^ I say go for it. I think my sinks in this were ~55C in a 21C room. That may have been at more total dissipation than you're planning for your F4s... I think I was at ~150W per side / pair of sinks when I tried to make it a true burning amp. I can check my files if it's critical. I think I took temps at each bias setting.
The 5U/400 have a wee tad more surface area / mass than the 4U/500... I recall like 2%. Also, Nelson published the doc attached... He notes 158W for a 30 degree rise.... so... that seems to be close enough...
Depending on the voodoo that you do, you'll be cool... or hot...
Both meaning ... Me... I'd go for it. but ... others may not like it quite so hot.
Edited to add - If you have the space... 5U / 500 ensures a proper fun factor.
The 5U/400 have a wee tad more surface area / mass than the 4U/500... I recall like 2%. Also, Nelson published the doc attached... He notes 158W for a 30 degree rise.... so... that seems to be close enough...
Depending on the voodoo that you do, you'll be cool... or hot...
Both meaning ... Me... I'd go for it. but ... others may not like it quite so hot.
Edited to add - If you have the space... 5U / 500 ensures a proper fun factor.
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Note - My temps are on the FINS... not on the hottest part of the sink. I was/am more concerned with the more practical, is it too hot to touch. I typically measured 10ish or so C higher on the hottest part of the heatsinks to see if the devices would break a sweat. In my case, the dissipation per device was no big deal, and I was not worried about junction temps.
Nelson's temps (I think) are calculated from the Modushop data (I believe) vs. actual measured temps from use. It's also lkely that those temps are from the hottest part of the sinks to make the temp data look the best it can look. They published their study. It's REALLY good. (Attached). That ModuShop data is not derated.
So... all that is to say... YMMV... and you're going to be close. If you've never put your mitts on a 55C sink, it's likely going to surprise you.
Do some calculations based on your expected dissipation and get a few others to chime in. I'm a fraidy cat, but I also don't mind a hot pair of heatsinks. No kids, pets etc, and no worries (too much) re: cooking output devices.
Edited to add a little more context and the modushop study upon which their data is derived.
Nelson's temps (I think) are calculated from the Modushop data (I believe) vs. actual measured temps from use. It's also lkely that those temps are from the hottest part of the sinks to make the temp data look the best it can look. They published their study. It's REALLY good. (Attached). That ModuShop data is not derated.
So... all that is to say... YMMV... and you're going to be close. If you've never put your mitts on a 55C sink, it's likely going to surprise you.
Do some calculations based on your expected dissipation and get a few others to chime in. I'm a fraidy cat, but I also don't mind a hot pair of heatsinks. No kids, pets etc, and no worries (too much) re: cooking output devices.
Edited to add a little more context and the modushop study upon which their data is derived.
^ Awesome! When I started getting things a tad warmer, it REALLY surprised me the difference between 45, 55, and 60. Nelson describes it well, but ... until I experienced it for myself. Resting my forearms on the sinks while tweaking pots was ill-advised.
Anyway... good luck... have fun... post pics.
Anyway... good luck... have fun... post pics.
I spend more time at hospital then I am working in 'shop' now. Bedroom lab can only handle so much. Time/body is losing out to stage 4 C.
I'm trying...
I know Zen, Danke.
Hope to get to 'shop' to finish these bedroom pre's and finish machining Legs for Dual F6.
Need more MOFO boards to build seperate sub to finish that project for the Range Wars.
Dual F4 case needs paint/polish and install of amps.
Then all the rest having to be done.
I'm really slow... It's embarrassing.
That has never been an option. My "good and enjoyment" has been at the very least tertiary My first and only 'vacation' was when I got out of bed and could not walk 3 years ago. I was not to make 3 months according to the experts. I was packing up my shop and building my last.
Now that I can't physically do as I did and refuse to sit around amps let me fight back.
Your point is well taken. As soon as I took time for me to finish my werk, it all stopped.
.... and getting some amps finished is a herculean task at times.
M.R. mentioned there will be more boards in store after BA. I have 2 pair monoblocs made for bi-amping or bridging. Newark messed up my heatsink order so I have a spare 180MM that I can use for a sub channel. Do I order another Boyd H/S and bridge or run what I have????
Here is link for what is done:
https://www.diyaudio.com/community/threads/build-this-mofo.313649/post-7404931
I've asked Scottmoose for a high SPL speaker design.
Right now Xmo is not letting me werk. I am thinking I will bridge a sub channel.
