Marshall DSL 401 no sound

[bearded madman]

So I was playing my Marshall and Mesa tonight switching between the two with an A/B pedal and after 10-20 minutes of playing both amps the Marshall quit making sound when I clicked back over to it. After trying a few things I noticed that it looks like one of the power tubes isn't lighting up. I have a couple of the old tubes that came out of it (groove tubes) but I had JJs put in it and am not sure if it's safe to just pop in one of the old tubes, not sure if the GTs match the JJs.

Wondering what you guys would recommend, just pop one of the old tubes in or take it to the tech?

 

[bearded madman]

Re: Marshall DSL 401 no sound

So I realized that I left my amp set at 16ohms when I plugged in my 8ohm cab. :smack: Hope I didn't burn up a transformer.

 

[Nostalgic Distortion]

Re: Marshall DSL 401 no sound

Do you know how to bias the DSL, if so you might be able to get away with just changing one? That said, your always better off going with a matched set. It's relatively easy as long as you already have some basic tube amp knowledge. Also there's a couple of really good demo videos that will walk you through it but please don't attempt it unless you feel reasonably comfortable with your skill set, they are DEADLY!!!

Hopefully you just burnt out a tube and your transformers are still alright!!! I'd start with the power tubes & kinda take it from there. If the tube doesn't do it take it to a tech....

 

[bearded madman]

Re: Marshall DSL 401 no sound

Not sure about biasing it myself, I can install pickups and pots but never gotten into anything that could give me a shock.

Couldn't I just pull the outside 2 power tubes and run it at half power? I bought the amp 10-12 years ago used from GC and the manager told me they had serviced and put new tubes in it. Last year I got curious as to what kind of tubes(brand) it had in it and found out it only had 2 power tubes in it the whole time I had the amp. So I know it can run off of only 2 tubes as long as I pull the correct tubes. Had the amp serviced less than a year ago and a new quad of JJ el-84s installed. It has probably been on less than 10 hours since and hadn't been powered up for 4 months or more until last night

 

[Kamanda~SD]

Re: Marshall DSL 401 no sound

Well that was dumb...

You would most likely smell a burnt transformer. Check your fuses and pop in the old tubes...I don't recommend pulling a pair.

Really though your better off bringing it to a tech.

 

[astrozombie]

Re: Marshall DSL 401 no sound

You can use the amp with a single power tube on each side.

I mean this.

4 tubes right? I own one.

tube (nothing) tube (nothing

(one of these two on the left) + (one of these two on the right)

0x0x

 

[astrozombie]

Re: Marshall DSL 401 no sound

Check the fuse, if it's blown I think it's just a power tube. Happened to me with a different amp and turned out to be the case.

check if the fuse is blown though...

 

[Drano Max]

Re: Marshall DSL 401 no sound

If you pull 2 tubes, make sure it is the 2 outer, or 2 inner power tubes, and you have to drop your impedance switch down to half of what it should be. Those amps can do that just fine.

If it's just one power tube not glowing, replace them and rebias it. If none are lighting up, check the fuse. You would probably smell it if the Tranny went. If it's not a tube or fuse, take it to a tech.

I'm guessing you just wore the tubes out with the impedance mismatch.

 

[bearded madman]

Re: Marshall DSL 401 no sound

Yeah I felt extra smart when I remembered the cab I plugged in was 8 ohm not 16. Only had it for 15 years or so.

I kinda felt like it might be a good sign that I never smelled anything burning.

 

[bearded madman]

Re: Marshall DSL 401 no sound

Both fuses look ok. I tried running the effect send to another amp and got no sound. Also tried running my pedals into the return and again no sound.

Think I will try pulling the outer 2 tubes and see what happens. It ran on 2 tubes for 10 years so I know it can be done but even if it works it will be going to the tech for some new tubes.

So when i'm only running 2 tubes does it run at 8ohms when set on 16?

Edit: looks like I had it backwards and the amp would be running at 16 ohms when set on 8. I'm going to do a little more research to make sure I've got this right