#1
Hello fellow guitarists and gentlemen,
I currently primarily use a Marshall VS-100 combo, i bought it used off a good friend a little while back (the man who inspired me to buy my first guitar), and its served me amazingly for a while! its got amazing tone, its PLENTY loud enough seeing as i have no problem playing above drums (its 100 watts, so it gets louder than drums at around 5 or 6), and i generally have no complaints about it, except for its recently developed a few problems...

1. The reverb does not work anymore; 2. It makes very loud popping noises when i adjust the volume; 3. Occasionally when i switch from treble pickup to rhythm pickup (using an Epiphone Les Paul) there is no sound from the amp for a few seconds (very annoying when i go from a chorus/solo back into a verse or bridge); 4. Rarely, the sound will be very very muddy for several seconds before eventually clearing up. 5. I occasionally hear radio stations (?), most commonly right after i turn the amp on; 6. And lastly, heavy buzzing occurs when on the clean channel, little to no buzzing when in overdrive.

So, my biggest issue is determining the source of these problems.. i know that some of them are due to the amplifier, seeing as it is pretty old i am not surprised that it needs some maintenance, but could others be due to instrument cables? issues with the guitar itself?

Any insight is greatly appreciated!
#2
1. check the connections to the reverb tank.
2. Needs a new pot.
3. Quite possibly the pickup switch on the guitar. Clean or replace it.
4. On which channel?
5. Could be the earth on the guitar or at the mains socket. Could also be a dodgey cable or faulty earth on the guitar.
6. Could be a lot of things; channel relay, faulty transistor or op-amp, any number of components really.
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
#3
The muddy tones usually occur on the clean channel, but i don't play on overdrive very often, and when i do its very low gain, so i don't know for sure that it wouldn't occur in overdrive. I will have to check that out tomorrow after work when my neighbors aren't sleeping! Thanks so much for the advice!

EDIT: i checked out the link in your signature to your custom made amplifiers... inspiring and refreshing! keep up the good work!
Last edited by risewtf2 at Nov 28, 2011,
#4
Stick a JJ ECC83S in it for the overdrive channel. It's mostly gimick but when they start to fail it does make a difference to the drive channel. Sounds to me like something's dying in there. Pretty hard to diagnose a SS amp on a forum. It would be worth giving it a good clean though, it's amazing how many things that will fix, often unexpected things.
Buy a can of contact cleaner, Deoxit is a great one. First clean all sockets. You just need an applicator, for that use a plug. You can use your cables and give all the plugs a clean at the same time.
Spray the end of the plug liberally then work it in and out of the plug a few times.
Pots can be cleaned but it's often a lot harder. You have to get some spray inside the body of the pot, it needs to get to the track. The best place is the gap between the contacts and the body. Most pots have a gap there. Spray it in and work the knob back and forwards a few times. This often works but it's a stopgap measure really, it's advanced warning that the pot needs replacing.
Replacing pots in a VS100 is a pita. They are board mounted so you have to remove the whole circuit board to do it.
Clean your guitar switches and pots the same way.
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
Last edited by Cathbard at Nov 28, 2011,
#5
I really don't want to mess any of that up haha so i will probably take it in to my local shop, and have them diagnose it. if i am correct, it is partially solid state and partially tube, so its not completely SS, but either way amps can be tough, and i agree. i'm considering fixing it up a bit and selling it or trading it for something all-tube, depending on how well it performs after a bit of TLC.
Thanks again for sharing your knowledge!