12,000 series and metro friedman variac difference

[chawonkey]

Sorry if this has already been asked but how does the 12,000 series and the metro friedman amp variac switches differ? Read somewhere that they were different but didn't know in what way.

[VelvetGeorge]

The 12,000 series variac switches only the high voltage. In the Metro-Friedman we are lowering all voltages in the amp.

I am thinking of changing the 12,000 to the M-F way. Will likely do that, but need to listen to it.

George

[demonufo]

I'm assuming that doesn't include heater voltages?

[Roe]

I'm assuming that doesn't include heater voltages?

yes, it seems to switch PT primary.

[chawonkey]

So I'm assuming that the variac on the M-F makes the amp even more saturated and distorted than the variac on the 12 series? Also I know the variac mode on the 12 series drops the output volume is it even more of a drop on the M-F?

[demonufo]

So I'm assuming that the variac on the M-F makes the amp even more saturated and distorted than the variac on the 12 series? Also I know the variac mode on the 12 series drops the output volume is it even more of a drop on the M-F?

Not very likely unless the B+ presented to the power tubes is lower in the Metro/Friedman. Lowering the voltages to the preamp will only create slightly more (and often nicer) saturation, whereas lowering the voltages to the power tubes in particular is going to be the only area where volume and headroom are decreased (although the headroom may also be SLIGHTLY decreased by the lowering of voltages to the pre-amp dependant on the level of saturation...)

I'm sure George can clear this up though.