[jtwrace]

I've always been curious to know how long at idle it really takes for my amp (Clayton Audio M-300) to heat up.  So, I used some equipment that I built for another purpose to do just that.

I have three thermocouples in total.  One near the back of the heat sink, one near the front and one measuring the ambient.  The calibration is within 5 deg of actual.  For this purpose this was fine.  I logged at the lowest I could which is 1Hz and even that was slightly overkill and I needed to filter the data every 5 seconds so keep that in mind when looking at the chart below.  600 seconds is really 3000 seconds (50 min).  I've always thought is took about an hour to really sound it's best....now I know that it's true!

Controller which has a 0-10VDC analog output


Heat Sink


Logger which is run via USB and run with LabView


Data

[geezer]

I've often thought of doing something like that, but never generated the energy. Thanks.

[Steve]

Nice info JT. Thanks.

Cheers.

[Bob in St. Louis]

Wow. That's awesome. I nominate you for geek of the year. 
I love that. I'd like to borrow your equipment.

Would be nice, if when we read equipment specs, it had this information.
Especially helpful for those pesky tube amps.

Do you have (can you have?) information for other equipment?
Would be interesting for driver magnets at a given dB level.

Bob

[srb]

Would be nice, if when we read equipment specs, it had this information.
Especially helpful for those pesky tube amps.

Temperature is good to know, but for those "pesky tube amps", Class A amps or other powerful amplifiers, how about calculating BTU output?

Don't see that specified too much, but I notice that Bryston publishes BTU Heat Load at idle and maximum power.
 
Steve

[bfr1992t]

What USB logger is that?

[Speedskater]

Let's see, 110F is about 570F above Absolute Zero.
So each degree is a 1/570 change. I think that the warm-up sweet spot is way bigger that that!. Summer to Winter room temperature or a different equipment rack will cause much bigger steady state differences.

[*Scotty*]

An infrared thermometer might be a quicker and easier way of getting readings like this. I have seen them for less than $80 on the web.Scotty

[rollo]

   Geek of the "Century" is more like it. Jason we love ya. The music the music. 



charles
SMA

[Æ]

Wow. That's awesome. I nominate you for geek of the year. 
I love that. I'd like to borrow your equipment.

Would be nice, if when we read equipment specs, it had this information.
Especially helpful for those pesky tube amps.

Do you have (can you have?) information for other equipment?
Would be interesting for driver magnets at a given dB level.

Bob

I've held some pretty warm magnets. But it isn't the magnet, pole piece temperature that matters, it's the voice coil.

[jtwrace]

An infrared thermometer might be a quicker and easier way of getting readings like this. I have seen them for less than $80 on the web.Scotty

Quicker maybe...but why do it that way if one has this? 

[Bob in St. Louis]

I've held some pretty warm magnets. But it isn't the magnet, pole piece temperature that matters, it's the voice coil.

Ahh yes. Good point. Would be interesting to have a temp sensor embedded next to the VC to watch it rise.
I've cranked my system loud enough a few times, I've begun to smell it. I'm not sure, but I think it's the glue by the voice coil. Not certain though. 

Bob

[*Scotty*]

Do you have any idea what SPLs you were hitting when you smelled something heating up? My speakers are allegedly 96dB efficient and I can't recall ever smelling the results my forays into high SPL territory even during watching LOTR.Scotty

[Bob in St. Louis]

Not sure the SPL, but it was 11 on the volume. 

[guest1721]

I've held some pretty warm magnets. But it isn't the magnet, pole piece temperature that matters, it's the voice coil.

Actually, the magnet temp can have a significant effect on the strength of the motor.  It's one of the distinguishing characteristics of speaker magnets.  Neo tends to be the worst, hence heatsinks on many neo motors, and ferrite not much better.  Alnico is quite a bit better in this regard, having the highest curie temp of any common magnet material in speakers.