[dgarratt]

Hi Guys,

I recently setup my new BP26 complete with 2 x 28B's. Both the 28B's are housed in a cabinet with all the recommended dimensions for hear dissipation. One of the amps is running much hotter than the other. Once in use for a 2 hours amp A is lukewarn while amp B is too hot to touch for more than a few seconds (i'm referring to the heat sinks on the side).

I tried swapping all of the cables (including power) on amp A to amp B to see if that would make any different...it didn't.

Any ideas? Both amps are brand new...should I be concerned?


Thanks in advance.

[James Tanner]

Hi Guys,

I recently setup my new BP26 complete with 2 x 28B's. Both the 28B's are housed in a cabinet with all the recommended dimensions for hear dissipation. One of the amps is running much hotter than the other. Once in use for a 2 hours amp A is lukewarn while amp B is too hot to touch for more than a few seconds (i'm referring to the heat sinks on the side).

I tried swapping all of the cables (including power) on amp A to amp B to see if that would make any different...it didn't.

Any ideas? Both amps are brand new...should I be concerned?


Thanks in advance.

Hi

is the stacked top amp the one that is hotter?

james

[dgarratt]

Hi James,

They're not on top of each other as in one sitting directly on top of the other but they are on shelves, one is on almost floor level and the other (the hot one) sits on the shelf above. I did wonder if that was the difference but I had a hard time believing that would make such a big difference in temperature between the two.

Maybe I should try swapping them over to see what happens??

Appreciate your reply and assistance!

[James Tanner]

Hi James,

They're not on top of each other as in one sitting directly on top of the other but they are on shelves, one is on almost floor level and the other (the hot one) sits on the shelf above. I did wonder if that was the difference but I had a hard time believing that would make such a big difference in temperature between the two.

Maybe I should try swapping them over to see what happens??

Appreciate your reply and assistance!

Hi

Sounds like positioning is not the issue.

Try leaving all the inputs and outputs (speaker cables) off the amp and just let it idle.  See if it still heats up.  It could need a bias adjustment.  Where did you purchase them?

james

[drummermitchell]

That happened to me a few yrs back only it was both 28's.
The 28s were both in open shelving and you could not touch either one on top for more than 3-4 seconds as they were that hot.
It was the bias setting.
If you take it to a dealer to adjust,make sure they do a three day check up on the bias as it needs to be adjusted more than once over a 24 hr period.
I had taken mine into my dealer and they said I could pick it up in a few hours(WRONG).
I did that twice with them and a total of a six hour drive over a two day period.
Bryston told them it need to be adjusted more than just a few hrs as it fluctuates.
So far after that all has been great with no heat troubles,even Mr. Russell was going to fly from eastern Canada to Alberta to fix it himself,that's SERVICE.

[dgarratt]

Hi

Sounds like positioning is not the issue.

Try leaving all the inputs and outputs (speaker cables) off the amp and just let it idle.  See if it still heats up.  It could need a bias adjustment.  Where did you purchase them?

james

Thanks James, I tried this and got the same result. Sounds like you may be right..may need a bias adjustment. I live in Australia and purchased them from Carlton Audio Visual in Melbourne. A three hour drive away..not even sure if my dealer can make these adjustments, it may have to go to Senheiser in Sydney. Is it possible for an end user like myself to make this adjustment? I have a good fluke multimeter which I feel i'm quite competent with.

btw, is this adjustment generally done before each amp leaves the factory? As stated before they are brand new and the serial numbers are only separated by a digit.

[James Tanner]

Yes each one is individually tested and biased.  Email Mike Pickett and see if he can help - it is not hard to do but you have to remove the top.

I am sorry for this.

mpickett@bryston.com

james

PS - there is no harm in continuing to use the amp.  If it gets to hot there is a thermal connector which will turn the amplifier off.

[dgarratt]

Yes each one is individually tested and biased.  Email Mike Pickett and see if he can help - it is not hard to do but you have to remove the top.

I am sorry for this.

mpickett@bryston.com

james

PS - there is no harm in continuing to use the amp.  If it gets to hot there is a thermal connector which will turn the amplifier off.

Thanks very much James, i'll contact Mike.

I also want to point out that this forum and your attention to Bryston customers is the reason I ended up choosing Bryston in the end. The sound quality coming out of this setup has well and truly exceeded my expectations! Thankyou!

[Laundrew]

Thanks very much James, i'll contact Mike.

I also want to point out that this forum and your attention to Bryston customers is the reason I ended up choosing Bryston in the end. The sound quality coming out of this setup has well and truly exceeded my expectations! Thankyou!

Ahhh.... the stuff that goosebumps are made from - time to warm up the Beasties 

Be well...

[Rod_S]

This is an interesting thread. So under normal conditions generally how warm should the 28's get if touching either the top or heatsinks? Both of mine get fairly warm and they are stacked one literally on top of the other until I can get amp stands and longer interconnects (been this way since Novemeber last year) but because I'm in an apartment, yeah I know I figure I'm probably runnining in Class A mode more often then AB thus the reason for the heat. Probably 80% of the time it's just regular tv being watched so they don't get a work out doing that. It wouldn't be until I listen to music or watch movies and play games where they would be insured to get into AB mode.

[SHV]

Here are the bias instructions for the SST series to give you an idea of what is involved to adjust bias.

http://bryston.com/PDF/Other/SST_BIASING_INSTRUCTIONS.pdf

Steve

[Laundrew]

This is an interesting thread. So under normal conditions generally how warm should the 28's get if touching either the top or heatsinks? Both of mine get fairly warm and they are stacked one literally on top of the other until I can get amp stands and longer interconnects (been this way since Novemeber last year) but because I'm in an apartment, yeah I know I figure I'm probably runnining in Class A mode more often then AB thus the reason for the heat. Probably 80% of the time it's just regular tv being watched so they don't get a work out doing that. It wouldn't be until I listen to music or watch movies and play games where they would be insured to get into AB mode.

Both of my Beasties are sequentially serial numbered and one does run noticeably warmer than the other, but not to the point that it would burn your hand. They do a great job of heating my room during extended listening sessions. My amplifiers are in the open as I am a proponent of maximum ventilation for electronic equipment.

Be well...

[Laundrew]

That happened to me a few yrs back only it was both 28's.
The 28s were both in open shelving and you could not touch either one on top for more than 3-4 seconds as they were that hot.
It was the bias setting.
If you take it to a dealer to adjust,make sure they do a three day check up on the bias as it needs to be adjusted more than once over a 24 hr period.
I had taken mine into my dealer and they said I could pick it up in a few hours(WRONG).
I did that twice with them and a total of a six hour drive over a two day period.
Bryston told them it need to be adjusted more than just a few hrs as it fluctuates.
So far after that all has been great with no heat troubles,even Mr. Russell was going to fly from eastern Canada to Alberta to fix it himself,that's SERVICE.

I consider myself extremely fortunate that Bryston is only a couple of hours away - peace of mind 

Be well...

[Rod_S]

Both of my Beasties are sequentially serial numbered and one does run noticeably warmer than the other, but not to the point that it would burn your hand. They do a great job of heating my room during extended listening sessions. My amplifiers are in the open as I am a proponent of maximum ventilation for electronic equipment.

Be well...

Yeah they do indeed put a noticeable amount of heat into the room Mine are also out in the open, up beside my main left speaker and will remain there when I get my amp stands, I'll just move one over by the right speaker. Here in the warmer weather of the summer I actually have a fan that blows on them.

[drummermitchell]

Mine are stacked and after a couple hours are warm(not hot).
No shirt,no shoes,no problem:

[Rod_S]

Here's a quick and dirty picture of mine