Have amp only 2 months & clean channel is muddy. it was clean when i bought it. its somewhere in between clean & drive

I once used uART & some latches to decode & hold the difference between "odd & even" midi program changes. Then used the output to switch a relay in a twin necked guitar to change between necks as it were in response to a midi pedal. Perhaps you could do something similar? Else get a Studiomaster MA-36 midi analyser & hack into it to use one piece of midi data (from across an LED?) to switch channels on your amp? Good Luck!

This is because your clean channel only runs through the pre-amp section, requiring an increased volume level to match that of the volume of the drive section which is overdriven by the pre-amp circuit. my suggestion is to use lower volume level on the clean channel of the amp. To get any volume boost you may need to match the two channels you could use a signal/volume booster or overdrive pedal between your guitar and amp input, switching it off and back on when you switch back and forth between channels.

I have the Boss ME 50. Here's things to try. Use wall outlet to power the 25 instead of batteries. Have volume on amp up, volume on pedal all the way up, volume pedal all the way up(depressed), no gain on amp(use clean channel or clean setting if only 1 channel)effects on amp off(reverb, chorus, delay, boost, etc.) mid range knob below 5. only 1 pickup on, guitar tone knob all the way towards treble. If this puts you in the ballpark you can then make slight tweaks to any of these settings. What we're trying to do is not run a dirty sound from the pedal board into an amp with dirty settings. That double dirt often causes a muddy sound. Aside from that you can back off on various effects in the patches. My 50 has a list of the patches and factory settings, so if the drive, for example is set on 8, I might back it off to 4, or the compressor, or the delay, etc. If you like the sound save it. If not continue on. Start with the amp 1st. Higher output tubes(such as JJ's produce a cleaner sound. Also the demo you heard was not coming from your guitar speaker which may not be on the clean side.

It sounds like you bought a defected amp. You should contact Marshall and tell them the problem. You should have some kind of warranty.

change the 9v battery and see what happens

For the Drive channel you need to use the Drive control AND the MASTER volume control. When the Drive channel is active, the Channel Indicator lamp should be RED indicating the Drive Channel is active. The Drive control knob is used to adjust the preamp volume and distortion level of the Drive Channel. This gives you a clue as to what to check if adjusting the controls doesn't work -- the preamp tubes. Having said that, ONLY try to check these tubes with the amp OFF! Never stick your hand up into the chassis of a live amp. It could be lethal. Your preamp tubes are the ones farthest from where the power cord enters the chassis. They have a rubber like stabilizer on them. They have a tendency to wiggle loose, which is part of the reason for the stabilizer. Again, if you're not familiar with the insides...stay out and get an amp tech to help you.

The Normal Channel only uses the Volume Control to adjust volume.

When i turn on my 212R it turns on in drive channel. if footswith is plugged in, then it turns on in the clean channel, but after switching in drive it is impossible to switch it back in clean channel. What could be wrong? Swith position doesnt change anything and it seems like switch is OK.

Wayne, There's a time to take the amp to a pro shop andf get it done right. It' saves time and headaches, and also keeps you from inadvertantly smoking other parts or yourself. Now is that time.

There are 2 channels, Which means there are 2 sets of knobs ... One for clean and one for crunch. Start out with a low master volume and set up the crunch, Then the clen and switch between the 2 and make adjustments until they match volume wise ... Then turn the master up.

Replace the switch. You gave no make/model number for your amp but if it has a jack for foot pedal operation of clean/dist function then try that. (on most amps) it will switch in spite of a bad front panel switch.