Bryston 7B3 vs 4B3: Extra Cost Worthwhile?

@jfrmusic My friend who has an incredible ear, heard my DAC3B and he had issues with the upper mid lower treble forward using the AHB2. We liked the warmer Schitt Yggdrasil+ LIM DAC with this setup. However, when the AHB2 was switched to the warmer Class A CODA #16 we liked the BM DAC3B more. This was with the Yamaha NS5000 speaker which is a bit like the Harbeth 40.1. The AHB2 + Yggdrasil+ LIM was still not perfect with the NS5000. I think it is the drivers of the NS5000 are not the best match for the AHB2.

Here is a little blurb about the ears involved in my home demo.

SR1a (6moons.com)

Interestingly, we both have the BM DAC3 and use it successfully for some purposes.

Here is the content of 2 emails I have from Rory Rail at Benchmark.

Yes, it will work well in your application. The feed-forward error correction keeps the amplifier distortion-free when driving low impedances. (asking about the low impedance Theil CS3.7 speaker)

The amp will sound identical in either mode. In fact, distortion measures the same in either mode. The only difference is that the mono mode plays about 6dB louder.

Best regards,

Rory Rall

Sales Mgr.

Benchmark Media Systems, Inc.

With the AHB2 monos you do suffer some low impedance continuous power. Say running at that impedance for 30 mins. However, your speakers do not dip down there. The distortion is not increased like in other amps doing the same thing. My old Thiel CS3.7 worked OK with the monos, but worked better with a very powerful amp like the CODA #16, Parasound A21+, CODA #8. These are better at low impedance needs. A stereo AHB2 is better than the monos with low impedence but the power tops out around 190 watts at 2 Ohms. My CODA #16 is 600 watts at 2 Ohm in comparison.

@jfrmusic Pass amps operate at about 104-105 degrees Fahrenheit. I own X260.8 monoblocks (previously owned X250.5, XA30.8).
Love these amps with my Wilson Sabrina. However, Pass amps have a warm and natural sound signature. I would not recommend making an assumption Pass and your Harbeth will be a synergistic combination - Harbeths are very warm sounding speakers. If you can go back to Overture and have them set up the same model speakers with Pass for you, it would be best to spend some time listening. 
If you like the sound, the X250.8 will most likely be all you need but it’s up to you if you want to go up to X350.8. I’m pretty sure that amp will never exit out of Class A with your speakers. Have a listen though.
 

@audphile1 

Overture have my speakers and DAC and streamer. So any audition will be valid. Plus I plan on bringing my ABH2 with me to include in the comparison. If zI went for the Pass it would be the X-250.8. Good to know I wouldn’t have to be concerned with the heat. 
 

@yyzsantabarbara 

So Hall is saying the ABH2 will not have any SQ disadvantages running in Bridged mode and with my 6 ohm Harbeths also no issue. 

@jfrmusic On Harbeths it will be excellent. Rory was saying that but with my harder to drive Thiel. On my old Thiels it was not as good as it could be to my ears. Saying that, the brother of the speaker designer (who posts here) uses the AHB2 monos with Thiel.

Glad I saw your post the day after I put my Bryston 4B3 into my system as I would have otherwise started stressing about your issue. Just a note, had planned to biwire my Tannoy Cheviots with Analysis Plus Black Mesh Oval 9 gauge cable as I have a long run to one speaker, and found the Bryston posts only will accommodate one spade, so am going to have to wait to have each pair of cables reterminated into one on the amp end.

The Bryston sounded immediately better than my Parasound A23+ as soon as I turned it on and expect it will sound even better in 100 hours or so, sonInsuspect you will be happy either way you go. So far the bass sounds much tighter, and I am hearing more detail and greater instrument separation, including instruments I never noticed even in some old favorites that have become standards For auditioning new gear. Also, having played jazz and seen a lot of jazz live, I was happy to hear an improved gritty realness in saxophones mixed low as backing instruments that I thought my pre-upgraded system already handled pretty well.

If you somaettle on a Bryston, I hope you post on your thoughts on preamps as a new one is next on my list (have the Parasound Halo P6)