19-04-2011, 12:14 PM
My bench variac / isolating transformer is rated at 2A / 500VA, which is plenty for most jobs.
I've also got a 8A unit that I hardly ever use.
Radio Rallies are always a good place to look, expect to pay £10-15 for an uncased or around £20 for a cased one.
Most important thing to check is the "track", look for arcing or burning. Check the graphite brush too, though these can be replaced.
When you turn to knob, you should get a nice smooth feel across the entire range with a slight buzzy sound / feel. If it's at all notchy, walk away.
Rob.
I've also got a 8A unit that I hardly ever use.
Radio Rallies are always a good place to look, expect to pay £10-15 for an uncased or around £20 for a cased one.
Most important thing to check is the "track", look for arcing or burning. Check the graphite brush too, though these can be replaced.
When you turn to knob, you should get a nice smooth feel across the entire range with a slight buzzy sound / feel. If it's at all notchy, walk away.
Rob.
