Tremoverb Send Pot

[.Double.Trouble.]

Hi
I bought a Trem-o-Verb Head (not sure which year, SN around 11.900) a couple of weeks ago and it worked fine without the loop but as soon as I would run my pedals trough the loop (Marshall Echohead & Boss Ce-5) it would start to get moody . It started to cut off in the middle of playing . After playing around with it for a while i figured out that when I play around with the Send Pot the problem goes away. Now it started to get worse and the only way I can get it to play right is when I have the Send Pot all the way up. Now My pedals still work fine but I can't get a clean tone out of the Amp and it's always a bit crunchy. When I turn the Gain down more it's much to quiet and it just doesn't sound good anymore.
The lead channel (I have Channel Cloning set to "Red To Vintage") doesn't sound right either. When I play simple Powerchords it sound ok but as soon as I play a more structural chord or even if I play some single note Metal stuff the higher notes sound terrible.
Does anyone know if this could simply be caused by a faulty Send Pot or would the problem be more complex than that?
Hope someone can help

Oh and I might have to add that I live in Europe so I have to run it through a transformer. Don't think that would have anything to do with it since it works fine without the Loop but you never know

 

[94Tremoverb]

It could be the Mix pot itself - turning it right up may 'fix' it is there is a break in the track near the top, but running it that high will overdrive the pedals and give unwanted (bad-sounding) distortion, which may be what you're hearing. If the Mix pot works when full up, but cuts out completely (not smoothly reducing the level) when you turn it down a bit, it's a bad pot.

If that's not what happens, try replacing V4, which is the preamp tube furthest from the input jack in the row of four - this is the tube that controls the loop, and is only active when the loop is on.

If it's not that, chances are you have a faulty LDR in the loop circuit - this is common on later Tremoverbs, due to a bad run of LDRs that Mesa got. If it's this, you'll probably need a tech to fix it, it's inside on the circuit board.

Running through a transformer is fine, but make sure it's got enough capacity for the amp - it needs to have at least as much as the full power draw, and preferably more, which means at least 500VA (W) with this amp. More is even better. This is nothing to do with the problem though, as you guessed...

 

[.Double.Trouble.]

Well when I turn the pot there are spots where it works just fine and others where the problem occurs. But those spots always change. Would a bad pot always cut off at the same setting or could it also cut off wherever it wants to?

 

[94Tremoverb]

It sounds like the pot may just need cleaning. You can easily do this yourself, you need a spray can of 'contact cleaner lubricant' (various brand names depending on where you are in the world) with the thin plastic tube to insert into small spaces. WD40 will work in a pinch but it's not really the best stuff for the job.

If you look at the pot inside the chassis you will see a slot between the flat board with the terminals on it and the casing. Aim the cleaner in there and give it a squirt, then rotate the pot a few times. While you're in there it's worth doing all the pots - they usually go a bit crackly eventually.

If that doesn't fix it, you probably need a new pot. The back panel pots on the heads seem to be a bit prone to getting bumped, which can damage them.

 

[.Double.Trouble.]

I'll try cleaning it as soon as I can and post whether it works or not
Now that you mention it, when i wiggle the Mix and the Slave Level knob they don't move at all whereas the Send pot does..probably did get beat up a bit

 

[.Double.Trouble.]

Ok so I took it to the shop today and it turns out that the pot was bent and didn't have any contact from being bumped somewhere. They just bent it back together and now it works like a charm..
Many thanks to 94Tremoverb for pointing me in the right direction!!! :mrgreen: