Is it possible/practical to set up a nonbridgeable amp in bridged mode?

[JohanK]

I'm wondering if this is a good idea. I would like to setup my Rotel 985MkII amp so that 4 of the channels will become 2 'bridged' channels. Basically, I want more power w/o buying a new amp. Thanx.

[Bing Fung]

Good Question Johan, i wonder the same thing. apperently it can be done by what this link shows http://www.sound.au.com/project14.htm#top
Can't say I have tried it though....




Bing

[ThomasW]

Bridging does work but it's almost always a sonic compromise, particularly for amps not designed that way during manfacturing. And even then there are sonic differences in the various mfgrs approach.

Bi-wiring is usually better option if that's possible.

Unless one is an experienced electrical circuit DIYer with lots of test equipment, including a "scope", I'd suggest not playing around with the circuitry shown on the ESP page. There just too great a potential for frying the amp.




theAudioWorx
Klone-Audio

[JohanK]

Thank you for the link Bing. I've got a little reading to do.

Thomas, that is what I thought but the concept intrigues me. However, from my experience, biwiring or (passive) biamping does not obtain a significant SPL increase. Can you elaborate on the sonic compromise of bridging? What 'effects' do you notice? Thanx.

[ThomasW]

Johan

This isn't anything I've played with at all. The reason for that is the engineering is at odds with what should be happening is a circuit. That being the less hardware in the signal path the better

The only way to do this "well" is the way it's done by Sony with their "BTL" amps, "Balanced Transformer Less" design. That design straps the output modules together without having any transformer in the circuit. This approach is the least damaging IMO to the signal. I have 2 amps that do this.

Using the aftermarket circuit is like trying to hook 2 motors together, and make them run as one. To do this the output from the first amp is basically dropped to line level to feed the second amp. So it's like throwing away one stage of amplification to get it to match the final.

So I think it's better to just trade up and get a larger amp.




theAudioWorx
Klone-Audio