2. amps-preamps
  3. 1341061762

Will Vincent st-70 upgrade

I just purchased a used beautiful Will Vincent upgraded st-70 power amp. This is my first tube power amp so I am somewhat of a novice when it comes to these units. On the top of the amp between the power supply transformer and output transformer there is a toggle switch. What does this toggle switch do? I don't want to mess with it not knowing its function.
ces4x4
marakanetz's avatar
marakanetz
5,473 posts
 
Most likely it's a switch between triode and ultra-linear mode. Triode less gain less power more transparent. Ultra-linear nearly doubles the power with larger gain and control.
ces4x4 OP
16 posts
 
Thanks for the info Marakanetz, curious since it is not labled is it ok to switch between modes while the amp is on?
marakanetz's avatar
marakanetz
5,473 posts
 
It's OK to switch even when the amp is playing so you'll find yourself better setting. If you idle the amp keep the toggle switch on triode mode once you hear the difference.
newbee
4,790 posts
 
If you only have one set of outputs that switch could, alternatively to Marakenetz's comments, change the output impedance from 8 to 4 ohms ala some Cary amps. Just a WAG though. Maybe another owner will actually know.
More to discover