input impedance on poweramps question.

[Carrier Flux]

ok here's my question, pertaining to reamping. and sorry about kicking the dead horse...which has been kicked so many times already...but I couldn't find a specific answer to my question on the reamp website or on this forum...so:

what are poweramps' input impedances usually rated at? for instance I own a mesa 20/20. I downloaded the manual from mesa but under "input impedance" there was nothing but blank white space..heheh. fuckers.

anyway here's what I'm thinking. I use a mesa rectifier preamp. I was thinking of recording the "poweramp out" (so it's a flat, unaffected signal) direct to my DAW, then reamping by sending that signal from the daw to my mesa 20/20's inputs. If the poweramp's inputs are low impedance then I suspect this will work, however if they're high impedance I'll need a reamp device etc correct?

I realize you need an impedance converter such as the reamp device for plugging into the front end of a guitar amplifier, but what about the inputs of a power amplifier specifically? thanks.

 

[Piecemaker]

From the schematics on tubefreak.com it seems like the Mesa 50:50 has an input impedance of about 250K. The 2-90 is switchable from ca. 50K (labeled instrument level) to 6.5K (line level). I don't know about the 20:20, though. My guess is it's similar to the 50:50.

I think you don't need an impedance matcher going from your DAW to the power amp. Connecting a low impedance output (like your soundcard) to a high impedance input (e.g. the 250K of the 50:50) is usually not a problem. But you have to keep an eye on the levels, because it takes a smaller signal to overdrive the input if its impedance is higher.

For me, the real question is: why would you re-amp the signal the way you described it? Sure, power amp, cab, mic etc. all influence the final sound, but most of the sound shaping goes on in the preamp. You'd have a ton more options if you recorded the direct guitar signal, before the preamp. AFAIK this is how re-amping is usually done. That way you can later decide you want to put a Tube Screamer in front of the amp to tighten things up, use more distortion, use less distortion, use a whole different amp, etc.

Piecemaker

 

[Andy Sneap]

yeah, I can't see your reasoning behind this, is it because you can't make noise where you are recording and need to mic later or something?

 

[Carrier Flux]

yeah, I can't see your reasoning behind this, is it because you can't make noise where you are recording and need to mic later or something?

yes exactly. there are windows of time where I can be loud, so having an option of recording the preamp section quiet and reamping later is attractive to me; even if I can no longer make any adjustment on the preamp side of things.

this will also give me the option of recording a preamp take along side any live takes [different input channels on the DAW] so I can reamp them later if I dislike my mic selection and position, or choice in cabinets. sure this is more limiting than recording a completely dry signal from the guitar, but I also don't have to invest in any new equipment using this setup.