What volume for my Audions with a pre?

I'm a little confused about this, my Audion power amps have volume controls on them but as I'm running multiple sources I use a pre already. What volume should the Audion's pre be set at? (I can't bypass it). At the moment I'm about midway. I guess I'm wondering about 2 things 1) sound quality 2) tubes being driven harder.

Thanks! Tim

 

I've use similar setups with two volume pots ....I tend to set the power amp to max output. I do this by having the contrl pre set to zero and the power vol to 30% then bring in the contrl vol this stops any full range by accident ....I then increase the power amp to near full or full vol tthe control pre is then increased to the desired volume ...... the settings are then left on the power amp and the volume contrioled by the first pot.

I find it sounds best with the power volume resistance reduced near zero ....

 

Set the volume control on the power amps to max and only use the volume on the pre to adjust gain.

 

Thanks guys I'll adjust them to max. Much appreciated.
Tim