Running Benchmark AHB2 in bridged mode and 4 Ohm Speaker

If we put aside the term "damping" , because thats not what really matters, we need to inform people that an amplifier with high output impedance may cause a marked change in the frequency reponse of their speaker. Thats what really matters.

Yes add that to the other cons, the amp starts to behave like a tone control.
(ie: not flat from 20hz to 20khz)

Cheers George

They are very similar yes? what do you think will happen if another measurement was done at 4ohm in the bridged mode????? It will be far worse than the non bridged into 4ohms or 8ohms, that’s why they didn’t give the graph even though they probably did measure it.

George, this is speculative at best.
The AHB2 has very comprehensive protection. I suspect the bridged AHB2 will maintain its ultra low distortion into low impedances until protection kicks in.

If you recall I said this in my initial response above:

George I agree with you that with efficient low impedance speakers the OP may likely be better off with a single AHB2.

What I took exception to was your incorrect blanket assumption that bridging the AHB2 would result in higher distortion. This is NOT true for the specified 6 and 8 ohm loads.

Despite what is specified, Benchmark demos at shows with 4ohm nominal speakers (see link above). Do you think they would do this if the sound quality was compromised?

I am just amazed at how well Benchmark marketing has pulled off selling 2x amplifiers.

Why are you amazed Roger?
Some of us own low efficiency 8 ohm nominal speakers - for which the bridged mono AHB2’s are perfect.
Honestly, Benchmark appears to be one of the least marketing oriented companies around. They don’t push BS, they comprehensively measure everything they make and are very much about accuracy and low coloration - not boutique sound tailoring.

If we put aside the term "damping" , because thats not what really matters, we need to inform people that an amplifier with high output impedance may cause a marked change in the frequency reponse of their speaker. Thats what really matters.

Yes add that to the other cons, the amp starts to behave like a tone control.
(ie: not flat from 20hz to 20khz)

Oh my gosh, another straw man argument.
This may be an issue with some amplifiers. The AHB2 has sufficiently low output impedance that this is not a problem.

No matter what sort of spin you want to put on it  tobes the fact is that this thread is about the OP and his speakers, and bridged AHB2's are not the way to go into his speakers 4ohm load.

"Bridging good for more watts, but everything else takes a hit." 

Cheers George 

@tobes 

Why are you amazed Roger?
Some of us own low efficiency 8 ohm nominal speakers - for which the bridged mono AHB2’s are perfect.
Honestly, Benchmark appears to be one of the least marketing oriented companies around. They don’t push BS, they comprehensively measure everything they make and are very much about accuracy and low coloration - not boutique sound tailoring.

I do fine with 35 watts so I am curious what is your listening level and speaker efficiency? Have you measured the peak voltage at your speaker? If not we can estimate it fairly accurately with just your efficiency and SPL at 1 meter. Can you do this for us please?

Since you brought up "extensive protection" what happens when this amplifier drives a 10 uF capacitor, typical of many ESLs.

What is straw man about informing people that damping not damping but actually a variation in frequency response due to impedance variation that occurrs with high output impedance?

I read JA's report. The Benchmark is about as perfect an amplifier as one can imagine. Yet we still dont know its current capability and some other things. This is an issue to a varying degree with many amplifiers, yours excepted, of course.

I find the "strawman" accusation most inapproptiate to this thread. We are trying to figure out something here. Does anyone have a schematic for me to peruse?