Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Having problem with a Bryston 3B
Having problem with a Bryston 3B
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 27th October 2007, 11:55 PM   #1
Unique is offline Unique  Greece
diyAudio Member
Join Date: Oct 2007
Default Having problem with a Bryston 3B


I own a Bryston 3B power amp and having a problem. After a short circuit of a device connected to the same outlet with my amp( pc speakers ) that may produced current peaks, my amp's right channel stopped working. Since I already have oppened my amp to replace it's power caps with newer ( phillips LL series, great improvement btw ) a few years ago and being familiar to it, i started to troubleshoot. My power caps are ok, my backboard pcb is ok ( since i crossed the amplifying pcb's and the ex-left amp circuit works fine on the right hand place. So, my problem is with my right channel amp circuit. When it gets power, it blows it's fuse off. Do you have any suggestions on what should I look first?
By the way, I read that many readers of this forum care to have pictures of Bryston's pcb's. If there is anyone interested in my 3B's pcb's, let me know ( i have it apart already, so it's not difficult for me to take some pics ).

Thanks in Advance
  Reply With Quote
Old 28th October 2007, 07:48 AM   #2
Jan Dupont is offline Jan Dupont  Denmark
diyAudio Member
Jan Dupont's Avatar
Join Date: Apr 2003
Location: Copenhagen, Denmark
Send a message via MSN to Jan Dupont
My guess is that your output devices are fried
And maybe also the drivers......

Try measure the output devices and see how many Ohms there is between the rail lines and output (remember to discharge your power caps before measuring). Or you can insert a 40W light bulb in series with the Mains from your wall plug, and make some voltage measuring across the drivers and output devices. The 40W light bulb should be able to keep some voltage floating in your amp with the fuses blow up.
Free Schematic and Service Manual downloads www.audio-circuit.dk
  Reply With Quote
Old 29th October 2007, 08:50 PM   #3
Unique is offline Unique  Greece
diyAudio Member
Join Date: Oct 2007
Hmmm, could the FT417B cause a problem like mine...?
I tested right channel's transistors ( those being placed on the heatsink ) and everything is ok altough one of the two 2N6609 measures a bit lower than the other. Everything except FT417B which when i tried to get it out, one of it's "legs" broke as if it was a rust copper cable( i hope you can understand what i mean ).
  Reply With Quote
Old 30th October 2007, 12:14 AM   #4
Unique is offline Unique  Greece
diyAudio Member
Join Date: Oct 2007
Default False alarm, burned transistors indeed...

Correction: As i said in the first post, i put the left circuit to the right.. So, when I tried to measure this afternoon i had forgoten the split... So, the problem is that i burned one 2N6609 and one 2N3773 transistors. So, now i have to buy new ones. Could you suggest me what to take care of? Some measurements that i have to make?
Thanks in advance.
  Reply With Quote
Old 7th November 2013, 09:35 AM   #5
Unique is offline Unique  Greece
diyAudio Member
Join Date: Oct 2007
Coming back after long time... I've managed to find the output devices, a full matched set but it still woundn't work. To be precise, there was a small improvement since it started to "whisper". I have ordered a set of 1% mica caps since mine look faulty ( they have turned to black ) but after a simulation on a circuit software, something tells me that the problem has to do with the bias small transistors ( 2N5400 / 2N5550 ). Since I am not an engineer, I am thinking of carefuly removing them one by one and measuring them. I also have found some lots of transistors to replace them, but I am not sure I know how to match them. Could someone advise me on that? And perhaps give me an opinion if my thoughts abouts the 2N's are correct?
Thanks in advance!
  Reply With Quote


Having problem with a Bryston 3BHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Bryston first digital amp Islander Class D 14 9th November 2010 02:02 PM
FS: Bryston 4B NRB akunec Swap Meet 0 13th December 2006 12:18 AM
Bryston 3B/4B-SST clone? taj Group Buys 3 9th December 2006 08:46 PM
FS: 2 Bryston 4b's dunderchief Swap Meet 1 14th October 2005 10:27 PM
Looking for a Bryston 4B ST clone Phil O.son Solid State 5 6th November 2002 09:36 AM

New To Site? Need Help?

All times are GMT. The time now is 11:52 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio