Isolation of mains xformers from circuit for headamp

Petman · 10th May 2002, 12:44 PM

Hi!

I've got a little existencial doubt. In europe the mains voltage is 220V. It happens that i'm going to build a Morgan Jones headamp based design found in headwize.com that uses 220V. I don't think that it's safe to connect the circuit directly to the mains socket, BUT, using 2 20VA transformers for isolation gets a bit heavy. Any sugestions?
BTW, A xformer rated at, say, 20VA means what? It's power (P=VxA)?

Thanks!!

paulb · 10th May 2002, 02:23 PM

A 20 VA transformer is not very large. Yes, it means Volt-Amps (AC). This is not the same as DC power in Watts, for various reasons. After conversion to DC, you can count on getting about half the AC VA as DC power in Watts.
Don't skip the isolation transformer. It's essential for safety.

And one more thing:
Don't skip the isolation transformer. It's essential for safety.

10th May 2002, 12:44 PM	#1
Petman diyAudio Member Join Date: Apr 2002 Location: Lisbon, Portugal	Isolation of mains xformers from circuit for headamp Hi! I've got a little existencial doubt. In europe the mains voltage is 220V. It happens that i'm going to build a Morgan Jones headamp based design found in headwize.com that uses 220V. I don't think that it's safe to connect the circuit directly to the mains socket, BUT, using 2 20VA transformers for isolation gets a bit heavy. Any sugestions? BTW, A xformer rated at, say, 20VA means what? It's power (P=VxA)? Thanks!! __________________ "and the music plays forever" - Pet Shop Boys

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10th May 2002, 02:23 PM	#2
paulb diyAudio Member Join Date: Jun 2001 Location: Calgary	A 20 VA transformer is not very large. Yes, it means Volt-Amps (AC). This is not the same as DC power in Watts, for various reasons. After conversion to DC, you can count on getting about half the AC VA as DC power in Watts. Don't skip the isolation transformer. It's essential for safety. And one more thing: Don't skip the isolation transformer. It's essential for safety.

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