[Dloines]

So after much back and forth and finding and reading as many write-ups and articles I could find, I gave in and bought a 4b3.  My system is mostly Bryston products, BHA1, BDA-2, BP25, and 4b3 (replacing my 4bsst2), Magnepan 3.7i, and a Marantz CD player.  Very happy with the sound quality prior to the 4b3,  the 4bsst2 really drives the 3.7i's   The 4b3 arrived 1 day earlier this Monday than FEDEX tracking noted, lucky someone was home to sign for it.

Setup was straight forward using XLR and spade connects, weight is about the same (heavy sucker ), black 17 inch from a distance looks the same as the sst2.  Green LED is standard (though you can change to blue) and will probably leave it that way, when all the units are on I have about 9 little green LEDS glowing, sort of cool looking at night with lights off

I'm no equipment expert so I try to read as much as I can on topics as in break-in of components.  But to be honest other than some headphones i never really noticed a measurable difference in sound other than my ears getting use to the sound.  So i started listening right away for about 4 hours the first day and plan to run it everyday for about 4-5 hours for the first week, and then come back in a day or so and listen some more.

Here are my observations so far:

1.   Not a night and day difference more of the same qualities from the sst to sst2
2.   More forward images 3d affect instruments come towards you especially brass instruments
3.   More string reverb on acoustic bass
4.   More Bass (more than expected)
5.   Vocal voices especially female are really life like breathing inhaling
6.   Cymbals and bells shimmer a bit more
7.   This one is hard to explain and I guess it has to do with a lower noise floor, but pauses in the music seem like they are a 1 or 2 seconds longer with dead silence like the system is off and then sound reappears, i often read will listening to music and when that happens makes you stop and look up.

Even thought I'm driving 4 ohm Magnepan planars the Amp never got much warmer than room temperature, but the sst2 is the same, with volume at around the 9:00 position about the same as the sst2, both drive the 3.7is with ease.   That's all i can comment on for now, will reevaluate in another week if the sound changes....

[PierreB]

You have a very nice system and I am sure it will give you years of joy. 
Do you use your 4B at 23 or 29db ??
How about putting a photo of you system.

[Dloines]

You have a very nice system and I am sure it will give you years of joy. 
Do you use your 4B at 23 or 29db ??
How about putting a photo of you system.

I started with 29db but I found it to have bit too much gain so I switched it today to 23db and that works perfect, just tried to load a picture....

[bummrush]

You could ask James. But dont you want to use more of your volume control?

[Dloines]

You could ask James. But dont you want to use more of your volume control?

good question not really sure, but what i was expirencing at 29db was that one press of the remote button was like the volume knob moving 3 ticks higher, and at 23db it seemed to move 1 tick at a time.  Volume knob is slightly below or above the 9:00 position on average.

[Dloines]

You could ask James. But dont you want to use more of your volume control?

re-reading the owners manual it states:

The 23dB setting is used when the source
output is actively balanced. This is the typical
setting for balanced operation. Or use this
setting whenever less gain is required. The 23dB
setting equates to an output of 100w @ 8 ohms
for 2V input (noise -113 dB).

I interpret this to mean if you are using balanced XLR which I am using and seems to work best for my system....

[XMAN]

I recently converted to balanced and found that the higher output made my volume control a little to sensitive i can't turn it much past 9 o clock.  The rule of thumb with electronic design is to design for mid scale so i for one am very happy i can experiment with the amplifier gain when my new 4B cubed arrives. Keeping a source signal as large as possible should in theory sound better.   

[PierreB]

I also use the 23db on my 2B SST even if I use non-balance(RCA) cables all around (phono, preamp/amp, cd).
I prefer to have more "play" on my volume control of my BP-25.

[jtinto]

Same here. I like to have a bit more play in my volume control as well.
I have my 7BSST2s set at 23db with BP26 and BDA3 all using single ended rca connections.

[Dloines]

So after much back and forth and finding and reading as many write-ups and articles I could find, I gave in and bought a 4b3.  My system is mostly Bryston products, BHA1, BDA-2, BP25, and 4b3 (replacing my 4bsst2), Magnepan 3.7i, and a Marantz CD player.  Very happy with the sound quality prior to the 4b3,  the 4bsst2 really drives the 3.7i's   The 4b3 arrived 1 day earlier this Monday than FEDEX tracking noted, lucky someone was home to sign for it.

Setup was straight forward using XLR and spade connects, weight is about the same (heavy sucker ), black 17 inch from a distance looks the same as the sst2.  Green LED is standard (though you can change to blue) and will probably leave it that way, when all the units are on I have about 9 little green LEDS glowing, sort of cool looking at night with lights off

I'm no equipment expert so I try to read as much as I can on topics as in break-in of components.  But to be honest other than some headphones i never really noticed a measurable difference in sound other than my ears getting use to the sound.  So i started listening right away for about 4 hours the first day and plan to run it everyday for about 4-5 hours for the first week, and then come back in a day or so and listen some more.

Here are my observations so far:

1.   Not a night and day difference more of the same qualities from the sst to sst2
2.   More forward images 3d affect instruments come towards you especially brass instruments
3.   More string reverb on acoustic bass
4.   More Bass (more than expected)
5.   Vocal voices especially female are really life like breathing inhaling
6.   Cymbals and bells shimmer a bit more
7.   This one is hard to explain and I guess it has to do with a lower noise floor, but pauses in the music seem like they are a 1 or 2 seconds longer with dead silence like the system is off and then sound reappears, i often read will listening to music and when that happens makes you stop and look up.

Even thought I'm driving 4 ohm Magnepan planars the Amp never got much warmer than room temperature, but the sst2 is the same, with volume at around the 9:00 position about the same as the sst2, both drive the 3.7is with ease.   That's all i can comment on for now, will reevaluate in another week if the sound changes....

So after 2 weeks with my new 4B3 I can honestly say that it is really a wonderful amplifier!!   "the demo is everything" I agree 100% and I was lucky enough to have both the 4b3 and the 4bsst2 together at home connected to my system to help me decide.  My summation is  "you don't know what you are missing until you hear it"  or "you don't know what you are missing if you've never heard it"    The sst2 is still a great amplifier and IMHO the 4b3 expands on all the things it does great and then adds a wider sound stage, black background of quietness, more separation of instruments, and more of a 3d effect of the music to give you that, your there feeling.  Sad to have to sell the sst2, but didn't need both.   Time to enjoy some Christmas music with the 4b3!!:xmas:

 

[Grit]

Merry Christmas!

And thanks a ton for posting your impressions. It's really helpful for those of us with SST2 amps who are considering a B3 upgrade.

[AG]

I enjoyed my time with the 4BSST2 but I wanted just a bit less sterility and  a touch more warmth. I wish Bryston made a class A or a class AB amp which stays in class A longer before switching to class B
I think that amp would be a huge success for Bryston

[James Tanner]

I enjoyed my time with the 4BSST2 but I wanted just a bit less sterility and  a touch more warmth. I wish Bryston made a class A or a class AB amp which stays in class A longer before switching to class B
I think that amp would be a huge success for Bryston

Hi

The Class AB2 designs we use actually have the same spectral balance of Class A but with less distortion.  So in our opinion you have the best of both worlds - Class A sound without the heat dissipation issues of pure Class A designs.

james

 

[James Tanner]

Bryston’s Proprietary output stage


What does ‘Quad Complementary’ mean?

When the transistor was first invented, it functioned only in one polarity.  That meant that there was asymmetry in amplification circuits, resulting in distortion of the signal.  Later, the other polarity of transistor was developed, making it possible to have a symmetrical, ‘complementary’ circuit, thus reducing distortion.

Unfortunately, these opposite polarity transistors are not exact matches to each other.  They have differences in bandwidth, differences in threshold Voltage, and differences in the way their respective gains track both Voltage and current changes.  Thus, there continued to be small variations in symmetry, revealing subtle but audible amounts of distortion, even in supposedly ‘complementary-symmetry’ amplifiers.  These distortions were worse with increasing frequency, giving a characteristic haze or graininess to transistor amplifier sound.
 
In most of the amplifier circuitry, the above asymmetries can be compensated for with proper design, but the output stage of a power amplifier is in direct contact with the speaker load, and thus experiences large variations in both Voltage and current with the signal. It is thus subject to ‘worst-case’ conditions for the asymmetrical distortions left in these opposite-polarity transistors.  It was for this reason that Bryston developed the Quad-Complementary output stage. This nomenclature stems partly from the fact that it requires at least four transistors to assemble the final section of the output stage, one of each polarity on both sides of the push-pull output section.

In this way, it became possible to eliminate almost all of the remaining asymmetry in the output stage of an amplifier, because each transistor is paired with another of its opposite number. This creates what amounts to a compound device, displaying the mixed characteristics of both.  Thus, the upper and lower halves of the output stage match each other’s dynamic characteristics exactly, at both high and low levels. Signal distortion is virtually eliminated.

This circuit also displays advantages in some other areas, like faster response and lower input drive current for the same output power. Those characteristics give the amplifier lower distortion in all areas, but especially in the important high frequencies.  Thus, a Bryston amplifier does not display the characteristic high frequency haze or grain often heard in other transistor amps.

james
 

[CanadianMaestro]

The last paragraph is especially true for the squared amps like 4B and 14B, as well. No HF edginess.

[alexone]

James,

correct me if i'm wrong, but i believe that the 2B (SST, SST2) and therefore the B100 weren't QC-designs

leads to the question if the new 2.5B3 amp is QC ?!?

al.

[assafl]

Bryston’s Proprietary output stage
 It was for this reason that Bryston developed the Quad-Complementary output stage. This nomenclature stems partly from the fact that it requires at least four transistors to assemble the final section of the output stage, one of each polarity on both sides of the push-pull output section.

When I first read about Bryston back when Peter Aczel was still writing I downloaded the circuit diagram for the Bryston SST amp. Studying the relatively straightforward (blameless) topology - it was the output stage that caught my eye and convinced me to buy the amplifier. It is more than 10 years old now (and with new capacitors - thanks to warranty)....

Up until that time I did not even think about buying amplifiers but (like Loudspeakers) were easier to design and build at home.