That is true of the very first KSA-50/100 amps but not of the MK-2 versions and the KSA-80B was all differential and something totally diffrent than very first efforts by"Dan The Man", but the KSA-80 is still considered an early Krell effort as well. Anyway, doesn't really matter how much feedback, how many pairs of Chrome plated muffler bearings are in the thing, as far as the Clone goes as its pretty hard amp to beat in its power class. Never owned an original MK-2 50 so can't comment on how one compares to the clone version but I suspect that the clone versions being built are alot better amps than an original.
Mark
We, or better : I’m trying to find actual pcb layout of 3B ST or 3B SST like good start point from where we may try to construct better clone-amp. If we have good starting point, something will be born at the and. My point is: we all have commercial and diy amps in every day use, so why not to have one more choice at disposal?
Like I stated in my first post, I didn’t finished my KSA-50 clone yet, but who cares! We are for DIY here or what???
Like I stated in my first post, I didn’t finished my KSA-50 clone yet, but who cares! We are for DIY here or what???
Hi Chris,
You are optimistic guy, pushing always forward!
I’m not interested to copy any amp exactly, but to push some already good design to the boundaries. I think 3B SST is that starting point. Having actual layout will help me to start from some proven point and than going further. Someone on this thread stated that brystons are good because have good (potent) psu, but than again, any decent amp must have that, right?
We must have more than one or two options regarding amps here, so bryston is interesting option I think. I’m not interested to do something just for me, I like to contribute to something that will be appreciated from more people.
Chicco
You are optimistic guy, pushing always forward!
I’m not interested to copy any amp exactly, but to push some already good design to the boundaries. I think 3B SST is that starting point. Having actual layout will help me to start from some proven point and than going further. Someone on this thread stated that brystons are good because have good (potent) psu, but than again, any decent amp must have that, right?
We must have more than one or two options regarding amps here, so bryston is interesting option I think. I’m not interested to do something just for me, I like to contribute to something that will be appreciated from more people.
Chicco
Hi Chicco,
Thanks, you're right about options. Reworking this amp is the best way to learn what makes it "tick". It does have an unusual output stage that may have some value. The input and vas are nothing special. You may find the PCB layout is not optimal anyhow. Certainly, pictures would provide a good starting point for a layout.
What I love about this forum are the endless options and ideas. Good or not, they allow us to think and look at alternatives. Hopefully, someone with access to one of these can provide what you asked for.
-Chris
Thanks, you're right about options. Reworking this amp is the best way to learn what makes it "tick". It does have an unusual output stage that may have some value. The input and vas are nothing special. You may find the PCB layout is not optimal anyhow. Certainly, pictures would provide a good starting point for a layout.
What I love about this forum are the endless options and ideas. Good or not, they allow us to think and look at alternatives. Hopefully, someone with access to one of these can provide what you asked for.
-Chris
I'm certainly up for getting a PCB designed for this, and would greatly appreciate any internal pics. It certainly looks like with this amp the magic is in the output stage, and after my experiences with re-imagining the KSA50, careful selection of modern devices seems to work well in these older designs.
Guys,
I think what makes the Bryston look alot different is just the way the output stage is drawn. Were it re-drawn in normal fashion it might resemble more familiar amps except for placement of a couple of the devices. I too look forword to a board GB and would certainly build this (sans any op amps) if there were a board available.
Mark
I think what makes the Bryston look alot different is just the way the output stage is drawn. Were it re-drawn in normal fashion it might resemble more familiar amps except for placement of a couple of the devices. I too look forword to a board GB and would certainly build this (sans any op amps) if there were a board available.
Mark
Have read it.... the point is that they also use non-standard drawing techniques that makes it look way different than it really is. Its just a triple darlington whose sucessive stages are driven by the previous stages output...... Pretty simple and I wouldn't call it all that unusual.
BTW: A friend that is Chief Projectionist over at Cinesphere remarked the other day that they have pulled all the Brystons out and replaced them with Sonics(Imax's sound company) own amps... which really are just Crown amps in disguise. The Brystons were all finally pulled out because of "repeated failures". Doesn't matter to me as cinema use is probably the most grueling use of a power amp and this project will be for home use and hopefully built to higher standards anyway. Am still anxious to hear one for my self.
Mark
BTW: A friend that is Chief Projectionist over at Cinesphere remarked the other day that they have pulled all the Brystons out and replaced them with Sonics(Imax's sound company) own amps... which really are just Crown amps in disguise. The Brystons were all finally pulled out because of "repeated failures". Doesn't matter to me as cinema use is probably the most grueling use of a power amp and this project will be for home use and hopefully built to higher standards anyway. Am still anxious to hear one for my self.
Mark
Hi Mark,
I've worked on them many times. Toured the old manufacturing plant. I'm not really impressed with them. I don't feel they are made to a high standard either. Cinesphere becomes yet another client to pull the darn things.
Brystons run very hot and cook themselves in a rack. If you get a chance, monitor the bias on one. When first turned on, and for a while after, the bias is low and they suffer from severe crossover distortion. After a long while they stabilise, and boy are the heatsinks warm! They sound okay after that. Now if you read the blurb on the Bryston site, you'd wonder why they need such a high bias, given the "perfection" of the output stage used. You also may wonder why they can't control the bias current very well.
When they repair a blown module, they only replace the blown parts. So much for output matching (not unless they changed their ways lately). I had measured a few that did not meet specs after service at Bryston, warmed up.
-Chris
I've worked on them many times. Toured the old manufacturing plant. I'm not really impressed with them. I don't feel they are made to a high standard either. Cinesphere becomes yet another client to pull the darn things.
Brystons run very hot and cook themselves in a rack. If you get a chance, monitor the bias on one. When first turned on, and for a while after, the bias is low and they suffer from severe crossover distortion. After a long while they stabilise, and boy are the heatsinks warm! They sound okay after that. Now if you read the blurb on the Bryston site, you'd wonder why they need such a high bias, given the "perfection" of the output stage used. You also may wonder why they can't control the bias current very well.
When they repair a blown module, they only replace the blown parts. So much for output matching (not unless they changed their ways lately). I had measured a few that did not meet specs after service at Bryston, warmed up.
-Chris
anatech said:
Dear Chris,
I disagree with you here. I can not speak for the older Bryston's but the SST's don't become hot at all. Non of the SST become hot! The bias is low, and for my 7BSST's the bias is only 12 mV over the emittor resistor. I monitored the bias in a cold 7BSST when turning on, and it is not that unstable. Just like every other amp it is flucterarting a little bit. Nothing special either. I don't messure any x-over distortion after just turning on. The sound changed not that much after a hour either. Even with 150 watt into a 8 Ohm dummyload the amp is still not that hot.
A studio where I work have a rack with 6 4BSST's without any space between the amps. And the temperature is still bearable. The listen so loud that the studio lights dim's with the rythm of the kickdrum, but whatver happend the bryston's always works!!!. If you don't want any heat at all, then consider PWM amp's. (with PWM **** sound) For a class A/B amp the bryston's don't run hot at all!
A friend of my is a touring bass player. He have a 4BST in his touring rack. The amp get abussed physicly and electrical, but never give any failure, and is able to prudce high sound pressure level's constantly!. The bryston amps in cinespere are very old 4B's with the hammond transformers. These amps are at least 15 years old now. and are in no way comparible with the Bryston's from today.
Bryston does a lot of good things. Take a look for instance at the mains input. The diode/capactior circuit to prevent DC go into the mains transformer. Clever and effective. They pay attention to it and that show's that bryston is a serious company.
The intermodulation distortion of a 7BSST is as low as I ever messured (19KHz. and 20Khz. sinewave the highest harmonic is still below 90dB.!). A square wave reproduction is as good I ever messured. And then I mean better then a lot of Mark Levinson's and krell's. The sound is wonderfull, with one of the best mid-high's. So natrual, so airy and in layers. I'm musician myself, and play a lot in bigbands etc. So much amplifiers have trouble with cupper brass isntrument's. Not the bryston. One of the not so many amps that know's how to reproduce difficult harmonics of a trombone, trumpet and alt sax. It better my old Krell KMA-200 mk2 mono's. It better the ML NO331 and it better the Krell KSA-250 and many more in natruality.
It is easy to diss the quality of bryston amps, but in fact they are really special. They just sound wonderfull, and meassure really good to.
You sure you are not talking about the old ST or NRB series?
With kind regards,
Bas
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