Bryston B4 NRB fix.

[ksrigg]

So Lee...Do you think Bryston has sacrificed sound quality for longevity? With a 20 year warranty perhaps they concentrated more on making the amp bulletproof than they did on the pure sound quality? Des it appear "beancounters" were involved in component part decisions? I jguess I'm wondering WHY Bryston sound quality is not top drawer, and since you have now been through one, you'd know the answer. What are your thoughts on their design philosophy after being inside?

 

[Web Police]

Thanks
Larry

He types out three paragraphs over two posts and exercises his remaining brain cells and all you got to say is Thanks?

Who, what huh? Hmmmmmmmmmmmmmmmmmm!

284 vs 348 really makes that much difference? I hardly ever crank my amps more than a watt or two, maybe five or ten for a few minutes.

 

[speakerman1]

Well---your welcome. I guess I expected more answer than that DUDE!!

What would you like me to say? Number don't mean everything?

Larry

 

[laatsch55]

I don't want you to say anything in particular, just thought you would have more to say over that.

 

[laatsch55]

Thanks
Larry

He types out three paragraphs over two posts and exercises his remaining brain cells and all you got to say is Thanks?

Who, what huh? Hmmmmmmmmmmmmmmmmmm!

284 vs 348 really makes that much difference? I hardly ever crank my amps more than a watt or two, maybe five or ten for a few minutes.

Headroom man, headroom. Well 10 watts wouldn't get me off the porch.

 

[laatsch55]

Sutton, I don't know enough about transistor properties to answer that question. I don't know why it souds different. They did not go cheap on the board level components. Matching requiures a lot of time and energy.

 

[Web Police]

Headroom man, headroom. Well 10 watts wouldn't get me off the porch.

Yep for me headroom is 20 or 50 watts peak. Either your speakers are mighty inefficient, you have a severe wax buildup or you like it mighty loud.

 

[laatsch55]

2 outta 3 Web.

 

[Web Police]

2 outta 3 Web.

Spoken like Meatloaf.

 

[laatsch55]

Ain't bad!!

 

[laatsch55]

True to my nature , I gues I couldn't leave it at "just a fuse". While trying to access the bias pot(with a metal screwdriver) I shorted out 3 drivers and 4 outputs. A little research concluded that there was a 90% probability the drivers were MJE 15032's and MJE 15033's. The outputs wetre either 2N3773's and it's complement or the MJ15024/15025 compeimentary pair. With the most recent Mouser order said parts were obtained, installed, brought up on the DBT and I was still surprised with the cycling of the protect circuit. Didn't take as long this time for that bulb to go off!! Sooooooooooo........we can have that Bryston Lottery finally.

Some test results so far....

 

[laatsch55]

BTW, I now have a pretty good selection of PLASTIC screwdrivers.....

 

[laatsch55]

It appears to be OK. We'll put it on the horns for therest of the day...........

 

[laatsch55]

I think I have identified the bias pot, and current limit pots, DC offset-not adjustable. Anyone got a clue to the procedures??

 

[mlucitt]

Does this help?

 

[laatsch55]

Yes, but this is a 4B NRB. Enough difference the power amp boards don't even look the same. Different pot and testpoint setup.

 

[laatsch55]

The Lottery Bryston is getting shookdown whilst we await a reply from Bryston Customer Service for bias and current limiting procedures. Some one is getting a very nice amp, delivered to their door, FOR FREE!!!!

Slightly more than 400 watts into 8 befopre clipping------and sounds good all the way to it!!

 

[laatsch55]

Not impressed with the Bryston customer service folk so far. Haven't answered a 4 day old e-mail, and a direct phone call resulted in getting someone's voicemail........

 

[mlucitt]

I heard they were friendly, if you can get a hold of them.

 

[laatsch55]

SERIOUSLY SHAKING DOWN the Bryston. No matter how hard I want it to get to mach 8 it JUST WON"T. I miss my WOPL!!