The Opamp thread
Aug 19, 2014 at 12:34 PM Post #4,726 of 7,383
Mouser and Digikey for opamps.
 
Some ebay sellers tend to sell fakes, especially where OPA627 and AD797 are concerned, or they sell opamps taken from very old, heavily-used equipment and call them "new".
 
Some more noteworthy chips: AD4898, AD8597, ADA4627-1B, OPA209, OPA1611, OPA602B, OPA1652, OPA1641, LME49860, and AD8610 (this last one is generally best in portable devices as it cannot take the voltage of full-sized equipment, generally).
 
Aug 19, 2014 at 1:04 PM Post #4,727 of 7,383
Mouser and Digikey for opamps.

Some ebay sellers tend to sell fakes, especially where OPA627 and AD797 are concerned, or they sell opamps taken from very old, heavily-used equipment and call them "new".

Some more noteworthy chips: AD4898, AD8597, ADA4627-1B, OPA209, OPA1611, OPA602B, OPA1652, OPA1641, LME49860, and AD8610 (this last one is generally best in portable devices as it cannot take the voltage of full-sized equipment, generally).

I'll do some more research and try to find one that matches my taste as far as sound signature. Natural and warm, yet slightly technical, and nothing close to bright.
That's 17 choices though, I have my work cut out for me.
 
Aug 19, 2014 at 1:37 PM Post #4,728 of 7,383
I'll do some more research and try to find one that matches my taste as far as sound signature. Natural and warm, yet slightly technical, and nothing close to bright.

 
Scott Wurcer(the designer of AD797) made very clear on diyaudio that opamps don't have a sound signature of their own and that blind rollers got it hard.
 
Aug 19, 2014 at 3:57 PM Post #4,730 of 7,383
EE's consider blind rollers like us to be plain idiots, just so you know =)
 
We're playing lego with highly integrated devices whose surrounding circuit is supposed to have been custom designed for them....as to why they sound different is open for debates, I'm sure MadMax will have beautiful theories to share
evil_smiley.gif

 
Of course some opamps aren't unity gain stable, meaning that they're not PNP by a long shot...AD797, OPA637 and LT1028 come to mind. If you roll them blindly, they will more than likely oscillate...making wooshing sounds, crackle, sound very harsh and bright and so on.
 
Aug 19, 2014 at 6:58 PM Post #4,731 of 7,383
  We're playing lego with highly integrated devices whose surrounding circuit is supposed to have been custom designed for them....

 
LOL - That's so true and I'm all for it.
tongue.gif

 
At least I use a thermometer to make sure nothing is overheating...  
 

 
 
And when they do overheat, I just close the case and attach a heat sink!
 
Tada!
 

 
Mike
 
Aug 19, 2014 at 8:10 PM Post #4,732 of 7,383
  EE's consider blind rollers like us to be plain idiots, just so you know =)
 
We're playing lego with highly integrated devices whose surrounding circuit is supposed to have been custom designed for them....as to why they sound different is open for debates, I'm sure MadMax will have beautiful theories to share
evil_smiley.gif

 
Of course some opamps aren't unity gain stable, meaning that they're not PNP by a long shot...AD797, OPA637 and LT1028 come to mind. If you roll them blindly, they will more than likely oscillate...making wooshing sounds, crackle, sound very harsh and bright and so on.

 
Well, I do change resistors and caps as well when rollin'.  Good ol' oldschool hand-wound resistors sound best. 
wink.gif

 
 
 
 
   
LOL - That's so true and I'm all for it.
tongue.gif

 
At least I use a thermometer to make sure nothing is overheating...  
 

 
 
And when they do overheat, I just close the case and attach a heat sink!
 
Tada!
 

 
Mike

 
That heatsink needs to go directly on the opamp!  On the case is fine when you've got voltage regulators sinked to the case or if you want a groovy room heater. 
 
Aug 19, 2014 at 10:24 PM Post #4,734 of 7,383
So basically, find someone who had success with an op amp in the same system you have, or just swap until it sounds great?
You guys are nuts! But I mean that in the most endearing way. I love it!
Personally, I don't want to fall into this trap. I have too much to tinker with already.
But I still don't understand why they sound different. Madmax, care to explain?
 
Aug 19, 2014 at 11:35 PM Post #4,735 of 7,383
Aug 20, 2014 at 12:21 AM Post #4,736 of 7,383
So basically, find someone who had success with an op amp in the same system you have, or just swap until it sounds great?
You guys are nuts! But I mean that in the most endearing way. I love it!
Personally, I don't want to fall into this trap. I have too much to tinker with already.
But I still don't understand why they sound different. Madmax, care to explain?

 
It's all leeperry's fault.
 
Galvanic isolation of his brain allows opamps to distort to some degree, resulting in the differences that we hear.
 
Yeah, just roll opamps until you get one that sounds best.  Taking a peek at the oapmp's datasheet helps tremendously.  You don't want to stick AD797 into an amplifier that only supplies the chip with +/-3V (797 requires a minimum of +/-5V), you probably also should not stick a 55MHz opamp into a circuit that was originally designed for an 8MHz opamp.  That faster opamp will probably oscillate to hell and back in that amplifier and will get hot enough to cook your breakfast.  Then some opamps are a little particular.  OPA1611 cannot have too much input electrical current or it will shut down according to its datasheet.
 
This rabbit hole goes on and on and on.  =X
 
You get the hang of it over time.
 
Aug 20, 2014 at 7:05 AM Post #4,737 of 7,383
It's essentially a hobby as it's a lot of fun to solder chips onto an adapter, pop them in and hear how things go. The only modifications non-DIY people can try is roll cables and that's it. Once you get the DIY bug, you start soldering/rolling opamps, rehouse+recable headphones drivers into wooden enclosures and so on. One step further is to roll caps but I personally haven't gotten into this (yet
tongue.gif
) and another step further is to solder a headamp from scratch.
 
 
Aug 20, 2014 at 7:58 AM Post #4,738 of 7,383
  That heatsink needs to go directly on the opamp!  On the case is fine when you've got voltage regulators sinked to the case or if you want a groovy room heater. 

 
That picture of a heat sink sitting on my PB2 case was a joke.  
wink.gif
  When the temps get way higher than other op-amps, I yank them, whether I can hear oscillation or not.  
 
I do use the Raytek MT6 laser thermometer in the picture above, however, as recommended by qusp when my 4x AD797s were getting really hot used as buffers with LME49990 in my PB2 - back when I was heavily into (obsessed with) rolling op-amps in 2012.   
 
   
How about wooden mods to those giant caps?
cool.gif

 
Wow, I admire his craftsmanship, but it seems like a solution looking for a problem.
 
 
I would only use those in tube amp, ugh.  I'm not a tube man.  I like my trebles in full-HD. 
k701smile.gif

 
Amen!   I'm done with tube gear (because I can't afford the tube gear that has good resolution).
 
Mike
 
Sep 2, 2014 at 9:54 PM Post #4,739 of 7,383
Has anybody here heard of or heard the Burson Audio Supreme Sound Op-amp? The thing is pretty massive, 16x42x21 mm for dual, and fetches $70. What do you guys think? Do you guys prefer IC op-amps over stuff like the Burson Audio SS and the Audio GD op-amps? This stuff still makes almost no sense to me, but I'm giving this stock OPA a good listen before I swap in my OPA2134.
 

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