Bryston 4B Refurbish
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- čas přidán 5. 03. 2021
- This is a belt and braces approach to fixing an Bryston 4B that was blowing fuses and had a hum.
The PSU filter caps still measured great so they will be left for another day.
The main intention of this video is to demonstrate a couple of steps to safely get the amp to mains voltage. - Věda a technologie
![The Fuses Keep Blowing! - A Really Nice Bryston 4B NRB Power Amplifier Repair [Video 30]](http://i.ytimg.com/vi/6SNAfE7bYpY/mqdefault.jpg)
A lot of people will write off anything that isn't the 'latest and greatest', but quality like this is quality forever.
Thank you for the video. Many helpful reminders that I have forgotten.
I am restoring my first gen 1978 3B (chrome handles) of which I have owned since new. Now that I am retired from the RCAF I can get down to business and bring new life into this wee beasty.
1978 that's crazy! I wonder what modern equipment will be still around after forty years?
Thank you for your video. I have what I believe is an older? 4B without a front panel power switch…..otherwise looks identical. I purchased the 4B year from gentleman with small service shop that said he had only “adjusted bias” before selling to me. Using the 4B with Magnepan .7s. The sound was wonderful. After six month the RH channel was running 40~50% hotter than the LH channel. Same gentleman readjusted the bias. Now running with even heat from both channels. Understand I could be running on borrowed time! ….but I’m really enjoying the wonderful 4 ohm 400 watt old girl and the Maggie’s. Wish you were in my neighborhood! Your great video encourages me to invest again when the need arises.
This is a splendid video. Fascinating.
Thanks so much this was so helpful to me repairing my Bryston 4BST.
Fascinating video!!
I was given a pair of old Magnepan SMGa's and kept searching for a Bryston and ended up buying a cheap NAD 302 that had the balance monkeyed with and it just sounded like it was in mono so I got rid of that and kept searching and found this very small amp callled a SMSL AO200 and would love to hear a side by side of this amp and the Bryston. I'm completely blown away by the SMSL.
I noticed, and you mentioned, a cap that you touched with your iron by the connecting wires for the daughter board . I don’t see those caps on the schematic and was curious what value they are and their location. I just replaced all outputs on a 4b and there is an oscillation at 50% power and above on the positive side of the waveform. Curious if that cap was added to cure that.
Very Nice. Thank-you.+-"look up the Queens skirt"-+ 1st time hearing that in NEW hampshire
Hello, I have a vintage chrome handle Bryson 4B that keeps blowing fuses on the right side. What is the best chores of action to fix something like this. I have taken it to get fixed but they just said it needed a good clean and it was good as new. But I have the same problem 2 months later. Should I invest in refurbishing this, or should I buy a new one. I am currently using it for my new-10s. Any advice would be helpful
Nice video! What do you think a hifi shop would charge for this job?
Thankyou nice video, was wondering if you replaced the main caps as I have an older B&k THX 2 7 channel amp and wondering where to locate replacement for those small beer can type capacitors.
I did not replace the main filter caps as they measured fine.....but you remind me now that I should check them every year
Thank you for the video. I am in the process of replacing the output transistors on a 4B amplifier. Using a transistor tester, the betas and VBE of the NPN (MJ21196G) and PNP (MJ21195G) transistors I received closely match when compared to the ones of the same type, but the betas of the PNP transistors and about 2X the betas of the NPN types. The data sheet shows that with increasing Ic the beta of the PNP transistors decrease while the betas of the NPN increase. Other than fake e-bay Chinese knock offs, these are the only transistors I can get. In your video you commented on matching transistors; can you expand on this a little so that I can make a decision on how to proceed. Thank you for sharing your experience and knowledge.
The “square” driver is a Robertson. That’s a very old 4B as it uses D Power transformers, now they use toroids.
I have 2 Bryston 4B-SST that power off after a few seconds. I was totally fascinated watching you work but have intentions to even begin to attempt what you did. 🤣
Good job man!
Late comment here, more of a question: what is the song that plays at the end of the video? Thanks!
It is a track called Dream from my 7.1.4 compositions. galactichorizon.com is a web site I have just started to learn about self distribution of atmos tracks.
@@reallyniceaudio You're awesome, thanks! Great videos by the way.
What did you use to clean the casing etc?
I like to go in first with antic-bac kitchen wipes, followed by IPA wipes except where there was heat sink compound where I used IPA on cotton Budz to remove large swabs of the compound.
I have a Bryston 4B as well, with identical hardware. I'm guessing that should be of the same vintage as yours.
One thing i found very concerning is the cords used for thermal switchs on top of each module. They are using very low quality PVC insulated lamp cord, and the plastic actually appeared to have oxidized and degraded over the years.
It would not be that big of a deal if they didn't route 120VAC mains power there, but they did. I personally consider that unsafe to use, and would highly recommend replacing those wires with more durable ones. Like silicone or teflon insulated wires. Which will resist degradation a lot better than PVC, for a lot longer at high temperature.
I haven't started refreshing my 4B (yeah, I'm a lazyass), but other than the usual ely cap, pot update and the wires, I plan to delete the input board and install both input and output connector directly on each module. To reduce the times that signal have to go from one connector to another.
Interesting/great video.
I have 6 of these Bryston 4B's that I want to sell. I think some of them need a service like this.
wow that would make for an epic Atmos rig!!
Bryston is the best sounding system on the market