High pitched squeal on O.D. Channel?

[dsl 401]

Hi all, I've got a DSL 100H Marshall head the has a high pitched squeal on the od channel.. The green (cleaner) channel is fine even with a distortion pedal at any volume.. When I switch to the red channel it will squeal even at lower volume settings.. Is this normal? Or do I need this thing fixed??
Thanks,
dsl 401

 

[Leonard Neemoil]

Not normal ime.

Where is the gain set and are you using lead 1 or 2?

 

[dsl 401]

Gain=full.. Lead 2..

 

[TonalEuphoria]

Just to take it out the equation, change the 12AX7or whatever tube your using for your red channel. Than see it if still happens. Take a look at the circuit while you're at it and see if anything looks burnt out or damaged.

 

[dsl 401]

O.K. I'll try..

 

[Trouble Free]

you need a spare preamp tube anyways

 

[Leonard Neemoil]

you need a spare preamp tube anyways

Power tubes too imo.

@dsl 401 , does the squeal go away if you turn the gain down?

 

[TonalEuphoria]

I keep multiple sets of spares myself. If it is the red channels tube, it wouldn't hurt to just change all the preamp tubes out to have them all in the same age for reliability. than just keep the originals for backups. Plus it would give you an opportunity to shape the tone if you wanted.

www.thetubestore.com - Pre-Amp Tubes

Vacuum tubes that are Pre-Amp Tubes are in stock and ready to ship!

www.thetubestore.com

 

[Trelwheen]

Oops. Wrong planet. So sorry

 

[jhs5150]

Hi all, I've got a DSL 100H Marshall head the has a high pitched squeal on the od channel.. The green (cleaner) channel is fine even with a distortion pedal at any volume.. When I switch to the red channel it will squeal even at lower volume settings.. Is this normal? Or do I need this thing fixed??
Thanks,
dsl 401

I've seen something similar before with a DSL 100 and it turned out to be the guitar. Try another one before you go digging into it.

 

[Old Punker]

Maybe a microphonic preamp tube?

I get the same thing on my Mesa Rectifier if I switch to the hi gain channel while I have the volume on 10 on my Les Paul, and that is with all new tubes. No problem if I mute the guitar with the selector switch.