[bluepearl]

I have been running twin 4BSST2 in bridge mono for several years, they run approx 1,000 watts @ 8 ohms in bridge mono which is the same outout as 28B's. I have considered going with 28B's but with nearly identical output I haven't seen the need. What would I gain by switching to 28B's ?

Thanks...

[john1970]

The 4B SST2 when bridged are going to have difficulty driving lower impedance loads relative to the 28B SST2.  I am curious on why you went with a bridged pair or 4B SST2 and not a pair of 7B SST2 mono amps which have much better low impedance drive (stable into 2 ohm loads).

Cheers,

John

[CanadianMaestro]

^ That's interesting about stability of driving low-Z loads. I'm curious as to where a 14B-SST2 stands vs 7B monoblocks. As you know, the 14 contains 2 x 7Bs in one chassis, so I am wondering whether having them in one enclosure would in any way compromise stability of driving lower-Z loads.

[95Dyna]

^ That's interesting about stability of driving low-Z loads. I'm curious as to where a 14B-SST2 stands vs 7B monoblocks. As you know, the 14 contains 2 x 7Bs in one chassis, so I am wondering whether having them in one enclosure would in any way compromise stability of driving lower-Z loads.

The 14b is not two 7B's in one chassis. The 7 B has twice the power supply capacitance of the 14b. I have always thought that using a stereo amplifier bridged in mono was a bad idea. The 4B in your scenario may be putting out a thousand watts per Channel but it's only seeing half the load. That means it has to work twice as hard as the 7B to drive the same load. As for the 28's, two bridged 4B's would not be in the same league. I once had a very difficult to drive pair of speakers I had two stereo amps bridged in mono and was always blowing output stage fuses. I switched the configuration to bi amp and never had a problem again.

[john1970]

The 14b is not two 7B's in one chassis. The 7 B has twice the power supply capacitance of the 14b. I have always thought that using a stereo amplifier bridged in mono was a bad idea. The 4B in your scenario may be putting out a thousand watts per Channel but it's only seeing half the load. That means it has to work twice as hard as the 7B to drive the same load. As for the 28's, two bridged 4B's would not be in the same league. I once had a very difficult to drive pair of speakers I had two stereo amps bridged in mono and was always blowing output stage fuses. I switched the configuration to bi amp and never had a problem again.

95Dyna brings up a good point that biamping your speakers with two 4B SSTs if possible would be a much better approach than bridging them into mono.  IMO in addition to the 7B having twice the capacitance (160000 uF) than the 14B (88000 uF) the 7Bs also have the following advantages:

1) They can be place close to the speaker allowing one to use the shortest speaker cable possible.
2) Individually at 55 lbs each they are much easier to lift than a single 14B at 90+ lbs.
3) The pair of 7Bs have more heatsink area relative to a single 14B.  (~300 inches squared vs. ~236 inches squared) 

Best,

John

[CanadianMaestro]

The real Q is: How do 2 x 7Bs SOUND relative to a 14B, at modest volumes that do not generate a ton of heat (my 14B2 barely breaks a sweat at my listening volumes).

Weight is not an issue for many -- once set in place, why would a 14B be moved thereafter? 

cheers

[James Tanner]

The real Q is: How do 2 x 7Bs SOUND relative to a 14B, at modest volumes that do not generate a ton of heat (my 14B2 barely breaks a sweat at my listening volumes).

Weight is not an issue for many -- once set in place, why would a 14B be moved thereafter? 

cheers

We have developed a special '"Bryston Amp Harness" to allow the 14B to double as a portable playback system !

james

[CanadianMaestro]

Headphone cable flap is on top....     Bryston logo optional....





Physiotherapy coverage (for your back) is recommended

[CanadianMaestro]

The 14b is not two 7B's in one chassis. The 7 B has twice the power supply capacitance of the 14b.

http://bryston.com/products/power_amps/14B-3.html

"The Bryston 14BSST² dual channel (stereo) amplifier is basically two 7B’s which have been combined in a dual mono modular design"

[James Tanner]

http://bryston.com/products/power_amps/14B-3.html

"The Bryston 14BSST² dual channel (stereo) amplifier is basically two 7B’s which have been combined in a dual mono modular design"

'Basically' is the operative word as there are some differences as stated above.

james

[David Cutler]

Continuing the 7s vs. 14s debate:

If you are driving the amps into 4-6 ohms at approaching full power then, with the 14, the on-board circuit breaker will limit your output with both channels driven. 
See lab report from "Australian Hi-Fi" (avhub.com.au)
Article link:
http://www.avhub.com.au/product-reviews/hi-fi/bryston-14b3-power-amplifier-review-test-467738
Direct link:
https://i.nextmedia.com.au/Assets/bryston_14b3_power_amplifier_review_test.pdf

With a pair of 7s, you get the full power (utility power sockets willing).

[95Dyna]

We have developed a special '"Bryston Amp Harness" to allow the 14B to double as a portable playback system !

james

Indeed, with a 14B strapped to your back you can run less than half your normal route and get the same workout.

[Elizabeth]

Aside of any actual reality.. 
I think of the 14 as a 28, just split in half to give two 28 juniors.
Where the 7 is just a gussied up 4. so a 7 is a 4 on steroids. And a pair of 7s are two zonked out steroid junkies. LOL

[95Dyna]

Aside of any actual reality.. 
I think of the 14 as a 28, just split in half to give two 28 juniors.
Where the 7 is just a gussied up 4. so a 7 is a 4 on steroids. And a pair of 7s are two zonked out steroid junkies. LOL

Or, put another way, a pair of 28B's = 9.3 3B's.  And then there is the formula that converts an amplifier into  a digital music player: (1)28B x 3.14166 = BDP Pi.