Marshall reverb pot doesn't do anything?

easlern

Boredom artist
I found an old jtm30 at a good price, really love the sound. Bought it, took it home and tried to see how it records. Decided to turn the reverb down. . . and realized the pot wasn't doing anything! It's stuck with like a half second spring reverb on all the time. I'm not missing anything, am I? I tried the fx switch on the foot switch but it didn't do anything either.

The store has a 10 day return policy but I wanna make sure it's not something simple before I go that route. . .
 
From the schematic I found for the JTM30 it looks like the Reverb pot should be able to kill the reverb altogether. The pot leg that goes to ground 'might' be broken. I found the owners manual and that states the footswitch is for channel switching, but not reverb or effects.
See if this looks like the amp you have...
http://www.marshallamps.de/fileadmin/_marshall/downloads/all-manuals/JTM31x-Handbuch.pdf

Schematic if it helps. VR7 is the reverb pot.....
http://www.thetubestore.com/lib/the...shall/Marshall-JTM30-30W-JTM310-Schematic.pdf

Perhaps the store might repair it to make it right(?)
 
Thanks arcaxis, that's great info. Yeah they seem cool, they can probably fix the reverb. But now it's starting to do other weird stuff, cutting in and out. I'm not sure this one should have been up for sale, I'm just gonna return it. :/ I was just dialing a pretty good sound too.
 
Thanks arcaxis, that's great info. Yeah they seem cool, they can probably fix the reverb. But now it's starting to do other weird stuff, cutting in and out. I'm not sure this one should have been up for sale, I'm just gonna return it. :/ I was just dialing a pretty good sound too.
Might not be the problem, but try plugging in a TS to TS cable (guitar cord or similar) into the effects send to return to 'bridge' them. There is a contact in the effects return jack, that if it gets dirty, can intermittently cause sound to drop in an out. I had this happen with an amp. A squirt of contact cleaner into the jack and plugging a cord into to it several times usually will clean it up.
Other things could cause the cutting out, such as loose or dirty tube pins. Definitely see if the store will make good on the repairs if you like the amp.
 
Thanks arcaxis, I tried that too. I think it's just a lemon, I'll put the return money toward something new. :P
 
I'm thinking on just getting a dsl15 head, it sounds great on youtube. I was thinking combo first because I wanted an open back speaker but I think just removing the back from my bassbreaker cab and hooking up the marshall head will work. Still kind of new to this stuff, I've been an acoustic guy most my life.
 
Lol well since you revived this thread, I'll follow up: I returned the jtm30 and got a dsl40 combo instead. I actually preferred the sound of the jtm30 sitting in front of the amp but when recording, the dsl40 is a lot easier to get a great sound. So it all worked out I think.

Also my bassbreaker just blew a power tube and had a catastrophic failure so I'll be getting pretty familiar with this new amp while I wait for a repair. :P
 
Comgrats on the new amp Nick. I have that DSL40c too. There was a thread on it here just two or three weeks back, if you did not see. Tell me more about the catastrophic failure of your Fender.
 
If I got any amp Id grab a DSL 40C, I came close for my sons /shared amp but hes afraid of gigging with a tube amp. for me its all home so... any inputs on gigging or jamming and mobile with the DSL40c? is it light road worthy?
 
I don't gig but I wouldn't use this if I did, it's 50 pounds and awkward. Plus a good target for thieves if you're playing sketchy places I imagine. :\

Ray I powered up the bassbreaker a few days ago and it made a huge noise for a few seconds, then shut down completely. Afterward one of the power tubes was cracked and powdery inside and the fuse was blown. I replaced the power tubes and the fuse but still not powering up. It's under warranty (5 years!) and there's a service place nearby so I'm not too hurt about it.
 
That sucks man. Tell them to make it right.

I hope we are going to hear some recordings with you DSL combo!
 
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