Stewart Pinkerton wrote in
:

On Sat, 29 Jan 2005 04:01:15 GMT, R wrote:

Eiron wrote in :

R wrote:

The only downside I know of (as long as both amp channels are
matched) is that permissable load impedance is doubled...IOW, if your
amp is rated for 4 ohms minimum, in bridged mode you can only connect
an 8 ohm load.

jak




That depends on the amp.
I know of at least 2 amps where the opposite is true. IOW, when in
normal mode impedance ranges are from 16 ohms to 0.5 ohms. When in
bridge mode the impedance range is 8 ohms to 0.25 ohms.


In that case the bridging is done by shorting the left and right
channels together at both input and output (with accurate balance
of gain and offset, and appropriate resistors to limit current).
so the voltage gain is the same and current capacity doubled.

Normal bridging doubles the voltage gain and leaves the
current capacity unchanged.


The amp in question can do either.

One can indeed simply tie inputs and outputs together and is called
mono-parallel. The other method runs one channel through an inverter
and the resultant signal 180 degrees out of phase with respect to the
other and is called mono-bridged.

The output impedance is halved for parallel and doubled for bridged.

The output power is doubled no matter which method you choose.

Nope, given adequate current reserves, the output power is
*quadrupled* for bridging, and remains the same for parallel
operation. If you're talking about some POS valve jobby, then of
course the output transformer taps make the whole thing moot.

Don't believe me. I don't care. No, it is not some "POS valve jobbie"
either. Please remember that I said that it "depends on the amp".

The owners manual certainly would indicate my statement to be true. In
addition they have made the same "error" in their 600 watt and 500 watt
versions as well as one of their current amp offerings.

Here is the link to the owners manual for the 300 watt version.
http://berners.ch/McIntosh/Downloads/MC2300_own.pdf

Their current offering indicates that the power is doubled when in
parallel.

http://www.mcintoshlabs.com/mcprod/....%5CMC402om.pdf

In case you don't have acrobat the specifications say:

"Power Output Stereo
Minimum sine wave continuous average power output per
channel, all channels operating is:
400 watts into 2 ohm load
400 watts into 4 ohm load
400 watts into 8 ohm load

Power Output Mono Parallel
Minimum sine wave continuous average power output is:
800 watts into 1 ohm load
800 watts into 2 ohm load
800 watts into 4 ohm load"

I should have qualified my last statement to say "The output power is
doubled no matter which method you choose with this amp."

r
--
Nothing beats the bandwidth of a station wagon filled with DLT tapes.