D. A. Rich has stated Bryston makes use of careful matching and years to refinement (layout, wiring, etc) to get their "simplistic" circuits to perform the way the do.
and who actually knows if the printed schematics are truly "true"
😉
mlloyd1
and who actually knows if the printed schematics are truly "true"
😉
mlloyd1
Hi Guys
The schematics are true*. Bryston is not a "voodoo" company with lots of secrets. They have always been open about what they do and why they do it. They welcome competition.
*I did notice an error on one schemo with a missing dot for a connection...
I can understand your caution when there are, for example, companies claiming new invention while using the old Hitachi mosfet app circuit with no values changed, and charging megabucks for it.
Have fun
The schematics are true*. Bryston is not a "voodoo" company with lots of secrets. They have always been open about what they do and why they do it. They welcome competition.
*I did notice an error on one schemo with a missing dot for a connection...
I can understand your caution when there are, for example, companies claiming new invention while using the old Hitachi mosfet app circuit with no values changed, and charging megabucks for it.
Have fun
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Joined 2009
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i could never describe my Bryston amp as having weak anything, the bass is rock solid in fact.
They do however, use op amps in some models - mine does. They are used to make a pre amp, mine is one of their integrated amps comprising of their pre and a 2B power amp. The preamp outputs are at the back panel with jumpers to the power amp input so you can use them separately.
They do however, use op amps in some models - mine does. They are used to make a pre amp, mine is one of their integrated amps comprising of their pre and a 2B power amp. The preamp outputs are at the back panel with jumpers to the power amp input so you can use them separately.
Hi Guys
You have misinterpreted the schematic, Bigun. An opamp symbol or indication is used on many of their more dense schematics, but it is ALWAYS one form or other of the discrete opamp - that's what "DOA" stands for. Other sheets of the schematic show those circuits. The number after the DOA indicates the Re value for the EFs, so "68" is for an EF output with 68R emitter resistors, "33" is 33R - basically the two standard values so far...
The only audio path where an IC opamp is used is on the sub out of the crossover. This only has to handle frequencies up to 160Hz or so, and an IC can do that well enough even to Bryston's standards.
Personally I do not find anything weak about Bryston's sonic output. It is just the fact that amps-with-character tend to have comparatively bloated bass, and if that is your reference, a Bryston would seem weak by comparison. This is again the difference between accurate sound and "subjectively pleasing" sound.
Have fun
You have misinterpreted the schematic, Bigun. An opamp symbol or indication is used on many of their more dense schematics, but it is ALWAYS one form or other of the discrete opamp - that's what "DOA" stands for. Other sheets of the schematic show those circuits. The number after the DOA indicates the Re value for the EFs, so "68" is for an EF output with 68R emitter resistors, "33" is 33R - basically the two standard values so far...
The only audio path where an IC opamp is used is on the sub out of the crossover. This only has to handle frequencies up to 160Hz or so, and an IC can do that well enough even to Bryston's standards.
Personally I do not find anything weak about Bryston's sonic output. It is just the fact that amps-with-character tend to have comparatively bloated bass, and if that is your reference, a Bryston would seem weak by comparison. This is again the difference between accurate sound and "subjectively pleasing" sound.
Have fun
Completely d'accord. The question for me was: given the slight problems with treble smoothness that quite some people, me included, had at least with older versions, is there something in the schematics which could give a hint? While I really like the solutions Bryston has found for their circuit topology, this is the only point where I personally would try to do something, even for the price of a a noise penalty.
On the other hand, reading the reviews, the treble problem apparently has been solved. Really would like to audition an amp from last generation.
Matthias
I'm looking for Accurate amps, but the real question is - What sonic version, of Accuracy is preferred?
Amps get a bad rap sometimes, when the bigger problem resides in the speaker design..For example, wave guides, horns and tweeters mounted to hard surfaces, can sound harsh because of diffraction smearing but I do feel Brystons will amplify this issue.. Seems like a transient problem with Bryston.
2 weeks ago had a 4bsst running my speakers.. The tweeter is mounted on top of box, in a spherical diffraction pod with felt wrap, and the midrange is also surrounded with 1/2" felt.. First order crossover.. Very nice, best results I've experienced, with 4B.
One Past experience, Bryston with metal domes, forget it..
I'm curious, what speakers are used in the OP?
Amps get a bad rap sometimes, when the bigger problem resides in the speaker design..For example, wave guides, horns and tweeters mounted to hard surfaces, can sound harsh because of diffraction smearing but I do feel Brystons will amplify this issue.. Seems like a transient problem with Bryston.
2 weeks ago had a 4bsst running my speakers.. The tweeter is mounted on top of box, in a spherical diffraction pod with felt wrap, and the midrange is also surrounded with 1/2" felt.. First order crossover.. Very nice, best results I've experienced, with 4B.
One Past experience, Bryston with metal domes, forget it..
I'm curious, what speakers are used in the OP?
Perhaps the issue was elsewhere and the amp was not providing some coloration or frequency response deviation? That strikes me as more likely.
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Joined 2009
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I would look at the frequency compensation - not just the schematic, but consider parasitics of the physical layout and parts. I believe that frequency compensation has an affect on the sound that is often underestimated.
In my experience, this is completely true. In all my own designs, I made and make the rather disturbing experience that a small change in stability margins may alter at least sound stage representation, in most cases also timbre.
In an earlier post, I named the clever input resistor at the non-inverting input of the power section. Indeed, it does have a large influence on the ULGF of the whole power section; I would name the trick as something like Miller compensation around the input transistor. The Bryston circuits are full of such tricks, see e.g. the absence of Miller compensation in the input buffers of the later versions. This again is only possible, since they use quite large source impedances at both inverting and non-inverting inputs. This also has a kind of Miller compensation effect around the input transistors; and indeed as pointed out by Struth, this may give good isolation against EMC inference from outside of the amplifier.
On the other hand, they feed back the global output signal to the inverting input of the power section, using lead compensation in the feedback network in combination with absent emitter degeneration. I do not at all claim that this won't work. But the past shows: they had some time of serious work to bring their amplifiers to the real leading edge (for audiophiles).
Matthias
This is my question, too.
I agree. Bad bass from a Bryston: this really points to a problem elsewhere.
Matthias
Hi Guys
"Accurate sound" is predicated on zero distortion and flat frequency response - basically no colouring at all. For an amplifier, the proverbial "wire with gain". This is what Bryston has always targeted.
The refinements made in the last twenty years have dealt primarily with layout and reductions of noise. Anything that reduces THD also reduces IM, as does any improvement in grounding. Internal impedances have been reduced and the implementation of input buffers with gain allows the PA gain to be reduced, further reducing THD, IM and noise.
You won't see emitter degenerated diff amps but you will see base-stops here and there. Transient problems simply do not exist in Bryston amps. Also, the protection circuits are dead simple because they are rail-referenced rather than output-referenced. They provide 60-degree current displacement before protection is invoked, and the already massive current capability means that protection really only comes into play with a dead short at the output.
From the beginning, when Chris Russell built the first Power-1, -2, -3 models (before the 'B' numbering came into vogue), a high slew rate was part of the standard. The individual amplifiers are all 60V/usec. When you bridge them, this doubles to 120V/usec as far as the load is concerned. (As one amplifier output moves towards +60V the other moves towards -60V, giving a 120V rise across the load - the same applies to any bridged amplifier). The 7B is designed as a balanced-drive or bridged amplifier - audiophiles do not like the term "bridged". This method of driving the load eliminates disturbances of ground currents, and thus the ground reference is highly stable.
There is no point to using voodoo cables, such as biwire - no one has ever provided evidence of its benefit in audio, and quite to the contrary all voodoo wire has been debunked many times. If you install expensive cable in your system and can hear its effect, you have just wasted your money. But... if you like what you hear then "what a great investment". Happiness is way under-rated.
As I said above, not everyone will like what a Bryston amp does in their system.
It is also no sin to not want true accuracy.
Have fun
"Accurate sound" is predicated on zero distortion and flat frequency response - basically no colouring at all. For an amplifier, the proverbial "wire with gain". This is what Bryston has always targeted.
The refinements made in the last twenty years have dealt primarily with layout and reductions of noise. Anything that reduces THD also reduces IM, as does any improvement in grounding. Internal impedances have been reduced and the implementation of input buffers with gain allows the PA gain to be reduced, further reducing THD, IM and noise.
You won't see emitter degenerated diff amps but you will see base-stops here and there. Transient problems simply do not exist in Bryston amps. Also, the protection circuits are dead simple because they are rail-referenced rather than output-referenced. They provide 60-degree current displacement before protection is invoked, and the already massive current capability means that protection really only comes into play with a dead short at the output.
From the beginning, when Chris Russell built the first Power-1, -2, -3 models (before the 'B' numbering came into vogue), a high slew rate was part of the standard. The individual amplifiers are all 60V/usec. When you bridge them, this doubles to 120V/usec as far as the load is concerned. (As one amplifier output moves towards +60V the other moves towards -60V, giving a 120V rise across the load - the same applies to any bridged amplifier). The 7B is designed as a balanced-drive or bridged amplifier - audiophiles do not like the term "bridged". This method of driving the load eliminates disturbances of ground currents, and thus the ground reference is highly stable.
There is no point to using voodoo cables, such as biwire - no one has ever provided evidence of its benefit in audio, and quite to the contrary all voodoo wire has been debunked many times. If you install expensive cable in your system and can hear its effect, you have just wasted your money. But... if you like what you hear then "what a great investment". Happiness is way under-rated.
As I said above, not everyone will like what a Bryston amp does in their system.
It is also no sin to not want true accuracy.
Have fun
In the meantime I have find out the main reason for bad sound.
None of your above mentioned conjectures are one of the reasons. The main reason was the too low impedance of the loudspeakers. The lowest value should be above 4 ohms. Then is to observe the absence of the described shortcomings by sound quality. By a closer look to the measuring results of the stereophile review (link in post #1) you will see the not good THD results at 2 ohms compare to the higher impedance values.
This means, the measuring results at low impedance values consistent with the impressions by listening tests.
Concerning the topology from output stage I read under
http://canadahifi.com/bryston-4b-sst²-c-series-amplifier/
this:
Bryston (resp. the developer Stuart Taylor) claims, that this design virtually eliminates aggressive high harmonic distortion products, producing a sound akin to pure class A but with lower overall distortion levels and less heat.
The disadvantage of this topology could be the unwanted high distortion in cases, where high (may be phase shifted) currents must provided for the loudspeakers.
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