The Opamp thread

[12Bass]

Never tried OPA627.... too rich for my blood! Plus, others whom I respect seemed to think that the OPA827 surpassed it, at lower cost, so I didn't see the point.

 

[ROBSCIX]

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif Never tried OPA627.... too rich for my blood! Plus, others whom I respect seemed to think that the OPA827 surpassed it, at lower cost, so I didn't see the point.

I have read that in a few places, I think they sound different though.
Maybe they are marketed to be the next in the series. They are great little units though I have a few built for myself and buddies keep asking for them also.

 

[Spacehead]

Quote:

Originally Posted by 12Bass /img/forum/go_quote.gif Never tried OPA627.... too rich for my blood!

I got 4 OPA637 for 10 euros!!

That is so cheap. I hope to get them working, on my X-FI and on my PPA v2 at the same time. Then I can compare them to
AD8599, AD8620, AD8066, OPA1611, ADA4898-1, ADA4627-1
those op amps characteristics I remember pretty well.

 

[ROBSCIX]

Hmm, hope they are real OPA637's. If you are unfamiliar with that chip it has no internal compensation so it requires higher gains to provide stable operation.

 

[Spacehead]

OK OPA637 didn't work on my Sound Blaster X-FI

I installed ADA4627-1 instead and it works fine. RMAA test results http://i39.tinypic.com/a27v6d.jpg

My X-FI looks like this: http://i43.tinypic.com/335f3ic.jpg

Are these real OPA637?

The web store I bought them from, is reputable, so I think they are real.

I had AD8597 on my PPA v2 for reference just before I installed OPA637. On the ground channel I have another JFET op amp, AD8620 (on dual to single adapter)

OPA637 sounds quite delicate
It is slower kicking than AD8599 but still keeps the rhythm very well. Like a good jazz drummer.
The bass is VERY heavy compared to AD8599. Details are all intact, nothing is hidden. It isn't overwhelming though.
I sense some echoing, more 3D soundstage, not too wide though.
I might be little biased because I was so sure that this would be excellent sounding op amp. And it is.
If I think OPA2132 is slow and muddy. This is relaxed and fast at the same time. Highs aren't overly bright. Sound isn't dark overall.
I think this doesn't remind me of any op amp I have tried. Bass is tight. Mids are strong but soft and exact. Claps sound most realistic I have ever heard them. It has OPA637 sound

These thoughts come from Above mentioned sound card and highly class a biased PPA v2.
ADA4627-1 is most transparent op amp I have, so I have removed it's influence from the sound signature of OPA637. Ground channel op amp doesn't influence sound too much.

 

[buz]

So I came around trying my LT1028C in my NG98. I think it sounds "faster" and more forward with the D2000 which is quite a welcome change. Bass impact likely also got stronger which is good thing for a bass head like myself

Now I just need to fix gain to get a little more flexibility with the volume knob and may actually delay buying an amp

 

[radiohlite]

I've got a CMoy with OPA2227 I'm not entirely happy with. Listen mainly to classical (orchestral). What opamp would better suit this?

 

[leeperry]

Quote:

Originally Posted by buz /img/forum/go_quote.gif So I came around trying my LT1028C in my NG98. I think it sounds "faster" and more forward with the D2000 which is quite a welcome change. Bass impact likely also got stronger

a friend of mine tried 1028AC in his NG27 and all it does is hissing

yes, its low end bass tightness is amazing

Quote:

Originally Posted by radiohlite /img/forum/go_quote.gif I've got a CMoy with OPA2227 I'm not entirely happy with. Listen mainly to classical (orchestral). What opamp would better suit this?

try an adapter w/ two OPA827/OPA132U maybe?

 

[Spacehead]

Quote:

Originally Posted by radiohlite /img/forum/go_quote.gif I've got a CMoy with OPA2227 I'm not entirely happy with. Listen mainly to classical (orchestral). What opamp would better suit this?

OPA627 would sound classical

 

[radiohlite]

Quote:

Originally Posted by Spacehead /img/forum/go_quote.gif OPA627 would sound classical

classical in what sense? I'm running some Grados out of it (heavily modded: they actually have bass and soundstage) so the one thing I don't want is more brightness. I've read OPA2227 is bassy & slow, but in this setup there's what I can only describe as 'digital glare', you know, the way early 80s digital recordings sound? It's not a FR problem, I think. I guess it's just the way this particular opamp sounds (I've also tried it with V6, HD600, K701, and D2000, but it's more pronounced with the Grados.)

 

[Spacehead]

Quote:

Originally Posted by radiohlite /img/forum/go_quote.gif classical in what sense? I'm running some Grados out of it (heavily modded: they actually have bass and soundstage) so the one thing I don't want is more brightness. I've read OPA2227 is bassy & slow, but in this setup there's what I can only describe as 'digital glare', you know, the way early 80s digital recordings sound? It's not a FR problem, I think. I guess it's just the way this particular opamp sounds (I've also tried it with V6, HD600, K701, and D2000, but it's more pronounced with the Grados.)

I assume that OPA637 sounds very similar to OPA627. They should be very similar to each other, only difference being the amount of internal compensation (which then leads to difference in specs)

OPA637 is slow but accurate. Mids detail is excellent with this op amp. It sounds more effortless. Soundstage feels more present. Bass doesn't sound boomy but it isn't light. Colorations are neutral, it doesn't feel dark or bright.

I tried to listen some classical songs, but I think my headphones cannot handle that task.
I tried to get a sense what would string instruments sound like with this op amp. I think the sound is detailed enough to tell what kind of wood is used on instruments body. The reflections are very realistic with this op amp.

But anyway I can recommend trying this.

Then there are ADA4898-1 and ADA4627-1 that reproduce at such accuracy that it can start to sound boring.

 

[foureight84]

can bad / fake opamps harm your speakers?

 

[joe_cool]

Quote:

Originally Posted by foureight84 /img/forum/go_quote.gif can bad / fake opamps harm your speakers?

Can greedy investment banks mess up your life savings? It's hard to say no to such an open-ended question. Poor quality control and outright fraud are both a problem IMO. I often tell myself "safety is no accident" and take appropriate precautions when working with expensive equipment.

Getting closer to 1000 posts! I need a real life...

 

[12Bass]

Quote:

Originally Posted by foureight84 /img/forum/go_quote.gif can bad / fake opamps harm your speakers?

If the fakes are just some cheap op amp like a TL072 or NJM4558, then probably not.... as long as bias currents (and DC offset) aren't a problem. But that assumes that the counterfeiters are using op amps and not something else....

 

[ROBSCIX]

I find the OPA637s have more high end extension then the 627's.
The 637 has a much higher slewrate...