Review and Measurements of Benchmark AHB2 Amp

[PGAMiami]

Very nice gear setup! How are those TADs when the bi-amping is used and adjusted for tone control?

The R1s are sensational. I typed R2 above in error.

I’m using a Pass XVR1 as an active LPF for the two woofers, and also as an active HPF in series with the stock internal passive crossover that drives the coax. Each TAD has one AHB2 on the woofers and one AHB2 on the coax. The passive LPF inside the R1s has been bypassed. It uses iron core inductors and does not have the more exotic capacitors that are in the passive crossover that on the coax. Andrew Jones was kind enough to set up the XVR1, which has many settings. Equally important is the work Mitch Barnett did designing a convolution filter that runs on Roon.

For movies I run this as a 4.0 system, no center, no subs (my -3db with the R1s is around 17 Hz) with a Denon 4800h driving the XVR1. For music I have a Meitner MA3. A trigger operated XLR AB switch selects the Denon or the Meitner as needed.

 

[Sal1950]

Biggest issue with the AHB2 is that there's no room on the front panel for some really
Kool VU meters. LOL

 

[Doodski]

The R1s are sensational. I typed R2 above in error.

I checked and was wondering if there where a model not listed at the web page...LoL.

Pass XVR1 as an active LPF for the two woofers, and also as an active HPF in series with the stock internal passive crossover that drives the coax.

Very cool. The balanced operation is very nice. I ran a single ended tri-amp'd active crossover system at home for some years. With Altec Lansing horns, KEF 107.2 tweeters and KEF woofers in a large transmission line cabinet. It was fun and I see that in your system too.

 

[Sal1950]

For movies I run this as a 4.0 system, no center, no subs (my -3db with the R1s is around 17 Hz) with a Denon 4800h driving the XVR1. For music I have a Meitner MA3. A trigger operated XLR AB switch selects the Denon or the Meitner as needed.

4 R1s ?
Incredible multich system !
Any future plans of expanding into a full 5/7.1 - 4 Atmos rig?

 

[PGAMiami]

4 R1s ?
Incredible multich system !
Any future plans of expanding into a full 5/7.1 - 4 Atmos rig?

Two R1s. For the rear just a couple custom made speakers using the Jeff Bagby Continuum II design. The room is only 12x18, and it images amazingly well now. Don’t see adding more speakers and it’s very hard to find a match for the R1s as a center channel. Dirac works great for movies.

 

[yanm]

As I understand, the clipping indicators on the AHB2 would be triggered if the amp starts to distort. I've never seen that happen in my room under real world situations with movies and music with TAD R2s, then again I have 4 in bridged mono biamping the R2s. Only time my amps clipped was one time when the volume was maxed out in error and deep bass techno started to play at levels no one would want to listen to. My friend with a pair of amps in bridged monos with TAD CR1s (that are less efficient than CR1s) also has never seen them clip. The TADs are not particularly difficult loads, but they are not easy either. These are easily the best amps I've had, including many 10x the price.

Indeed, if the clipping indicator light up when the difference between the amplified output and the input scaled by the gain is above a set threshold, it is an almost perfect indication that the amplifier is not having issue driving that attached load / speaker. Any idea about what is the threshols used by the AHB2? ( too lazy to check the user manual, and I don’t know if it’s mentioned there )

I’ve actually never seen the clipping indicator triggered on my AHB2 (apart during the self test at power up). On the other hand, I’ve never driven the volume very high, mostly listening between -20 to -50 dB FS. Even if my speakers are not super efficient -89dB SPL (2.83Vrms at 1m)- as per data sheet, this result in loud enough sound in my environment (condo).

Anyway, adding the test for the reactive loads would be a worthy addition to the AHB2 review.

 

[sprellemannen]

@PGAMiami post photos of your system.

 

[Sal1950]

The room is only 12x18, and it images amazingly well now.

I've got a 5.2.4 in a room the same size.
I wouldn't worry over the center channel, without it your AVR will deliver an awesome phantom center image.
Now 4 overheads for immersive mixes, that's the bee's knees.

 

[Angsty]

Has power cube plot.

AHB2 - Lab Report - Oh Hyeonil - Studio51, Sinlyul Lee Ph.D. - Sonicast

Author: Oh Hyeonil, Studio51 Test data provided by: Studio51, Sonicast, Sinlyul Lee, Ph.D. The original report can be downloaded here in PDF format: The following is a translation of the original report: Introduction The measured performance of an audio amplifier can be quantified with...

benchmarkmedia.com

 

[RichB]

AHB2 - Lab Report - Oh Hyeonil - Studio51, Sinlyul Lee Ph.D. - Sonicast

Author: Oh Hyeonil, Studio51 Test data provided by: Studio51, Sonicast, Sinlyul Lee, Ph.D. The original report can be downloaded here in PDF format: The following is a translation of the original report: Introduction The measured performance of an audio amplifier can be quantified with...

benchmarkmedia.com

Thanks for posting this, power cube and all.

https://cdn2.shopify.com/s/files/1/0321/7609/files/PowerCube_Plot_Stereo.png?v=1562960159

- Rich

 

[Jimbob54]

@PGAMiami post photos of your system.

Perv ;-)

 

[pogo]

Has power cube plot.

The Bridge Mode would also be interesting.

 

[PGAMiami]

@PGAMiami post photos of your system.

 

[Rottmannash]

Very clean layout. Bet it sounds killer as well! Those are interesting looking panels in the ceiling. What are they made of/where did you get them?

 

[PGAMiami]

Very clean layout. Bet it sounds killer as well! Those are interesting looking panels in the ceiling. What are they made of/where did you get them?

RPG Abfusors on ceiling and side wall.

 

[RichB]

The Bridge Mode would also be interesting.

The AHB2 might well be the most measured and excellent measuring amplifier on the market. But, one more is required…

- Rich

 

[PGAMiami]

The AHB2 might well be the most measured and excellent measuring amplifier on the market. But, one more is required…

- Rich

Some amps run out of voltage first, some current, depending on the load. The AHB2 is very capable both in terms of voltage swing and current. And they are very stable into reactive loads. I’ve not been able to reach its limits nor do I expect most anyone will in residential or studio use.

 

[PGAMiami]

I checked and was wondering if there where a model not listed at the web page...LoL.

Very cool. The balanced operation is very nice. I ran a single ended tri-amp'd active crossover system at home for some years. With Altec Lansing horns, KEF 107.2 tweeters and KEF woofers in a large transmission line cabinet. It was fun and I see that in your system too.

These are great pieces and customer service at Pass is exceptional. I found a mint second hand unit that was acting up a bit, so I had Pass check it to make sure everything was OK. No charge. Came back perfect. Try this with Spectral … Too bad there is no real consumer demand for active analog crossovers. I haven’t found anything like the XVR1 in current production.

 

[PGAMiami]

The speakers are very close to the front wall and in the corners. You can see with the room gain the deep bass needs to be attenuated 10-15 db. For music this is accomplished with a Mitch Barnett convolution filter (lighter colored on the graph) running on Roon; for home theater I use Dirac on a Denon 4800h. The attenuation then becomes extra headroom for the woofers and the -3db point is below 20hz. No subs needed.

The wall treatments in the corner consist of RPG Modex bass traps covered in 1” fiberglass, so from mid bass up there is quite a lot of absorption.

In theory the TV should be a BIG problem, but in reality it’s not. I have custom RPG abfusors that I can place in front to the TV for critical listening. In practice, they don’t make much difference and they are in my attic gathering dust.

 

[sprellemannen]

@PGAMiami Amazing speakers (I have listened to TAD R1 for several hours), which in my opinion also is the most beautiful looking speakers in the market, and of course superb AHB2 amplifiers (which also look amazing and have a very practical small size)