DSL20CR Speaker works intermittently Is it the tubes?


Edit: Replaced the tubes. Still cut out or no sound at all when taken off standby. Check the fuses. They look brnd new. Bypassed the FX Loop and it seemed to work fine foa  day then went right back to cutting outor no sound when taken off standby. 

Full discalimer I don't have a lot of experience with tube amps.  Not many tech options to take it to where I live. I recently bought a used DSL20C and it is in imaculate condition.  Still has the tag on it. For the first few days it worked perfectly as expected.  I turned it on this weekend and let it warm up for a couple of minute, plugged my guitar, flipped off standby  and no sound.  Not even the usual hum that let's you know it's on.  I tried different guitars and cables. I confirmed and visible conections. Eventually, after switching the standby switch a few times it did eventually make sound. There were some pops and volume changes but it worked. I didn't press my luck and turned it off.  I took the back off and made sure the tubes were still seated properly (it was shipped to me).

This is the first time I used it with the speaker instead of the emulated line out. I really had to crank the volume to get good volume in my headphones.  I don't know if that's normal or a symptom. BTW the Emulated line out worked even when the speaker wouldn't. 

Does this sound like it need new tubes or am I looking at something more complicated.  I appreciate any help.

edited 12 Jul 2022 at 10:22 PM

Bill Tibbett

asked 27 Jun 2022 at 06:10 PM

Bill Tibbett
Answers: 1


Hi Bill,

From your description it sounds like it may have output valve failure and the HT fuse may have blown.

The reason the emulated output works is because it’s run from a different supply from the power amp.

I would get it checked over by a qualified and competent engineer who is familiar with valve amplifiers.

The headphone volume is deliberately quite low to avoid hearing damage.


Marshall Support

answered 29 Jun 2022 at 08:17 AM

Thank you for this answer. The output to the speaker is intermittent. For example, I turned it on at it last night to see if I could tell a difference in the glow of the tube (was one not lighting up). They looked ok and when I plugged in it worked fine for about 15 minutes but, then started cutting out (I turned it off immediately at that point). Would that happen? I assumed (we all know what happens when you do) that if a fuse was blown that there would be no sound. I guess the short question would have been can sound come out if the fuse is blown? - Bill Tibbett 29 Jun 2022 at 02:12 PM
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