Ch 2 crunch mode problem

[Harbinger]

Hi everyone!

Hey I have just noticed that the crunch mode in ch 2 is losing gain on and off but mainly off. It sounds like a dying battery or something ( my guitar has no battery and no pedal connected). I mainly use ch 3 Mark 4 mode which is currently unaffected, has anyone else experienced this or have any clues what it could be? Also its there in 90,45 and 10 watts and in variac and full power.

Thanks in advance.

 

[elvis]

Most likely a preamp tube.

 

[Harbinger]

Thanks mate, even though ch 3 is fine?

 

[Monstercastle]

Here are the tube functions. V1, V2, V3 all are gain stages for channel 2.

V1A- Input Stage All Channels
V1B- 2nd Gain Stage CH1/CH3 3rd Gain Stage CH2
V2A- 2nd Gain Stage CH2
V2B- N/A
V3A- 3rd Gain Stage CH1 4th Gain Stage CH2
V3B- 4th Gain Stage CH1
V4A- Reverb Driver/Send
V4B- 4th Gain Stage CH3
V5A- 3rd Gain Stage CH3
V5B- Reverb Return
V6A- 6th Gain Stage CH3
V6B- Effects Return Stage
V7A&B- Driver/Phase Inve

 

[loylo69]

So V2 may be the culprit. If it were V1 or V3, it would also affect at least one of the other channel.

 

[Monstercastle]

That's how I see it too. You can try swapping V2-V3 with each other and see if the symptoms change.