Transformerless amp, 1:1 isolation xformer

[MWJB]

A pal of mine (harp player) has a Alamo amp with no PT (35W4, 50C5, 12AU6), now in the US a 1:1 isolation transformer would be recommended. As he is using a 240VAC-120VAC transformer, doesn't this effectively do the same job in isolating him from the mains?

[hasserl]

Yes, it does. The ratio is different, but the effect is the same. Wouldn't be a bad idea to add a mains fuse as well.

[Albert Kreuzer]

Be careful and make sure that it is indeed an isolation transformer. Some step-down transformers do not provide mains isolation (so-called "auto-transformers).

[Enzo]

I am with Albert here, MANY step down transformers are auto-transformers - single winding with tap - and provide ZERO isolation.

If a 230/115transformer is in fact a primary and secondary type transformer with no connectiion between the two, then yes it provides isolation.

[dai h.]

yeah, third the motion (to be sure what kind of trafo for safety's sake). A lot (seems to have to do with economy--cheaper, less heavy being the benefits) are single winding (i.e. no isolation).

[MWJB]

Thanks guys.