Marshall DSL40C (new version)

[Valvehead]

Ive got a newer Vietnam made Dsl 40c here ...the pcb is stamped DSL100-60-00 Issue 1 .

not sure if theres any schematics out there for these yet ?

So the amp seems to function , except it has hardly any volume...but when i turn up the Reverb level on either channel , I get full amp volume .

Theres a switch for the loop , on/off , but it doesnt seem to help either way ,, and ive tried inserting the cable in the loop.

This model has an onboard digital reverb .

Anyone worked on these yet ..or seen this problem ?

[The Dude]

http://music-electronics-forum.com/a...-60-02-v02.pdf

Does this look like the one?

[Valvehead]

not sure , i havent compared that to mine...but my pcb is a dsl100-60-00 Issue 1

[Valvehead]

Initially looks like the same amp....

I guess the mystery is why the dry signal is getting killed with the reverb pots on 0

[The Dude]

Does the amp volume level affect the reverb level?

[Valvehead]

well, its kind of the other way around....the reverb pots act like Master volumes for each channel !

[The Dude]

Yes, but if you turn down the master all the way, do you still get reverb? Trying to figure out if RL2B is switching.

[Valvehead]

No--- with master volumes on 0 and reverb levels on 10---no volume

if i turn up the volumes i start to get signal and verb

[Enzo]

So the master still controls the volume.

I really suspect you have a couple of the little two-wire connectors swapped. Is the board for the front panel controls DSL100-61? On that, the master out, or at least the feed after the post controls, is CON7, which connects to CON11 on the tube board. The reverb out is CON9 which goes to CON7 on the main board. The reverb signal from the reverb itself feeds into the front board via CON8, which is wired to the reverb board.

ANy chance this applies to yours and maybe one or more of those is on the wrong posts? Well, two of them would have to be wrong at least, hard to get only one connector in the wrong place.

[Valvehead]

Nope---different layout. There is a main pcb that has the pre tubes on it and also the pots. The power tube sockets are actually mounted alone on the chassis.

the reverb pcb is 2"x2" and has about 10 long pins on the bottom --it sits down into a socket on the main pcb

this thing isnt like the older jcm 2000 amps ive seen

i can post a pic

[Valvehead]

2 pics

[Enzo]

Your board number has DSL100 in it, so I was hoping other DSL100 boards were used.

Meanwhile, does this amp have a bunch of little cables connecting various parts like the DSL and TSL100s do?

Edit: Aha, your photos came up. Yes, I don;t see much opportunity for cable swapping.

[Valvehead]

yes, but WAY less of them !

[Jazz P Bass]

My guess is that you have something going on with the reverb board.

Does pulling the Rvb In/ Out connector improve on the volume control issue?

[Valvehead]

i dont think there is a connector for that---the digital verb pcb has 1" long vertical pins , about 10 or 12, that sit down into a socket on the main pcb . This amp doesnt look like the jcm 2000 series--theres only 4 or 5 connector style cables in it.

i pulled the reverb pcb out of the amp and it didnt help

you can see the reverb pcb in pic 2