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Running 220V on 240V tap = Variac?
Posted: Mon Sep 07, 2009 10:46 am
by hunter
Stupid question, but could I use the 240V tap on an amp running on a 220V supply to simulate a kind of VariAC?
Re: Running 220V on 240V tap = Variac?
Posted: Mon Sep 07, 2009 11:25 am
by Roe
yes, if you get high enough heather voltages
Re: Running 220V on 240V tap = Variac?
Posted: Mon Sep 07, 2009 11:42 am
by 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.
Re: Running 220V on 240V tap = Variac?
Posted: Tue Sep 08, 2009 2:29 am
by 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?
Re: Running 220V on 240V tap = Variac?
Posted: Tue Sep 08, 2009 4:47 am
by 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!