Adapting tube amp circuit to guitar effects?

Solidhex · Post by **Solidhex** » 09 Apr 2008, 11:04

Hello

New guy here. Wasn't sure where to post this but thought since it was very amp related might as well start here. Curious what type of approach one would take trying to emulate the sound and physical operation of a tube amp circuit for use in a pedal? Although I haven't built any I've always been intrigued by the Run Off Groove website's various pedal adaptations of amps. Not really looking to capture "tube" sound in a pedal. Just interested in how one would approach the process.

Thanks, Brad

soulsonic · Post by **soulsonic** » 10 Apr 2008, 07:59

I think one essential component that seems to be missing in most tube amp "modeling" pedals is the output transformer. The transformer is as much a part of the tube amp sound as the tubes themselves.

Solidhex · Post by **Solidhex** » 10 Apr 2008, 09:47

Definitely no replacement for the real thing.

--Brad

klingo · Post by **klingo** » 19 Apr 2008, 13:31

hello,

Scratch-building a tube amp could be cheaper than buying a boutique pedals.......if you are strong enough to give it up with the "just another one" syndrome

sometime i like to think that Rock&Roll was born with power tubes pushed into distortion and died (in punk spasms) with invention of "master volume".

JHS · Post by **JHS** » 20 Apr 2008, 08:47

Old transformer coupled Ge-trannie AB-amplifier circuits for batt. powered radios from the Mullard reference book sound a lot like tubeamps when overdiven.

JHS

Solidhex · Post by **Solidhex** » 20 Apr 2008, 09:09

Dig it. Yeah as opposed to the general " I want a pedal to sound like a tube amp" I'm more thinking of specific guitar amp circuits that I like the distortion sounds of. I was looking at the schem for the Marshall Lead 12 (as in the Marshall Micro stack) just as a testing ground. No tubes I know but just from a standpoint of plucking certain sections of circuits and adapting them for pedals it seems like a good place to start. I eventually would want to try it with some tube amp circuits as I've seen some other people do it and it sounds like a fun project.

--Brad

JHS · Post by **JHS** » 22 Apr 2008, 08:13

The Lead 12 sound really good as a preamp but it's very hard to get one of them. Marshall only made a few of them and never sold the top alone only with those speaker caps, that's the reason why I never bought one.

If you want Marshall tube tone buy a cheap Park 10W trannie amp, it's similar to the lead 12. This thing sounds more plexi and tubelike like than a lot of the newer Marshall tube amps or FX-emulaters.

The Carl Martin Plexi drive is close too and an easy build if you drop the output boost. You can power it with +/-9V via charge pump and use a IC with higher slewrate for archieving the same dynamic response.

JHS

Solidhex · Post by **Solidhex** » 22 Apr 2008, 09:44

Yo

Yeah lead 12 is good times. I remember hearing something about Billy Gibbons having one modified to run of his car battery. He was installing it as a built in car guitar amp.
Just noticed this on ebay by the way. Looks like a guy custom toilexing old micro stacks ...

https://cgi.ebay.com/Marshall-Lead-12-R ... dZViewItem

--Brad