Dsl20 Gut Shots Before & After Marshall Update

[Deerhunter1972]

As you know from my previous threads, I bought a used DSL20CR that had the usual "wind,blowing" noise issue, volume knobs not working with emulated out using headphones, volume drops when using the FX loop....etc. Marshall "updated" the amp free of charge. I just had to pay to ship there. They let me just ship the chassis and tubes minus the cab to save a lot on shipping. Took just under 3 weeks to fix from the time I shipped it to the time I received it back. The amp is now dead silent on standby. There is a very slight constant hum when on 10 amp and 20 amp power with nothing plugged in which seems normal to me as it is a tube amp. The volume controls work perfect now when using the emulated out with headphones. The FX loop works perfect too with no volume drops or humming when engaging the FX loop. It sounds amazing in both classic and ultra with new JJ's and a G12M. The only problem it still has is that it "pops" when switching from ultra gain to classic gain while notes are ringing out. Switches silent when strings muted. Marshall would only tell me the "update" consisted of changing out a few capacitors. I am not an electronics guru so maybe you guys can see what was fixed. The only thing that I see that changed was a couple of cables at CN22 and CN23 by the classic gain volume knob were moved. Hopefully this helps anyone out with all the problems with the DSL20 line in repairing it yourself. If anyone has an idea how to fix the "popping" sound when switching from classic to ultra that would be great too. I am awaiting my 3rd head replacement from Sweetwater, but they said all 20 they have in stock pops when channel switching. They are in talks with Marshall to see what can be done with the popping issue. Marshall needs to recall these amps and stop production in Vietnam! Oh well. Reply if you can see what other "updates" they did.

Gut Shots Before the "Update"

 

[Deerhunter1972]

More Gut Shots before "Update"

 

[Deerhunter1972]

Gut Shots After the "Update"

 

[Michael Roe]

So, what is different??

 

[Len]

So, what is different??

Too difficult to see with just pics. Someone needs to actually trace out the circuits.

 

[Michael Roe]

I see a difference.
There are two wiring harnesses not connected at CN22 & CN23 that are in my amp and your old one. On mine the CN22 goes to CN20 and the CN23 goes to CN21.
I copied your pic and circled the CN22 & CN23 in red and the CN20 & CN21 in yellow.

Can you see where your CN20 & CN21 are connected to after the update? I can't tell by the pics? It looks like one of them now is looped where all the wires are bundled with a zip tie. Is CN20 now just connected to CN21 and they did away with the other harness?

 

[Deerhunter1972]

I see a difference.
There are two wiring harnesses not connected at CN22 & CN23 that are in my amp and your old one. On mine the CN22 goes to CN20 and the CN23 goes to CN21.
I copied your pic and circled the CN22 & CN23 in red and the CN20 & CN21 in yellow.View attachment 54145

Can you see where your CN20 & CN21 are connected to after the update? I can't tell by the pics? It looks like one of them now is looped where all the wires are bundled with a zip tie. Is CN20 now just connected to CN21 and they did away with the other harness?

Yes. Mine were wired the same way also. They did away with the harnesses on CN22 & CN23 and connected CN20 to CN21. Sorry about the pictures. MF limits the resolution on picture uploads so I had to screenshot the pictures to scale them down.

 

[Antmax]

I had a before photo from another thread, reoriented that and put it side by side with deer hunters new after pic. So it is easier to see differences.

Might be easier to cross reference. I enlarged the after a little to match the before pic and added labels so we know which is which.

If the hookup cables are the only thing done to fix the problem. Then it's a bit sad that the factory screwed up something so simple. Cool for us because it's a 2 min job once you get the chassis out and reversible.

 

[Armando]

The C39 seems to be different too???

Regards.

 

[Michael Roe]

View attachment 54226

The C39 seems to be different too???

Regards.

Looks like those two resistors to the left of C39 are also different.

 

[Armando]

It's true, I had not noticed. They are the famous R56 and R70

 

[Armando]

Someone with the modification can take a better picture from that zone.

Thanks in advance.

 

[Deerhunter1972]

Someone with the modification can take a better picture from that zone.

Thanks in advance.

Here is a close up picture of that area

 

[axomann]

Hello,

I have the same issue with the emulated output. It has a constant volume level and it cannot be controlled by the volume knobs.

I changed the configuration as showed in the pictures above. I disconnected the harnesses CN22 & CN23 and connected CN20 to CN21. The result is that the volume on the classic gain not works anymore and it is at 10. The gain works.

There must be another trick on this modification or maybe they connected a jump under the motherboard. Maybe someone can take a pictures of the downside.
Or maybe they reorganize the cables came from CN103 & CN104 in another way.

Here my amp with the cable mod.

 

[Michael Roe]

Hello,

I have the same issue with the emulated output. It has a constant volume level and it cannot be controlled by the volume knobs.

I changed the configuration as showed in the pictures above. I disconnected the harnesses CN22 & CN23 and connected CN20 to CN21. The result is that the volume on the classic gain not works anymore and it is at 10. The gain works.

There must be another trick on this modification or maybe they connected a jump under the motherboard. Maybe someone can take a pictures of the downside.
Or maybe they reorganize the cables came from CN103 & CN104 in another way.

Here my amp with the cable mod.

View attachment 54240

Oh man, I wouldn't have done that. That was just something we noticed that was different. Could have smoked your amp Yes, there could be other stuff going on we can't see like on the bottom.
I was visiting another forum and read where a guy sent his back to Marshall and the result was exactly as you are describing.

 

[axomann]

I change the cables back again. Don't worry they are only signal cables..........

 

[Michael Roe]

Just got off the phone with sweetwater to see if they could give me any info on the problem. They say, basically that Marshall does not claim there is an issue with the amp. They also say that the manual doesn't claim that the volume knobs do anything when using headphones and that it is meant to go into a mixer ( I assume that was told to them by Marshall?). They did however say that Marshall owned up to the speaker jack problem with the Origin amps and they had sweetwater techs fix that problem. They gave me the contact number of a local marshall service center to get mine fixed. I will be doing that and then I will side by side compare it with my other DSL20HR to see what the fix is. I ended up recently trading my DSL 15H for another 20HR. Of course it has the "isuue" as well.

 

[Antmax]

I posted about the line out being fixed volume on my.marshall.com They just responded with this is normal. See quote below.

Another forum member who had theirs fixed posed a lengthy comment too but that was deleted.

DSL20 CR and HR headphone/line-out level only adjustable via gain knob?

Quite a few people on various forums are concerned about the emulated out of our DSL20H and DSLCR amps. It seems that there is a set level for the emulated line out and headphones which can only be adjusted with either the guitar volume knob of gain channel knob. The channel volume does nothing to the line out/headphones only to the speaker output.

Is this normal behaviour? Where the gain knobs are the only controls on the amp that increases the loudness of headphone/line out.



Speaker Headphones Volume line-out DSL20HR DSL 20 Emulated DSL20CR

asked 28 Oct 2018 at 01:25 AM

Adrian Tysoe

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Answers: 1

Hello Adrian,

Thank you for your e-mail regarding your question, this is normal so you can adjust the level of the output compared to the level of the line out.



Kind Regards

Marshall Support

I plug my line out into a headphone amp or just direct to my interface and boost the signal till it's acceptable volume. Naturally that does add a little extra white noise, though it isn't too bad. Still, it seems that volume should work, and it doesn't exactly help passive headphone users if the volume is fixed.

 

[Armando]

Thanks Deerhunter1972

Does anyone know what the difference between the yellow block and the blue block C39 may be?

As for the emulated output and the use of headphones, in my amp the headphones work without problems and the volume control increases or decreases the volume of the headphones (always in stand by mode) what happens is that if you play without headphones I have the volume in 2 (at home for example) with the headphones I have to put it in 12 to hear it at similar volumes (I understand because it is more thought out for output to a mixer with which to control the desired volume, which for headphones) and the gain is maintained at the same level with or without headphones.

 

[trovador]

It's true, I had not noticed. They are the famous R56 and R70

Why are they famous?