[sbright]

Hi all,

I've had a peculiarity with my system for a little while now that I'm curious to get to the bottom of.  I have 2x7BSST's hooked up to the BP26.  They are powered up via the 12V trigger connected to the BP26.  Also running balanced XLR cables throughout.

The peculiarity is that when I initially power up the system all works fine for a couple of minutes.  Then, there's a popping sound (similar to the discharge that happens on power off) and one of the 7B's starts running at about 5% volume level.  Then, after about another two minutes the offending "quiet" amp decides it's ready to party and returns to normal volume levels.  It's always the same temperamental amp.

Any thoughts?

Thanks

[James Tanner]

Hi

Sounds like a relay - send Mike Pickett in service an email - mpickett@bryston.com

james

[werd]

Hi James

Just out of curiosity. On mono blocks when one breaks do you want to see both amps come back or just the broken one?

[vegasdave]

Good question.

[James Tanner]

Hi James

Just out of curiosity. On mono blocks when one breaks do you want to see both amps come back or just the broken one?

HI,

Generally it is not necessary as the amplifiers are independently tested to meet a performance criteria so any mono 7B can be used with any other mono 7B as long as they are in the same series (NRB, ST, SST etc.)

james

[sbright]

Hi all,

Update on this for anyone else that may strike a similar issue.

A couple of months after I posted the offending amp died with a pop and a whiff of smoke.  Since then one of the driver boards has been replaced and now everything is peachy.   

[NiToNi]

I'm having a similar problem with my 7B-SST. After 10-15 min warm-up, it goes silent. I then have to turn it off for 5-10 min to allow it to cool down a little bit, before I can turn it on and it works again (literally for days, if need be, without another hitch).

I've learned to live with it so I haven't brought it in (too lazy) but I fear that pop and whiff of smoke 

[James Tanner]

I'm having a similar problem with my 7B-SST. After 10-15 min warm-up, it goes silent. I then have to turn it off for 5-10 min to allow it to cool down a little bit, before I can turn it on and it works again (literally for days, if need be, without another hitch).

I've learned to live with it so I haven't brought it in (too lazy) but I fear that pop and whiff of smoke 

Sounds like a bias problem but the thermal shutdown prevents an 'puffs' from occurring.

james

[Howard Swayne]

I had a pair of those and loved them. THey would actually drive the Maggie 20.1's I had at the time. Never had any problem, but with Bryston's 20 year warranty, whats to worry. Kudos to Bryston.  :thumb:Glad you got it resolved.

[NiToNi]

Sounds like a bias problem but the thermal shutdown prevents an 'puffs' from occurring.

james

Thanks, James.

I guess bias adjustments have to be done by a qualified technician and not by the consumer...?

[James Tanner]

Thanks, James.

I guess bias adjustments have to be done by a qualified technician and not by the consumer...?

Correct - as the unit heats up it is adjusting bias based on temperature.  So it is not something you can do yourself.

james

[drummermitchell]

I should add also if the 7's relate to the 28's bias settings,whoever the tech is don't let them tell you that they'll be ready in a few hours.
I went thru that with my 28's and it took 3 days.
First time it happened they said come back in a few hours(so I did)took them home (3hr drive) same thing,couldn't touch the top of the amps after  7-8 seconds,dam hot BBQ.
Anyway James and Stuart got on the case and had the tech do the bias over 2-3 days.
Now they are just warm to the touch and it's been over a year at least and all's well .