[fiddler]

Bored, not terribly interested in building anything fancy, so wired up another CMOY (my first in like, years and years).

24V switching power supply (yeah I know, but what can I say, I found one in my basement, so it's free! I bet it still sounds better than a single 9V battery), 470uF power caps, uh the rest is standard... ~5X gain. Did it on a perfboard that has no connected busses, so assembly took a bit of time...

Let's plug 'er in... nothing's in the case yet, just using alligator clips on a naked perfboard for this test.

Maiden test with OPA2132 with Ety ER4S, jeeeez how could i forget how sweet a simple CMOY can sound. It's gonna be sure hard to plug the Etys back into an iPod directly... People make fun of this chip for tubby bass, and sure, it's a bit on the loose side, but there's something nice about the overall presentation, a bit of "magic" that is reminiscent of the big boys OPA627/637.

Ok, moving on to the next chip.

[Oh jeez, why did I have to jam into the socket so hard... bent some pins pretty bad pulling it out (it's been a while, you see.)]

Ok so I salvaged the OPA2132 without breaking any pins, yay.

Put in 2227... meh. Kinda boring, dunno what it is, kinda "slow" sounding. Bass might be tighter than 2132, bit more detail in the treble, but that liquidy smoothness isn't quite there. Not likin' it. Moving on.

AD823 - ok, I can sorta see the "house-sound" resemblance to the AD8610. But only sorta. Something kinda hyped up about the midrange, you could say overly lean and bright, false "detail" freaks might like this one. Maybe just terrible synergy with Etys. No way.

Basically I got a "mmm yum" surprise reaction (I mean come on, it's just a CMOY!) with the OPA2132, and these other two chips just didn't have the "magic" to my ears. Sure it has flaws, a bit loose in the bass, and not quite enough clarity as you can get from higher-end chips, but in this contest, for me it was hands down victory to the OPA2132 for enjoyability.

A quote from an old post of mine:
Quote:

I'd take the sound of an AD8620 on a MINT board over an OPA2132 on a META42 board any day. Just my opinion.

Hmmm, it seems I might have highly underrated the OPA2132 back then. Oh well, so things change!

 

[funch]

Great to see you back, fiddler!

Yeah, I like the 2132 also. That 'warm' bass and forgiving sound is kinda like comfort food. When I listen to my cMoy, I find myself able to relax and listen to the music instead of critically listening to the equipment. It's also very forgiving of less than stellar sources.

 

[synaesthetic]

I prefer the OPA2227 to the OPA2132, personally. The bass is tighter and it's more detailed, but I will agree it's not as soft-sounding as the 2132.

Next to the AD843JNZ, the OPA2227PA is one of my top opamp choices. Definitely my favorite dual opamp.

 

[rds]

ad8620 is pretty nice too

 

[fiddler]

Yeah I do like the AD8620, it's a different sound, but I do like it. I just don't have right now to listen to.

My old main amp (a classic META42) had that chip in it...

Doing a bit more listening, there are certainly a few things the 2227 does better than the 2132. Namely, soundstaging and instrument separation, and also vocals seem a bit more natural on it as well. Yeah, I've definitely warmed up to it since the initial listen. Maybe I'll revise my first impressions a bit and say rather than that they are "kinda boring", I'll say that they're "more polite."

Vocals sound like nasal ass on the AD823. I don't like this chip much, can you tell?

 

[majkel]

OPA2227 is terrible. Dull, slow, dark, boring, ugly, blah! Good sounding op-amps for Cmoy are TLE2072 and TLE2082. AD8620 is quite good, near the TLE2082. Probably the best results would be with the AD8022 but I put the Cmoy experiments aside prior to trying this chip in more advanced applications. It's great but might be nasty sometimes.

 

[synaesthetic]

AD8620 makes my head feel like it's about to explode. It's too sharp and too crisp.

 

[peranders]

Indeed, I think AD8620 is very clear. It's fantastic in fact.

I'll suspect your AD8620 didn't have optimal working conditions.
This ad8620 design sounds excellent.

 

[synaesthetic]

I used AD8620 in a number of PIMETA builds I have done, since it is the op-amp recommended by Tangent. I prefer the OPA2227PA to it, but it could be because the headphones I use tend to already be aggressive sounding and do not have good synergy with the AD8620.

I am very fond of the AD843JNZ because it has all the detail of the AD8620 but it does not sound as fatiguing to me. I would say it is my favorite opamp.

 

[majkel]

Dual:
OPA2604
AD8599
AD8022
LT1364
Single:
AD825
OPA604
LT1028
LT1363
AD8021
AD797
These op-amps only matter to me now. All others are a waste of time to use it for audio, including AD843, AD744, AD8620 and many others well known.

 

[NelsonVandal]

We should join forces and make a discrete opamp based headamp, just for the hell of it and hopefully kick some butt.

I think a folded cascode design with diamond buffer as output stage would be interesting - like AD797, AD829 and LT1469. AD829 is the simpler of them and it simulates exceptionally well and seems fairly easy to stabilize.

LT1363/64 and amps like it also simulate extremely good. A simplified LT1363 is also fairly easy to tame I think.

 

[peranders]

I have already done it in my headphone amp QRV01

 

[NelsonVandal]

Quote:

Originally Posted by peranders /img/forum/go_quote.gif I have already done it in my headphone amp QRV01

Yes, I've seen your amps, they look great and I guess they sound as good as they look. I (almost) only listen while doing household work, so I need my amps to be portable. So they need to be smaller, operate at lower voltage and draw less current. An amp like this have to be less complex.

Why not design a discrete 6F22 battery powered class AB amp to fit in a Hammond C801? That would be novel.

 

[Bilavideo]

I bought a Cmoy from BSG on Ebay. He thought the Opa 2132 was boring so he swapped it out with what he thought was the perfect all-around chip, at least on the cheap side: Opa 2227. I didn't mind it but after reading some blogs and threads - including his own webpage - I asked him to send me the LM4562 and the AD823. I liked all of the chips, but I found the LM4562 to be too veiled and boring (even with some pretty nice bass). I'd heard that the 823 was detailed and aggressive, to the point of sometimes sounding brash, maybe even nasty. But to my ears, the 823 was delightfully revealing, even if its output was on the low side.

Saving up my nickels and dimes, and ordering the chips (and an adapter from Hong Kong), I bought a pair of the famous 627s - but I don't yet see what all the fuss is about. These chips are power hungry, so I've upgraded the power supply, which has eliminated a lot of clipping, but the chips still sound pretty grainy.

Somebody tell me that burn-in isn't just psychological and that the 627 will eventually rock my world. I haven't put more than 30 minutes into them so far, but what I'm hearing is just sonically inferior to everything I've been listening to so far. I've got the 8620 on the way, and am looking to try out the 8066 but so far, the 823 is my choice for best chip.

 

[rds]

If you paid less than $18/chip for these they are almost certainly fake. Just the fact that these 627s came out of Hong Kong would have me betting my money that they're fake.
The 627 being grainy and inferior just doesn't add up.
...also imo op-amps absolutely won't burn in.

EDIT Just want to add that the only way to be certain that you've bought an authentic chip is to order from a legitimate distributor like Mouser or Digikey. Faking an op-amp, especially when selling to people who have no means of testing them, is extremely easy. Simply remove the lettering from an identical looking op-amp and stamp it with the lettering of a 627.