Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: chris s on November 25, 2022, 07:08:50 pm

Title: Adding a Fet Preamp to a Lamington Reverb - potentiometer reccomendation
Post by: chris s on November 25, 2022, 07:08:50 pm

Hey all I'm wanting to try adding a lnd150 Fet preamp to the front of a Lamington Reverb to compensate for the slight volume drop when on. http://www.hawestv.com/amp_projects/amp_solid_tube/art_guitar_amp/lnd150_preamp.png (http://www.hawestv.com/amp_projects/amp_solid_tube/art_guitar_amp/lnd150_preamp.png). As I'm only wanting a relatively small volume increase I'm assuming I'll need to add a volume pot at the end. Just wondering what size pot would be appropriate. Thanks!

Title: Re: Adding a Fet Preamp to a Lamington Reverb - potentiometer reccomendation
Post by: tubenit on November 25, 2022, 07:33:54 pm

I don't know if this would be helpful or not?  It's the only amp I can think of that has an FET at the front end of a tube amp.  Disregard if not useful.


with respect,  Tubenit

Title: Re: Adding a Fet Preamp to a Lamington Reverb - potentiometer reccomendation
Post by: acheld on November 26, 2022, 10:42:19 am

The schematic looks like a Dumble FET section in an ODS, if I'm not mistaken.   In any event, there is a fair amount of discussion regarding FET sections over at the ampgarage in the Dumble Discussions sub-forum.