Two of Brian's LM4780 boards, one toroid

[Russ White]

First the application:

I am building a simple office subwoofer with two 8" drivers. Each driver will get its own amp. It will only be handling the LFE channel from an HT reciever in mono so crosstalk is of no concern to me.

The toroid is 650VA with dual secondaries at 21V measured.

The question:

Should I use one of Brians rectifier boards and split the DC current to both amps.

Or.....

Should I split the AC current to two seperate rectifiers.


I was leaning toward the second because I thought it would make the load lighter on the diodes in the rectifiers.

I am a total newb though, so I will humbly ask for help.

Thanks.

[Sherman]

Originally posted by Russ White
First the application:

...Each driver will get its own amp. It will only be handling the LFE channel from an HT reciever in mono so crosstalk is of no concern to me.

The toroid is 650VA with dual secondaries at 21V measured.

...Should I use one of Brians rectifier boards and split the DC current to both amps.

Or....

Should I split the AC current to two seperate rectifiers....

Thanks.

Russ,
That's a good question and I would also like to know if there is a definitive answer.

The "intuitive" answer is what you are leaning toward, two rectifiers, lighter load therefore better sound. However it seems that those who have tried both have decided that a single rectifier is the way to go as far as sound is concerned.

Having two toroids of decent output 24V secondaries, 300VA I tried it myself. (Keep in mind this is a P2P wired GC, not one of Brian's kits.) After much listening I finally decided I couldn't hear a really noticeable difference but a single rectifier
may get a slight nod. There are too many variables to take this as any sort of definitive result though.

If your main interest is a lighter load on the components then two rectifiers would do that. Also I think that since this is a sub that you probably wouldn't hear any difference at all.

I would be interested to see if anyone has actually made any measurements (power output, distortion, ringing, etc.) using both setups.