frequently-asked modification questions;
"Why is the reverb all mushy and unusable above 3? Quick answer (a) because you've probably got the side-mounted version. Relocate it to the base of the cab where it belongs, ie horizontal not vertical. And (b) because the reverb unit is driven too hard in these amps. Find a way to cut it down (may be as simple as turning down the front-end volume and turning up the master, or putting a weaker tube like a 12AX7 in v2). MY reverb isn't mushy, so there.
sound so nasty?"
No one answer will please everybody but (a) try the most
expensive valves you can afford in v2 and v3 (b) read this
away when I select the lead effect?" This
isn't good but it is normal, I'm afraid. Read about v2here.
the legendary Rivera tone circuit which is only
selectable with the footswitch?"
Quick answer: there's no
thing; it's a myth, not put around by Fender.
I install an effects loop?"
The quick answer is, "yes, but it would be really difficult".
I don't know anyone who's done it. It would require some new
design work, new circuitry, and major surgery. A variation on
the question is "can the reverb send-and-return be converted
to an effects loop?". The quick answer is "yes, but it's still
not a 5-minute job." The levels and frequency response of the
'send' are all wrong. The 'return' might need some work too. I
usually ask, "why do you want one? Isn't the PRII quiet enough
to put pedals etc into the front end?"
the Hum Balance for? (a
control on the back panel) Technical answer - it provides an adjustable ground
reference for the valve heater circuit. So there. It has nothing to do with the
Practical answer - If your PRII isn't humming, leave the Hum Balance control alone. If your PRII is humming, take a flat-blade screwdriver and turn the control one way and then the other. Leave it at the point of minimum hum. If there's still an irritating level of hum, something else is wrong.
VOLUME, GAIN AND DISTORTION MODS
SPEAKER DIRECTIVITY CURE (JAY MITCHELL FOAM DONUT)
INSTALLING TILT-BACK LEGS
HORRIBLE MODS (DON'T GO HERE)
NEW FEB 2013 - COMPLETE
TESTED REBUILD TO SOUND MORE LIKE A DELUXE
PHOTOS for reference
As with all the other
pages on my site, the details are believed correct but I won't
take any responsibility for what happens if you attempt them.
Valve/tube amps store lethal voltages even when switched off and
unplugged from the wall, and if you don't know what you're
doing, you can be badly hurt.
If you have tried any modifications, I would be delighted to hear from you - even if you're not satisfied with the result, it's useful information for the rest of us! I'm specially interested if you've converted to cathode bias, converted to tube (valve) rectification,added a sag resistor, or added a triode-output switch.