That cross-conduction flaw might be why Crimson who majored on three stage CFP (both quasi and complementary) have an HF detector around the VAS that cuts off supply to the LTP and VAS CCSs, operating at about >=50kHz.
Below that they amplify superbly.
Below that they amplify superbly.
Terry Demol said:
Yes, I don't completely understand why Bryston continues to use a stacked output stage for their higher-power designs, except that it allows them to use a lot of the same circuitry up front.
I guess if it works, don't fix it?
Cheers,
Bob
Hi,
if EF works and quasi which is half EF and half CFP also works, then CFP on it's own should also work.
When all those can be made to work individually then please explain why combining them as Bryston have done in their EF+CFP quad output stage cannot work.
And why do Bryston offer a 20year warranty if this HF cross-conduction thing is such a big problem?
if EF works and quasi which is half EF and half CFP also works, then CFP on it's own should also work.
When all those can be made to work individually then please explain why combining them as Bryston have done in their EF+CFP quad output stage cannot work.
And why do Bryston offer a 20year warranty if this HF cross-conduction thing is such a big problem?
Hi Andrew,
Bryston has made a big marketing commitment to this output design, so they will not discontinue it. The have been crowing about it for years on end.
Do not confuse a 20 year warranty for quality. It is advertising, period. Many other amplifiers are more reliable.
I would truly love to hold up Bryston and say "What a great Canadian amp!", being Canadian and all. I can't do it, I know too much about the truth of the product. Recently they are supposed to be much better. I'll accept that. I will not accept the rest of the nonsense in advertising though. The 20 year warranty is only a cost of doing business they have accepted. The same as any other advertising gimmick.
-Chris
Bryston has made a big marketing commitment to this output design, so they will not discontinue it. The have been crowing about it for years on end.
Do not confuse a 20 year warranty for quality. It is advertising, period. Many other amplifiers are more reliable.
I would truly love to hold up Bryston and say "What a great Canadian amp!", being Canadian and all. I can't do it, I know too much about the truth of the product. Recently they are supposed to be much better. I'll accept that. I will not accept the rest of the nonsense in advertising though. The 20 year warranty is only a cost of doing business they have accepted. The same as any other advertising gimmick.
-Chris
Chris,
Very surprised to hear of Bryston reliability problems not only because of the 20 year warranty but also because a significant portion of their business appears to be in the professional market.
From their schematics, Bryston appears to use the Onsemi NPN-PNP pairs (not ThermalTrak). Their topology market differentiators are the "proprietary" power output configuration and the use of discrete opamps.
How do Bryston amps fare on the test bench? See:
http://www.stereophile.com/solidpoweramps/725/index.html
...Jim
Very surprised to hear of Bryston reliability problems not only because of the 20 year warranty but also because a significant portion of their business appears to be in the professional market.
From their schematics, Bryston appears to use the Onsemi NPN-PNP pairs (not ThermalTrak). Their topology market differentiators are the "proprietary" power output configuration and the use of discrete opamps.
How do Bryston amps fare on the test bench? See:
http://www.stereophile.com/solidpoweramps/725/index.html
...Jim
Hi Jim,
One thing you really must understand about Bryston. They would have you believe that their products don't fail. They certainly do! Spectacularly some times. Understand that they use normal (not supernatural charmed) parts. They have a failure rate ('cause they are the same ones you and I can buy). This failure rate increases with temperature (like all mortal parts) and they normally run their amps HOT. The early amps had a bias circuit defect and an underrated power switch. No speaker protection at all in case they went DC (they can without a preamp's input) and no inrush current limiting. These were all preventable faults brought on by a defect in design. Their face plates used to tear off when roaded in racks (like how real pro stuff is) due to another design defect. The 4B is the example here. I have seen these issues first hand, even though they refused to admit anything. Basically, they were lying and were caught at it. They even tried to tell one of my main customers I was a hack, on and on!! The customer knew better and replaced all their Bryston gear with real amplifiers that did not have these issues. They had witnessed Brystons fail and their own tech confirmed what I had found. They especially did not like the low handed tactic that was used by Bryston. That was the final straw really.
So, while the older products had serious issues, the new ones are supposed to be better. As I mentioned earlier, I'll accept that. All I have really said here is that their propaganda is simply advertising and that the 20 year warranty is only advertising.
Oh, those special parts with a great reliability used in the 4B series? Motorola outputs (good) and almost everything else was ..... Philips. The least expensive junk they could buy - from Electrosonic I'm guessing. Most other amplifiers of that time period used far better parts with lower failure rates. The Motorola stuff, I don't know. The house numbered their parts. 🙄 The drivers were special with longer legs, that's it for special. For all I know they may have used MJ15015 and MJ15016, economy parts as far as Motorola was concerned. Or they may have been 2N3773 and 2N6109 (?) or other real transistors. I don't know.
On the test bench I have had some amps fail their specs fresh back from Bryston service. They do require 1/2 Hr to 1 Hr to get their bias currents running. They sounded awful before that (low to no bias current).
-Chris
I didn't say they are not reliable, but they do have their problems. I serviced some of their early models, including some that just came from their service department. My knowledge is of their early models to be fair.
One thing you really must understand about Bryston. They would have you believe that their products don't fail. They certainly do! Spectacularly some times. Understand that they use normal (not supernatural charmed) parts. They have a failure rate ('cause they are the same ones you and I can buy). This failure rate increases with temperature (like all mortal parts) and they normally run their amps HOT. The early amps had a bias circuit defect and an underrated power switch. No speaker protection at all in case they went DC (they can without a preamp's input) and no inrush current limiting. These were all preventable faults brought on by a defect in design. Their face plates used to tear off when roaded in racks (like how real pro stuff is) due to another design defect. The 4B is the example here. I have seen these issues first hand, even though they refused to admit anything. Basically, they were lying and were caught at it. They even tried to tell one of my main customers I was a hack, on and on!! The customer knew better and replaced all their Bryston gear with real amplifiers that did not have these issues. They had witnessed Brystons fail and their own tech confirmed what I had found. They especially did not like the low handed tactic that was used by Bryston. That was the final straw really.
So, while the older products had serious issues, the new ones are supposed to be better. As I mentioned earlier, I'll accept that. All I have really said here is that their propaganda is simply advertising and that the 20 year warranty is only advertising.
Oh, those special parts with a great reliability used in the 4B series? Motorola outputs (good) and almost everything else was ..... Philips. The least expensive junk they could buy - from Electrosonic I'm guessing. Most other amplifiers of that time period used far better parts with lower failure rates. The Motorola stuff, I don't know. The house numbered their parts. 🙄 The drivers were special with longer legs, that's it for special. For all I know they may have used MJ15015 and MJ15016, economy parts as far as Motorola was concerned. Or they may have been 2N3773 and 2N6109 (?) or other real transistors. I don't know.
On the test bench I have had some amps fail their specs fresh back from Bryston service. They do require 1/2 Hr to 1 Hr to get their bias currents running. They sounded awful before that (low to no bias current).
-Chris
Jim Hamley said:
The answer, in my opinion, based on the CCIF IM results: not bad but not great. Below is how it fares against the Parasound JC-1. The Bryston numbers are on the left, the JC-1 on the right. The Bryston has more energy from the 9th on up. All numbers are dB down:
order Bry JC-1
3rd: -90 -84
5th: -101 -98
7th: -98 -98
9th: -101 -102
11th -105 -109
13th -110 -110
15th -99 <-110
Cheers,
Bob
Hi Bob,
Which Bryston amp was the test performed on? This one "looks" like a current model.
Did you ever run a 4B through the mill?
-Chris
Which Bryston amp was the test performed on? This one "looks" like a current model.
Did you ever run a 4B through the mill?
-Chris
Bob Cordell said:
Anyway, these are only measurements at one power level, and almost sure different for both amplifiers. Then I would be careful in comparisons. This is a magazine review problem. If it have said anything, the spectral measurements should have been done at many power levels covering 100mW, 1W ...... to full power. The spectral change with power will depend on output stage, NFB etc. etc. Imagine spectrum of this:
at different power levels. I can do it 😉
What kind of amplifier is this?
One from the sixties, when many bad transistorized amps hit the market?
One from the sixties, when many bad transistorized amps hit the market?
Edmond, it is written in the picture What amp it is. Remember what you were saying to Jan recently 😉
PMA said:
Hi Pavel,
It is an Ayre MX-R, I didn't overlook that. But what is it? Japanese stuff from the dark sixties? It looks like the manufacturer has never heard of NFB. 😉
Cheers, Edmond.
Edmond Stuart said:
He finds it advantageous, though high order harmonics he has are quite high!
http://stereophile.com/solidpoweramps/407ayre/index4.html
And this is 1W. We often hear that first watt counts 😀
Look at the favorite 7th harmonic, it is the highest!! John, how would it sound??
PMA said:
Pavel, I think you are under the erroneous assumption that Edmond remembers everything he says to me. Or that I do. 😀
Jan Didden
PMA said:
So long as the teflon wire has been sufficiently burnt-in and the snubber networks have been expertly tuned to quash objectionable transgressive sonic impulses, overstuffed marshmallows will sound lusciously translucent in their spontaneity.
This is both quite unlike and in stark contrast to the beleaguered and impotent performance of Edmond’s noxiously misguided, band-aided designs, which corrupt sonic experiences with the full deleterious force of sinisterly applied negative feedback to the tune of amorous periwinkles.
It is only through the scholarly study of the linguistic and communicative abilities of gorillas that this profound dichotomy can be fully understood mostly in its entirety.
janneman said:
Hi Jan,
As a matter of fact, I do remember what I have said to you (about Stochino's article), don't you remember? 😉
Cheers, Edmond.