I have an EI transformer from an old Yamaha AV receiver that I'm hoping to reuse for a project.
My understanding is that at least some Yamaha receivers (this one included) had 2 sets of transformer secondaries for the amplifier section, this one having both +/-28v and +/-40v, and flicking the speaker impedance switch to 6ohm simply switched to using the +/-28v secondaries.
Would it be problematic to use both the +/-28v and +/-40v rails in a project, or is it too hard to know without knowing how the transformer is wound? The reason is that I'm looking to put together a 3 channel (2.1) amp, with the sub running from the higher voltage rails.
My understanding is that at least some Yamaha receivers (this one included) had 2 sets of transformer secondaries for the amplifier section, this one having both +/-28v and +/-40v, and flicking the speaker impedance switch to 6ohm simply switched to using the +/-28v secondaries.
Would it be problematic to use both the +/-28v and +/-40v rails in a project, or is it too hard to know without knowing how the transformer is wound? The reason is that I'm looking to put together a 3 channel (2.1) amp, with the sub running from the higher voltage rails.
It's easy enough to work out how the transformer is wound.
Start by taking some resistance readings between the secondary wires.
I would expect the higher voltage windings to just be extensions of the lower ones.
Start by taking some resistance readings between the secondary wires.
I would expect the higher voltage windings to just be extensions of the lower ones.
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Sorry I should have mentioned the voltage checks I did a bit more.
They're both centre tapped with those centres connected however when I hooked it up to mains there was no potential between the secondaries (i.e. either side of +-28v to either side of +-40v showed nothing, making me think that they are separate windings.
However I get your point about checking the resistance, I should've thought to do that and will now do so.
They're both centre tapped with those centres connected however when I hooked it up to mains there was no potential between the secondaries (i.e. either side of +-28v to either side of +-40v showed nothing, making me think that they are separate windings.
However I get your point about checking the resistance, I should've thought to do that and will now do so.