Take a look at the main caps and you will see the voltage rating.

The majority of the amplifiers' output specifications are given at a specific power into an ideal resistive load, but remember that a loudspeaker does not have a constant resistance across its frequency range. Instead, the voice coil is inductive, the driver has mechanical resonances, the enclosure changes the driver's electrical and mechanical characteristics, and a passive crossover between the drivers and the amplifier contributes its own variations. The result is a load resistance that varies fairly widely with frequency, and usually a varying phase relationship between voltage and current as well, also changing with frequency.
IMO, if you give a dynamic set of speakers to the B4 it will shine like a star.

Matching a speaker to an amp is one way of compensating for an amp's deficiencies but IMO, that is a compromise. What I heard with this Sonics/Bryston amp indicates the attack and decay are not vertical and that some rounding is present. While use of compensation in the form of tone controls or speaker choice can restore some balance, tone compensation further distorts the input signal such that delicate nuances are pushed further into the background or simply lost.

Speaker dynamics and impedance matching involves matching the response curves so that where the amp is weak, the speaker compensates with greater response. A notable example of speaker/amp tuning is the Pioneer SX receiver line and the HPM speaker line. The SX-1250 is somewhat dull, which the HPM-100 compensates by having about 3 db increase above 3 kHz. While there is synergy in this pairing, the result is never better than mid fi. I have no expectation that a "more dynamic" speaker will improve the Bryston's accuracy.

In my experience, vertical attack and decay are the keys to accurate signal reproduction. Vertical attack and decay once lost cannot by restored through compensation of any sort.

I use the strict objective definition of accuracy to be comparison of input and output signal. My subjective preference aligns with this objective definition. However, your subjective preferences may not and as long as you enjoy what you are hearing, I am good with the difference.

Wow, surprising results! I've never heard a Concept but have heard a few Bryston's which have always held my respect. There is a Concept 16.5 for sale on the local CL for $450 and I passed on it without a second thought. Might have to see if I can't arrange an audition on it now.

You've certainly piqued my curiosity. Thanks for the write up!

The 16.5 is worthy of consideration but keep in mind, my comparo was of the amp section only. I didn't comparo the 16.5 preamp with the Kenwood L-07C although I suspect it does well enough.

I have heard the Concept before.
It is a nice unit.
It would be interesting to compare it to a Pioneer SX-1250,it was aimed directly at that market.

I used to own a SX-1250. Although I didn't compare them back to back, the SX-1250 is noticeably slower than the 16.5 resulting in a ponderous sound. At that time, I also owned HPM-100 speakers and the balance improved as expected with staying in the Pioneer family. IMO, the SX-1250 was tuned to work with the Bart Locanthi designed HPM-100. My theory is Pioneer gave Locanthi a free hand in order to lure him away from JBL. So, the Pioneer engineers simply dumbed down the SX-1250 to make the family pairing sound better in the showrooms. It worked as Pioneer outsold everyone else.

I am confused, what I think you are saying in this quote is that because the 4b has different filter voltage a speaker change would not held improve the sound but in the sencond quote, a speakers would sound significantly different with this receiver, why would the pioneer be the only one that would sound different?

elroy

some of the guys on this site have an extensive amount of working with electronics and know what resistence and capacitance, etc is, I dont have any, all I know is that there are a bunch of do-dads all over the inside of a receiver/amp/tuner/electronic equipment.

so for me, my logical step for better sound is throw money at it, and what I mean by that, is if I have a kenwood ka8100, and uprade to the yamaha mx2000, it should sound better, just on the sheer force of what the yamaha retailed new, I realize there are gems out there that are a lot cheaper, and by no means am I saying the concept is a slouch, from what I have read about that receiver is that it is one hell of an receiver.

that being said, from my experience every change in components, from speakers to cables to cdp's to whatever I change, there has been a change in the music sound. some good some not so good, some subtle some not so subtle. and my last post I was confused it seemed like you might have inadvertently contradicted yourself, I am sure you meant something else, i just probable didnt read it close enough.

elroy

I should have been clearer my thoughts were not a rule but a relationship that shows a strong correlation. There are many exceptions to the voltage rail equals better sound such as the Marantz 2500/2600 with 100v caps. IIRC, the SX-1980 and the SX-1250 both have 80v caps and neither of them are lively in any sense of the word. Having been a former owner of the SX-1250 and talking to other collector buddies, I think I have a good feel for the 1250's sonic signature. And, my theory on why the SX-1250 is not more lively is just that, a theory. However, the consensus opinion on the sound cannot be denied.

Many will disagree with the objective approach I take to reviewing gear with replies such as "if you enjoy the sound, who cares what it can do on the bench" or worse, "science be damned!" However, I have given auditions to my local (and very modest) enthusiast group and I feel confident I can demonstrate the benefits of higher speed amps. Whether you like what you are hearing is another story but at least you will have heard the difference and been able to make an informed choice.

that makes sense to me

I love my Sansui BA-2000 amp but do not feel it's a quick amp.

No biggie- most speakers, even some of the heavier hitters, just don't care.

However, some of the very difficult speakers I own just demand more. Best i've offered them are a B&K EX-442 Sonata, though I'd like to try some of the Forte, some of the Audire, and some of the Dunlap Clarke products.

The CA-2000 is a classic, and sounds oh so sweet, but paired incorrectly with bastards of a demanding speaker, it's just not a match made in heaven.

The benefits of a fast amp with certain pairings of speakers is a magical combination and he benefits can be clearly and decisively heard.

Regarding the Pioneer big-boy receivers, there's a certain house sound to them. And although one may find them rich or euphonic, I don't consider them a fast design.

Nothing wrong with them by any means. Just important to remember, they are what they are.

Thed, there is no question that Sansui and Marantz when paired with bright ported speakers like JBL's, HPM's, RSL's, and some Infinities have a synergy that is greater than the sum of the parts. However, I am debating whether a fast amp is always better than a slow amp even with not particularly balanced speakers. Except for the brightest HPM's and RSL's, I'm leaning toward a yes on this question. Generally, fast amps do not round off the signal as much thus reproducing the input signal more accurately. This gives the speaker the best preserved signal and allows the speaker to achieve whatever potential it may have. As Elroy and others here have mentioned, pairing amps with speakers and assessing the results is great fun.

My point is for some pairings it's not that important. I've run some speakers that just don't demand a fast amp.

But if I had my choice- I'd lean in favor of a fast amp. A fast amp has the capabilities of handling just about any pairing, while a slow one in the wrong combination/pairing will just not suffice to get the job done, and you'll notice it, from sloppiness, to a lack of control of bass, therefore flabbiness of bass, to reduced bass output.

While I've never tried the Sansui on my Thiels, while the warmth imparted by the Sansui yould be nice on the top end, I bet the bass would be presented slovenly, weakly, and, well, just inadequate.

I imagine the aDs L1290s would be more forgiving. Monitor Audio silver 8s as well.