Allen & Heath ZED 14 mixer, schematic here:
https://www.manualslib.com/manual/2457417/Allen-And-Heath-Zed-14-2.html?page=14#manual
Is it worth it -- even a little bit -- to upgrade any of the TL072 opamps to something more snazzy? Asking mostly to learn why not, but if there is even a small benefit, I guess even great opamps are like $20. I would consider doing it on one mic pre. I asked this same question about a much worse mixer, but this one is already good. Any thoughts?
https://www.manualslib.com/manual/2457417/Allen-And-Heath-Zed-14-2.html?page=14#manual
Is it worth it -- even a little bit -- to upgrade any of the TL072 opamps to something more snazzy? Asking mostly to learn why not, but if there is even a small benefit, I guess even great opamps are like $20. I would consider doing it on one mic pre. I asked this same question about a much worse mixer, but this one is already good. Any thoughts?
Normally the best SQ benefits come from upgrading the PSUs to lower noise. Once that's done and you can appreciate the improvement, then upgrade the opamps to OPA1642 or OPA1656 (on adapters).
Just for the sake of argument, is there a power supply I can grab off the shelf (as opposed to building bespoke) or grab from something else for a unit like this?
The one in there is probably about the same as this:
https://www.fullcompass.com/prod/264983-allen-heath-003-778x-power-supply-pcb-assembly-for-zed-24
The one in there is probably about the same as this:
https://www.fullcompass.com/prod/264983-allen-heath-003-778x-power-supply-pcb-assembly-for-zed-24
That PSU looks to be an SMPSU which I would only recommend for a mixer if two other noise reduction boxes are ticked. First one is - all inputs and outputs from the mixer are balanced ones. Meaning all XLRs and no RCAs to provide immunity from common-mode noise. And second is - there needs to be a linear regulator (LDO) stage after the switching output to get a sufficiently low level of normal-mode noise at the final output.
As regards your first question, it would depend on what the total current requirement was and how many rails are needed.
As regards your first question, it would depend on what the total current requirement was and how many rails are needed.
I just realized they're surface mount, so I'm not going to monkey with them. Glad to learn about this stuff anyway. Maybe I need a DIY mic preamp project to scratch that itch.
Cool yeah it's an Allen & Heath so it sounds quite decent. It's just interesting that you can use TL072s in good gear and they didn't bother with better opamps. It seems like the fine distinctions are probably overhyped.
When you know how to design with a given part type, there is few to gain from changing the given part to something different...
A&H knows their stuff... You could have a tried opa 2134 in place of TL072 as they are basically the same kind of opamp ( jfet input) and can be swapped one for another. The opa have overall better distortion figure and a bit different sound you could prefer but nothing like the miracle some guy seems to experience in opamp rolling ( or tube rolling or cap rolling or...).
Sound is first and foremost into the schematic ( iow design choice). Components have an importance but...
A&H knows their stuff... You could have a tried opa 2134 in place of TL072 as they are basically the same kind of opamp ( jfet input) and can be swapped one for another. The opa have overall better distortion figure and a bit different sound you could prefer but nothing like the miracle some guy seems to experience in opamp rolling ( or tube rolling or cap rolling or...).
Sound is first and foremost into the schematic ( iow design choice). Components have an importance but...
Indeed. I have a bad fader so I might get in there anyway and it's a modular design so it's possible I might have a go at it. I can hear the differences in preamp tubes for sure, but opamps I don't know, I think the difference is much small. Usually high frequency hiss is the only thing that bothers me, but in this unit it's very low.