new and in need of advice

[turboak]

I am new to the forum and have an issue. I'm not sure whare to post my question to get the best response, anyone help? My problem is this: I rehearse with my band in my garage. During rehearsal the guitars' (Charvel and Epiphone running through POD XT and X3 lives into a 2 ch 100 per side, yamaha solid state power amp into Marshal 4x12 cabinets) volume and overall tone fluctuates wildly. The same thing happens when we use combo amps instead of our half stacks. We can be sounding great tone and volume wise and half way through a song one or both guitars' tone gets very thin and just sounds bad overall but the volume increases by at least 30%. We have the suspicion that we may have a electrical power issue but I do not know how to check this out other than putting a voltage meter on the outlets, which seems to be fine to my non-electrician's eyes. ANY suggestions would greatly be appreciated! Thanks in advance!

[cyclecamper]

I think you're on the right track.

Watch an incandescent light on the same outlet...same side of the balanced mains lines. See if it gets brighter or dimmer. We are very spoiled in the US, very consistent power. If some lights get dimmer when others get brighter, then you have a problem with the neutral getting pulled away from ground by a heavy load on one side.

The POD and other digital emualations have very narrow settings ranges where they sound good. Real analog devices are much more forgiving. But the tone changes you are experiencing...assuming that is the power problems...I can't explain; that might be the power amplifier. But I have no experince with what a POD might do with the incorrect power voltage.

The speakers will be less efficient as they heat up, and become quieter.

Guitar amplification is often not like HI-FI reproduction; it is actually part of the instrument job to create sounds, not always to just reproduce them. You may actually want compression and power supply sag, or desire an emotive harmonic distortion tone availalbe on-demand with your harder touch, chords, or bends. I recommend you try a Fender circuit like in an Alembic preamp or a Marshall circuit like in a Soldano preamp into a tube power amp. At low volumes it lets you appreciate the dynamic range of the guitar and at high volumes it compresses that dynamic range and lets you enjoy a complex timbre.

There's only one rule in blues and rock: whatever sounds good and works is correct. So you'll have to experiment. Get a cheap LED power monitor, or a cheap VOM. Swap in differnt power amps and preamps. You say you have the same problem with combo amps, well that sounds like it's indeed a power problem since you've changed everything but the power and the guitars.