Bryston 7B3 vs 4B3: Extra Cost Worthwhile?

yah only live once.   Well maybe not but the next life you might have an exoskeleton. 

https://www.audiocircle.com/index.php?topic=149863.0

I had the 4B-SST and the 7B-SST. I played my Revel Salon1 real loud, and the 7B-SST was better in that regard. Those speakers also ate up the additional power. 

Do you have a demanding speaker? 

I’d call Bryston and see what they have to say.

I have owned Bryston and live a couple of hours away from the facility. Lots of representation up here in Canada. 

The sound quality is quite neutral. Don't expect a different sound between the two. Bryston quickly gets harsh and compressed when driven hard or with difficult loads as an FYI. Internally they are lacking on the stiffening caps and transformer for what ratings they have. 

Never had an issue with reliability nor have even a single one of my friends. Just hasn't happened. I also have Luxman M02's and some NAD amps. Last year I bought a Pass Labs X350.5 and it puts every other amp I owned to shame. I completely different level of effortlessness and grip. If you are considering moving up the Bryston line I strongly suggest a used X350.5 or .8 at a fraction the cost.

My speaker is not demanding. 6 Ohm Harbeth C7es-XD. But not concerned with playing loud. Looking for control and dynamics as I listen to mostly Classical. 

For a Harbeth a 4B3 is more than enough. I think the neutral Bryston is a good choice for the Harbeth. I would have gone with the Benchmark AHB2 in mono myself.  I like the top end on the AHB2 more. The bottom end on the 4B3 is better.

@yyzsantabarbara 

That is another option as the AHB2 is my current amp. Some have said not to use a stereo amp in bridge mode as distortion increases. My impeadance is 6 so half of that probably not an issue for the Benchmark. 
 

what SQ advantages did you experience with AHB2 bridged?

@jfmusic I know the AHB2 really well. I owned that amp so many times. In both stereo and mono form. Your warm Harbeth will go nicely with the ultra-clean sound of the AHB2. Now that sound is not for everyone, but I like it. Some people find it sterile. 

The AHB2 monos are rated at 6 Ohm, not at 2 Ohm like the stereo AHB2. The mono AHB2 becomes quieter and louder than the stereo AHB2. Otherwise, the sound is the same. The power delivery is what is different. Sometimes the stereo is better than the monos and vica versa. It depends on your speaker. For the Harbeth, monos would be better. The AHB2 does suffer some of the same things as other stereo amps going into mono, but it is a bit more capable in this regard. You may want to ask Rory Rail at Benchmark for their reasons why they like monos (of course they sell more too).

I have a speaker somewhat like your Harbeth, the Yamaha NS5000. It is also a 6 Ohm speaker. The single AHB2 drives it well, though monos will provide greater range in the volume. I did not like mono in my old 2 Ohm Thiel CS3.7, preferred the stereo AHB2. That did not have much power in stereo, so I gave up on the AHB2 for that setup.

I came back to the AHB2 with the NS5000. I did a shootout with the AHB2 stereo | Sanders Magtech | CODA #16. I preferred the Sanders and #16 over the AHB2, mainly because of the greater power.

The AHB2 was also a tiny bit harder on top with the Zylon drivers of the NS5000. Even though I think the NS5000 is slightly warm I think a warmer amp than the AHB2 is needed with the NS5000 for my ears, but not too warm.

If you are interested, I have a 1-year-old silver AHB2 sitting idle that I can sell. I only expect to use it again in about 2 years when RAAL 1995 comes out with the replacement for the SR1a earphone.

BTW - I use Audience FrontRow cables with the AHB2 and all speakers, but the Benchmark speaker cables with SpeakON termination worked well with a bright headphone I owned.

Thanks 
 

My speaker is not demanding. 6 Ohm Harbeth C7es-XD. But not concerned with playing loud. Looking for control and dynamics as I listen to mostly Classical.

The 4B3 is dual mono with two transformers and puts out 300Wpc into 8 Ohms and almost 500Wpc into 4 Ohms that will be more than ample for both control and dynamics with your speakers.  The only reason I’d see for going with the 7B3 monos is to be able to place an amp close to each speaker enabling the use of shorter speaker cables. Is that worth double the price? I think not.

As you get up in years, system simplicity becomes a bonus!

@jfrmusic As another data point, I have one AHB2 for my Focal speakers. I like the AHB2 at this stage in my path, but it is not be for everyone. I have been considering a second AHB2 and enjoy trying different arrangements and listening for differences. I tried the AHB2 in bridged mode and vertically passively bi-amped, as well and the usual stereo configuration with the jumper, all using just one amp into one speaker. The sessions were relatively short and I don’t have golden ears, nor extensive experience. All were with a 10’ speaker cable.

I feel somewhat confident that I found the bridged mode to sound worse. This is not what I was expecting. There was less detail across the board and the bass was less controlled as compared to traditionally stereo but with one channel powering the entire speaker with the jumper. I am assuming this is due to the damping factor with the same speaker cable length. A much shorter speaker cable would improve the damping factor.

I believe the vertically biamped sounded better than the traditional connection (one channel of the amp power the entire speaker with the jumper across the speaker posts). The bass had the same impact, maybe a bit better however across the board there was more detail and clarity. I focus on detail, and don’t try to make it louder. I prefer about 75 to 85 db. I would need to listen alot more over various days and bring in friends/family to say with certainty, but these are my impressions so far, for my ears, on those days, in my room.

@piebaldpython 

How warm does the Pass 350.8 get?  Don’t want something hot to the touch or warming the room..

How warm does the Pass 350.8 get?  Don’t want something hot to the touch or warming the room..

The 350.8 is absurd for your speakers, and the 150.8 would be more than adequate.  Moreover, Pass has a different sound signature from Bryston — they are not substitutes.  Figure out what sound characteristics you want first, find a brand that exhibits those qualities, and then pick the model with adequate juice to adequately power your speakers.

Sorry to disagree. There is no amp that is absurd for my speakers or any speaker of high quality. There is no such thing as too much power. I believe the Pass 150, 250 and 350 are  excellent amps. I will audition them. But was interested in how warm/ hot they might become over a long listening session. Power is not just for driving loud volumes. It dynamically controls the speaker and provides reserves for dynamic peaks especially with large scale Classical  Music which I Listen to. 

@jfrmusic When the X350.5 turns on it draws 600W. After that it depends on what I do with it. If it just sits there it will be warm to the touch on the fins but that’s about it. I don’t have a problem grabbing them with pressure and it’s not hot at all.

Here is when it does get hot. When I drive difficult loads. Below I copied and pasted the impedance details of the speakers I am using now. I do hop on the volume control I can assure you and when I do the X350.5 does get hot however when I drive my PSB Stratus Gold i’s with authority the amp does not get nearly as hot. Here are my speaker impedance specs.....

As can be seen in fig.1, the impedance remains at or below 3 ohms for two-thirds of the audioband, relieved only by the reflex peaks in the low bass and a region between 4 and 6 ohms in the upper midrange/low treble.

Compounding the drive difficulty of this low impedance is an electrical phase angle that varies considerably. So not only is the minimum impedance a current-hungry 1.8 ohms at 58Hz, this is combined with a phase angle of –25 degrees. And a little lower in frequency, even though the impedance has risen to a more manageable 3.8 ohms at 43Hz, the phase angle is now –61 degrees

The Pass Labs X350.5 is on a completely different level from Bryston in every respect. Both the X350.5 and the 4B3 are about the same power stated but completely different leagues when it comes to smoothness, effortlessness, bass grip, dynamics and what the recording really is. If large scale classical is on your list like mine the extra power is a GOD sent. As I turn it up the effortlessness does not change unless the music I am listening to gets so aggressive (lots of information such as bass pedals, drum roll and bass guitar hit with an open E) and volume so high that short passage will compress up a bit. With the Bryston as soon as I ask for more than maybe 10W continuous it just starts compressing the sound and the number one reason my friends all use Bryston on secondary systems. Thing is though even my friends that use them for DJ’ing and such have never had an issue with them which is a true testimony to the amazing reliability of Bryston power amps.

Pop the top of both the X350.5 and the 4B3 and see what an amazing difference there is between the two.

@piebaldpython 

Thanks for the info. Unfortunately your specs didn’t show. From what you stated I might expect my easy to  drive 6 ohm Harbeths ( lowest impedes 5.2) to not cause significant temperature issues with the Pass. 

@jfrmusic

Please take a look on the net for Krell Resolution 1’s and Stereophile review for the details. Difficult load yes.

I am suggesting you purchase an amp that will suffice for upgrades to come. The Benchmark is an excellent amp if you go that way. If you ever upgrade to speakers that will need a powerhouse amp then you have it with an entry level high end amp like an X350. If I were to redo my decision and stay away from difficult loads I would select a 50W/ch amp such as an old Krell KSA 80B and prepared for the high maintenance costs or something newer such as the Coda 5.5 which seems to have great reviews for price. To tell you the truth if these positive reviews continue for the 5.5 and they come back as no difference in sound bridged or not then I would definitely sell the X350.5 and get a pair of 5.5’s.

With your speakers no there will not be a super heating of the room. I looked, your speakers are a rather easy load to drive and even large scale orchestral won't cause any issues taxing the amp to create real heat. 

I hope people do not laugh hysterically before they try however if someone wants to try to see how to heat up an amplifier play The Key the Secret from Urban Cookie Collective 5 times one after the other and hop on it. Not to the point of clipping on transit but right there LOL. People can decide if they have the "powerhouse of the century" amplifier or not. This song is filled with information all over the frequency range, recorded in a bit of unusual fashion and a constant bombardment of power sucking requirements. If anyone can detect power consumption during playing please report back on that when the women only is singing.

Yes those Coda 5.5s look very interesting. I thought the same about bridging two. 

@jfrmusic I spoke with Doug at CODA earlier this week on bridging 2 S5.5's for my Yamaha NS5000. He said like most stereo amps bridging is not the optimal way to use the S5.5. He suggested another CODA amp for my speaker. That is a heavy one so not useful for you.

The Benchmark AHB2 is a bit better in regard to bridging a stereo amp. The AHB2 is unfortunately not a the very best match for my NS5000.

@yyzsantabarbara 

Once I get my new streamer and DAC I will give my AHB2 a new audition. Maybe the upper mid lower treble forward  issue I didn’t like was a product of the DAC3. Still waiting for the DAC to arrive at the dealer. Probably this Wednesday. If it sounds better then I might consider getting a second and going bridge mode. But I keep hearing negatives about bridging stereo amps. Right now I haven’t felt completely good about my choices. Although I will be able to audition the 4B3 and the pass x250 at my dealer. And he can deliver to my house. 

@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)

Recent info from Benchmark Support   

No worries with the AHB2. In mono, it will drive down to 1Ohm. Into 6Ohms, the bridged AHB2 will output 480 watts.The input impedance whether stereo or mono is 50kOhms The amp will draw up to 8 amps. 
Also the specs state that distortion at all levels will be identical to Stereo mode and SNR will be 3db better in mono mode and that it will sound the same in either mode with the difference being available power in mono.   

I would be interested to know Benchmarks thoughts on damping factor. Assuming the same 10’ cables are used, I believe the damping factor is halved, down to 85 bridged in to an 8 ohm speaker.

From Benchmark web site:

Nevertheless, it is possible that this 0.2 dB variation could be detected in a A/B or A/B/X test between two amplifiers having different damping factors (one with a damping factor of 100 and one with a much higher damping factor). If we match the amplitudes at 3 kHz, one amplifier could be almost 0.2 dB louder at 119 Hz using our example speakers.

The general rule of thumb for A/B and A/B/X tests is that levels should be matched to better than 0.1 dB. If this is not done, the level changes can be detected by many listeners.

This seems to conflict with their statements to you and does not address any issues with less bass driver control. The solution is to use a much shorter speaker cable to increase the damping factor, however, that involves additional cable cost albeit nominal if you use the BM cables.

My current speaker cables are 6’. 
 

I haven’t decided what I’m going to do. Benchmark insists that unless I’m clipping the amp there is no reason to get a second and that I will not hear any difference other than the ability to play louder. 
 

Still considering 

Bryston, CODA, Pass, Ayre, and Accuphase. 
I find amplifiers the most difficult component to select.