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The Opamp thread - Page 316

post #4726 of 4752

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).

post #4727 of 4752
Quote:
Originally Posted by Mad Max View Post

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.
post #4728 of 4752
Quote:
Originally Posted by Pwn3r4Life View Post

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.

post #4729 of 4752
Quote:
Originally Posted by leeperry View Post

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.
So then what is the point of all these different Op amps? Can't you just measure one better than all the others?
post #4730 of 4752

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:

 

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.

post #4731 of 4752
Quote:
Originally Posted by leeperry View Post
 

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. :p

 

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

 

Raytek_MiniTemp_MT6_-_Same_as_Fluke_62.jpeg

 

 

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

 

Tada!

 

iBasso PB2 staying cool with a passive heat sink attached. (Just kidding!)

 

Mike

post #4732 of 4752
Quote:
Originally Posted by leeperry View Post
 

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:

 

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:

 

 

 

 

Quote:
Originally Posted by zilch0md View Post
 

 

LOL - That's so true and I'm all for it. :p

 

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

 

Raytek_MiniTemp_MT6_-_Same_as_Fluke_62.jpeg

 

 

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

 

Tada!

 

iBasso PB2 staying cool with a passive heat sink attached. (Just kidding!)

 

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. 


Edited by Mad Max - 8/19/14 at 5:12pm
post #4733 of 4752
Quote:
Originally Posted by Mad Max View Post
 

Well, I do change resistors and caps as well when rollin'.

 

How about wooden mods to those giant caps? :cool:

post #4734 of 4752
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?
post #4735 of 4752
Quote:
Originally Posted by leeperry View Post
 

 

How about wooden mods to those giant caps? :cool:

 

I would onoly use those in tube amp, ugh.  I'm not a tube man.  I like my trebles in full-HD.  :k701smile:

post #4736 of 4752
Quote:
Originally Posted by Pwn3r4Life View Post

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.


Edited by Mad Max - 9/2/14 at 8:51pm
post #4737 of 4752

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:) and another step further is to solder a headamp from scratch.
 


Edited by leeperry - 8/20/14 at 4:44am
post #4738 of 4752
Quote:
Originally Posted by Mad Max View Post
 

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.  ;)  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.   

 

Quote:
Originally Posted by leeperry View Post
 

 

How about wooden mods to those giant caps? :cool:

 

Wow, I admire his craftsmanship, but it seems like a solution looking for a problem.

 

Quote:
Originally Posted by Mad Max View Post

 

I would only use those in tube amp, ugh.  I'm not a tube man.  I like my trebles in full-HD.  :k701smile:

 

Amen!   I'm done with tube gear (because I can't afford the tube gear that has good resolution).

 

Mike

post #4739 of 4752

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.

post #4740 of 4752
I've heard about them for years, but don't know anyone who has tried them. They are not ICs, but rather discrete components that, together, emulate an IC-based op-amp. (Actually, the ICs emulate the discrete components!)

Mike
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