[JfTM]

Stealing the idea from the 4/7 thread.

The 4B (bridged), the 7B (which is sort of a 4B bridged), and the 14B (which is sort of two 7Bs) all produce about the same power.

In various threads over time there have been discussions around the specific differences.  i.e a 7B isn't just a 4B bridged, a 14B isn't really two 7Bs ....

If one was looking in that power range, what would the decision factors be?  Or is there really no difference?

[James Tanner]

HI,

It will all depend on the type of load (speaker) being driven.

james

[JfTM]

Thanks James 

Are there guidelines, or is it best addressed individually?

[James Tanner]

Thanks James 

Are there guidelines, or is it best addressed individually?

As the difficulty of the load increases the more you move in this direction - 4B Bridged then 4B Stereo then 14B then 7B for the real tough stuff.

james

[drummermitchell]

Or if you don't want to keep upgrading...28's END OF STORY .

[Ron D]

Not to take anything away from the potential sale of a new amp if it were me I would wait out for a used 14BSST2 or a pair of 7BSST2 amps and not get on the upgrade merry-go-round. James gave me similar advice back in the 80's (sorry James ) when I spoke to him about the 2B Vs the 3B on a pair of small pair Maggies - SMG-A. He advised me to wait until I could afford the 3B as it would be a better fit and that amp served me well for a number of years. You could look at it as "pay me now or pay me more later". If you buy new I would suspect that IF you have to upgrade you are going to lose somewhere - either selling the amp used or on a trade in and if your dealer takes it back at full value (not done as often as it used to be) you'll probably pay list on the new amp.

Now I have owned a variety of Bryston amps (all bought new) since the old 3B upgrading for either power or later technology but with my current and the latest version 7BSST2 amps I no longer look at replacing them. While the 28s are a "tad" more expensive than the 14B/7Bs (both new and used) I think the 14BSST2 and 7BSST2 at used prices are the sweet spot when factoring in power and sonic presentation, again IMHO.

Good luck with whatever your choice is

[Laundrew]

Or if you don't want to keep upgrading...28's END OF STORY .

O Canadiana ensues...

My dad always told me to purchase the largest snow thrower you can afford because a day will come when you are going to be up to your ears and you will be happy that you did...

Be well...

[JfTM]

As the difficulty of the load increases the more you move in this direction - 4B Bridged then 4B Stereo then 14B then 7B for the real tough stuff.

james

Thanks, got it now 

[drummermitchell]

Yep,I took the Bryston highway 4bsst,then detoured on 7Bsst and ended up on freeway 28.
Of course I enjoyed each turn in the road.
                                         I'm done.

[Sasha]

I had all 3, tried them with more than one pair of speakers. First let me say that there is no passive speaker that is an easily load, or to put it the other way, if it is an easy load then it is severely compromised design. It is not possible to come up with passive crossover that will provide at the same time good integration of drivers with good power response and an easy load.
Having said that, if you want passive speakers then 7B is quite better than 14B and enormously better than 4B.

[SoundGame]

You can't argue that the more power you have on tap the better but it's still a question of budget and priorities.  Take a given speaker with a given power handling and difficulty you still need to weigh in the cost over the extra benefit of moving to a more power amp vs. improving other things such as source components and even power isolation e.g. Torus. 

Depending on what you're driving it could be that a 4B-SST2 with a Torus RM15 will provide you with a better result than a 14B-SST2 on it's own, without the Torus - add in also that with the extra money you could get a BDA over just using your redbook CDP...decision, decisions....as long as you have finite cash resources.

[PRELUDE]

For my type of usage it always been 2x4b and a pair 7b and I just changed to newer one (all 4 pices)
I move stuff around and try different things a lot and that is the only reason I like the 7b because it is lighter otherwise I could be very happy with 14b with no problem.
Keep in mind that the numerical impedance are most likely different in the real world then what you see on user manuals and it changes too.There are some monitors that have 16ohm impedance.
If the price and staying compact is important to you then stay up to 3B.For monitors go with 4B and you will be happy that you did.Use the 7B or 14B for tower speakers and if you want to go with big floor standing speakers even if it has only one 10" driver I would like to go with 28.
But if you get the 7B or 14B for any speaker,then you won't think about upgrading that soon.
My two cents.

[mv038856]

... if it is an easy load then it is severely compromised design. It is not possible to come up with passive crossover that will provide at the same time good integration of drivers with good power response and an easy load.

I would disagree on that point. I think it might be a little oversimplified. While there might be some speaker concepts with exceptional sonic potential that inherently tend to be difficult loads, there are companies, Dynaudio as an example, that design crossovers in a way that makes them (or the speakers) a load that is easier to handle. They do need power, yes, but they don't present a load that either has low impedance or phase shifts. And I would cretainly claim that they do provide great sound.

Cheers

Markus

[rmurray]

  You have never used JBLs.? My 4b with the Ti series(1988) is an amazing combo . They are easy to drive but performs so well I need to go no further for dynamics and overall coherence IMO .

[Sasha]

I would disagree on that point. I think it might be a little oversimplified. While there might be some speaker concepts with exceptional sonic potential that inherently tend to be difficult loads, there are companies, Dynaudio as an example, that design crossovers in a way that makes them (or the speakers) a load that is easier to handle. They do need power, yes, but they don't present a load that either has low impedance or phase shifts. And I would cretainly claim that they do provide great sound.

Cheers

Markus

If you want to talk about Dynaudio in general, Dynaaudio does not have good power response, it cannot due to the slope chosen. It may sound good to you, in specific room at specific distance, but it does not make it good performer in all aspects and it is essentially a compromised design when compared to well designed active speakers. You can never achieve with passive what you can with active.

[95Dyna]

As the difficulty of the load increases the more you move in this direction - 4B Bridged then 4B Stereo then 14B then 7B for the real tough stuff.

james

Here's a real life example in support of what James is saying here.  I have a pair of one of the most notorious "amp Killer" speakers that have ever been manufactured, the Infinity 9 Kappas.  They take a dip to .8 ohms in the low 30 Hz range accompanied by some nasty phase shifts.  I drove them for years with a pair Nelson Pass designed Adcom GFA 555 MK IIs.  At first I used the bridged mono mode thinking it would work well because of doubling the output power.  The fuses in these amps would pop so frequently that I returned them to stereo mode and bi amped.  This experience is where I learned about the halving of the impedence the amps see whenbridged in mono rendering doing so a bad idea IMHO.  The fuse problem went away and they worked fine thereafter except that I always had a sense these speakers could do better.  The soundstage seemed to always be bunched in the lower right, imaging was only fair and the midrange seemed congested. Two years ago I went looking to upgrade my amps and settled on Bryston after an exhaustive search.  Then I decided on the 7B SST2's over the 14B SST2 for one reason, the pair has double the power supply capcitance of the 14B.  The result is that these beasts (the Infinity's) are under complete submission to the 7B's.  Driving them is a walk in the park for these amps.  The soundstage has exploded to above and beyond the speakers and the instruments and vocals are placed appropriately within the stage.  Acoustic bass solos are breathtaking and the piano sounds so real you could close your eyes and sense that it is in the room.  The cool thing is that everything holds its place no matter how loud or demanding a passage my be.  This is a sure fire indication that the amps are not breaking a sweat. The 7B SST2 is worth every penny of its price especially for me as I feel they have diverted my attention from buying that new $15K pair of speakers I've been considering.