Rockster gain stage

[jestaudio]

Following up a suggestion from Mark Fowler i,m wondering how hard it would be to add a switchable gain stage to the rockster, the main isuues being the volume increase and where in the circuit to add it, it seemsa waste not to use that spare half of a 12ax7 and matbe switch 1 complete tube in to keep clean head room on v1 and use v2 for the drive, as usual and suggestion are welcome

[RJ Guitars]

Try this for some generic info then use the TAG guys here as the worlds best tech support network...

http://www.rjguitars.net/Rocket_Booster.html

The way I have implemented this circuit is to basically copy the recovery stage from a Fender type reverb and use it as an extra gain stage...

http://www.rjguitars.net/V-2_HG.MOV -- you'll need quicktime player to hear this. Sorry about the noise in the background, a true low budget recording for sure

If you want the simpler boost control then just add a switch to open and close the ground on a bypass capacitor on the 2nd gain stage. If you want a higher frequency gain then use something like a 1uF bypass cap. If you want to boost all frequencies then use a 22uF cap... or use a on/off/on switch to get the option for both.

rj

[roberto]

Otherwise you can simply add a cold stage (or not.. anything between 100k 10k and 100k 2k2 will work) à la jcm800 with a dpdt switch going from gain pot wiper to added stage (then a classical 22n 470k 470k divider) or directly to the stage before the CF (rewired as V2 only).

[lions den]

I second the idea of the cathode bypass cap on the second stage. I just added that to my rocket and put it on a switch to activate as needed. Very simple mod and keeps the overall tone character with some extra umph.

I used a 25uF cap and really like the results.

Sean

[jestaudio]

Try this for some generic info then use the TAG guys here as the worlds best tech support network...

http://www.rjguitars.net/Rocket_Booster.html

The way I have implemented this circuit is to basically copy the recovery stage from a Fender type reverb and use it as an extra gain stage...

http://www.rjguitars.net/V-2_HG.MOV -- you'll need quicktime player to hear this. Sorry about the noise in the background, a true low budget recording for sure

If you want the simpler boost control then just add a switch to open and close the ground on a bypass capacitor on the 2nd gain stage. If you want a higher frequency gain then use something like a 1uF bypass cap. If you want to boost all frequencies then use a 22uF cap... or use a on/off/on switch to get the option for both.

rj

What i,m trying to achieve is a switchable boost with seperate gain and volume so your idea off a parralel gain stage looks as if it could work if it can be switched

[pablogt]

You could also lift the tonestack's ground for a "tweedy" gain. That's what Dumble's PAB switch does. Or combine this with any of the other possibilities.

Pablo