[mklibra]

Hello, recently I made a 4 BSST C work hard with the quite demanding JBL 4412 3 way pro monitors, over a couple of hours on high volume levels. The amp went VERY warm but the temperature was considerably higher on the left side than on the right. I wonder if it is natural and bound to 4B SST structure inside? I hope everfything is ok with my unit bought new through the German SunAudio Bryston dealer (no official dealer in Poland). I noticed NO difference in sound between the right and left channel.

By the way, I realy recommend the pro JBL 4412 as one of the best price/performance ratio pro monitors paired with the Bryston. Also check out Kimber 8TC cable (a revelation!!!). Linear, linear, linear...

James please, any comments ?? Thank you.
Marcin
 

[niels]

If it doesnt engage protection mode I guess you have nothing to fear...

[jethro]

mklibra:

When you say very warm, do you mean too hot to keep your hand on the amp, or
about how hot a car's dash gets in the sun ?
Your speakers are fairly efficient, unless your are listening in a big room or
your ears are bleeding. Make sure you aren't clipping (flashing red LED).
I've found the 4B-SST runs much cooler than the 4B-ST.

[James Tanner]

Hello, recently I made a 4 BSST C work hard with the quite demanding JBL 4412 3 way pro monitors, over a couple of hours on high volume levels. The amp went VERY warm but the temperature was considerably higher on the left side than on the right. I wonder if it is natural and bound to 4B SST structure inside? I hope everything is ok with my unit bought new through the German SunAudio Bryston dealer (no official dealer in Poland). I noticed NO difference in sound between the right and left channel.

By the way, I relay recommend the pro JBL 4412 as one of the best price/performance ratio pro monitors paired with the Bryston. Also check out Kimber 8TC cable (a revelation!!!). Linear, linear, linear...

James please, any comments ?? Thank you.

Marcin
 

Hi Marcin,

Each channel in every Bryston is totally independent so they are 'bias'and QC'ed separately to ring the maximum performance from each channel.  You may find one channel rums warmer than another on heavy load because the bias adjustment and the speaker load may be slightly different. Also the preamplifier feeding the amplifier or the source component may have slight differences.

Try two experiments.

1. if the ampis just at idle ( say for an hour or two) do both channels have the same temperature?

2.Swap the left and right channel inputs and outputs and see if the heat issue stays on the same channel or moves to the other side.

james

[mklibra]

Hello, thank you all for your posts. I have been away for some days, so the tests recommended by James will take place on Wednesday this week, then I will come back with the feedback.

Jethro, by very warm I mean approx. 70 degrees celcius. I took the speakers to the 120 square meters room in my company. Of course there was no clipping and yes volumes close to the ear-bleeding. This test was not to prove anything, it was only done just to let the 4B sst work much more than it usualy does in my appartment. Also the JBL's were not in use for a couple of months as not being my primary speakers. In both the cases (for JBL and Bryston) it was a kind of break-in again. On a data sheet the 4412 are fairly efficient but in my opinnion to realy make them sing you need no less than 200W. I tried them so far with different electronics, in most cases not exceeding 100W with satisfactory results but, it was only with the 4B sst that the JBL's started to sing.

[niels]

In the Stereophile test of B100 where they ran it at 60% load for an hour this was also too hot to touch, but it didnt shut down either.
My old class A would be around 60 degrees all the time and I was dead worried untill I learned why !

[mklibra]

Niels,

The point is not that my 4b sst got hot, what I am concerned about is that ONLY 1 side (left) got hot, whereas the right side remained warm. The difference in temp. being approx. 40%. As far as I know, the 4b sst in its internal structure is like 2 monos located on both sides of the amp box. I am not an electronic man at all, but this would suggest that that the temperature of the amp should be even on both sides.
Thanks Niels for your points. I can wait till tomorrow to carry out tests recommended by James Tanner.
Marcin

[Phil A]

I have a 14BSST and one side gets hotter than the other.  I've talked to Bryston technical support and it is not a defect.

[mklibra]

Thank you Phil, as long as I can hear NO difference in sound between the left and the right channel, the temperature of any particular part of the amp will not bother me at all. Still, If it had not been for this insane heavy test I would have never found out the differnce in temp. between left & right. Regards. Marcin

[Phil A]

My speakers are torture for most amps (Thiel 7.2s).  I had a 6BSST (a 3-channel 4BSST) on the front 3 channels at 1st (I picked it up light used in a good deal about 3 yrs. back).  I then decided to try the 14BSST (which I also got light used).  I like the sound but when I played certain demanding things (for 20+ minutes) one channel would cut off as it got much hotter (and it is not in a rack and lots of space around it and you could burn your hand).  On a demanding movie soundtrack I did get the other side to cut-off once.  I sent a bunch of E-Mails to Bryston and talked to them too.  I have a very large room (about 16x20 ft. with 19 ft. ceiling and it opens into other spaces).  The Thiel 7.2s are also not the most efficient things in the world.  I built a custom amp stand with fans when I play demanding stuff and it has not cut out at all with the fans in use.  I had the 6BSST for probably several mos. before I got the 14BSST and did not notice any issues with it.  I now use the 6BSST on the center and rears.

[mklibra]

Hello, finaly finished the tests recommended by James Tanner...

1. When my 4B sst has been left on for 1 night without any pre or speakers hooked to it, the temperature was the same for both channels. (measured with the digital termometer)

2. When I switched left/right from the source and the pre and the speakers and let the amp bleed gain, it was the same story with the same left channel and side of the 4b sst getting hot, whereas the right was only warm. But this time, due to the incerdibly high temps in Poland (32 celcius) during the test, the left channel shut down (no clipping, just temperature).

Aparently, there is a difference between the left and right channel in terms of its temp. behaviour when pushed hard.

Aparently, there is NO difference in sound between the right and left channel.

And again, I would have never got into this knowledge if I had not taken the 4b sst for this test out of my home to the company. At home my Bryston works within its 30% power capability.

Still, with my so-far experience with the power apms like Plinius, Krell 150, Mark Levinson 331, Cello Encore 50, Audio Research VT 100 mk II, Conrad Johnson MF2500 , I had no such peculiarities. But still, none of these amps were pushed as hard as the Bryston. Yet still, none of these amps turned out to be as good sonicaly as Bryston 4b sst, even though some of them were much more expensive.

Please note that the problem of the temp difference has been noted by Phil with his 14B sst and just in the recent post from Mag with his 3b sst.

Regards. Marcin

[Phil A]

Before the SST stuff, I had Proceed HPA amps on the front channels (and before that a Bryston 4BST).  I have as noted a very large room with Thiel 7.2s that of course are not the most efficient or the easiest load in the world.  The ST once or twice on demanding HT (very) momentarily had the LED go (yellow and then) red.  The HPA drove the speakers no problem.  A bit on the cold and analytical side vs. the SST but nicely built and sounding (some might prefer the sound).  I had the 6BSST on the front channels for several mos. and did not play anything that I had a problem with.  After picking up the 6BSST lightly used I got a 14BSST also lightly used a few mos. later and ended up just building an amp stand with fans and it has been fine with the fans going.  With Bryston slow into HT and the little bit more power I needed, I got rid of the 4BST (yrs. back).  The warranty and service brought me back.  It's not fun when you spend big bucks on stuff and as I've noted in the past anything can have a problem.  The better cos. are the better cos. for how they handle those issues. 

[mklibra]

Hello, I am now quite worried, my 4b sst gets hot on the left side and then shuts down after approx. 15 minutes of playing, even on the low volumes, with my home Proac Studio 100 2 way paper cone easy stuff. With the JBL's it is taking 4 minutes of a loud, but still I would say 50% of what 300W should handle, listening to the music. Obviously something IS wrong with the left channel. Please James anything you can help ?

The unit bought new through Sun Audio, the respectable German dealer, since there was no dealer in Poland.

The great disapointment is that the studio workhorse ( this term is often used in the descriptions over the net) designed to work under heavy conditions, turns out to be problematic in the basic home application. The bitter thing is that my Bryston was the first unit bought new over the last 10 years, just to be SURE that it will run for 20 or so years. Sonicaly, it is the most rewarding amp I have encountered so far, after the 15 years hi-fi/end trauma. Am I a just another bad luck guy or....??
Marcin
 

[Phil A]

Hello, I am now quite worried, my 4b sst gets hot on the left side and then shuts down after approx. 15 minutes of playing, even on the low volumes, with my home Proac Studio 100 2 way paper cone easy stuff. With the JBL's it is taking 4 minutes of a loud, but still I would say 50% of what 300W should handle, listening to the music. Obviously something IS wrong with the left channel. Please James anything you can help ?

The unit bought new through Sun Audio, the respectable German dealer, since there was no dealer in Poland.

The great disapointment is that the studio workhorse ( this term is often used in the descriptions over the net) designed to work under heavy conditions, turns out to be problematic in the basic home application. The bitter thing is that my Bryston was the first unit bought new over the last 10 years, just to be SURE that it will run for 20 or so years. Sonicaly, it is the most rewarding amp I have encountered so far, after the 15 years hi-fi/end trauma. Am I a just another bad luck guy or....??
Marcin
 

Marcin - while you sort it out, does a fan on the side that gets really hot do anything.  My 14BSST when I had the channel shutting down would go about 20 minutes or so at relatively demanding volumes.  Also, have you tried it plugged into a different circuit at all?  It should not happen at low volumes.  My amp can go all day at low volumes and just be slightly warm to the touch.  Mine is out in the open on a custom built stand with tons of room around it (about 18 ft. above over 2/3 of the amp and 10 inches over the rest of it).

[James Tanner]

Hello, I am now quite worried, my 4b sst gets hot on the left side and then shuts down after approx. 15 minutes of playing, even on the low volumes, with my home Proac Studio 100 2 way paper cone easy stuff. With the JBL's it is taking 4 minutes of a loud, but still I would say 50% of what 300W should handle, listening to the music. Obviously something IS wrong with the left channel. Please James anything you can help ?

The unit bought new through Sun Audio, the respectable German dealer, since there was no dealer in Poland.

The great disapointment is that the studio workhorse ( this term is often used in the descriptions over the net) designed to work under heavy conditions, turns out to be problematic in the basic home application. The bitter thing is that my Bryston was the first unit bought new over the last 10 years, just to be SURE that it will run for 20 or so years. Sonicaly, it is the most rewarding amp I have encountered so far, after the 15 years hi-fi/end trauma. Am I a just another bad luck guy or....??
Marcin
 

Hi Marcin,

It should not be shutting down. There must be a bias problem - please contact Sun audio and they will assist you.

james

[mklibra]

Phil, there is no fan in 4B SST. The amp has more than enough of room to breathe.
The power circuit is ok (actualy I tried both in my company and home). I think James Tanner is right that the left chanel is faulty. The strange thing however is that still the sound of both channels IS the same with the diffrenece in temp betwen right and left being 40 and 80-90 celcius. Soon I will contact Sun Audio for help. Regards. Marcin