Germino Lead 55 Trouble - We Summon The Amp Gods:

On the 4 hole amps, such as this one, i frequently see a jumper connecting two of the 4 jacks. My 2203 was this way, but i was told the amp must have corresponding internal modifications to emply this feature.

Thoughts???
 
Robert Herndon said:
Got this in from a friend...Brand new tubes and this starts making this loud static/scratchy sound after about an hour or so of playing. Once the scratchy noise starts, it doesn't go away.

Lots of dust inside, so i am going to start with a good cleanup.

What should i be looking for???

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I definitely don't know what the issue is and don't go poking around in guts of amplifiers, but I had an amp once that did something very similar and it was diagnosed with overheating. Adding a fan to it cured the problem. YMMV.
 
Robert Herndon said:
Lots of dust inside, so i am going to start with a good cleanup.

What should i be looking for???
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Verify all input and output jacks, switches, and pots are clean.

Chopstick every single component and solder connection. Look and listen for a cold solder joint.

Tubes, tubes, tubes... Gotta make sure each one is working properly. Make sure the tubes sockets are clean. Move and lightly tap the tubes around. Start swapping tubes.

Pull all the tubes. Turn on amp and listen for noises. If no noise, install the power tubes only and turn amp on and listen. If still no noise, now install the PI tube... Keep working your way towards the first tube until those noises appear. You'll single out what part of the circuit is being affected.
 
Faults like these can be hard to track down. Could it be a valve socket that needs cleaning &/or re-tensioned, yes, but you'd expect the noise to show earlier than after an hour of playing. Definitely clean the "lots of dust in there" out thoroughly. Dust is the enemy of valve amps. It's conductive, & when it conducts it usually burns up & leaves a carbon track, again conductive. Unless they are "sealed" types, give all the pots a shot of cleaner (no WD40 type :poo:) & a good back & forth twiddle. Same with the input jack sockets, a shot of cleaner followed by a few insertions/removals with a jack. If the problem persists, how do you feel about working on a "live" (powered up) amp? Sysco just beat me to a lot of suggestions, but yes, "chopsticking" the circuit would be next. If, after Sysco's suggestions you still have no joy, get it to a tech, there's so many things it could be & blindly going through the amp hoping to luckily remedy the problem will prove frustrating. One question, when you say "new tubes", do you mean "all" or just power tubes? Hope it's an easy fix, it should be a great amp. Cheers
 
So, this one time... We were trying to get my uncle's boat to run. The outboard kept dying when it would get warm. I figured it was an ignition problem, probably the module. I get my cousin to pull a plug wire and hold to the engine to look for spark while my uncle cranks the engine. I'm standing on shore. My uncle is in the boat. My cousin is standing in 3 feet of water. Both of these guys are electrical engineers. It was really funny.
 
ivan H said:
Faults like these can be hard to track down. Could it be a valve socket that needs cleaning &/or re-tensioned, yes, but you'd expect the noise to show earlier than after an hour of playing. Definitely clean the "lots of dust in there" out thoroughly. Dust is the enemy of valve amps. It's conductive, & when it conducts it usually burns up & leaves a carbon track, again conductive. Unless they are "sealed" types, give all the pots a shot of cleaner (no WD40 type :poo:) & a good back & forth twiddle. Same with the input jack sockets, a shot of cleaner followed by a few insertions/removals with a jack. If the problem persists, how do you feel about working on a "live" (powered up) amp? Sysco just beat me to a lot of suggestions, but yes, "chopsticking" the circuit would be next. If, after Sysco's suggestions you still have no joy, get it to a tech, there's so many things it could be & blindly going through the amp hoping to luckily remedy the problem will prove frustrating. One question, when you say "new tubes", do you mean "all" or just power tubes? Hope it's an easy fix, it should be a great amp. Cheers
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Good points. Yes, all the tubes were replaced - both EL34's and (3) ECC83S's.
 
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