hello.
these are jfet-opamps.......upgrade it with low noise jfet-opamps( like opa 604/2604, opa 134/2134, tle............and so on).
but i would begin with an upgrade of the power supply unit (cleaning supply voltage, e. g. better and bigger elcaps,better and more regulators,..........).and perhaps after that substitute some opamps.
greetings.........
these are jfet-opamps.......upgrade it with low noise jfet-opamps( like opa 604/2604, opa 134/2134, tle............and so on).
but i would begin with an upgrade of the power supply unit (cleaning supply voltage, e. g. better and bigger elcaps,better and more regulators,..........).and perhaps after that substitute some opamps.
greetings.........
IMHO the TL071 and 072 are fine. I don't buy into this "for audio" bullspit too much myself, I trust specs more. Look here, 2nd to last page, for some real numbers if you want to upgrade: http://www.national.com/an/AN/AN-1485.pdf
I would agree, it's likely to make little or no difference - if he wants to try one channel, try just changing the input opamp for a low noise OPA series device, that's the only one likely to make a noise difference.
I actually changed a 741 for a TL071 (or 081 - can't remember now) in an old mixer amp, just on one one channel. Did it make any difference?, not a bit - I couldn't even tell which channel had the different chip in it.
I actually changed a 741 for a TL071 (or 081 - can't remember now) in an old mixer amp, just on one one channel. Did it make any difference?, not a bit - I couldn't even tell which channel had the different chip in it.
My experience was different. I did a whole Tascam 8-channel board (in a 388) over with 5534s, taking care that each closed loop gain was well under the open loop gain, and the mixer went from lo-fi to hi-fi.
Of course the Wima poly bypasses on the signal-path electrolytic capacitors helped too.
I chose 5534s because they are dirt cheap and they are the lowest level really hi-fi chip there is. Almost tube-like sound. But I moved to newer and fancier stuff in the mix (output) areas because the LM4562 came along and why not.
I'll sell the 388 one of these days, if anyone cares.
B
Of course the Wima poly bypasses on the signal-path electrolytic capacitors helped too.
I chose 5534s because they are dirt cheap and they are the lowest level really hi-fi chip there is. Almost tube-like sound. But I moved to newer and fancier stuff in the mix (output) areas because the LM4562 came along and why not.
I'll sell the 388 one of these days, if anyone cares.
B
Thanks for answers. I also suspect changing opamps will give me lass gain than other mods. But The TL072s have large rsistances in series with the outputs, and I want to experiment with running the opamp's output stage in single-ended class-A, just for fun.
I've done some maintenance work on studio mixers in the $100k+ price range, and even these have cheap opamps and use electrolytics for coupling between stages. Granted, with so many features jammed into the mixer, there simply isn't space for large film caps, but I still got suprised at the amount of un-audiophile components in there.
My priority plan for my mixer is something like this:
1. Upgrade powersupply.
2. replace coupling caps with film types.
3. replace faders with Penny&Giles faders.
4. Insert LED level meters at all inputs.
5. replace opamps.
Now all I need is time...
I've done some maintenance work on studio mixers in the $100k+ price range, and even these have cheap opamps and use electrolytics for coupling between stages. Granted, with so many features jammed into the mixer, there simply isn't space for large film caps, but I still got suprised at the amount of un-audiophile components in there.
My priority plan for my mixer is something like this:
1. Upgrade powersupply.
2. replace coupling caps with film types.
3. replace faders with Penny&Giles faders.
4. Insert LED level meters at all inputs.
5. replace opamps.
Now all I need is time...
You know, even if you just jump the signal electrolytics with polypropylenes, you won't do anything for the back end of the dilectric absorbtion problem, but the front edge of the waves will kick a lot better. And the bypasses can be, oh...figure 10k-ohm loads throughout (look at the loads)...with 0.22 bypasses you're in polypropylene down to 80Hz....
Before I put in the ppns, the front edges were so indistinct I actually couldn't play parts on the beat. After I did, the beats snapped like James Brown's band.
Before I put in the ppns, the front edges were so indistinct I actually couldn't play parts on the beat. After I did, the beats snapped like James Brown's band.
The ADA4627 and the OPA827 (successors of OPA627 - I think) could be now the best choice - go to
http://www.diyaudio.com/forums/soli...-1-outperform-burr-browns-opa-627-opa627.html
for more informations
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