AU 717 bridged for mono??

Can the AU 717 be modded or used as a mono bloc? Or is it just a silly/bad idea?

The AU-717 is two Mono Blocks. Each channel of the amp section is a stand alone amplifier.

- Pete

I would not risk any damage to this valuable amp.

That is what I had presumed. I came across a deal for 2 of them in good shape. Might purchase them this weekend. Perhaps I will try running one of them for the highs and the other for the lows. Bi-Amp setup on my speakers.

_R

Running amps in bridge mode puts tremendous stress on the outputs. It also requires inverting one channel. Unless they put a switch on there to accomplish it, I wouldn't consider it.

Agreed, I had read someplace a while ago on one of the forums where a guy had 2 Sansui's modded for bridge mode. Cannot recall the model and there were not any technical details. But since this model is truly 2 discrete amps it would seem near impossible to match the 2 channels as single. At least with any degree of clarity/reliability.

ConradH said:

Running amps in bridge mode puts tremendous stress on the outputs. It also requires inverting one channel. Unless they put a switch on there to accomplish it, I wouldn't consider it.

Click to expand...

Why? what is the difference with the switch put on and without it? The stress if there is some will be the same switch or switchless.



Runningan amp in bridge mode is not a science. Only thing you have to make sure , is both channels are performing exactly equal , or very close to equal.
The phase inverting circuit can be found anywhere and cheap.
I had once convert my big g22k into bridge mode but the center of my home theatre wasn't up to this kind of power. Damn thing pushed out almost ideal 3 times the power of single channel . My center channel speaker barely survived , although it was a 4 way 5 driver design with twin 10" bass drivers.

Why? Consider one half the output stage. Normally it swings close to one or the other power supply rails, with the other side of the speaker at ground, and the expected current flows. In bridge mode the other side of the speaker will be near the opposite power supply rail, so the current is much higher and the SOA of the output transistors are more easily violated. If the amp wasn't designed with bridge operation in mind, it could easily fail. Obviously you're getting much higher power output in this mode so it makes sense that the stresses on the outputs are much higher. There's no free lunch.