Hmmm, What to do?

[fishyfishfish]

Hey my Mark III is sounding well, almost tired sounding. I kind of think that I don't have as much gain as before, (Was set at 6, needs to be at 8 on the gain knob) and I have tried new power tubes. New pre amp tubes? Caps? Shop time? This is my main amp(Made in 1987) and kind of wondering whats up. Any clues to whats going on would be a great help. Thanks Fish.

 

[Neptical]

Yeah, I'd say if you feel like it's losing its balls, you should start with your V1 preamp tube...especially since you've claimed to have to turn the gain up. Give it a whirl.

 

[mark2boogie]

I would also suspect the V2a,b; V3a,b and V5a,b tubes, since these are more driven than V1a,b, and then prone to use faster. Try a replacement, unless you have the suitable tube test equipment :

I would also have a look to the cathode resistor decoupling caps, as I sometimes find some of them dry or suffering internal oxidization (1 or 2µF instead of 22µF), which can equally be responsible of a gain drop.

A+!

 

[fishyfishfish]

GOOD LORD! That looks like a soviet radio station :lol:

 

[mark2boogie]

GOOD LORD! That looks like a soviet radio station :lol:

I would like to find one day a CCCP ?????????? ???? (tube tester), all written in Cyrillic... :lol: The ones you see there are US and French.

Do you have checked something as I discussed in the previous post ?

A+!

 

[fishyfishfish]

Yes I did, sorry for late reply. No real changes so I think I might run it down to the shop.