[stump4545]

if you take a 200watt 2channel amp and make it a monoblock would that always double the power to 400watts.

thanks

[JohnR]

If you mean bridging it, and the load impedance is twice what the per-channel load impedance was, and provided that the amp topology allows it... I can't think of a reason why not.

[Wayner]

It depends on the output devices, but you may actually tripple the output. A phase inverter is required to do this and the amplifier design must be of common ground (left and right channel negative outputs share the same termination) or the amp will suffer a sad fate. The inverted signal also cancels internal distortions naturally, so there is also a side benefit to doing this besides the increased power (and headroom).

Wayner 

[macrojack]

I used to use a pair of BEL 1001 amplifiers in mono. The designer, Dick Brown, told me that doing so increased the output power from 50 watts stereo to 200 watts mono. That is more than double so the rule is not ironclad. There are probably other examples like this.

[srb]

I don't know if this is an ironclad rule, as it may differ among amplifier topologies, but most amplifiers when bridged see half the load impedance, so 4 ohm speakers are generally not recommended for use with a bridged amplifier, as the effective load impedance will be 2 ohms (or less).
 
Steve

[gerald porzio]

I'm w/ SRB on this. There's no free lunch. A nominal 8 ohm load or higher is recommended for bridged amps for good reason.

[rollo]

I'm w/ SRB on this. There's no free lunch. A nominal 8 ohm load or higher is recommended for bridged amps for good reason.

:

  thanks good to know.



charles

[stump4545]

i have a gamut 200mkiii which outputs 200watts into 8ohms.
i was thinking about picking up another gamut to make a pair to power my salk HT3's.

 what can i except in output from a gamut monoblock and in your opinion, is this a good road to take to get my ht3's more power?

thanks

[gerald porzio]

It should work out fine since the HT3s are 8 ohms. There's no shortage of macho pwr. amps. The shortage is usually wallet related.

[JohnR]

Those amps are spec'ed at 400W into 4 ohms, so bridged should deliver around 800 watts into 8 ohms.

They're also supposed to be able to drive down to 1.5 ohms (!) (on the review I found, can't read the data on the gamut site for some reason) so could be used bridged with a 4 ohm load.

I'm not sure the best way to generate the out of phase signals, the output of a balanced preamp might be one way, or I wonder if a TVC can be used that way... hm... still, these are rather expensive amps to be messing around with, I'd be inclined to suggest trying it with something cheaper first.

[Edit: just had a thought - if the XLR inputs on the amp means that it has true balanced inputs, you could just drive the opposite phase input on each side.]

You could ask Gamut too. Let us know what they say

[stump4545]

emailed gamut, and they didn't advise to use my gamut as a monoblock.  they said there would be no sonic benefit in doing so.

they did say something about i needed a phase inverter but not sure what that means.
i guess if they feel there is no benefit then i guess i will stick with only 1 gamut which is still pretty awesome.  just wanted to see what more power would do to my HT3's.

thanks again

[ctviggen]

You could get another one and biamp each speaker.  That is, split the output of the preamp and run two right outputs to one amp and the two outputs of the amp to the two inputs on one speaker.  The same would be done on the left side. 

[macrojack]

Why don't you seek advice from your speaker manufacturer? He can surely advise you better than we can.

[gerald porzio]

The advantages of passive bi-amping might be dubious @ best along w/ a minimal pwr. increase. The $ might be better spent elsewhere in the system or elsewhere period. YMMV.

[JerryM]

emailed gamut, and they didn't advise to use my gamut as a monoblock.  they said there would be no sonic benefit in doing so.

they did say something about i needed a phase inverter but not sure what that means.
i guess if they feel there is no benefit then i guess i will stick with only 1 gamut which is still pretty awesome.  just wanted to see what more power would do to my HT3's.

thanks again

There is plenty of sonic benefit to be had by bridging two amps. 

Read this page from the Audio by Van Alstine website. It explains the benefits pretty clearly.

BTW, this past weekend there was a newer AVA Insight Bridge on A'Gon for about $700.00.

Have fun,
Jerry

[JohnR]

Thanks Jerry - interesting info there from Frank on using an inverter with a stereo amp - had never thought of that before.

they did say something about i needed a phase inverter but not sure what that means.

To use an amp in bridge mode, one of the channels is run out of phase with the other. It's like (pardon the flawed analogy) using both arms to compress a bullworker instead of just one.