Hi Charles, are you able to give any circuit diagram advice ?
I fitted a V5 op amp to an integrated amp last year (after reducing the rail voltages to +/- 15v)
I've just picked up an old rotel pre , with the hope of trying the V6's, there are three opamps inside (one in the tone circuit) but I'm not sure if only one, or both of the others are worth changing ?
Thanks mart