Helping Out With Strange DSL40C Problem:

Inspector #20

Inspector #20

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Last night during our routine rehearsal, one of our guitar slingers started having trouble with his DSL40C. I took over while he switched to the backup MG50CRD.

The amp would start emitting a sound that I would describe as an "electrical short circuit," or very similar to what it sounds like when you touch the end of a guitar cable that is powered up, only louder. When this noise was present, guitar output could not be heard.

The noise would seemingly come and go, flaring up during some songs, but not on others.

Cables were checked, but he had zero noise issues the rest of the night after switching to my MG50CRD backup.

I have several sets of tubes on hand, and I kinda think that this might be the problem, but I wanted to get some opinions from our amp gurus.

Thanks...
 
Robert Herndon said:
Last night during our routine rehearsal, one of our guitar slingers started having trouble with his DSL40C. I took over while he switched to the backup MG50CRD.

The amp would start emitting a sound that I would describe as an "electrical short circuit," or very similar to what it sounds like when you touch the end of a guitar cable that is powered up, only louder. When this noise was present, guitar output could not be heard.

The noise would seemingly come and go, flaring up during some songs, but not on others.

Cables were checked, but he had zero noise issues the rest of the night after switching to my MG50CRD backup.

I have several sets of tubes on hand, and I kinda think that this might be the problem, but I wanted to get some opinions from our amp gurus.

Thanks...
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If it's not the tubes:
You have to go through some tests probably. You need a digital volt meter.

The circuit board can arc and burn at the output tube socket. The tests will tell you if the board is bad.
When you fix the board you usually replace the bias adjust pots also.
 
syscokid said:
Pick up the amp and take it outside. Find a dumpster. With as much force as you can muster, slam the DSL into the dumpster. Go online and order from Sweetwater and order the Soldano SLO-30. You're welcome... :cheers:

View attachment 52661
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It belongs to a bandmate. He would not appreciate that...He's shown here with his '76 Gibson Les Paul Deluxe.

His pair of DSL40C's are visible next to the Bandleader's Germino Lead 55.

FB_IMG_1602384407327.jpg

I keep all instruments and amps running in this band, in addition to my position as #3 rhythm/lead guitarist and lead/backing vocalist.
 
Robert Herndon said:
I seldom see bad power tubes in the amps that I maintain. I generally change them as a proacive measure and not because they are bad...
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My first one went bad at about 4 months after purchase, but it was also a floor model.
I had taken the back off to check and when I tapped it with the pencil it lit up very bright and the noise I was hearing was right there, so I swapped out both, 2 years later a similar problem arose and I swapped them again!!
Thanks
 
There's quite a few things that could possibly cause this kind of symptom, but the first thing I would say is have someone play through it at the same sort of volume used when the problem showed up, while you watch the tubes (power tubes would be the most likely culprits, but watch pre-amp tubes too). You'll most likely see if one of them is breaking down/arcing internally etc when the symptom arises.
If not tubes, as AMS said, testing internally will be needed to locate the problem.
Don't read too much into pre-amp tubes popping when taped. Actually, I'm not big on tapping tubes,,, people tapping them with a pencil looking for microphonics,,,, next thing they find microphonic tubes because they keep bashing the fricken things with pencils.
Cheers
 
Robert Herndon said:
Found tubes V2 and V3 would exhibit evidence of a short/arcing when the noise anomaly was present.

Replaced all 4 pre amp tubes...back in business just in time for Friday Night's Show...

Thanks, Hombres...
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More often than not, it's the preamp tubes. We see a lot less problems with output tubes.

But DSLs in general suffer from a Voodoo curse.
People love the way they sound. But those DSL amps act up a whole bunch.
 
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