Went back to tubes last night, lost my lead channel

[SkyhighRocks]

After 2+ years of running direct, I gigged with my 5153 50 watter last night. I had dialed it in all week and it was sounding GREAT. I was going to use all 3 channels. At soundcheck, clean was fine, blue channel was fine but when I stepped on the lead channel...no sound. I thought maybe the volume was down. It was at 5 so it should have been blaring. I also noticed that I could hear it coming out of my cab but crazy low. I'm hoping it's just a tube...would you guys check preamp or power first? It's been so long that I have cobwebs about this stuff.

But damn did the other 2 channels sound good.

 

[jc986]

I'd think it would most likely be a preamp tube if the other two channels were okay.

 

[hatrick00]

pre amp tube, easy fix

 

[jc986]

Start with V2, V3, V4 or a combo of those three tubes, as those three are dedicated to the red channel. V1 affects all channels so it should be fine since blue and green were good. V5/V6 are for the blue/green channels, and V9 is the PI.

 

[Racerxrated]

Pre

 

[Chris6870]

Other than the trouble how was it? Make you want to stay with tubes or no?

 

[SkyhighRocks]

So, I've tried a new preamp tube in the lead slots but I get the same result. Barely any volume and fizzy sounding. The other 2 channels seem fine. Anyything else I can try?

EDIT: I got volume again...there's something going on with the knobs. After turning all of them back and forth, I get a helicopter sound coming thru the speakers...and the volume will go up and down...

 

[SkyhighRocks]

Yup....the sound is cutting in and out on the lead channel now. I can hear some kind of propeller cycle through the speakers. If I turn the high knob back and forth, it will bring the volume back but then will cut out again. Tapping on the tubes in V3 and V4 sound good. Tapping V1 and V2 I get a hollow sound but I've tried new tubes in those slots with the same results.

 

[gtrplr71]

I had that issue before with my 50 watter it is the V3 pre amp tube.

 

[SkyhighRocks]

I had that issue before with my 50 watter it is the V3 pre amp tube.

Tried swapping 2 different tubes there...didn't change. when I start messing with the knobs on front, the sound jumps up and down in volume.

 

[nevusofota]

First thing is change preamp tubes. Next, unplug the footswitch and see how it sounds when changing the channels via the front panel.

If still a problem, email Howard Kaplan at Fender.

 

[SkyhighRocks]

First thing is change preamp tubes. Next, unplug the footswitch and see how it sounds when changing the channels via the front panel.

If still a problem, email Howard Kaplan at Fender.

Yup, already did all that. No fx plugged in either. Just guitar straight in and switching on the front.

 

[JamesPeters]

Whatever knob you're turning that gets you sound again (temporarily turn it up and down rapidly a few dozen times. (With the amp off.) If the potentiometer's resistive material has some oxidation or other contamination, the wiper of the pot may clear off enough of it (as you're turning it up/down) that the pot works correctly again. If that helps, then it was just a dirty potentiometer. And if you want to clean it better, open the amp and squirt some control cleaner (not contact cleaner) inside the pot and turn it up and down several times.

Diagram of inside of a potentiometer:

http://i.stack.imgur.com/iiTjO.gif

 

[SkyhighRocks]

Whatever knob you're turning that gets you sound again (temporarily turn it up and down rapidly a few dozen times. (With the amp off.) If the potentiometer's resistive material has some oxidation or other contamination, the wiper of the pot may clear off enough of it (as you're turning it up/down) that the pot works correctly again. If that helps, then it was just a dirty potentiometer. And if you want to clean it better, open the amp and squirt some control cleaner (not contact cleaner) inside the pot and turn it up and down several times.

Diagram of inside of a potentiometer:

http://i.stack.imgur.com/iiTjO.gif

Thanks James. I did that and the volume seems to stay a little more consistent now. I'm still hearing the propeller sound when not playing. Would that be due to it being dirty? would using the cleaner get rid of that or is it potentially something else going on?

 

[Chester Nimitz]

$5 bucks @ walmart ...

 

[SkyhighRocks]

Going to pick some cleaner up tomorrow...my question is...will that take care of the helicopter sound or is that another issue?

 

[Chester Nimitz]

Going to pick some cleaner up tomorrow...my question is...will that take care of the helicopter sound or is that another issue?

Can't say for sure cuz im not there but seems like you're descibing an oscillation of sorts.

As a last ditch effort id replace all the preamp tewbs.

 

[SkyhighRocks]

Going to pick some cleaner up tomorrow...my question is...will that take care of the helicopter sound or is that another issue?

Can't say for sure cuz im not there but seems like you're descibing an oscillation of sorts.

As a last ditch effort id replace all the preamp tewbs.

Yes, I did replace them all and nothing changed until I started messing with the knobs on the front panel. Volume is back to normal but that propeller sound is still there. Howard Kaplan suggested I find an authorized fender repair shop. waiting on EVH support to get back to me...hopefully soon as I need this for my next gig.

 

[lessthan12]

is yours one of the vietnam made ones? There's a known issue with those and i can't remember if it was something to that extent

 

[Chester Nimitz]

Going to pick some cleaner up tomorrow...my question is...will that take care of the helicopter sound or is that another issue?

Can't say for sure cuz im not there but seems like you're descibing an oscillation of sorts.

As a last ditch effort id replace all the preamp tewbs.

Yes, I did replace them all and nothing changed until I started messing with the knobs on the front panel. Volume is back to normal but that propeller sound is still there. Howard Kaplan suggested I find an authorized fender repair shop. waiting on EVH support to get back to me...hopefully soon as I need this for my next gig.

Try cleaning all the pots with an ether based contact cleaner before you put it in the shop.

It can't hurt.