Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mjcyates on May 08, 2021, 07:33:14 am

Title: AC30/6 Parts Question
Post by: mjcyates on May 08, 2021, 07:33:14 am

I am building an AC30/6 and am trying to find the right part for the 2 way rotary switch for Vib/Trem and the 3 way rotary switch for Speed. Can anyone suggest a good choice for these switches and where I can get them. Doug sells a 3 way impedance switch in his store which would probably work but may be a little overkill for this application. Any help would be greatly appreciated.

Title: Re: AC30/6 Parts Question
Post by: sluckey on May 08, 2021, 08:15:38 am

Here's a 3 position rotary that is small and will work fine.

     https://www.tubesandmore.com/products/switch-rotary-3-poles-3-position

     https://www.mouser.com/Alpha-Taiwan/Electromechanical/Switches/Rotary-Switches/_/N-5g2i?P=1z0zlgnZ1yvsm2e

And here's a 2 position from Mouser.

     https://www.mouser.com/Alpha-Taiwan/Electromechanical/Switches/Rotary-Switches/_/N-5g2i?P=1z0zlgnZ1yvsm2a

I just used a 3M-RA pot in series with a 220K for a variable speed rather than only 3 fixed speed selections on my AC-15. I also just used a toggle switch for the vib/trem and Brilliance switches.

Title: Re: AC30/6 Parts Question
Post by: pdf64 on May 08, 2021, 08:53:12 am

I suggest to use 1M or 10k CTS pull-push switched pots for both.
Swap the tracks with those from CTS 3M3RA and 500k lin pots.
Use one for modulation oscillator on/off (in parallel with or replacing the footswitch) and oscillation freq.
Use the other for vib/trem selection and effect depth (replacing the depth preset trimmer VR5).
Hey presto, increased range of control and convenience, no alteration to the front panel or its aesthetics.

Title: Re: AC30/6 Parts Question
Post by: mjcyates on May 08, 2021, 09:01:10 am

Thank you both for the suggestions! Much appreciated.