RM4 Outputs...

Should the the RM4's pre-loop outputs and post-loop outputs, sound different from each other? I was playing around today, and I set the Effect Mix level knob to 0% and tried plugging into the pre-loop out, and the post-loop outs. It seems like both have different tones; infact, the pre-loop out sounded "tin" like, flabby, and unfocused; while my post-loop outs where slightly better sounding.

Shouldn't they sound the same when no effects are plugged in? Or is there something weird going on with my unit?

Well, in theory they ought to be pretty much the same...but then the tubes in your RM4 chasis come into play...

The RM4 has 3 preamp tubes. The bottom one is the input stage that feeds all the modules. Top right is for the effects send, preout and return mixer. Top left is for the post loop outs.

If one or more of these tubes are not up to snuff, you could conceivablely get significant variation in the outputs.

Replacing or switching the top two tubes would seem to be the best way to determine if one or both of these tubes are at fault.

I actually replaced all of the tubes with new Electro Harmonics 12ax7s, but I'm hearing how Randall has been getting a bad batch of them, so I'll throw in some older JJs.