Bryston's don't like low impedances and are dynamically limited. I've said this for several years and Stereophile confirmed this in their last review of a very large Bryston amp. Sonically, i find them to be both unimpressive and uninvolving.
If you have a softer ( treble and upper midrange reduced ) sounding speaker that maintains a higher average impedance and you listen to music that is both moderate in terms of dynamic range and average spl requirements, have at it. They are ruggedly built and have a phenomenal warranty that they definitely DO stand behind. Sean
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Dynamically limited relates to the quantity and speed of power available during dynamic transients. In other words, i've found Bryston's to be lacking in "useable" dynamic headroom. The aforementioned Stereophile article notes this also, as the reviewer found the 500 wpc Bryston going into clipping before the 350 wpc Levinson unit that he compared them to. There was also another smaller ( than the Bryston ) amp mentioned in that review ( can't remember what it was ), but they also stated that it also "dynamically" out-powered the Bryston.
Other than that, a well designed SS amp just keeps delivering more power as impedance is reduced. Obviously, it's going to run out of steam at some point, but prior to that point, it's either got it or it doesn't. Sean
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Adding to my last post, the lack of headroom and resultant momentary clipping could explain why some folks experience listening fatigue with Bryston's. That is, the non-linear high frequency distortion and smearing that result bother them enough to make the amps unlistenable over a period of time.
Obviously, not everyone or every situation may run into this problem. Some can hear things that others don't. Some have loudspeaker & cabling loads that might aggravate the situation whereas others may have more benign loads. Some might / might not listen loud enough for the problem to arise. This could be why there seems to be such a controversial take on this specific subject. Sean
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If the 7B is rated at 500 wpc at both 8 & 4 ohms, that was the amp / Stereophile review that i was referencing. When i saw that spec, i laughed out loud and immediately thought that Bryston was a fan of SS Mac designs.
As far as being dynamically limited, this has to do with many different factors, impedance being one of them.
In terms of "doubling down" and rated power, most all of that is BS. Very few amps come close to doubling down in reality, even if they are factory rated to do so. If you doubt this, forget the "rated power" and start looking at the actual power as measured at clipping vs impedance. Manufacturers can fudge a rating however they want to make a product look good on paper, but what it actually does "balls out" is what really counts.
Once you start looking at the power at clipping vs impedance, you'll soon see that most amps are quite lacking in power supply, quite lacking in output capacity and / or a combination of the two. Things really get hairy when you start seeing what some of these supposed "big" amps do when called upon to deliver steady state power into very low impedances.
There are some highly reviewed SS amps that actually do less power at 2 ohms than they do at 8 ohms. Needless to say, these amps will behave like "sonic chameleons" depending on the speaker / cable load that they are connected to. Just as the impedance dips and the amp needs to step up to the plate, it lays down and "bogs out".
Needless to say, this doesn't sound good, although it may be difficult to understand why a certain amp / cable / speaker combo just doesn't sound "right". That is, unless one knows how to interpret test results and can put 2 + 2 together.
This is one of the reasons why some speaker cables seem to work better with some amp / speaker combo's. That is, by changing the nominal impedance ( along with some other factors of the cable ), the cable itself can act as a "buffer" to what the amp sees. Obviously, if the amp is having a hard time driving lower impedance loads, using a higher impedance cable can help stabilize the system.
On the other hand, if the amp is truly up to driving the speakers, and the amp and speakers are both reasonably accurate performers, something along the lines of the flat Goertz cabling / Electro-Fluidics ( British made Goertz clones ) / Magnan Reference and possibly the Ridge Street speaker cables should sound best. I can't say for sure about the RSA's as they don't have any worthwhile info posted about them on their website. From what i can see, they would appear to be a low impedance design utilizing flat solid core conductors for minimal skin effect. This description should not be confused with the design of Nordost speaker cabling, as it is anything but a low impedance design.
Selecting an amp that exhibits unstable performance into low impedances can tend to have you juggling tons of variables, especially cabling, in order to get decent performance out of it. In the long run, many find that it is both cheaper and easier to just buy another amp that is both more stable and more robust in design.
In this regard, the Bryston 14 that you referenced wasn't quite this bad, but it only went up 30 watts going from 8 ohms to 2 ohms at clipping. You have to admit, this is pretty pathetic in terms of percentages vs what one would / should expect according to theory. On top of that, and if you REALLY look at the chart, the amp is actually going into clipping just prior to the rated 900 wpc rating @ 4 ohms. You can see this as the distortion by-products start to climb through the roof on what looks almost like a straight vertical climb at this point. This is usually a sign of high negative feedback, which tends to make the amp sound "sterile" and lifeless. High frequency performance of such a design is sometimes described as sounding cold, hard or bright, especially when being pushed.
While some would say that this power level is so high that nobody would ever hear it / experience this under normal conditions, those are the same people that have never really measured dynamic power demands of low efficiency, low impedance speakers at higher volumes. Obviously, some of this can be avoided through careful system matching, but once again, unless one knows how to properly interpret test results, this can be a long and frustrating path.
Obviously, everything that i've discussed here pertains to SS designs ( and not just Bryston's ), as tubes work in a VERY different manner. Tube amps really are very different creatures in most cases. Sean
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Keneallyfan: There are NO tubed amps that "double down", at least as far as i know. As i mentioned, tubes operate very differently than SS amps. There really is no comparison in terms of power and current capacity, especially as impedances drop.
Bob: Amp designers are only at the mercy of their own skills and design / manufacturing budget. After that, it's strictly a matter of the consumer doing their homework and purchasing / using compatible equipment. Hopefully, this thread and some of the information contained within it may help some people do just that i.e. further educate them about this subject and help them with their future purchases. Sean
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Something is a bargain only if it does everything that you need or expect of the product at a drastically reduced price as compared to the competition. Obviously, this would be system and personal preference based, resulting in the value of any audio based item being left up to the "ear of the beer-holder" : ) Sean
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Bob Reynolds: Until the mass majority of speakers are able to present relatively benign loads with consistent impedances to them, my thoughts are that a supposedly "beefy" SS amp should be able to deal with most anything you throw at it. Obviously, there are exceptions ( big Apogee's, etc... ) to every generalization ( including this one ), so take that for what it is worth.
Obviously, not all SS amps are "beefy", nor are they all able to deal with various loads equally. Even if the manufacturer thinks their products are up to snuff and rates them accordingly, that doesn't mean that they actually will be able to in real life. Knowing what to expect ( good or bad ) and / or what one may end up dealing with ( good or bad ) before shelling out big coin can be a real blessing.
Keneallyfan: When one can substitute any one of a couple dozen amplifiers into the same system in a matter of minutes, it's not that difficult to make comparisons of what each amp brings with it, how they sound with those other specific components, how well each amp can drive that specific load, etc... Drawing both logical and repeatable conclusions from such an approach becomes rather easy after a while.
With that in mind, most people don't have the means or capacity to do such things. At the same time, many of these same people seek the honest opinions of others and want to hear their thoughts about that specific subject based on their experiences, observations, etc... As such, hearing the good and bad of any situation allows one to make a more informed opinion, even if one might not agree with all of those opinions expressed. Sean
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Keneallyfan: When it comes to pool cues, you adapt to the differences presented to you and make the best of them. That tells me that you have both skill and experience in that particular field. If such were not the case, you would not have been able to discern the subtle differences between presentations and you would be lacking the skill / experience to adapt accordingly.
Without being skilled and experienced, you wouldn't know that compensation was needed. Nor would you know how much compensation was needed or where, when and how to apply it. You've obviously developed skills, and my guess is that it has come over a period of time, primarily due to exposure and experience.
Audio really isn't all that different. Just like pool, there are some things that remain concrete, but most of it boils down to personal feel and proper implimentation of the tools and knowledge at hand. In that respect, nobody can teach you what feels "right" for you, you either know it or you don't.
There are obvious parallels between playing different tables in different environments to system requirements in different acoustics, and both require skill, experience and logic. Obviously, not everyone has the same level of skill, experience or logic, so some may achieve more consistent results than others. This is to be expected.
The bottom line is, one must enjoy what they are doing and the results that they achieve. Otherwise the "fun" factor disappears and we no longer enjoy what we are doing. I want to try and keep this "fun", so this is where i'll shut up. I hope that we can all enjoy ourselves at whatever we do. Otherwise, it's simply not "fun" : ) Sean
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Tt509: That's called protection circuitry. Most commercially built amps have this to one degree or another. Many believe that it is this type of circuitry that audibly degrades the sonic potential of some otherwise very solidly engineered amps.
Outside of that, you can do much the same thing to a Crown, but the difference is, the Crown will probably keep working far longer than a week after the problem has been resolved. With all of that in mind, that doesn't mean that a Crown actually sounds good or that i want to use one for my home audio system.
As far as warranty service goes, Bryston is untouchable in that regards. I experienced much the same thing with them and can say nothing but good things about Dennis at their U.S. repair facility. Kudo's to both Bryston and Dennis for standing behind their product. Sean
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Look at the gauge of conductor in a fuse, the materials used in a fuse and then compare that to what you're trying to pass signal through the rest of the way. Having said that, yes, fuses in the signal path do degrade the sonics of a product. Breakers do too. Sean
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