Running 220V on 240V tap = Variac?

[hunter]

Stupid question, but could I use the 240V tap on an amp running on a 220V supply to simulate a kind of VariAC?

[Roe]

yes, if you get high enough heather voltages

[paulster]

It'll give you an 8% reduction in supply voltage so your heaters will probably still be in a good range but it's worth checking in case you've got a particularly low notional 220V supply. Most tend to be on the hot side anyway, so you may find the voltages are better on the 220V setting throughout the amp.

[hunter]

Thanks for all the feedback.

Well here we usually get like 230V, so using the 240V tap would make it a 4% reduction. Maybe not enought to have a real variac effect methinks ... nothing like the 110V->90V EVH was running (20%). So what would the experts say, waste of time?

[paulster]

Check your heaters and B+ voltage. If your wall voltage is actually 230V then you'll probably want to be on the 240V tap to get the voltages where they should be anyway. So much for the so-called European voltage harmonisation!