hi all, maybe some seasoned 2550 users can help me here.

Just picked up a used (in most excellent shape) 2550. Thing is, I have no idea what the heck I'm doing here. I've dialed in some good tones for sure but kinda confused on what exactly output mater, lead master and output gain all do, seems each channel they have different functions.

- It looks like there's a foot switch inside on the top of the chassis...what the heck does that do.

- Rhythm clip..I can hear what it does but what is it doing under the hood and what scenario is it best used in?

thanks in advance!

The Rhythm Clip is just that.  It connects a couple of diodes to ground which symmetrically clips (square wave) the waveform.  There is a capacitor across the diodes to help filter some of the harsh harmonics but it is still going to sound buzzy.  If you push the Master Volume enough to get the power amp to distort, it will smooth it out some and may be a sound you like.  But mostly it's just kind of gimmicky.

The Lead channel uses a more complicated network of diodes/LEDs that is much more musical sounding due to being asymmetrical.

..Joe L