Bent on keeping that opamp, well check out Verne's posts over at HC, "Supercharging a V8." http://acapella.harmony-central.com/...rcharging-a-V8
The V8 is the V5's big brother. First thing Verne did was put in a high quality chip! Replaced the TL072, check it out, and Verne is still around and could help out keeping the opamp intact. You can compare the schematics and see where the V5 cut a few corners to "cheapen" up the amp.
Here is a favorite quote of Verne's:
"The problem with the opamp implementation as found on the V8 – particularly the hiss and extremely low amount of clean headroom – isn’t the USE of an op-amp, but the CHOICE of op-amp. The TL072 is a cheap [20 cents in quantity] component that probably introduces as much noise as using a tube, so it defeats the purpose. Because of its low headroom, it actually introduces a bunch of noise that keeps you from really cranking the gain to its sweet spot.
The “fix” is to replace it with a TLE2072. This is one of Texas Instruments Excalibur series and is renown for being the best of the best. You can get this chip from Mouser for around $2.50. The only complicating factor is that SLM soldered the TL072CN to the circuit board."