[donny619]

Hi All,

Over the past 2 months, I've had the middle channel (#3) on my 9B-SST go yellow on two occasions. Once during a movie near the end on regular movie volume and once during some game playing on relatively lower volume. Is this a heat thing? It goes green again after shutting down for a few minutes and powering back up, or is it an indicator that the channel may be going bad?

I have 2 channels on 9B-SST going to my center speaker. The #3 channel goes to the tweeter of my B&W HTM-2, using the balanced output from my SP 1.7. The #2 channel is using the unbalanced output and goes to the woofer of the speaker. It remains green when the #3 channel goes yellow.

If it is a heat thing, is there a reason why it's happening to one and not both? Any ideas would be great. Thanks.

[SoundGame]

What's your ventilation like around the amplifier?  Since channel #3 perhaps is dead centre - it might be facing the most heat retention. 
 
Have you used the same guage of speaker wire throughout?  How about the length of speaker wire? 

[donny619]

I admit, the ventilation could be better but it's something that has not happened before. The two sets of cables going to the center channel from the power amp are identical (gauge and length).

Is the yellow light definitely a heat indicator?

[James Tanner]

I admit, the ventilation could be better but it's something that has not happened before. The two sets of cables going to the center channel from the power amp are identical (gauge and length).

Is the yellow light definitely a heat indicator?

Yes the yellow indicates the channel has shut down due to excess heat.

james

[SoundGame]

I admit, the ventilation could be better but it's something that has not happened before. The two sets of cables going to the center channel from the power amp are identical (gauge and length).

Is the yellow light definitely a heat indicator?

Bass frequencies tend to be more challenging on amplfiers - demanding more current and generating more heat but since this is the Centre Channel - which is predominantly mid-range / lower-treble in terms of delivering the voices in movies - it is likely that your #3 channel is being taxed a little more, along with the fact with it being in the centre, may be leading to more heat retention. 
You say ventilation could be better - don't tell me you have something like an inch or half inch clearance....LOL. 
How much clearance to you have on the top, sides, back of the amp?  Is it sitting on or next to other heat producing equipment i.e. audio / video components. 

[donny619]

Thanks James for the confirmation that it is a heat issue.

Soundgame. LOL. I have good clearance (12 inches) but the item next to it is my 4B-ST (yea, I'm a Bryston whore). I've always thought of getting fans and it looks like I'll have do so now.

Also, you mentioned that being in the "center" leading to more heat retention. I DO have a channel on the 9B-SST doing nothing (the #4) channel. Perhaps I'll move what's on the #3 there. Thanks again!

Bass frequencies tend to be more challenging on amplfiers - demanding more current and generating more heat but since this is the Centre Channel - which is predominantly mid-range / lower-treble in terms of delivering the voices in movies - it is likely that your #3 channel is being taxed a little more, along with the fact with it being in the centre, may be leading to more heat retention. 
You say ventilation could be better - don't tell me you have something like an inch or half inch clearance....LOL. 
How much clearance to you have on the top, sides, back of the amp?  Is it sitting on or next to other heat producing equipment i.e. audio / video components.

[Marius]

Hi,

Just out of interest: what do you play on them/how do you use them? My 28b's play non stop most of the time, but I've never been able to feel them heat-up.

(cat likes to take its nap on top of it though...)

Greetings,
Marius

Thanks James for the confirmation that it is a heat issue.

Soundgame. LOL. I have good clearance (12 inches) but the item next to it is my 4B-ST (yea, I'm a Bryston whore). I've always thought of getting fans and it looks like I'll have do so now.

Also, you mentioned that being in the "center" leading to more heat retention. I DO have a channel on the 9B-SST doing nothing (the #4) channel. Perhaps I'll move what's on the #3 there. Thanks again!

[donny619]

When I listen to music, I only use the 4B-ST. I've never had heat issues with that amp and like you said, I can run that all day without worry about heat. It's the 9B-SST that gets extremely hot (and I'm only using 4 of the 5 channels). I have it on only when I'm watching movies or sometimes playing video games (2-3 hours at a time). They do share the same cabinet now too so again, I'll be looking to find ways to keep the area 'cooler'

Hi,

Just out of interest: what do you play on them/how do you use them? My 28b's play non stop most of the time, but I've never been able to feel them heat-up.

(cat likes to take its nap on top of it though...)

Greetings,
Marius

[Marius]

ok , good luck with that! still seems odd. And be careful..

When I listen to music, I only use the 4B-ST. I've never had heat issues with that amp and like you said, I can run that all day without worry about heat. It's the 9B-SST that gets extremely hot (and I'm only using 4 of the 5 channels). I have it on only when I'm watching movies or sometimes playing video games (2-3 hours at a time). They do share the same cabinet now too so again, I'll be looking to find ways to keep the area 'cooler'

[niels]

Could it be it needs a bias adjust?

[donny619]

I read about that. Will it really reduce heat?

Could it be it needs a bias adjust?

[niels]

Well, James can probably give you an answer, but I believe that if the bias has drifted the amp can get extremely hot so i think you should have it checked.

[Joe Keifer]

Could it be it needs a bias adjust?

I would agree that a sudden erratic operation of one of the amplifier channels with no other changes, environmental or otherwise, signals a failure of that specific channel.  I've reviewed the procedure associated with aligning the bias in a 4bSST and wouldn't recommend trying to accomplish the alignment without adequate knowledge, test equipment or "adult" supervision.