3 Channel amp Schematic #4

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Bob-I
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Joined: Thu Feb 02, 2006 10:06 pm
Location: Hillsborough NJ

3 Channel amp Schematic #4

Post by Bob-I »

I've decided that switching only the input isn't working. The mixer is always connected to the channel outputs and they load each other down. I tried a manual switch on it and the loading is pretty bad. It sounds far better with the output of the channels switched.

Right now the input relay ckt is ripped apart and I've drawn in what I plan to do.

A few issues.

1) Folks are saying not to ground the relay supply. How? If I don't ground it, it'll be floating and might not work.

2) I'll need to parallel 2 relays coils, the SPDT input and the DPDT output. Is this ok?

Damn this is getting complex. :oops:
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BobW
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Try this

Post by BobW »

Bob, This may help, but pardon me if this seems to trivial.
Any circuit needs a closed path to operate, but the closed path doesn't always need to be connected to a chassis ground reference. Your relay coil circuit is an independent circuit that doesn't rely on the chassis for a ground reference or return path for the 10VDC. The coil circuits ground reference is at the (-) side of the coil on the attachement, not the chassis. Think of the relay coil circuit as a flashlight, completely independent of the chassis. however, the relay contacts are not referenced to the coil circuit, but to the preamp ground reference, the chassis. HTH 8)
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Bob-I
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Re: Try this

Post by Bob-I »

BobW wrote:Bob, This may help, but pardon me if this seems to trivial.
Any circuit needs a closed path to operate, but the closed path doesn't always need to be connected to a chassis ground reference. Your relay coil circuit is an independent circuit that doesn't rely on the chassis for a ground reference or return path for the 10VDC. The coil circuits ground reference is at the (-) side of the coil on the attachement, not the chassis. Think of the relay coil circuit as a flashlight, completely independent of the chassis. however, the relay contacts are not referenced to the coil circuit, but to the preamp ground reference, the chassis. HTH 8)

Good point Bob, thx.
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