Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Paulycoo on August 24, 2017, 02:58:43 pm

Title: Vvr power reduction with Hoffman Princeton reverb build
Post by: Paulycoo on August 24, 2017, 02:58:43 pm

Hello from the Lake district UK.
I'm nearing the end of my Hoffman Princeton reverb build and was wondering if I could add a small power scaling or vvr/vcb to it?
I've found a simple kit on Ampbuilders site that's for cathode biased amps.
I've read that my Princeton is adjustable fixed bias.
Could anyone advise please?
Many thanks Paul McNamara

Title: Re: Vvr power reduction with Hoffman Princeton reverb build
Post by: sluckey on August 24, 2017, 03:25:19 pm

The VVR for cathode biased amps will not work with a fixed bias amp. You need a VVR for fixed bias amps. May I suggest you get the 'stock' amp working first then modify it after you know it's working properly?

Title: Re: Vvr power reduction with Hoffman Princeton reverb build
Post by: SILVERGUN on August 24, 2017, 04:12:46 pm

Read more here:
http://www.londonpower.com/about-power-scaling-kits (http://www.londonpower.com/about-power-scaling-kits)

Title: Re: Vvr power reduction with Hoffman Princeton reverb build
Post by: Ed_Chambley on August 24, 2017, 05:17:37 pm

Check attachment.

Title: Re: Vvr power reduction with Hoffman Princeton reverb build
Post by: Paulycoo on August 29, 2017, 10:55:23 am

Thank you much appreciated