Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: dsones on November 17, 2025, 11:35:43 am

Title: VHT special six ultra push/pull volume pot replacement
Post by: dsones on November 17, 2025, 11:35:43 am

I have two VHT Special Six Ultra amps. In one amp the push/pull volume pot is shorting so I need to replace the pot. The pot is not like a standard DPDT pot. Do you know what kind of push/pull volume pot I need. When the switch is in the push position B, C, E, F all have continuity with each other. In the pull position A, D, B, E all have continuity. Also lugs A and D are not connected too any thing.  This is very different from the push/pull switches I’m use to (like the picture). What am I missing?

Title: Re: VHT special six ultra push/pull volume pot replacement
Post by: danhei on November 17, 2025, 11:41:00 pm

If B and E are always connected couldn’t you use a standard DPDT pot and jumper across B and E? And are you measuring the connections in-circuit or with the pot removed?

Title: Re: VHT special six ultra push/pull volume pot replacement
Post by: kagliostro on November 18, 2025, 03:02:52 am

https://robrobinette.com/Special6UltraMod.htm (https://robrobinette.com/Special6UltraMod.htm)

Looking to the schematic seems that the PP Pot switchs were simply connected in parallel as to perform a DPST from a DPDT

Franco