Volume leap DSL20. Help!

[Rocurus]

Hey everyone!

New to the thread here. I have a Marshall DSL20 HR and up until recently worked great. Got it second hand so pretty sure sending it back is not an option.

Anyways, here's the issue I'm having and maybe others are having it as well.

Classic Gain -> no problems, sounds great. However, when I switch over to ultra gain, no matter where the volume is set to on the front, it sounds as if it was on 10. Just a HUGE volume leap. Turn the amp on & off again, I can switch between the channels once, but second time, same issue. Volume is just maxed out despite what knob reads, and it even doesn't react to knob turning.

Took the back off and everything seems in order. Nothing is loose. Not that I would know otherwise as I'm not very knowlegable in these things.

Now in the 10 watt mode, everything is fine. No volume leaps between channels.

Any ideas? I don't want to surrender to only the 10 watt mode if I don't have to.

Thanks everyone!

 

[fitz288]

Hey everyone!

New to the thread here. I have a Marshall DSL20 HR and up until recently worked great. Got it second hand so pretty sure sending it back is not an option.

Anyways, here's the issue I'm having and maybe others are having it as well.

Classic Gain -> no problems, sounds great. However, when I switch over to ultra gain, no matter where the volume is set to on the front, it sounds as if it was on 10. Just a HUGE volume leap. Turn the amp on & off again, I can switch between the channels once, but second time, same issue. Volume is just maxed out despite what knob reads, and it even doesn't react to knob turning.

Took the back off and everything seems in order. Nothing is loose. Not that I would know otherwise as I'm not very knowlegable in these things.

Now in the 10 watt mode, everything is fine. No volume leaps between channels.

Any ideas? I don't want to surrender to only the 10 watt mode if I don't have to.

Thanks everyone!

to the forum.
I've never had the problem you are describing with my DSL20RH, but I'm not a circuit guru either.
You've provided some good info of what's happening, so hopefully someone smarter than me will chime in.
Hang in there - you've come to the right place!

 

[Leonard Neemoil]

Yes, welcome to the forum.

I don't know much about the 20 but at least some of the hR amps have programable footswitches. So maybe it has something to do with that.

As for returning a second hand amp goes, depending on where you bought it from you should have no problem sending it back for another. Musicians friend and guitar center have no questions asked 45 day return periods. I had to return a couple of used amps to them last summer due to one fault or another. Don't let them trick you into paying the return shipping either. If the amp is faulty then that's on them.

Someone more knowledgeable should be along shortly.

 

[PelliX]

Manners first; !

I can switch between the channels once, but second time, same issue.

This reeks of the microcontroller doing something wrong. So, just to get this straight, you turn it on with the Green channel, all good. You switch to the Red channel, all good. Switching back to Green is OK, but a second time switching to Red rips the paint off the walls?

Not that it really matters in your case, but do the volume controls work on either channel via the Emulated out? There was a production "issue" where they incorrectly wired this section in a number of those amps. The volumes are *intended* to work via the E-out. If they don't, then you have one from that era/batch.

Now, to the actual problem at hand, does toggling the FX loop change anything, and does it switch correctly once the 'problem' is there? If you're comfortable with a multimeter inside the amp, would you care to check the voltage on the ATmega chip? See DFX1 on the second schematic, contacts 11/12 and 21. I'm suspecting these voltages are low...

I'll skip the disclaimer about there being high voltage DC in there. Be careful, obviously.

 

[PelliX]

Also, perhaps a mod could move this to the Workbench section?

@Dogs of Doom @crossroadsnyc

 

[Mitchell Pearrow]

To The Forum
I have nothing to ad here
But @PelliX had some great advice

 

[Pete Farrington]

Assuming those schematics are good, it seems to be a problem with relay 2, eg bad connection, sticky contact.
Relays 1&2 are switched together, and all relay 2 seems to be doing is switching the channel volumes.
When it’s in the fault mode, does the classic gain master control the volume?

 

[Rocurus]

Yes, welcome to the forum.

I don't know much about the 20 but at least some of the hR amps have programable footswitches. So maybe it has something to do with that.

As for returning a second hand amp goes, depending on where you bought it from you should have no problem sending it back for another. Musicians friend and guitar center have no questions asked 45 day return periods. I had to return a couple of used amps to them last summer due to one fault or another. Don't let them trick you into paying the return shipping either. If the amp is faulty then that's on them.

Someone more knowledgeable should be along shortly.

Hey Leonard!

Thank you for your reply! When you wrote that, something inside me knew there was some truth to it. Investigated it today.

Here's how the issue was resolved for anyone out there experiencing the same thing.

Even though I keep my head in a dust cover and the pedal in a bag, it appears there was something wrong with the connection. Took some DeOxit d5 connection cleaner - seriously this stuff is worth it's weight in gold and can be found at sweetwater for cheap- and hit the input of the footswitch on the head.

First test was without Marshall pedal switching between channels - all good. Normal performance. That narrowed it down to pedal issue.
Plugged in pedal (without pedal board, just guitar and Marshall pedal) after hitting the port with Deoxit - full performance. No issue
Final test, plug in the rig. No issues!

Thank you again to everyone that reached out. Couldn't have done it without you and glad that it wasn't something much more labor intensive. I don't have the knowledge -or time- to do it myself and not the discretionary income to pour into this amp. This community feels really helpful and I was shocked by the amount of support I got. Thank you!

Back to ripping riffs!

 

[Rocurus]

Assuming those schematics are good, it seems to be a problem with relay 2, eg bad connection, sticky contact.
Relays 1&2 are switched together, and all relay 2 seems to be doing is switching the channel volumes.
When it’s in the fault mode, does the classic gain master control the volume?

Hey Pete!

Thank you so much for your time! Turns out it was a dusty contact in the F/S input jack. Hit it with Deoxit d5 and it's back to normal! I wrote the full description to solve - for anyone else out there experiencing this issue - in another reply.

Back to ripping riffs! Thanks again!

 

[Rocurus]

Manners first; !



This reeks of the microcontroller doing something wrong. So, just to get this straight, you turn it on with the Green channel, all good. You switch to the Red channel, all good. Switching back to Green is OK, but a second time switching to Red rips the paint off the walls?

Not that it really matters in your case, but do the volume controls work on either channel via the Emulated out? There was a production "issue" where they incorrectly wired this section in a number of those amps. The volumes are *intended* to work via the E-out. If they don't, then you have one from that era/batch.

Now, to the actual problem at hand, does toggling the FX loop change anything, and does it switch correctly once the 'problem' is there? If you're comfortable with a multimeter inside the amp, would you care to check the voltage on the ATmega chip? See DFX1 on the second schematic, contacts 11/12 and 21. I'm suspecting these voltages are low...

I'll skip the disclaimer about there being high voltage DC in there. Be careful, obviously.

Hi PelliX!

Thank you so much for your time in diagnosing this issue! It's clear you really know your stuff about amps! Turns out it was a dirty connection from the footswitch. Hit the input with Deoxit D5 and the issue seems to have resolved itself.

Tested without pedal, then tested with only Marshall pedal then tested with full rig and the issue is gone. Hopefully it is gone permanently but if it arises again, will use the Deoxit D5 again. Stuff is really helpful and I believe every ax wielder should have some.

Back to rippin riffs! Felt so good to have the 20 watt crunch back!

Thanks again!

 

[Leonard Neemoil]

Great, glad you got it figured out!