Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kagliostro on September 27, 2014, 12:52:06 pm

Title: Has anyone done a comparative test between cathode follower and source follower?
Post by: kagliostro on September 27, 2014, 12:52:06 pm

That a mosfet as source follower give good sound result if used in a tube amp there is more of an example here in the forum

and Tubenit is surely one of the guy who experimented a lot with this architecture

What I would like to know is if anyone has done a comparative test between a CF and a SF (in the same circuit)

as to listen to the subtle difference between the two

Thanks

K

Title: Re: Has anyone done a comparative test between cathode follower and source follower?
Post by: tubeswell on September 27, 2014, 04:04:36 pm

I've used IRF820 source followers in buffer stages for bias-vary tremolo in several amps, but that isn't in the signal path. However I can say that high-voltage mosfets (as SF) do work well for LFO buffering, and it saves the worry about h-k insulation breakdown that you can get with modern tube CF stages.

Title: Re: Has anyone done a comparative test between cathode follower and source follower?
Post by: kagliostro on September 27, 2014, 05:04:30 pm

Hi Tubeswell

This response does not answer my question, but despite this, it is an interesting subject and I'm glad you've shared your experience

Thanks

Franco

Title: Re: Has anyone done a comparative test between cathode follower and source follower?
Post by: kagliostro on September 30, 2014, 02:41:15 am

Here an interesting article about CF vs SF

http://milas.spb.ru/~kmg/irf_en.html (http://milas.spb.ru/~kmg/irf_en.html)

K

Title: Re: Has anyone done a comparative test between cathode follower and source follower?
Post by: Ritchie200 on September 30, 2014, 06:41:07 am

Franco,

Found this:
http://amtelectronics.com/support/articles/source-follower-on-the-high-voltage-mosfet-as-cathode-follower/ (http://amtelectronics.com/support/articles/source-follower-on-the-high-voltage-mosfet-as-cathode-follower/)

And this is an interesting discussion:
http://www.diyaudio.com/forums/analogue-source/11386-common-cathode-triode-vs-source-follower-hexfet.html (http://www.diyaudio.com/forums/analogue-source/11386-common-cathode-triode-vs-source-follower-hexfet.html)

Although I'm not sure any of these answer your sonic question.  Interesting subject.

Jim

Title: Re: Has anyone done a comparative test between cathode follower and source follower?
Post by: kagliostro on September 30, 2014, 09:57:17 am

Many Thanks Ritchie

Interesting links

K