Thermo Shutdown

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Mag

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Thermo Shutdown
« on: 26 Oct 2018, 09:05 pm »
With the high resolution of my system I am experiencing thermal shutdown with my Bryston 3B SST/2 amps. Like I am listening to Rush- Exit Stage Left dvd on my new Yamaha BD-A1060 and I can't make it through the show without my amps shutting down and I only have the volume at 10 o'clock not my typical 12 o'clock position.

Any ideas on how to prevent thermal shutdown other than lowering the volume? :scratch:

James Tanner

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Re: Thermo Shutdown
« Reply #1 on: 26 Oct 2018, 09:09 pm »
HI Mag

If they are overheating it is because they are being asked for more power than they can deliver.  You could try a whisper fan aimed at the heatsinks.

james


Mag

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Re: Thermo Shutdown
« Reply #2 on: 26 Oct 2018, 09:31 pm »
So bigger amps would solve the problem? Would the Model T's overheat with the extra power?
Before I directed the bass to the sub which took the strain off the amps, but my sub quit so all the bass is going through the main speakers.

gbaby

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Re: Thermo Shutdown
« Reply #3 on: 26 Oct 2018, 09:54 pm »
So bigger amps would solve the problem? Would the Model T's overheat with the extra power?
Before I directed the bass to the sub which took the strain off the amps, but my sub quit so all the bass is going through the main speakers.

So, are you trying to use the Yamaha as a pre-amp? You never mentioned anything regarding your pre-amp so I assume you are using a blu-ray player with a gain control. It may be causing your amp to clip. What is your pre-amp, the blu-ray player? :o

Ron D

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Re: Thermo Shutdown
« Reply #4 on: 26 Oct 2018, 10:16 pm »
And please confirm your speakers.

You did mention Model Ts - if you have these then here in lies the problem. Some may disagree but IMHO the 3B is underpowered for Model Ts, whether they are running full range (no sub) or not. If you have 2 of them in play in bridged mode it's no wonder they are cooking.

I ran 7B squared amps with my Middle Ts and could get them warm...

James Tanner

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Re: Thermo Shutdown
« Reply #5 on: 26 Oct 2018, 10:28 pm »
So bigger amps would solve the problem? Would the Model T's overheat with the extra power?
Before I directed the bass to the sub which took the strain off the amps, but my sub quit so all the bass is going through the main speakers.

Hi Mag

Yes you definitely need more power if you are running them full range. Also as mentioned above if you are running the 3B in mono the impedance will be down around 3 ohms.

James

Mag

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Re: Thermo Shutdown
« Reply #6 on: 27 Oct 2018, 07:25 pm »
So, are you trying to use the Yamaha as a pre-amp? You never mentioned anything regarding your pre-amp so I assume you are using a blu-ray player with a gain control. It may be causing your amp to clip. What is your pre-amp, the blu-ray player? :o

I'm using a SP2 with my BDA-1 piggybacked thru the SP2 dac. This gives me higher resolution on playback, so my amps are not clipping but working extra to reproduce the higher resolution. With Rush- Exit Stage Left dvd the bass is heavy and sustained, goes down pretty low on some songs. Even with the volume at 10 o'clock it was pretty loud. Normally however I have to have the volume knob around the 1 o'clock position for thermal shutdown to occur with some other music. Lower sustained bass with higher spl levels will cause thermal shutdown. :smoke:

gbaby

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Re: Thermo Shutdown
« Reply #7 on: 27 Oct 2018, 10:41 pm »
I am surprised you are experiencing a shutdown as your speakers are rated to play 91db with a 1 watt input which is pretty efficient. And, the 3B-SST2 puts out around 250 watts on a 4 ohms load. You must be playing at extremely loud ear drum bursting level.  :lol:

Mag

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Re: Thermo Shutdown
« Reply #8 on: 27 Oct 2018, 11:19 pm »
I am surprised you are experiencing a shutdown as your speakers are rated to play 91db with a 1 watt input which is pretty efficient. And, the 3B-SST2 puts out around 250 watts on a 4 ohms load. You must be playing at extremely loud ear drum bursting level.  :lol:

I would say it's loud, not extremely loud to the point of hurting my ears. I believe recordings have an optimal playback volume which is generally somewhere between 92 & 95 dbs 'A' weighted, concert level. However I gotz plenty of bass which generally measure between 100 to 110 decibels 'C' weighted.

When funds allow I guess I'll have to upgrade to a 14B-SST/2 or 3. I don't have space for two 7B's. :smoke:

gbaby

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Re: Thermo Shutdown
« Reply #9 on: 31 Oct 2018, 01:30 pm »
Wow! :D

CanadianMaestro

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Re: Thermo Shutdown
« Reply #10 on: 31 Oct 2018, 10:15 pm »

When funds allow I guess I'll have to upgrade to a 14B-SST/2 or 3. :smoke:

The 14B-2 is the best d--- amp Bryston has ever made. Disappears competely from the signal chain.  :thumb:

sfraser

Re: Thermo Shutdown
« Reply #11 on: 11 Jan 2019, 07:19 pm »
I am a little late seeing this thread but here it goes, for the short term until you purchase  more powerful Bryston(s), try running the amps in regular mode (2 channel) and remove the connector at the woofers and mid/tweeter binding posts. Connect it so  the left channel of each amp powers the woofers  and the right channel of each amp drives the mid's and high's.  Still not ideal, but the higher  impedance seen by the amp outputs may lower the current requirements  enough to keep the amps cool enough to avoid thermal shutdown and you can enjoy the entire RUSH  concert. It will cost you an extra set of speaker cables however.   I am  not that familiar with the Model T's (unfortunately) internal makeup, but I believe this may be an easier configuration for the amps to drive.

Scott

Mag

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Re: Thermo Shutdown
« Reply #12 on: 11 Jan 2019, 09:35 pm »
I am a little late seeing this thread but here it goes, for the short term until you purchase  more powerful Bryston(s), try running the amps in regular mode (2 channel) and remove the connector at the woofers and mid/tweeter binding posts. Connect it so  the left channel of each amp powers the woofers  and the right channel of each amp drives the mid's and high's.  Still not ideal, but the higher  impedance seen by the amp outputs may lower the current requirements  enough to keep the amps cool enough to avoid thermal shutdown and you can enjoy the entire RUSH  concert. It will cost you an extra set of speaker cables however.   I am  not that familiar with the Model T's (unfortunately) internal makeup, but I believe this may be an easier configuration for the amps to drive.

Scott

Thank you for the suggestion, I might try that if I can picture in my mind what you are saying. I have two amps driving two sets of speakers.

I apologize though for this incident as I actually was clipping my amps. When I was installing my 4K TV I had bumped my audio settings without noticing. So this is why the amps shutdown pre-maturely with the Rush concert.

However I still occasionally get thermal shutdown with some songs if I push the volume control. This is pretty loud in my room, for the most part the 3B- SST/2 has enough power to drive my speakers at the volumes I typically listen without shutting down. :smoke:

HsvHeelFan

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Re: Thermo Shutdown
« Reply #13 on: 11 Jan 2019, 10:19 pm »
I'm running a Bryston 4B-ST and I'm using a Parasound pre.  I don't recall if my input gain on the 4B is 23 or 29 db.   I suspect it's 29db.

On the bench at Bryston, it tested at 288 watts per channel at 8 ohms.

My speakers are KEF Q70's.  They're rated at 6 ohms and spec'd at 90dB at 2.83V at 1 meter.   The KEF's are rated for a source of 10 -150 watts.  Since my KEF's are 6 ohm,  I think i'm putting around 430 Watts per channel on them with the 4B-ST. 

At 11 o'clock on my system,  you can't be in the same room with it.  It's freaking LOUD and I've never even seen the Bryston input LED's even flash yellow.

I bought the Bryston because my 1984 vintage Yamaha integrated in 2001 decided it would occasionally go into thermal shutdown and both times it nuked my KEF tweeters.  In 2001, KEF Q70 tweeters were $125 each.   After replacing the tweeters twice in a couple of months,  I started looking hard at other amps.   I borrowed a THx rated 4B over the 2001 July 4th weekend from a friend that had a Spectral Amp and big Thiels and bought my 4B-ST on Sept 21, 2001.   He knew I'd love the Bryston and he was right.  I also auditioned 3 different Parasound Amps and an Adcom.  All were in the 100 to 200 Watt per channel range.

I have an  handheld infrared thermometer and when I've had the Bryston on for while and rocking and rolling,  I check the heatsink temps.  I don't think I've ever seen more than 135 degrees F.  158 degrees is 70 Celsius and that's the temp limit for most commercial grade electronic components such as transistors or integrated circuits.

If you're experiencing thermal shutdown, my recommendation is bigger Bryston's.   You can never go wrong with bigger Bryston's.

HsvHeelFan

sfraser

Re: Thermo Shutdown
« Reply #14 on: 11 Jan 2019, 10:49 pm »
As per my post above, I think the correct term is Bi-Amping the speakers. I believe the Model T's have 3 sets of labeled binding posts which are the  external connections to the passive crossover   These  binding posts, are bridged together by external  metal clips. These clips can be removed,  effectively isolating the the binding posts and you can use separate amp for your woofers, mids and highs. If you just remove the clip to isolate the woofers , each Model T speaker would require two amplifier channels , one for the lows, or woofers and one for the mids/highs. Of course each 3B not in mono mode  has two channels (left and right) .   We are changing the speaker configuration around AND configuring the amps back into 2 channel mode. The amp should be "happier" because the current draw should not be as high, but for sure you a bigger amp for high volume playback should be your end goal. Maybe James could chime in regards to the impedance of the woofer network. 

Mag, I don't know your technical background, and  if you are not sure about the above configuration I would not suggest you  attempt it.  You have a really expensive rig and there are a couple things that
could really wrong if you mis -configure the above . If you have any doubts, discuss the above configuration as a possible option with your dealer before attempting. I would hate to see anything go boom. That is very very nice rig you have and we all want to keep it that way.

Cheers,

Scott