New love for DSL 401?

[giblesp]

So I've been previously moaning about my DSL 401 for a while.

But for the last couple of months, I've had it in the bedroom and been using as my bedtime practice amp.

I've found new love for it. Instead of saying it sounds inferior to my much more expensive JVM stack, I'd say it's a fun amp to play through.

No, it's not as articulate as my JVM. A bit compressed. But it's a good amp. Picked it up for a mere £75 a while back, the reverb and effects loop don't work. A bit tattered and battered.

But good little tube amp, with lots of character. They go cheap on eBay, and while I wouldn't recommend them as the main amp for a more serious player (ok, all subjective I know!), I'd definitely recommend one if you need a smaller combo to back up your main rig, or have one around the house.

Rock on.

 

[RCM 800]

I liked mine a lot. Only sold it because my bro was in need of an amp and I had an excess of them at the time. I think I gigged more with it than any other single one of my amps come to think of it.

 

[TonalEuphoria]

If you don't like as much, I would try to shape it more myself and change the speaker. And maybe the tubes depending. What's in there now?

 

[giblesp]

If you don't like as much, I would try to shape it more myself and change the speaker. And maybe the tubes depending. What's in there now?

Red channel keeps fading out, so it could be in need of a tube change. Any suggestions?

I'm assuming it's just the original tubes in there.

 

[JohnH]

fading out sounds like a tube heater cutting off. The amp is famous for heat issues causing bad connections. Fixable though. Does it do it on Orange too? or Green? When it's faded out, can you look in to see if all the tubes are glowing?

 

[TonalEuphoria]

Red channel keeps fading out, so it could be in need of a tube change. Any suggestions?

I'm assuming it's just the original tubes in there.

It's always best with a tube amp to change the tubes first and then go from there. There the most common cause and than you know it isn't that if the problem continues.

 

[giblesp]

fading out sounds like a tube heater cutting off. The amp is famous for heat issues causing bad connections. Fixable though. Does it do it on Orange too? or Green? When it's faded out, can you look in to see if all the tubes are glowing?

Just the OD channels cut, though very rarely now for some reason. Green is fine. Reverb and fx loop also out of action.
So needs a bit of work!

 

[tmingle]

Like John H said earlier, It's probably solder joints or possibly the bridge rectifier for the filaments to V1, V2 & V3, & is under rated, IIRC. If it's a really old 1(mine was a '99) it supposedly had bias issues(although the math works out perfectly) as well. I also installed a fan on mine. It definitely helped with the heat issues, but did nothing for the reliability of the amp.
The most important accessory for this amp is a soldering iron. The tubes are probably fine.

 

[JohnH]

I'm pretty sure that in the preamp, there is a tube that is only active on OD channels. I think it's V2? (V1 is in a metal can, V2 is next)

I reckon it could be an issue near there, either bad solder or trace, or the valve is bad or not seated right. When it's cut out, does V2 glow?

We know the power amp section works
We know the input and clean channel works
This time its not just the bridge rectifier, which heats all of V1, 2 and 3 and would take out all channels.

All that is just speculative...

(Beware of lethal high voltages)

 

[giblesp]

Like John H said earlier, It's probably solder joints or possibly the bridge rectifier for the filaments to V1, V2 & V3, & is under rated, IIRC. If it's a really old 1(mine was a '99) it supposedly had bias issues(although the math works out perfectly) as well. I also installed a fan on mine. It definitely helped with the heat issues, but did nothing for the reliability of the amp.
The most important accessory for this amp is a soldering iron. The tubes are probably fine.

Yeah, that's a good point. I don't much about the technical side of amps, but it sounds good when it works.

For some reason, it hardly cuts out anymore. Used to cut out after 5 mins on the red chanel. Weird.

Know that there's probably a thousand articles on this, but would it improve the sound to change tubes? Novice question I know...

Only criticism is that the amp sounds a little compressed, but perhaps that's due to the design of the amp.

 

[giblesp]

Am playing this amp a couple of hours a day right now, have it as my bedside practice amp

I'll maintain that it doesn't sound as good as my JVM rig, but still sounds good and is fun to play. My JVM and cab cost £900 (used head, new 1936), the DSL £75.

At this point, I'm going to keep it as my combo. Great for when my whole rig isn't needed.

 

[tmingle]

Am playing this amp a couple of hours a day right now, have it as my bedside practice amp

I'll maintain that it doesn't sound as good as my JVM rig, but still sounds good and is fun to play. My JVM and cab cost £900 (used head, new 1936), the DSL £75.

At this point, I'm going to keep it as my combo. Great for when my whole rig isn't needed.

If it has the EI tubes in it, do not change to something else unless 1 fails. Also IMHO, the bias mod detailed from Marshall nuetered the amp when I tried it.

 

[JohnH]

If it has the EI tubes in it, do not change to something else unless 1 fails. Also IMHO, the bias mod detailed from Marshall nuetered the amp when I tried it.

Yes indeed! Mine came with the updated 550mV bias, which was WAY cold. The original-spec bias (1375mV) was WAY hot (but sounded good). Once I added fans, I found a good place in between at 750-800mV.

I did a tube change, just to JJ's. All fine except the JJ at V1 sounded dull, so i put an original tube back there which brightened it back up.

 

[giblesp]

That do anything to relieve the compressed sound, or is that more to do with it being a small combo?

 

[tmingle]

IIRC, I restored the bias circuit to factory specs. My 401 was a very early model(the ones with the most issues) with the 1.375v bias settings. The service bulletin had you changing 2 resistors in the bias circuit. It totally castrated the amp & I was only able to set bias to .700V IIRC. It still got hot as all hell so, I restored to factory & ran the amp at about 1.2V(which did sound better) but still got hot . There is a thread here somewhere that explains that the 1.375 setting is actually 70% dissipation. I beleieve JohnH has a newer version & would assume that other changes were made to the circuit as well. I loved the 401 until I got a great deal on a 40C & sold it. I should have kept it & hand-wired something in the cabinet. The transformers are the most expensive parts of the amp & I could have reused them.