The Opamp thread

[svyr]

>IC extraction tool?
 
As per above (well, the edit). Tweezer-like tool and suction pen. Wondering which is the better one. I don't think I saw any small enough tweezer-like extraction tools (i.e. for 4 or 8 pin ICs). , plus on some of my gear access is blocked by caps and other soldered on things. 
 
 
>LM6172 is fast and might be unstable
 
Are LME49720 considered to be fast as well? (it's what I had in the Aune for a while and now migrated to the SRM-300). If so, should LM6172 be ok?
 
p.s. as for AD825 and OPA827 - haven't seen any dip-8 ones (don't want to solder it, and the adapters make them almost 2x the original price?)
 
p.s.s. re: taste - something like lme49720, but not as harsh for highs - i.e. present and detailed mids and bass, overall balanced or slightly mid centric, no harsh highs? (2am descriptions aren't fantastic, I know)

 

[beerguy0]

Quote:

I should probably get the chip extraction tool... It's likely cheap and saves money. 
Tweezer-like or 'sucking pen' lol?
 

 

The tweezer-like tools are for thu-hole parts, while the suction pens are for handling SMT devices while placing them on the PWB to be soldered.

 

[svyr]

>for handling SMT devices while placing them on the PWB to be soldered.
 
aaaah. okies...Thanks for clarifying! In that case I don't need it, but having ordered both for a nominal price of each $2.5 incl shipping I'm probably not sorry for buying them both

 

[12Bass]

Quote:

Are LME49720 considered to be fast as well? (it's what I had in the Aune for a while and now migrated to the SRM-300). If so, should LM6172 be ok?  
p.s. as for AD825 and OPA827 - haven't seen any dip-8 ones (don't want to solder it, and the adapters make them almost 2x the original price?)
 
p.s.s. re: taste - something like lme49720, but not as harsh for highs - i.e. present and detailed mids and bass, overall balanced or slightly mid centric, no harsh highs? (2am descriptions aren't fantastic, I know)

 
LME49720 is faster than some... but the slew rate of the LM6172 is considerably higher.  Some chips require extra supply bypassing or they will oscillate, usually at ultrasonic frequencies.  If you don't have a scope, you can do a finger test to see if they get hot.
 
That description sounds like you might enjoy OPA827, which I find warm, yet detailed, and nicely present in the midrange.... not harsh or sterile, IMO.  Of course, that would require two on an SOIC => DIP adapter.  Lots of the better op amps come as SOIC singles.
 

 

[svyr]

>but the slew rate of the LM6172 is considerably higher. Some chips require extra supply bypassing or they will oscillate, usually at ultrasonic frequencies. If you don't have a scope, you can do a finger test to see if they get hot.
 
I see, thanks. I think my list had a couple of >100V/us chips, so I take it this is a possibility for all of them. Is there anything I can do to determine whether it'll oscillate on my setup before buying and installing it and then doing a 'lick-test'

?
 
 
>Of course, that would require two on an SOIC => DIP adapter. Lots of the better op amps come as SOIC singles.
 
Heh, my smallest soldering iron has a tip the size of the soic op-amps

....Guess I can ask some of the sellers on ebay. A lot of them also sell adapters.

 

[Mad Max]

So I've been spending some time with a new round of opamps:
 
ISL28127FB: Very low noise floor, a bit more than 4627-1. Extremely clean, smooth, and well nuanced with wide soundstage, yet stereo separation isn’t all that good, I’m not sure how to describe it. Very refined and neutral, though not as neutral as 4627-1B, it is pretty close. It is slightly laid-back with okay articulation and lacks a little timbral transparency, not sure. Slight hint of "yellowish-brown" in its tone.

AD8597AR: Very clean and smooth, kind of artificially analogue-sounding, crazy articulation. The midrange is simply thrilling at first, but then I get bored quickly of the sound. It tries too hard to sound exciting and over-articulates every sound. Bass is too forward.

OPA1611: Very warm and slightly energetic at first, but the color went away with burn-in, now it is more or less neutral. Very good overall with good detail and clarity and what not. Slightly lacked bass compared to the other opamps at first, but then got a bit bassier later. This one has a very wide soundstage like ADA4841-1.  Articulation and timbral transparency is very good.  I think it does still retain a touch of color, but I can't quite put my finger on it.

THS4081: Very neutral, clean, clear, very  detailed, highly articulate without overdoing it like AD8597 and very accurate, kind of natural-sounding and smooth. Crystalline sound with weighty, wicked bass response and tightness. It brings out sounds towards the far left and right like 4627-1. Very beautiful sound overall. Heck, I don't hear a whole lot of difference between this one and 4627-1B. Dang, this one is just more detailed and a touch tighter. Great low bass. This is one of the best opamps I've ever heard.

THS4051: Very neutral, clean, clear, very  detailed, highly articulate without overdoing it like AD8597 and very accurate, kind of natural-sounding and smooth. Crystalline sound with weighty, wicked bass response and tightness, but a bit less bassy than 4081. It brings out sounds towards the far left and right like 4627-1. It is like a slightly lesser 4081.

LT1115: Very clean, articulate, neutral. It is very similar to THS4081... Well good grief! This one also sounds a lot like THS4081 and ADA4627-1B. It doesn't seem to be quite as extended at the extremes, though. A slight difference. Overall a touch closer to THS4081 than ADA4627-1B.  It didn't like my portable amp for some reason, but has wonderful timbral synergy with the Compass DAC.

ADA4004-1: Very clean, pristine, neutral. A bit bassy, though not as much as 797 or LT1028, and very intimate. Bass and lower mids are slightly smoother than the other opamps.  Wonderful sound.

LT1677I: Very clean, pristine, neutral as well with good detail. Slightly lacks bass compared to the other opamps I've tried.  Somewhat inarticulate. It sounds slightly greenish-white.  It is slightly bright, probably from the slight lack of bass, though I think there may be a slight hump in the treble, around the beginning of the upper treble I think or a little lower, not sure.  I'm really liking female vocals on this opamp over the others in this round.

OPA827:  Almost neutral, very clean, clear, and fluid. Decent detail, it seems to have a very slight smiley curve to its sound.  Reminds me somewhat of 4627-1B, but a pinch aggressive.  Wonderful sound, slightly rich and a bit tuneful.  Not quite as transparent as some of the others.  Excellent articulation.  This one is kind of nice with my SR325is, but the lack of resolution is a bit of a bottleneck for the Grado grunge.
 
I may add to this later.

 

[leeperry]

I agree on AD8597AR, it's trying too hard to impress...but fails blatantly.
 
OPA1611, no likee...don't remember why. typical Boring-Boring IIRC.
 
LT1115 isn't unity gain stable, it's a lower grade of LT1028 I think...and it was audible too.
 
LT1677I: yes, too bright and harsh...not very colorful.
 
OPA827: usual BB sound...not my thang.
 
so what's your all-time favorite you crazy roller?

 

[Mad Max]

I didn't find 1611 to be bad in any particular way.
Or 827, nor did it sound like a "typical" burr brown.
I didn't find 1677 harsh either.
 
What did you test them in?
 
All-time favorites?  It would have to be a toss up between 4081A and 4627-1B.
I have loved AD744AH, OPA1611A, ADA4004-1, AD8091, and Sun, and OPA1641 is another good one.  Hard to decide whether to call 1641 a favorite, it is very good overall but the loose bass... =(

 

[krisno]

forget it.....

 

[ROBSCIX]

Quote:

I didn't find 1611 to be bad in any particular way.
Or 827, nor did it sound like a "typical" burr brown.
I didn't find 1677 harsh either.
 
What did you test them in?
 
All-time favorites?  It would have to be a toss up between 4081A and 4627-1B.
I have loved AD744AH, OPA1611A, ADA4004-1, AD8091, and Sun, and OPA1641 is another good one.  Hard to decide whether to call 1641 a favorite, it is very good overall but the loose bass... =(

 
The OPA1611,1612, were well liked by many around here.  I noticed you tried some of the THS series, have you had a chance to test out the THS4032 or the singles THS4031.  It seems many people recommend these for I/V section for DAC's.  They can be rather unstable if used improperly.
Have you done any further testing with the mentioned units?
 

 

[leeperry]

 

I have loved AD744AH, OPA1611A, ADA4004-1, AD8091, and Sun, and OPA1641 is another good one.  Hard to decide whether to call 1641 a favorite, it is very good overall but the loose bass... =(

I hated Sun-V2, it's missing so much stuff that it was making me feel half-deaf..majkel also mentioned this lack of "substance".
 
I've got some OPA1641, kinda lazy to solder them though.

 

[Mad Max]

Andrea told me I wouldn't be missing much by skipping 4031/3032.  Further testing? Like what?  I don't have anything else to test them in except Minibox-E+ and my Compass DAC.  I've been pondering about getting another opamp test bed, perhaps an NG98 or P3+, they seem to offer more possibilities for combining opamps and what not.
 
Sun is really funky with its roller-coaster FR, it can even play tricks on you too.

Once you get used to it, it is really fun, but definitely an acquired taste.
I don't find that it really lacks anything, it is just quite different.
 
 
Is it the aim of opamps to sound neutral with cleaner power and a circuit they are suited for/compatible with?
 
 
Edit: w00t! Successfully installed ADA4841-2 in place of OPA2338 in my FiiO E5.  Much cleaner sound.  Now to test the battery life...

 

[leeperry]

I loved it when Audio-GD told me that many recording studios were buying Sun-V2 to install in their mixing boards..hahaha their main salesman should consider stand-up comedy
 
Even an opamp w/ +120dB PSRR still benefits from a clean PSU, it's about dirty ground I think.
 
If I were you, I'd avoid anything from HA-Info..

 

[cent]

I had opa2111kp for treble and opa2107ap for bass soldered in my amp, I found that it is lacking of low mid(whispering is barely audible in movie).

What opamp shall I change for my xonar essence stx to gain the low mid for easy listening with wider soundstage, clearer and warmer sound?
I have opa2132pa, opa2111kp, opa2107ap, opa2277pa, opa228pa, lt1028, lt1363 and lt1364 here.

 

[majkel]

Quote:

I loved it when Audio-GD told me that many recording studios where buying Sun-V2 to install in their mixing boards..hahaha their main salesman should consider stand-up comedy
 

I appreciate their sense of humor.