hahaha his mighty boomstick
Hi Dennis -
Just to be sure... b/c I never can get dissipation correct. These are my "startup" settings for the BA-3.
12 devices at 0V075 across 0R22 => 0A34 * 12 * 23V1 rails => 94W per side.
Never anticipated that much sag under load with 2 x 400VA transformers. ~26V unloaded. Mains voltage is down a bit to 118 vs. normal 120, so ...
Ambient 22C - Base of sinks at bottom near devices ~43C. Tips of fins 40C.
Measured with the el-cheapo probe with DMM. Calibrated with Nelson's hand scale.
Hope that helps.
All -
It's up and running, stable. I put it in the main system, and so far I am very impressed. I need to tinker with P3, but that will come on another day.
I'm glad I pulled the trigger on these, I got them today and they are the real deal, beautiful!!
Now I need to find matching screws, any ideas?
Those are beautiful.
Hard to tell surface finish match in pictures, but maybe something like this... https://www.amazon.com/50PCS-Screws...ocphy=9019639&hvtargid=pla-578695372307&psc=1
Or.. if you want a contrast, just a nice stainless steel?
Edited - Wrong link to wrong screw type. Corrected.
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Those are beautiful.
https://www.amazon.com/50PCS-Screws...ocphy=9019639&hvtargid=pla-578695372307&psc=1
Yes, I ordered those last night I hope they match the plating tone
Dennis -
A bit more data. I upped the bias to 0A4 on the output devices.
I thought the probe on the DMM would be more accurate, but based on the Papa scale, I think my infrared thermometer might be closer.
49C with probe. 53C with my infrared thermometer.
That's about as hot as I really like. I can hold my palms on the sinks for as long as I want, but it's clearly "hot" not warm. My hands are pretty calloused. My forearm only wants to be on the sinks for 10s.
Not incredibly scientific, but I hope it helps a bit more.
Edited to add - Alex ...
A bit more data. I upped the bias to 0A4 on the output devices.
I thought the probe on the DMM would be more accurate, but based on the Papa scale, I think my infrared thermometer might be closer.
49C with probe. 53C with my infrared thermometer.
That's about as hot as I really like. I can hold my palms on the sinks for as long as I want, but it's clearly "hot" not warm. My hands are pretty calloused. My forearm only wants to be on the sinks for 10s.
Not incredibly scientific, but I hope it helps a bit more.
Edited to add - Alex ...
I can't remember if I posted this or any kind of a summary. Forgive me if this is repetitive or posted elsewhere. Early on in the thread, Gianluca was most kind to post the study they did for their heatsinks, and 2 Pico Dumbs indulged all my questions re: potential temperature rise vs. dissipation.
Attached is a chart and a graph I put together using data from the study. I also did some makeshift de-rating analysis and put together a really lousy regression equation in an attempt to predict de-rating / temp rise above ambient for heatsinks/chassis not included in the study based on heatsink width and height as the independent variables and assuming the same heatsink profiles and mass per unit area.
Note - from the study, it appears that ambient was 27C.
Perhaps it may help someone. I can share more info if desired. It's in no way complete or in any way reviewed by anyone other than me, so forgive any errors.
Attached is a chart and a graph I put together using data from the study. I also did some makeshift de-rating analysis and put together a really lousy regression equation in an attempt to predict de-rating / temp rise above ambient for heatsinks/chassis not included in the study based on heatsink width and height as the independent variables and assuming the same heatsink profiles and mass per unit area.
Note - from the study, it appears that ambient was 27C.
Perhaps it may help someone. I can share more info if desired. It's in no way complete or in any way reviewed by anyone other than me, so forgive any errors.
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