LM3876 schematic

[!]

TL072 is not exactly a high spec opamp, I'd change that before anything else. With single supply you need a coupling cap between output and power amp input then your opamp center voltage (ground) is not at the same potential as the amp ground.

The best answer is do as I (and others) suggested. Use a higher voltage transformer like 25-0-25 VAC to get close to +/- 35VDC power rails, regulate those down to +-15V for the opamps, but not for the power amp. As for opamp choice, put sockets on the board and you can swap them later if you want to. Everyone has their own preferences but spec wise, TL072 is dated and "some" people claim other opamps sound better. Here are a few people swapping them in and out of guitar amps, though the specific circuit it's being swapped on makes a difference too:
Buying the parts [Archive] - Telecaster Guitar Forum

[happy hippy]

There has bee some talk about the OPA2132 op amp, but I have seen nothing about the OPA2134. Has anyone used it in a preamp? I plan to put in a socket, and then try both of these in addition to the LM072.

Thanx
The Happy Hippy

[happy hippy]

My bad. That should be TL072.

Thanx
The Happy Hippy

[!]

OPA2134 is essentially the same as OPA2132 for audio purposes, though as always there are a few who have felt the more expensive of the two, OPA2132, sounds slightly better but they are more alike than TL072 is. OPA2134 is the better value for the money but if you were going to buy both anyway, I see no need to do that as there is no reason to use OPA2134 instead of OPA2132, if you would have one or the other lying around unused.

The overall trend, at least to my ears, is jfet input and a fairly high GBP helps. OPA2132 is only 8MHz, better than TL072, but (for more money) even higher GBP opamps would be my preference, something like AD843, but it's > 6X more expensive (one per channel or filter) and possibly overkill for a guitar amp.