#1
So my DSL401 (Yeah, not the best amp ever, I know) has random volume drops, which went away for a while and just recently came back. And since I'm not well versed with knowledge of circuitry, I figured I'd come here. Any ideas on why the volume could be fading out, and how much it'd cost to fix the problem? They don't seem to occur for any reason, some happen right when the amp starts, others when I've been playing for a good hour or more. Sometimes it goes weeks without any sort of problem.

edit: the tubes aren't old, so it most likely isn't them.
Splawn Quickrod
Avatar Contemporary 2x12
Various Pedals
PRS Custom 22
Ibanez RG560
American Standard Strat
Last edited by mailbox2112 at Nov 30, 2011,
#2
you may have a tube or tubes, going bad. But it could be something more serious than that also.
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
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#3
The tubes are fairly new, and it had the same problem before I changed them, so I'm thinking it's probably something other than that.
Splawn Quickrod
Avatar Contemporary 2x12
Various Pedals
PRS Custom 22
Ibanez RG560
American Standard Strat
#4
Quote by mailbox2112
The tubes are fairly new, and it had the same problem before I changed them, so I'm thinking it's probably something other than that.

I would take it to a good tech and have them check it out then.
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#5
First thing you do always is give everything a good clean. Pull the tubes and spray the pins liberally with contact cleaner and work them in and out of the sockets a few times. Then do the same thing with all the input and output jacks using a plug as the applicator.
If that doesn't work it's time to try substituting your spare tubes - you do have spare tubes don't you? If not, why not?
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Cathbard Amplification
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#6
I did clean everything, and I tried swapping out the tubes, and it's still doing it. My guess is there's a bad solder in there somewhere, or something worse.
Splawn Quickrod
Avatar Contemporary 2x12
Various Pedals
PRS Custom 22
Ibanez RG560
American Standard Strat
#7
That would be my guess too, either that or a leaky capacitor somewhere.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#8
Well, time to take it to a tech, it seems. Hopefully the fix won't be too expensive.
Splawn Quickrod
Avatar Contemporary 2x12
Various Pedals
PRS Custom 22
Ibanez RG560
American Standard Strat
#9
Here's what you would normally do in such an intermittent fault. Get yourself a can of freeze and a hairdryer. Systematically freeze things and then heat them up with the hairdryer (not the tubes - be careful). The fault will hopefully manifest itself with the rapid change of temperature.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#10
What would I be looking for? I'm a noob at electronics, so I apologize if I ask too many questions
Splawn Quickrod
Avatar Contemporary 2x12
Various Pedals
PRS Custom 22
Ibanez RG560
American Standard Strat
#11
Well, first you'd just look for bad joints. If a joint looks dodgey, resolder it. Heat changes should show that up too. Next try the capacitors. Make up some cardboard sleeves to protect the tubes before you start spraying freeze in there. The glass is pretty tough but freeze will crack them like an egg. There isn't a lot else in there that will behave like you are explaining. Something is failing when it gets hot.
PS: be very very careful as you have to work on a live circuit. Be sure to switch off the amp at the wall and discharge the filter caps before doing any soldering. When in there with your freeze and hairdryer kepp one hand in your pocket and watch what your pinky finger is doing. The pinky has a tendency to stick out and touch things. I don't know how many times my pinky has touched 240V, even with one hand in your pocket it bloody hurts. And remove all jewellery, I can't stress that enough - no rings, bracelets or any other metallic objects. I worked with a guy that lost his ring finger working on 50V. You'll notice that techs and sparkies don't wear jewellery - that's why.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#12
So I took it to my local shop and their response was "We can't fix that, we only repair vintage handwired amps and amps without a printed circuit board."

Am I out of luck since the amp has a PCB, or does their tech just suck?
Splawn Quickrod
Avatar Contemporary 2x12
Various Pedals
PRS Custom 22
Ibanez RG560
American Standard Strat