A really is in a class of its own as well, though AD743 bass is pretty well-controlled with just a touch more bloom. AD744 class A doesn't sound as obviously "full" like AD743 or SA5534, but it doesn't need to b/c it fully communicates every ounce of music. Listening to AD744 class A through my AKG K1000 via SM v.3 is nothing short of a revelation. But for something like Ety4S and for mass-produced pop/rock/hip-hop, I prefer AD743. AD743 is more forgiving, subjectively warmer/darker, kind of reminiscent of something like Cardas Golden Reference cable. In fact I may prefer AD743 to SA5534 class A or even OPA627, though they are close.
But really, I think class A biasing is very special for certain op-amps, and I'm now spoiled for life. Just wish there was a way to easily force OPA627, AD743 into class A. Xin?
Addendum
AD829
A sound a studio mastering pro would love? When one switches from AD743 to AD829 (non class A), there's a jarring difference that makes you uncomfortable. AD743 is warm, comfortable, "natural" yet pretty neutral and detailed. AD829 gives you "just-the-facts-ma'am" type of sound, and whatever softening, rounding, blooming AD743 (or SA5534, NE5534 class A) gave you becomes obvious by their absence in AD829. There's tons of texture and detail, especially in male vocals, that makes Leonard Cohen, etc just project with shocking alacrity. A bit too excessive texture/grain in male vocals IMO in fact, which makes these vocals a bit too dry and well, unnatural. Yet the sound is robust and immediate with great control. A special quality I appreciate is the sense that mid-treble to upper-midrange range is RULER flat, revealing everything that's good and bad in the recording in this range. I'm really torn about this opamp b/c while it does some things better than any other opamps, I couldn't live with it long term due to the unnaturalness. Kind of reminds me of a speaker using those Focal inverted titanium tweeters and Focal Kevlar mid/bass units by a designer who isn't quite the master speaker-designer yet..
AD829 Class A
Ahh, that' more like it. This is like that Focal speaker above designed by a master speaker designer. Retaining the extreme speed, detailing, and neutrality without undue irritation or peakiness or grain. The mildly excessive texture/grain of non-class A AD829 is brought to within my listening comfort zone. There is just a touch of sweetness and naturalness that's added to make the whole experience a lot more natural and enjoyable. Still more detailed than AD743 or SA5534 in class A IMO and retains a bit of forwardness and liveliness that suits rock, pop, techno, etc. There's an incredible sense that the entire frequency range is under iron grip, much like how you feel when you replace 100 wpc amp with 300 wpc monster on same speakers.
I'm not 100% decided which I prefer yet, AD829 class A or AD744 class A. AD829 A does have better bass quantity than AD744 A, not more defined but just as defined yet more quantity of bass. The slightly overdefined bass is AD744A's one slight Achilles' heel in this comparison. However, AD744 still retains a slight edge in conveying a sense of flowing spring water type of purity and refinement without losing any detail resolution to AD829 A. AD829 A is like the best dynamic speakers while AD744 A is like the best electrostat speakers just to give you a flavor difference. I'll Have to do some more comparisons between these 2 over a long time and also comparisons to something like SE5534, ON brand NE5534 class A and report back.
Edit. Well, upon further comparison, I do like AD744 A better overall than AD829 A. AD829 A may do male vocals with a bit more authority and texture, but AD744 A is preferable for female vocals and higher frequencies. These ranges just have sweeter, airier, more 3-D dimensional sound. It just sounds fresher even with repeated listening and plain exquisite.
Sorry, no AD8610. I do have some but did not want to use up the few Browndogs left in my possession.
THS4061MJG
Some people really like this op-amp, and it is good, but compared to OPA627/637, it just sounded a bit veiled and less transparent. Triangles, Cymbals didn't sparkle and decay like 637, and instruments/vocals didn't have that "open" quality many people talk about with 627/637. Bass was pretty neutral sounding but didn't have quite as much Oomp of 627/637. Music also sounded a few rows more laid-back compared to others, contributing to less immediacy. The upside is that it's very forgiving of bad recordings, but it gives up too much transparency IMO. Still, you wouldn't notice much of these "shortcomings" unless directly A-B'd with songs familiar to you.
AD797
I really like this op-amp. General tonality/flavor is somewhat more similar to THS4061 than to OPA627/637, but with few important differences. Compared to THS4061, instruments/vocals "project" more with more texture, verve, and character. More exciting and engaging sound. It also is more forgiving than 627/637, sounding a bit more liquid and smooth throughout the low-treble/upper-midrange area. Sibilance in poor recordings are more tolerable and less grating. Bass is not as thick and round as OPA627/637 but barely so. Well-balanced sound without any offensive flaws with enough detail/texture to prevent boredom. If you find your setup with 627/637 a bit too intolerant of poorer recordings, definitely give 797 a listen.
OPA627
The "King" is in the house. Very detailed, textured, robust throughout mid-treble to low bass range. VERY involving and engaging sound, very much reminiscent of a very high-end 300B push-pull tube amp, for example. Bass is slamming (with SM3 bass boost on) and rich, upper-midrange/low-treble is very open and seductively breathy, which is what sets 627 apart from other op-amps. Very hard to give up this quality once you're used to it. Loved my SM v.1 with 627 and love my SM v.3 with it as well. What's not to like? Well, it is pretty unforgiving of those heavily processed rock/pop albums that have boosted treble/upper-mids. But those same albums sound just as annoying over $100K super high-end speaker systems as well.
OPA637
Basically my choice with one caveat. You must use use good bass boost, like SM3's switch. 637 is a little more extrended in high treble compared to 627 and sound a bit faster as well. On naturally-miked female focals, for example, the voice sounds more even and continuous through the entire treble range(including high treble) than 627, which seems a wee bit rolled off/darker in extreme treble, which in turn makes voices a bit thicker/richer. So it'll be a preference thing. 637 does sound a bit more pellucid and crystalline, but without some bass boost, all that transparency can sound a little too "naked" with many CD's. Throw on the SM3 bass boost, and the rich bass balances out the clarity resulting in truly stunning high-end sound. But I can see others preferring 627 over 637. Once again, it's a preference/synergy thing. I suppose 637 can be called even a little less forgiving than 627, but when I do run into those really nasty recordings, I just throw in the crossfeed switch, which softens the treble a bit.
Well, this is about all I can stand to do in one day, but soon I hope to do the comparison again when I can make up the 4-pin XLR adapter for my AKG K1000, which Xin keeps saying should be OK with SM v.3.
ADDENDUM:
AD744
Perhaps my favorite, but then again, there are so many opamps that sound great in SM v.3 that perhaps "favorite" is pointless. AD744 does not "wow" you at first, but more you listen, the more you like its combination of neutrality AND detail AND musicality. Nothing stands out as emphasized or recesed, yet there is rich tonality and focus through midranges. There's also this pleasing texture to instruments and vocals, which is not 'quite' as present in something like OPA637. OPA637 does seem to have a bit more extended and translucent high treble, but that's OPA637's strength over all others.
Oh, did I mention the bass is simply Perfect? At least for Ety4S w/ bass boost on? The right amount of slam, tautness, extension, and warmth. Oooh, yeah.
AD744 Class A biased -- "AD744A"
Improvements are across the board over AD744, as hard it is to imagine. Class A biasing tends to burn off haze and veil mostly, which you didn't think was present until it was gone. More transparency, detail, immediacy, and delicacy come right through. This is High Fidelity and High Resolution with capital letters. It really sounds amazing, and it pulls off the trick of "wow'ing" you WITHOUT emphasizing certain parts, which is indeed a tough trick. It's even more detailed and resolving through the ranges than OPA637, yet it gives more body and 3-D density to vocals/instruments. What's the catch? Alas, there is a catch after all. Even though bass quality is probably better, bass quantity decreases a bit over AD744. With a lot of full-sized cans, this is going to be interpreted as tighter, more controlled bass. But with Ety4S, even with bass boost on, AD744A bass to my ears is 'just' shy of my imagined perfection. Oh, well. The other downside is that combined with increased detail and a bit less bass quantity, AD744A is less forgiving of poorly recorded material than AD744. Such is life..
NE5534
The cheap prior "default" opamp Xin used to ship SM v.3 with. Frankly, I didn't even try it before now due to my low expectation of this $1 opamp. But even in stock form, there are some pleasing aspects of this opamp. First off, you get very round, harmonic, forgiving, rich, musical presentation. Voices sound bigger and more robust. It's near impossible to hear irritating sibilants, "digititus" through this opamp. But there is obvious shortcomings in transparency and detail department in midranges. Treble is rolled off and soft, and bass is a bit ill-defined.
NE5534 Class A biased-- "NE5534A"
Once again, class A biasing seems to burn away a good amount of veil and haze. Transparency improves as well as detail. Treble becomes less soft and bass more tight and slamming. All this while retaining the pleasing roundness, richness, and KILLER tone and texture. With Ety4S, this might be the ideal match for many folks b/c while there is good amount of detail in class A mode, just enough becomes forgiving that those poor recordings with screechy highs and irritating sibilants become a lot more listenable. This is most obvious when you crank up the volume with Ety4S, something you can't do very much with something like OPA637 or AD744 class A. After a certain loudness level (pretty loud actually), a lot of recordings, even of decent average quality, become too grating. With NE5534A, you can crank up the volume all you want and grin
Downside is that AD744A still has more detail and resolution, especially at low to moderate volume levels.
Perhaps Xin could do his magic thing and provide 2 sets of different op-amps on his board with a switch to easily go back and forth?
ADDENDUM
SA5534AN class A
Biased to class A, SA5534AN sounds very good. A word of warning for class A biasing fans. SA5534AN pins are the most brittle of all the op-amps I've tried. I was unable to bend the pin away without it breaking off, no matter what. No such problems with opamps like AD744 and even NE5534, so just different manufacturing technique/material it seems. I haven't directly A-B'd SA5534 class A to NE5534 class A, but SA5534 does seem a bit clearer. What is surprising is how close SA5534 A sounds to OPA627 in A-B comparison. Before class A, NE/SA5534 sounds significantly less transparent and less detailed than OPA627, but it catches up with OPA627 after class A biasing. Both SA5534 and OPA627 have rich, detailed, open sound with a sense of fullness across the ranges. Both are great choices with Ety's.
AD744 class A Revisited
I've finally done some comparisons with AKG K340 and AKG k1000. Yes, you read that correctly. K1000 was driven by SM v.3 via my DIY 4-pin XLR to mini adapter. Both are punishing load, K340 being 400 Ohm! load and K1000 being 120 Ohm load with sensitivity in 70's. SM v.3 drove both to moderate levels pretty well, actually, but beyond that distortions set in.
Anyway, with these other phones, I've now decided AD744 class A is my favorite. Even compared to OPA627 or SA5534 class A, there's just more resolution and clarity. There's sense of "freshness" and the feeling that you can infinitely zoom in on instruments or parts of music and see everything. The small issue of diminished bass quantity with Ety's when AD744 is biased class A is not an issue b/c these full-size cans interpret that as even more solid, agile bass. That sense of fullness with OPA627, SA5534 now seems to me like artificial fluffyness overlaid on music.
As long as I don't betray the volume knob with these phones, I'm getting some real serious high-end sound quality out of these phones. Stay tuned for AD829, etc.
Addendum
AD743
A nice surprise as I wasn't expecting that much. There's a rightness about the sound that gets the basics right, leading to immediate connection to music. Generous, full tonality with nice textured details without brightness or peakiness. Not one of those thin, midrange-recessed sounds, which I hate. Detail resolution is on par with something like OPA627 but not at the level of AD744 in class A. AD744 A remains the king of resolution with surgical scalpel precision and insight into microdynamics and subtle intonations, texture in vocals/instruments.
Bass definition of AD744A really is in a class of its own as well, though AD743 bass is pretty well-controlled with just a touch more bloom. AD744 class A doesn't sound as obviously "full" like AD743 or SA5534, but it doesn't need to b/c it fully communicates every ounce of music. Listening to AD744 class A through my AKG K1000 via SM v.3 is nothing short of a revelation. But for something like Ety4S and for mass-produced pop/rock/hip-hop, I prefer AD743. AD743 is more forgiving, subjectively warmer/darker, kind of reminiscent of something like Cardas Golden Reference cable. In fact I may prefer AD743 to SA5534 class A or even OPA627, though they are close.
But really, I think class A biasing is very special for certain op-amps, and I'm now spoiled for life. Just wish there was a way to easily force OPA627, AD743 into class A. Xin?
Addendum
AD829
A sound a studio mastering pro would love? When one switches from AD743 to AD829 (non class A), there's a jarring difference that makes you uncomfortable. AD743 is warm, comfortable, "natural" yet pretty neutral and detailed. AD829 gives you "just-the-facts-ma'am" type of sound, and whatever softening, rounding, blooming AD743 (or SA5534, NE5534 class A) gave you becomes obvious by their absence in AD829. There's tons of texture and detail, especially in male vocals, that makes Leonard Cohen, etc just project with shocking alacrity. A bit too excessive texture/grain in male vocals IMO in fact, which makes these vocals a bit too dry and well, unnatural. Yet the sound is robust and immediate with great control. A special quality I appreciate is the sense that mid-treble to upper-midrange range is RULER flat, revealing everything that's good and bad in the recording in this range. I'm really torn about this opamp b/c while it does some things better than any other opamps, I couldn't live with it long term due to the unnaturalness. Kind of reminds me of a speaker using those Focal inverted titanium tweeters and Focal Kevlar mid/bass units by a designer who isn't quite the master speaker-designer yet..
AD829 Class A
Ahh, that' more like it. This is like that Focal speaker above designed by a master speaker designer. Retaining the extreme speed, detailing, and neutrality without undue irritation or peakiness or grain. The mildly excessive texture/grain of non-class A AD829 is brought to within my listening comfort zone. There is just a touch of sweetness and naturalness that's added to make the whole experience a lot more natural and enjoyable. Still more detailed than AD743 or SA5534 in class A IMO and retains a bit of forwardness and liveliness that suits rock, pop, techno, etc. There's an incredible sense that the entire frequency range is under iron grip, much like how you feel when you replace 100 wpc amp with 300 wpc monster on same speakers.
I'm not 100% decided which I prefer yet, AD829 class A or AD744 class A. AD829 A does have better bass quantity than AD744 A, not more defined but just as defined yet more quantity of bass. The slightly overdefined bass is AD744A's one slight Achilles' heel in this comparison. However, AD744 still retains a slight edge in conveying a sense of flowing spring water type of purity and refinement without losing any detail resolution to AD829 A. AD829 A is like the best dynamic speakers while AD744 A is like the best electrostat speakers just to give you a flavor difference. I'll Have to do some more comparisons between these 2 over a long time and also comparisons to something like SE5534, ON brand NE5534 class A and report back.
Edit. Well, upon further comparison, I do like AD744 A better overall than AD829 A. AD829 A may do male vocals with a bit more authority and texture, but AD744 A is preferable for female vocals and higher frequencies. These ranges just have sweeter, airier, more 3-D dimensional sound. It just sounds fresher even with repeated listening and plain exquisite.
