IntroductionBryston's new "cubed series" amplifiers are claimed to provide lower distortion with commensurate greater transparency than the preceding SST Squared series amplifiers. I didn't have a 4BSST2 to compare the 4B3 to. I can state that the previous power amplifier in my office system, an Adcom GFA-565SE ($1499), metaphorically went down in smoke and flame when it went up against the 4B3 ($5695).
If your attention span and/or time is short, skip the preliminaries and scroll down to "The Sound" section.
Figure 1. I initially didn't like the front panel "belt buckle" styling of the 4B3. That didn't deter me from buying it
because I didn't think it rose to the level of "ugly", plus, it would be out of sight anyway. The color of the LEDs can
be changed from green to blue by setting a jumper inside the amplifier.In person, the 4B3 has a somewhat "aggressive" appearance...and I like it.
Figure 2. The previous series 4BSST2 featured a simple and elegant face plate. [Photo from Audio Advisor website.]Figure 3. There are few pictures to be found of the 4B3. Bryston only has one 4B3 photo on their web site.
[Photo from Audio Advisor website]Figure 4. Thank you Bryston...for the user selectable front panel LED colors! All you have to do is move a jumper to
the top two prongs to switch from green to blue.Taking the jumper off was easy. Getting it back on was a little bit tricky due to the ribbon cable in the way and the raised metal panel to the right of the jumper switch. The best method I came up with was to roll a small piece of painter's tape sticky side out, put that on the tip of my left hand index finger, put the jumper on the tape, then use the index finger of my right hand to slide the jumper in place once it was properly positioned by my left hand.
Figure 5. Handsome, jewel-like, binding posts...with plastic enclosures for enhanced safety against accidental shorting.I spent a few seconds trying to attach my speaker cable spades to the underside of the posts...before realizing the bottom was closed off and cables could only be attached from the top...just as shown on page 6 of the manual. I must admit that it was easier attaching the cables from the top in that cramped space under my desk.
PreliminariesPrior to the 4B3's installation, I treated the transformers of the BDA-3 DAC, BDP-2 digital player, and GFP-750 preamp with Dynamat Xtream vibration damping material. The results of the BDA-3 and BDP-2 transformer treatments were discussed in this thread:
http://www.audiocircle.com/index.php?topic=142396.0The same sonic improvements heard after the BDP-2 and BDA-3 transformer damping were heard with the GFP-750. However, whereas the transformer bolts of the BDP-2 and BDA-3 were left loose and the transformer was allowed to "float" on a Dynamat pad, the GFP-750 sounded best with the bolt tightened just snug enough to prevent movement.
Figure 6. The GFP-750's transformer gets tamed down.Figure 7. The famous made-in-the-USA "blue board" version of the GFP-750.Figure 8. Yes, the 4B3 really is dual mono with a transformer for each channel. I will probably drape these in
Dynamat...once I gather up enough courage to go through the tedious remove/reinstall process.Tale Of The TapeFigure 9. Adcom GFA-565SE and Bryston 4B3 front panel comparison.Figure 10. Adcom GFA-565SE and Bryston 4B3 side view.Figure 11. Adcom GFA-565SE and Bryston 4B3 rear panel comparison. I was relieved that the 4B3's IEC jack was
oriented with the ground pin up-just like the 565SE. That meant I didn't have to fight and subdue that stiff power
cable into an opposite orientation.The 4B3 is 12 pounds heavier at 63 pounds, with a second transformer, an aluminum chassis, and premium hardware components. I was really impressed with the 4B3's finish and construction quality.
The 4B3 provides user selectable gain of 23 dB or 29 dB. The 565SE had a gain of 27. I selected 29 dB for the 4B3 and I am running balanced XLR cables. The 4B3 provides a lot more power into 4 ohms, 500 watts per channel compared to the 565SE's 350 watts per channel. The 8 ohm figure is 250 wpc for the 565SE and 300 wpc for the 4B3.
InstallationFigure 12. After a thorough listening session with the GFA-565SE, with detailed listening notes and aerial and lateral
mapping of the size and location of sound images, the 4B3 was readied for installation.Figure 13. What's going on here? The 4B3 is being slid into place on top of the PS Audio P10 AC regenerator.The easiest thing to do from a physical perspective would have been to slide out the P10 AC regenerator on its MDF platform, place the 4B3 on top of it, and slide them back in place under my desk. But that wouldn't have been the easiest thing to do from a sonic perspective. I would have had go through a tedious removal/reinstall procedure of aligning, twisting and bending of those garden hose size power cables. Then I would have had to wait 24 or more hours for them to "settle" down because they always sound "off" after they have been moved substantially.
Figure 14. Careful now...we don't want to "disturb" those power cables.Figure 15. The 4B3 is ready for business!Figure 16. The corners of the 4B3 and P10 are protected from knees and shoes by 1/4" thick foam pads.Every component in this computer audio system is plugged into the P10 AC regenerator. The total idling load is 16% of capacity. The power and current draws are 155 watts and 1.76 amps respectively. Incoming THD of the power from the wall is 2.1%. Outgoing THD of the power from the P10 is 0.2%.
The SoundThe comparison between the 4B3 and the 565SE was reminiscent of one of Mike Tyson's 12 second knockout bouts. The 565SE was outclassed, outgunned, and outperformed in every aspect of stereophonic performance. I still think the 565SE is a great amp for the money, but it was being compared to an amp nearly 4X its price.
Music from the 4B3 sounded heavier, slower, and louder during the first hour. After the 4b3 had warmed up, the initial "slowness" in the pace, rhythm, and timing of music had disappeared. The improvement in bass speed, bass articulation, bass detail, and tactile sensation made it sound like a subwoofer had been added to the system. It wasn't that the bass was calling attention to itself in a tonally unbalanced way. It was calling attention to itself from the perspective of hearing sound details and feeling tactile sensations not previously heard and felt from this system. All this was with bookshelf speakers with a 3db bass response of 42 Hz.
For the first time, on this system, I heard John Coltrane's tenor sax solo on Miles Davis' "So What" coming from behind, and to the far left of, the left speaker...just like on my two channel system at home. Cannonball Adderley's alto sax solo was projected in front of the right speaker...just like on my two channel system at home. Previously, Coltrane's and Adderley's sax images were confined to the front speaker plane.
The 4B3 brought the following stereophonic performance enhancements to my office system:
1. More image weight, a strengthened sense of palpability to sound images.
2. More depth at the sides of the sound stage.
3. More forward projection of images forward at the sides of the sound stage.
4. More clarity and detail, more sounds of a singer's lips, throat, and chest.
5. More "wood body" sound on acoustic bass.
6. More reedy, woody edge on saxophone.
7. More subtle texture in drum rolls.
8. More thunderous bass.
9. Music sounded apparently louder due to the lower noise floor.
10. Far more low level detail, and the bass does not "disappear" if I turn the sound level way down.
11. More of that growl that I like...from electric and acoustic bass instruments.
After four days of listening, I did not note any performance improvements over those noted after the 4B3 had warmed up sufficiently on the first day. Bryston burns in their amplifiers for 100 hours at the factory. This might reduce or remove the need for further "break in" by the owner.
The quality of music reproduction in my office system now sounds like a smaller scale version of my home system...and my office seems like an extension of my home.
Further StudyI have gone far further in performance, in my office rig, than originally planned. I initially just wanted to replace my CD based system with a computer audio system. One improvement lead to another...and...here...I...am.
I was recently asked if I felt the Adcom preamp was "up to snuff" with it's playmates. The more I think about it, the more I think...no.
In the future, when I am more dedicated to audio than I am now, I will take the 4B3 for "test drives" in my two channel and home theater systems. The thought of moving the heavily laden cabinets of either of those two systems away from the wall...and (figuratively) fighting my way through miles of thick cables...and putting all that back together...is not something my mind can process at the present.
Figure 17. Two channel system: I'm not quite brave enough to do anything that requires pulling out the equipment
cabinet, disconnecting/reconnecting cables, and putting everything back in place...then waiting a day or two for my
cables to settle down again.Figure 18. Home theater system: In addition to the issues with cabinet weight and a mass of thick heavy cables
that would put most jungle vegetation to shame...there was the considerable financial risk that I might end up
replacing the three Adcom GFA-5500 amplifiers that power the center, front, and surround speakers.Associated EquipmentBryston BDA-3 digital to analog converter
Bryston BDP-2 digital player with IAD sound card upgrade and 500GB internal drive
Adcom GFP-750 preamplifier
PS Audio xStream Transcendent XLR interconnects for DAC and preamp
Revelation Audio Labs Prophecy Cryo-Silver CCIC USB cable
PS Audio Premier SC power cords for DAC, digital player, power amp and preamp
PS Audio P10 AC Regenerator
PS Audio AC-12 power cord for P10 AC Regenerator
Polk Audio SDA CRS+ (1989 version) loudspeakers (heavily modified)
Douglas Connection CDF92 speaker cable (9 AWG)
HiFi Tuning Classic Gold fuses for preamp, AC regenerator
HiFi Tuning Silver Star fuse for DAC.
Dell Venue Pro 11 7140 tablet computer, with dock, for digital player and DAC control
ReferencesOffice System Upgrades:
http://forum.polkaudio.com/discussion/168871/pure-overkill-computer-audio-office-systemBDP-2 Review:
http://forum.polkaudio.com/discussion/comment/2230125#Comment_2230125BDA-3 Review-Polk Forum:
http://forum.polkaudio.com/discussion/comment/2227414#Comment_2227414BDA-3 Review-Audio Circle Forum:
http://www.audiocircle.com/index.php?topic=142396.0