D
Deleted member 24284
I visited this surplus dealer in person in the City of Torrence in Southern California: Apex Jr.Home Page
I found some wonderful heat sinks. I bought all nine of these. That's all he has. The heat sinks are 7" x 7.5" x 3".
I also bought a lot of the filter capacitors shown.
Maybe some of you can visit his warehouse too. Those heat sinks were not on his online catalog, since he didn't think he had enough of them to bother putting them on the online catalog. I was there, and I was lucky.
These let me realize my dream (as I mentioned in an earlier post) of putting all electronics in a small tight bundle to minimize wire lengths, and thus series inductance in those wires.
I found some wonderful heat sinks. I bought all nine of these. That's all he has. The heat sinks are 7" x 7.5" x 3".
I also bought a lot of the filter capacitors shown.
Maybe some of you can visit his warehouse too. Those heat sinks were not on his online catalog, since he didn't think he had enough of them to bother putting them on the online catalog. I was there, and I was lucky.
These let me realize my dream (as I mentioned in an earlier post) of putting all electronics in a small tight bundle to minimize wire lengths, and thus series inductance in those wires.
Attachments
Good find!
Your heatsinks look to be (or very similar to) this Aavid profile:
Thermal Engineering and Heat Sink Manufacturing - Online Store
Cheers,
Dennis
D
Deleted member 24284
I still think Nelson's Aleph 3 cases were the coolest looking cases I've seen . I hope one day they do an Anniversay Aleph with the same case.
You could probably do something similar.
You could probably do something similar.
D
Deleted member 24284
I see!
My thoughts are that I'll build a monoblock, so it'll be like a Star Wars tie wing fighter, with the electronics bundled tight in the middle. The heat sinks will be the wings, one on each side. The power transformer will be situated some distance away, while the filter caps will be directly underneath the electronics. I can use a single power transformer with dual secondary windings, and put it in between the two monoblocks.
Attachments
Looks like Nelson recommends Idss of around 8mA.
Would 9.5mA be considered to high, I don't want to burn them out.
Would 9.5mA be considered to high, I don't want to burn them out.
where and what ?
9.5mA x 23V =218mW
if they're too hot for your fingers , put some clip-on sinks
9.5mA x 23V =218mW
if they're too hot for your fingers , put some clip-on sinks
Yeah 218mW.
I might select some around 8mA instead.
I'll save the higher rated ones for another project.
I might select some around 8mA instead.
I'll save the higher rated ones for another project.
Rectifier Diodes
I have MUR3020WT, HFA50PA60C, and the blocky things KBPC3504.
Anyone have experience with these or have a preference?
I'm tempted just to use KBPC3504 but I'm quite happy to hear what you guys have to say.
I have MUR3020WT, HFA50PA60C, and the blocky things KBPC3504.
Anyone have experience with these or have a preference?
I'm tempted just to use KBPC3504 but I'm quite happy to hear what you guys have to say.
I think my decision has been made easier. Can't find the heatsinks so might just use the blocks
So far I am at 132,000uF per rail as main bank. I'm thinking of adding another 33000uf per rail for each channel independent of the main bank (similar to Nelson's idea)
Anyone using more than this?
Anyone using more than this?
There's in principle no problem if you consider the dissipation of each individual device at the resulting ambient temperature - approx 60 degrees with the right amount of bias. Most devices derate to half dissipation at that point, except resistors which maintain full power rating to 70 degrees, with some exceptions.
Caps would be happier with a PCB between them and the heatsink. They tend to dissipate (and pick up) heat from the jacket, so any kind of barrier between jacket and sink would help, plus the base is much less thermally conductive than the barrel. Hence the parallel mount method may in fact work better for them (for example).
50-60 degrees is usually not a problem for any device per se, but self-heating under circuit conditions - including stressed operation, need to be factored in.
Modified Turbo Front End
What do you reckon:
1) 2x paralleled pair for total of 16mA
2) A single pair cascoded for total of 16mA (or even more)
What do you reckon:
1) 2x paralleled pair for total of 16mA
2) A single pair cascoded for total of 16mA (or even more)
Hole alignment on Deluxe 5U case is out. I'm going to have to drill the holes out bigger on the pcb. What a pain in the **** (not really just disappointing).
