DSL40CR Sound went out turned off FX came back on

I don't even have this amp one month. Last night as I was playing the volume drop to barely audible. I turned the FX Loop off & the volume came back. I tried the FX Loop again but was still no there was no sound. I turned the amp off & then on & the FX Loop worked again but it's not as loud & doesn't sound the same it sounds a bit fizzy & much quieter with & without the FX Loop. All pre-amp tubes are glowing & the 2 PT tubes are glowing. I'm shipping it back but I'm curious as to what the problem could be or if anyone else had this problem?

 

First, clean the loop jacks with something like DeOxit.
If that didn't work:

Try the amp with nothing connected in the loop.
Then try with just a patch cable connecting the loop.
Then try with just your guitar connected directly to the loop return.
Then, if you have another amp, try connecting just the loop send to the other amp.

The loop jacks operate differently.
Connecting just the send splits the signal, and the dry signal still goes to the power amp.
Connecting to just the return cuts off the preamp signal.
The above tests should show where the problem is.

Good luck.

 

I vaguely remember having an issue like this some time ago. Turned out to be a bad connection / dirty jack in my effects chain. Nothing to do with the amp.

 

Yep .. the switching jack needs a squirt of DeoxIt !!!

 

Thanks for the reply guys. @SkyMonkey what I don't understand is, when I turn the amp off & on it worked again. I did plug in the guitar to the amp & the volume is much quieter before this happened. I will follow the steps & see if that helps.

 

If shipping it back don't do anything to it!! Could be a weak fx driver tube too I suppose.

 

So the FX has a tube in this amp also? What kind is it?

 

No it doesn't, as far as I know.
If it is an amp issue, the switching IC is more likely the culprit. That is a send away repair.

 

I tried everything last night & it keeps cutting in & out. Man every amp I get there's a lemon. Where do they send it out & how long to receive it back? I bought the amp to play & it's discussing. Is the Pro Gear coverage worth it? I bought a Marshall Origin50H with it & it seemed like like waste when I had a problem as they wouldn't just give me a new one cause it was after the 45 days. Seems like GC gets junk. Had a problem with my Fender GTX 2 to 3hrs & it broke.

 

I thought loop was tube driven . My mistake! Just grasping at things.
It does seem like the IC is usually the culprit.

 

@Robert Machine if it is the ic chip send it back, I thought like @Jethro Rocker that one of the 4 preamp tubes may have something to do with it, they will still glow and appear as if they are fine but could be going out.
Good luck with your amp brother I know how you feel.
Cheers
Mitch

 

Thanks! I called & setup a return. Hopefully I'll get a good one knockwood God bless.

 

@SkyMonkey I found this. He thinks the 4th tube is either a phase inverter or has something to do with the fx loop. @7:00 do you have any idea what that tube is?

 

I've always heard it being referred to as the Phase Inverter or PI. The 2 halves of a PI need to be evenly matched. I don't think it can take on two tasks.

 

Yep 4 is PI for sure. Wasnt sure if half of V3 was loop but it appears not.
Carry on.

 

@SkyMonkey @Jethro Rocker Thanks guys!

 

I had a similar problem with my 2018 DSL40CR.
The volume would drop, sometimes very quiet.
I would turn it off and then back on and it would be fine.

It happened at a few gigs too. At first I couldn't tell if it was ear fatigue or what but then it happened one night when I was just messing around.

Since it was under warranty, I took it to local Marshall service center and they were told by Marshall to replace the whole motherboard.

So far, I been OK.

 

It's quiet frustrating. I'm glad I'm one the only one (but I am sorry for your problems). When I seen the inside I thought oh great look at all this digital stuff. I wasn't excepting that & thought it would be a easy repair. I think Marshall is jamming too much stuff in. I wish they'd stick to their roots & it would be dependable. I really hope this problem or others isn't on most of them. I've searching YT & one person had 2 that had bad tubes. The Eganator Tweaker 40 is the next amp I've heard that sound semi-good but I still l rather this one.

 

I received a 2nd DSL40CR from GC on March, 7, 2021 same problem. The only pedals I have in the FX Loop are: "Outlaw" Quick Draw, & an "Erie Ball" VP Volume pedal

 

This might be important information, if it's happened twice with 2 different amps the might be some incompatibility with one or both pedals. To try and eliminate any obvious problems with the FX loop, unplug both pedals and see if you can replace them with something else, try to borrow an EQ or another boost. Maybe there's an impedance mismatch that's tripping the DSL in some funny way.