Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: cusebassman on February 19, 2020, 09:08:47 am

Title: Amps with 3+ Preamp Gain Stages
Post by: cusebassman on February 19, 2020, 09:08:47 am

Hey all - can you give recommendations for amp circuits to study that use more than 2 or 3 triodes for high-gain in the preamp section? I do mean triodes, not preamp tubes, since the Fender tweeds I've studied (and built) used multiple preamp tubes, but for all manner of reasons, most of which were not to add extra gain. Just looking to learn more and maybe tinker with a build for moderate to heavy tube distortion.

Title: Re: Amps with 3+ Preamp Gain Stages
Post by: d95err on February 19, 2020, 10:28:54 am

The Soldano SLO is the father of all 4-stage high gain circuits.

I’d start there.

Title: Re: Amps with 3+ Preamp Gain Stages
Post by: d95err on February 19, 2020, 10:39:34 am

If you want to go really deep, I recommend reading The Ultimate Tone 6 by Kevin O’Connor. It has a chapter describing the evolution of high gain amps, from the Plexi, JCM800 on to modern amps and various  boutique amps. It has schematics and detailed analysis of each circuit.

Title: Re: Amps with 3+ Preamp Gain Stages
Post by: SILVERGUN on February 19, 2020, 10:45:36 am

Reading d95err's response reminded me of this excellent resource. I highly recommend reading everything you can from this site:
https://www.ampbooks.com/mobile/classic-circuits/soldano-slo/

Title: Re: Amps with 3+ Preamp Gain Stages
Post by: cusebassman on February 19, 2020, 01:05:18 pm

This is just what I was looking for. Thanks much!