I turn it on and at the volume set @ U or straight up(midway) nothing comes out. if you turn it all the way up of course you get alot of buzz and barely get any sound from a mic or mixer signal,etc. could it be a solder problem or something. i dont think its the amp, because the volume makes the buzz get alot louder when the volume knob is turned up.

Bad connection? Loose fittings? I used to get a crackle from my amp when I turned the volume or balance knobs. A quick spray of WD 40 down the shaft after removing the knobs fixed it.

Check to see if the unit can have the electronics reset to factory defaults. Look in manual or go to web site for help.

Buzzing could be normal for this amp, especially if you have the gain cranked way up (or the volume way up) see if the buzz goes away when you turn the gain/volume down. If not, there is a problem that needs to be properly diagnosed by the amp tech at your local music store. The crackling is also unfortunately rather normal for an amp that's a little older. Oxidation builds up inside the knobs and makes that noise as you turn them. If it only happens when you change settings I wouldn't worry about it, but if it gets bad, a tech guy can clean it out for you.

The cause is a lack of proper earth grounding in the 8 track so your jack-lead is acting like a radio aerial. The solution is simple - buy a Direct Injection (DI) box to place between the guitar and recorder.

What is the source of the input signals? These need to be balanced lines and the sources need to be balanced. If you happen to be using condenser mics, you probably haven't turned on the Phantom Power in the mixer. If you are recording from a sound card in the PC, those have a lot of noise and are unbalanced and you have to use DI's with ground lift ahead of this mixer.

I do NOT believe it is possible to do this to the straight volume with Marshalls. The controls only vary the overdrive features and turning them on and off.

okay so buzzing noise. i have seen this once before. the extension cord feeding a power strip with two amps plugged in and powered on off of a low amp electrical outlet with fluorescent lights overhead.......try running only one power unit off of the electrical outlet you are using, just one straight into the wall with the lights out. if you still hear it i wonder if the output transformer is starting to go south. if you listen close sometimes you can hear the buzz of a transformer powered on, example: you can hear the buzz of a power transformer on a power pole in peak hours. tubes usually make hisssing, crackling type noises. next would be to tap on the tubes while in play with an orange stick or pencil eraser to listen for microphics or the tapping itself thru the speakers. if you hear with out a doubt change them.

If the buzz disappears when you unplug the cable from the amp. check your cable.
If the buzz disappears when you unplug the cable from the instrument, there's something thay may have come loose inside the instrument.
If you unplug the cable from the amp., and the buzz persists, you'll have to have a competent tech. check your amp.

try connecting speakers to another sound source or if you have access to a ohm meter, check impedance of speakers, should measure 4~8 ohms.

the buzzing is indicative of an open ground connection, check the cord by substitution or with an ohm meter, if the cord is good look at the connections to the jack inside the amp ( im guessing you built the amp from a kit). Is this a solid state amplifier? Tube amps have lethal votages and should not be experimented on without knowledge of electronic safety. Also if there is more than one input to the amp try plugging the guitar into another one and see if its still the same.