Q about connecting transformer 6v-0-6v

[Hubba]

Hello,

I've got a 6v-0-6v / 5A transformer which is used to power a simple Crystal c3310 Volume remote control preamplifier kit.

My question is: Can I use the same transformer to power a speaker protection board which requires 12VAC? (And still have the transformer connected to the pre-amp with the 6-0-6 input)

Cheers,
Fredrik

[AndrewT]

Hi,
Yes,
if the speaker protection circuit can float, i.e. does not need a voltage reference to zero volts.

But, how many inputs does the protection circuit have? Can they all operate without a reference to ground?

[Hubba]

Thanks for the reply Andrew,

Electrical stuff are not exactly my best field, so bear with me if I give you the wrong info.

I believe that the protection circuit does not need a reference to zero volts. It just has a 12VAC input feeding the board; in total 2 inputs which is supposed to be fed by a standard 12VAC transformer with no CT.

Thank you,
Fredrik

[AndrewT]

the 12Vac is one input, the flow and return between transformer and PCB.

There must be other inputs!!
How does the protection know to stay ON or to turn OFF?

[Hubba]

OK,

So, not counting the AC input there are two (stereo) inputs and two (stereo) outputs for the speaker signal. The speaker signal just passes through the Relays and connects to the speaker output terminals. There a start-up delay of about three seconds when applying the 12VAC to the board. The board is receiving 12VAC as long as the amplifier is running. (The power amp section is running on a separate transformer).

Regards,
Fredrik

[AndrewT]

the relay switched speaker connections are very likely to be isolated.
The two (stereo) channels must have a flow and return. That return will probably be labeled GND.
You need to find out how this GND connection works (what it connects to) to determine if the circuit is isolated from the rest of the amplifier.