DSL Nosounditis

mike_l

Bugger.

Luckily I know the right person to speak to. Yay.

 

I suspect it's no more than an output valve gone south. But I'm bollocksed if if sticking my delicate pinkies in an amp.

Voxman

If a single valve went you'd still likely hear something but if there's no sound at all, could be a fuse.

mike_l

There is sound, but really faint, and only on the lead channel. Also it's mahoosively distorted (think metalzone, doubled), says output valve to me.

Also it was working normally last week

jpfamps

Could also be output transformer.

What year is it?

mike_l

Around 2007, it's going to the amp doctor tomorrow.

TinLip

Me have DSL50. Me blow EL34 valve from hard rocking (and moving amp too much). Amp no sound. Me buy valves matched pair from HotRoxUK.com. Me follow YouTube video of American man changing and biasing valves. Amp sound. Me hard rock again.

TinLip

mike_l

TinLip said:

Me have DSL50. Me blow EL34 valve from hard rocking (and moving amp too much). Amp no sound. Me buy valves matched pair from HotRoxUK.com. Me follow YouTube video of American man changing and biasing valves. Amp sound. Me hard rock again.

Me no have time to do. Well not enough, and I'm not that happy working with that much voltage. me pass to amp doctor. he fix. Me pay, he fix

TinLip

Furry muff.

Me too scared of high voltage transformer in amp. Amp made in England not efficient China. Lazy solder maybe.
Me sweat buckets and clench starfish when open amp. Valves far away from transformer. Me crack glass on valve and have to hoover out of enclosure. Me clench balloon knot again when stick hoover into amp. Me have Mrs Lip on standby in case TinLip fry.

mike_l

Cheers @TinLip your wording has made I chuckle.

I'd rather let someone who knows what he's doing do it, rather than fry Mike_L.

 

ICBM

If it's that quiet it won't just be an output valve as jpfamps said - although it could have taken out a fuse.

It could also be various other things, including the switch in the 16-ohm jack which is a design fault and one of the causes of blown OTs. Although not if you were actually running it at 16 ohms.

The factory bias setting is also WAY too hot on these as said in that video, which doesn't help.

welshboyo

don't the DSL's suffer from main-board failures as well? or is that a different model/symptom?

jpfamps

welshboyo said:

don't the DSL's suffer from main-board failures as well? or is that a different model/symptom?

Pre around 2005 do.

The problem manifests itself in the power valves going to thermal runaway, and can take out either transformer.

I've seen transformer failures in later models too.

SRich

TinLip said:

Furry muff.

Me too scared of high voltage transformer in amp. Amp made in England not efficient China. Lazy solder maybe.
Me sweat buckets and clench starfish when open amp. Valves far away from transformer. Me crack glass on valve and have to hoover out of enclosure. Me clench balloon knot again when stick hoover into amp. Me have Mrs Lip on standby in case TinLip fry.

Me likey too............have a LOL

Voxman

jpfamps said:

Could also be output transformer.

What year is it?

Its 2015 - and I thought I was bad never knowing what day it is!   >:D<

ICBM

jpfamps said:

welshboyo said:

don't the DSL's suffer from main-board failures as well? or is that a different model/symptom?

Pre around 2005 do.

The problem manifests itself in the power valves going to thermal runaway, and can take out either transformer.

I've seen transformer failures in later models too.

Same here. I've seen a board fault on a later model than that too, and I don't think they've cured it completely, just reduced it. There are also still some of the original design flaws - the switch in the speaker jack, the band-aid cap on the power valve nearest the PT to stop it arcing, the jumper connector to the bias adjusters to name a few - which have never been addressed.

Then there are a whole series of *different* faults on the DSL combos... Got a 201 here just now, typical MV control gone open circuit on one side and blown one of the power valves. You wonder who designed these things, since some of the faults are really obvious potential causes of trouble.

jpfamps

ICBM said:

jpfamps said:

welshboyo said:

don't the DSL's suffer from main-board failures as well? or is that a different model/symptom?

Pre around 2005 do.

The problem manifests itself in the power valves going to thermal runaway, and can take out either transformer.

I've seen transformer failures in later models too.

Same here. I've seen a board fault on a later model than that too, and I don't think they've cured it completely, just reduced it. There are also still some of the original design flaws - the switch in the speaker jack, the band-aid cap on the power valve nearest the PT to stop it arcing, the jumper connector to the bias adjusters to name a few - which have never been addressed.

Then there are a whole series of *different* faults on the DSL combos... Got a 201 here just now, typical MV control gone open circuit on one side and blown one of the power valves. You wonder who designed these things, since some of the faults are really obvious potential causes of trouble.

But at least they sound great.

Nerine

I believe this could also be caused by the fx loop board in the amp.
Something similar happened to my mates.
Sometimes you could temporarily solve it by cleaning the fx loop jacks. Eventually the board needed replacing.

ICBM

Nerine said:

I believe this could also be caused by the fx loop board in the amp. 
Something similar happened to my mates. 
Sometimes you could temporarily solve it by cleaning the fx loop jacks. Eventually the board needed replacing.

That doesn't really make sense - if the FX loop jacks were faulty they could have been changed.

There's a fair amount of other stuff on that back board though, not directly related to the FX jacks which could maybe have been disturbed by cleaning them. Even then I can't think of any reason you'd need to change the board rather than the parts, it's not like the main board which can actually burn due to arcing through the thickness of it or between nearby traces. The back board doesn't carry the high voltages which do that.

But the bottom line is that it's a poorly-designed amp which suffers from board layout and quality problems as well as other faults, which makes it quite difficult to fix really well.

Nerine

Well, it didn't work properly, produced no sound other than a faint buzzy chainsaw tone, and he took it to Marshall and they replaced the fx loop PCB. Not saying that's all that was wrong with it, but it was definitely being affected by it. Maybe there was a bad connection on it, and cleaning the jacks made it connect briefly. I don't know.

However, it was reported a lot back in the days of HCAF when I used to frequent there, that a "dirty" fx loop could cause similar problems on that amp. Several members had issues.

As you said. They were an amp that was affected by all manner of issues.

As "nosounditis" is somewhat vague, I'm only trying to pass on some other things that I have encountered or read about which could be causing the problem here.

There's far more than just one or two possibilities of what is causing the problem here. It could nearly be anything..

ICBM

Nerine said:

There's far more than just one or two possibilities of what is causing the problem here. It could nearly be anything..

Totally agreed! Although about the one thing it can't be is a blown power valve since that should give either a lower-volume (but not very low) sound, or silence if it's taken out the HT fuse as well.