Solid State Guitar Amp Forum | DIY Guitar Amplifiers

I've got a question regarding the fender Pro 185. I think it's a great amp with tons of features and very warm for a s.s. amp.
It has two channels plus a boost. Here's the problem : whenever I set the boost louder than the distortion and go and shut off the amp there is a volume swell even if I'm in the clean channel. In other words say I'm using the clean channel set to 3 and go and turn off the amp and the boost is set to 5 as soon as I turn the amp off the volume swells up to boost volume.
Is anyone having the same problem? Please help. Thanks

I'm not familiar with the circuit, but during power off all rail voltages drop because supply is cut off and the load introduced by the surrounding circuit gradually drains the filter capacitors. This thing happens all over the circuit and may cause all kinds of strange stuff such as noises or temperamental operation of some circuits. For example, circuit that controls switching typically receives "On/Off information" in a form of DC voltage potential (e.g. 0V = Off, >5V = On, or vice versa). This voltage typically saturates a switching transistor or activates a relay, or something. Thus it is easy to see that a supply voltage drop may easily initiate a "command" that tells to switch on the boost. Anyway, I see no problem since this happens only when you turn the amp off. It's not like it's behaving erratically in a normal condition.

Thank you Teemuk