Store Heat Sinks - Thermal Numbers

[Mikerodrig27]

Ahh, well... Maybe your cheaper option is the switch... Hopefully, things will cool down where you are soon.

 

[AudioSan]

I have to agree with Nelson here. This sinks can handle a lot of power. The raggered fins have much to do with this. You get a lot more surface erea.
i calculated the 5U400 to handle around 150W pr side with 30C rise back in the day. It seams i was pretty close on those calculations.

 

[AudioSan]

This one. A 5ch class A/B amp, is sitting at about 10C above rom temp. Whit internal sinks. 5x 4U300mm sinks. Best estimate is that internal chassis temp is about 3C above rom temp. so the sinks sits at about 7C above ambient. With 130W powerburn at idle/mild use.

 

[alazira]

Interesting idea... either add a knob to dial the bias or put in a switch circuit marked Summer / Winter with a red switch (and RED LED) on the front panel.

My living room gets hot in the summer, around 84F without running the AC. And the A2s (5U400s) run hot all the time, pretty much out on the open. so it becomes a feedback circuit with the amps acting as heaters in a hot room. The AC here in Coastal SoCal is affordable only by politicians and Hollywood Royalty. So, when it gets pretty hot, I switch to a tube amp.... or just don't listen.

Running the AC is not only expensive, but the flow of air does make some noise.

Bret D'Agostino (RIP) had an "eco" (lower bias) mode on his amps

 

[Sagen]

I have noticed quite a few questions about the suitability of the store's
heat sinks for various projects, and since I have tested and documented
most of them here, I am happy to present my list of the sinks and their
respective thermal resistance numbers. Toward the bottom it lists the
wattage for a 30 deg C rise on a single side and the number of TO3-P
type packages it is drilled for.

Good evening, I have a friend that is going to build a A-40. Can you recomend any good heatsink for the project? He build the A-40 40years ago but ended up selling it. Here is a picture from 1984 hifi magzine from Norway at a "home visit" at Jans home with the A-40.

Frank

 

[R-K Rønningstad]

Seems I wrote that piece 40 years ago!

 

[Zen Mod]

40 yrs ago I just started learning what's hand-side of soldering iron

was so clueless that I resorted to gun-iron for few more years

is going to build a A-40

presumed dissipation per channel?

 

[Sagen]

Zen Mod, not sure what you asking ( : If you mean heat for heatsing, looking for 50-60`degree at 20 degree room temp.

 

[Zen Mod]

A40 - I'm asking how much Watts your Buddy intend to burn per channel

there are myriad ways to build such an amp ........ that's why the question

 

[Sagen]

Zen Mod, as I read at Nelson Pass site it says 100W idiling dissipation. I ask him tomorrow, I wisit him then.
He showed me a picture of a type heatsink with no: DSC00455

Frank

 

[Zen Mod]

for 100W per side, look for these Modushop Dissipante cases as adequate:

4U high, 500mm deep

5U/400

5U/500

first two are enough, third one more than enough


you need to look both 1mm steel covers and 3mm Al covers to find all options

https://modushop.biz/site/index.php?route=common/home

 

[R-K Rønningstad]

40 yrs ago I just started learning what's hand-side of soldering iron

was so clueless that I resorted to gun-iron for few more years





presumed dissipation per channel?

One year before that we even visited Threshold Corp in Sacramento.

 

[Mikerodrig27]

I love the big beefy heatsinks on the old thresholds.

 

[tomchr]

ModuShop/Hifi2000 has some information on the thermal resistance as well:
https://hifi2000.shop/site/user/pages/05.docs/PESANTE _ DISSIPANTE Thermal info.pdf

It looks like they consider the maximum heat sink temperature to be 75 ºC, which is quite toasty. I'd walk it back to maybe 55-60 ºC, maximum. That'll result in an increase of 13.7 % of the thermal resistance, so multiply the thermal resistance values given by ModuShop by 1.137 (or divide the maximum power by 1.137). Note that the maximum power in the document is for the entire enclosure, i.e., all heat sinks, with equal power dissipated in each heat sink.

Tom

 

[Zen Mod]

by my experience........... 4U/400 is good for 80W/side, 5U/400 for 100W/side, 5U/500 for 120W/side

count on fact of ZM Omnichicken, not a member of Pa's FABC

 

[pwayland]

Or you can turn up the bias beyond power dissipation spec for dead air and move some air. It takes some temperature monitoring, but it is amazing how much heat dissipation can be achieved with a small amount of airflow. PS ambient 18 deg C in picture so no fan.

 

[Aleph5]

As this project has been semi-active here for years, the construction article states: "...for each channel we will require a heat sink with a 0.25° Celsius per Watt thermal characteristic."

So 4U/400 or bigger for Modushop offerings.

 

[Sagen]

Hi again, have now been at Jans home. He say at 3.2A it will burn of 250W pr canal. So need something huge / effective.
R-K Rønningstad: He also talk about old days when he was at your place and listen to A-20, some ML-2 and Quads.

Frank

 

[R-K Rønningstad]

With the risk of derailing the discussions…
I haven’t seen Jan for years.
Correct, I once had a pair of ML-2s. At the time (the bold and brave eighties) I found I had to use them for the Quads (57). I later changed to the 63s and found the ML-2s was not necessary.
The 57 Quad was the prime ear opener. A true revelation. Well, all those devices are long gone.

 

[Zen Mod]

He say at 3.2A it will burn of 250W pr canal.

consider caliber of Modushop 5U/500 for one channel, needing to arrange output parts in 2 groups, one per heatsink

that for ready made solution

if going DIY - look at PL site and take one of their bigger amps with commercial type of heatsinks as recipe

easy to collect heat info from there