Benchmark AHB2 - To 'mono' or not to 'mono'

ssnkssnk
After being disappointed with mono-bridge SQ, I have now tried @georgehifi’s suggestion of vertical bi-amping.
I can already see, what @georgehifi was saying, and where I can go with this approach.
With this approach, the sound-stage is just mind blowing, which has +ve impact on overall enjoyment/experience. I am hearing things which I never heard on the familiar tracks and that too on the very low volumes. The overall SQ has improved. Its just more musical (to my ears).
For me (and my ears) bridge-mono is definitely out.

Glad you found that out, as I’ve said many times all you gain from bridging (mono’ing) amps is extra wattage, but every other measured parameter that makes for a good amp take a hit for the negative.
Please let us know once you’ve got vertical bi-amping setup with better cabling that you want to get, how much further the sound quality progresses.

Cheers George

Also, it will give me only 200watts per channel, and not 380watts, which I expected to get from the setup. Let me know, what you think.

As I showed someone else, your ATC SCM-19’s have quite an easy 5-6ohm impedance curve (green) and a -phase angle that’s fine also (red) and are 85db efficient, so to have 200w or 380w won’t matter, as you will not clip the amp/s either way, before bottoming out the speaker first.
http://www.avmentor.net/reviews/lab/2016/atc_scm19/display/atc_scm19_impedance.jpg
So go with the better sounding configuration, and that’s vertical bi-amping of the 2 x stereo amps, you will be very pleased. 
And leave the bridging (mono’ing) up to guys that "think" they need the extra watts even though they are oblivious to the "fact" it effects the quality.

Cheers George

Tell me you’ve done it both ways with this amp and your way is better; I will gladly spend what I have to in order to try it.

Yes with many amps I have, not with this amp. There is no valid reason to believe it won’t be the same as EE engineering principals would prove it to be the same also.

There is no "magic voodoo" circuit in the AHB2 that can turn the EE engineering principals around 180 degrees and make it better spec’d bridged than in non bridged mode.
It will always have better specs in "stereo mode" than in "bridged mode", (save for extra wattage in bridged that all.)
Believe what you want, it sad though.

Cheers George

wwoodrum OP
How do I split the output from the pre-amp/DAC?

There are heap of them on the market.
Here are some cheap ebay ones.

https://www.ebay.com.au/itm/7061-2pcs-Gold-Plated-AV-Audio-Splitter-Plug-RCA-Y-Adapter-Adaptor-1-Mal...

https://www.ebay.com.au/itm/1RCA-to-2RCA-Y-Double-Adaptor-Male-to-Female-Gold-Plated-Audio-Video-Splitter/183750354809?epid=28028167746&hash=item2ac85fe779:g:DTkAAOSwwpVcm1UA

These are higher quality Audio Quest ones
https://www.crutchfield.com/S-7sR0h0wV9Ei/p_703M22FRHD/AudioQuest-Hard-RCA-Splitter.html

https://www.google.com/search?rlz=1C1CHZL_enAU820AU820&q=high+quality+rca+splitter&tbm=isch&source=univ&sa=X&ved=2ahUKEwja2eKek6HiAhUKX30KHW5HBpcQsAR6BAgJEAE&biw=1362&bih=913#imgrc=_



Cheers George

but since the AHB2 only accepts XLR

Plenty like these around, if you look at all differing prices.

https://www.ebay.com/itm/A15-1-5m-5ft-unbalanced-RCA-to-balanced-XLR-M-Canare-L-4E6S-Audio-Cable-/322492289636

https://onecall.com/audioquest-mackenzie-2m-rca-xlr-analog-interconnects-cable-pair

I am going with the opinions of those who say they’ve done it.

Pitty, no I’ll rephrase that, sad, you’ll never know then, just how much better your system can get, by vertical bi-amping, instead of bridging (mono’ing) your amps.

Cheers George

georgehifi in order to make that work right you need a rather expensive digtal crossover to do it right.

No sorry your wrong, forget digital xovers your still using the speakers internal xovers.
Just vertical bi-amp as per the link, if you have 4 speaker terminals on each speaker (remove the links between them).
The sound will be far better than bridging the amps into mono.
http://www.av2day.com/wp-content/uploads/2014/05/biamp2.jpg

Cheers George

With two AHB2 (in mono configuration), the sound quality has changed considerably. Tracks which sounded thin earlier, were fuller with more ‘body’ and warmth.

That to be expected with half the damping factor and double the output impedance, that will always make the bass and lower mids sound richer.

Now try vertical passive Bi-Amping with the both amps back in stereo mode, and prepare to be amazed!!!
http://www.av2day.com/wp-content/uploads/2014/05/biamp2.jpg

Cheers George

(with the addition of a 3/4 ohm series resistor in the primary) which means they will drive anything.

You have successfully just made the damping factor that was already diminished because of bridging, even worse by installing even more series resistance, good work.

I was thinking that the extra power would improve almost everything about this, particularly in more dynamic recordings.

If you don’t use all the dynamic headroom power with a single stereo amp, you will gain nothing by bridging having even more. Headroom is head room, if you haven’t reached it there’s no reason to make it higher by bridging and taking a hit on everything else.

You just take that was a good stereo amp, send it down the path of becoming a mono P.A. amp because of the reduction in all the other parameters it will take a hit on by bridging.

You guys need to see the forest for the trees, if you want/need more power and want to have two of these stereo amps, just vertically bi-amp them, then you gain the power in the bass and dynamic headroom, without taking a hit on everything else if you bridge them.
http://www.av2day.com/wp-content/uploads/2014/05/biamp2.jpg

Cheers George

Clean up aisle 7

wwoodrum OP
mrdecibel
seigen

What I will also add, if one amp has enough power to easily drive said speaker, you can gain extra dynamics and more bass grunt without losing quality by what I said before. To vertically passive bi-amp two stereo amps (linked).
What happens then is all the bass power from the power supply from one amp, has it available to just that one bass driver, of the channel it's hooked up to. The other has the same. 
So you can get better sound with two amps, (just not in bridged mode.)
  http://www.av2day.com/wp-content/uploads/2014/05/biamp2.jpg

Cheers George

wwoodrum
Benchmark AHB2 - To ’mono’ or not to ’mono’

I’ve said it before in other threads here it is again

"Nice amp, if you want to hear them at their best, don’t bridge "if there’s no need to", as all you’ll gain is watts, everything else takes a hit when you bridge amps.

Pro’s=
More watts.

Con’s=
Worse damping factor
Higher output impedance (has relevance to damping factor)
Lower stability (especially into low impedance’s)
Current ability is reduced (especially into low impedance’s)
Higher distortion.

And if you have two of them better to run them in stereo mode and vertically bi-amped, instead of bridging (mono’ing).
http://www.av2day.com/wp-content/uploads/2014/05/biamp2.jpg"

Cheers George