Thanks Amplidude.....yah..changed many components and checked voltages across R38-41, connected to speaker and checked sound quality before mount power transistors then mounted a pair of power transistor and adjust bias voltage.Same thing happened to me and powered for seconds but likely nothing happened .
The big problem with Chinese Amplifiers is not provide good technical support documentation. It is very important to know circuit to troubleshooting problems or create a assembling strategy to avoid problems like we have here.
I assembled the original Bryston schematic in my bench and did lots of tests supported by LTspice simulation and find exist some changes that make this amplifier to become really bad and unstable.
It is a really good amplifier and make boards in my country (I suppose it is rule in all country) is very expensive.
I asked Chalky and Amplitude for actual schematics and I had no answer. I asked schematics to seller and he charged me US$10. Interesting I have original schematics for free in Bryston site.
This is a expensive amplifier to assembly and without documents I gave up this project.
Good luck to all interested in this expensive project.
I assembled the original Bryston schematic in my bench and did lots of tests supported by LTspice simulation and find exist some changes that make this amplifier to become really bad and unstable.
It is a really good amplifier and make boards in my country (I suppose it is rule in all country) is very expensive.
I asked Chalky and Amplitude for actual schematics and I had no answer. I asked schematics to seller and he charged me US$10. Interesting I have original schematics for free in Bryston site.
This is a expensive amplifier to assembly and without documents I gave up this project.
Good luck to all interested in this expensive project.
Hi merola
Yes documentation can be quite poor, but must say that documentation that came with 4bsst was okay, well some stuff in Chinese.
Merola the files you seek are posted here in this thread.
My boards worked alright first time, only trouble was me not grounding correctly.
Yes documentation can be quite poor, but must say that documentation that came with 4bsst was okay, well some stuff in Chinese.
Merola the files you seek are posted here in this thread.
My boards worked alright first time, only trouble was me not grounding correctly.
I found all PDF files. Thank you.
The only missing files are related to Power Supply Board. I hope it have the great AC Line DC protection circuit used by Briston and refered here by lots of Diyer. In My personal opnion it is the best one and is very close to the one used by Mark Levinson in reference amplifier (only some extra resistors to discharge electrolitics caps).
It looks to follow original Bryston Schematics and the input circuit from power board looks to be correct. It is critical and if removed ( to minimise costs in a begginer vision) give lots of troubles and damage all good performance of this amplifier.
I will compare my note.
Regard to all.
The only missing files are related to Power Supply Board. I hope it have the great AC Line DC protection circuit used by Briston and refered here by lots of Diyer. In My personal opnion it is the best one and is very close to the one used by Mark Levinson in reference amplifier (only some extra resistors to discharge electrolitics caps).
It looks to follow original Bryston Schematics and the input circuit from power board looks to be correct. It is critical and if removed ( to minimise costs in a begginer vision) give lots of troubles and damage all good performance of this amplifier.
I will compare my note.
Regard to all.
Last edited:
Fetamp
Sorry to ask you a personal question, I hope you do not matter.
How much you expend in this project?
I suppose It is a good reference to other.
Thank you again.
Sorry to ask you a personal question, I hope you do not matter.
How much you expend in this project?
I suppose It is a good reference to other.
Thank you again.
build it you won't regret.
My build was quite cheap because I had most of the expensive parts already, I had the 2 toroidal, charging caps, and output transistors.
Think total spend is 700- 800 is dollar.
Im coming from PA
Its beautiful but from my views, but its waste of money for material, you dont need 30 % of it for HQ High End Audio
So much Capacitor I need for
2 to 3 PA Powerful Class AB PA Amplifier driving very large Subwoofer.
Or big Power Half bridge Class D Amplifier to avoid Bus Pumping at full output power 100 V DC Rail / 1000 W RMS Power
Never really never for HI-FI it makes any sense.
When you will testing your amp at live perforance, you will agree 100 %
I’m also had most expensive stuffs....i agree with Amplidude it cost around 500 usd
I agree with amplitude; with good matching and high quality components its an excellent amplifierKSC2690/KSC2690A. the PN100 and PN200 used for the differential pairs in the pre and power amp are now obsolete and hard to find, I could never get the pnp and npn types to match very well for hfe. On the other hand the BC546C/BC556C pair are higher gain and the two batches I've bought have been nicely match with a gain of around 530 for both the npn and pnp types. These are still made by Diotec ( and probably others ) and readily available. An all round better choice than the PN100/200. Just remember to put them in the wrong way round. Similarly the KSC2690/KSC2690A are a better choice than the MJE172/182 used in the preamp output stages. Higher gain, better matching.
Thanks Amplidude ...I used BD140/139 instead of MJE182/172 ,they are little hot as there is no space to install heat sink in this input boards.