How many Gainclones can be powered off a single rectifier?

[sangram]

they are in series and both pass the full current.

I stand corrected, of course that is the case.

[AJ Bertelson]

Originally posted by sangram
[BThe OP is planning to run two LM4780 amps off a single rectifier. [/B]

Nope, I have some left over 3886's from BrianGT's original group PCB buy.

[Redshift187]

Originally posted by AJ Bertelson

Nope, I have some left over 3886's from BrianGT's original group PCB buy.

There isn't a lot of difference. An LM4780 is two LM3886s in one chip. The maximum heat dissipation is lower, but the power consumption is very similar.

[pacificblue]

Originally posted by Redshift187
In my research, I haven't been able to come up with any explanations involving two bridge rectifiers, one for positive and one for negative. Is this a series arrangement?

It is not a series arrangement. It is more like two separate circuits, where the positive rail of one is connected to the negative rail of the other. The use of a single rectifier for a split power supply is kind of an economic version.

The advantages of separate rectifiers for positive and negative rails are less losses in the transformer, better power distribution across the secondary windings, better regulation and better suppression of noise (hum) during unbalanced load situations. Disadvantages are higher component count = higher price and double the voltage drop. And of course two separate bridges only make sense with double secondaries, not with center tapped transformers.

Originally posted by Redshift187
this would (almost) double the current capability, as only the positive or negative would be used depending on the polarity of the audio signal at any given moment.

However, I discovered that with a bridge rectifier, each diode must be rated for the full current. Despite two diodes conducting at any given time, they are in series and both pass the full current.

Yes to both.