[sdiy] Op amp distortion unit

[Seb Carr]

Hi all, thanks in advance for any help.

    Okay, i just built a small (1 op amp, 6 diodes, a couple of caps)
distortion unit (soft distortion from practical elctronic musical effects
units, R.A. Penfold) for guitar and while it generally sounds great, and i'd
recommend it, mine has a small glitch: When the input level rises too high,
the gain is reduced resulting in the sound fading to a clean sound then back
again. If the input level rises any hifger then the sound cuts completely
(annoying as i like to play guitar quite hard).  I wasn't sure if this was
due to the input level clipping ( the op amp in question is a low noise
ne5534p) due to input gain, or if the high output gain draws more current
than the 9v pp3 battery can supply (it was designed to run from one of
these).  i cannot say if the problem changes with output gain as it is fixed
for simplicity.
    Another query is, what would be the effect of replacing the 6 diodes
(OA91) with something germanium or leds.
    If the above problem is due to lack of current supply, would using 2
pp3's help, and if the supply voltage was changed would more diodes be
needed to be added?

Thanks

Seb Carr