You changing to double sided boards now?
Are you using one heatsink per channel (board)?
Go to google and search for "wakefield thermal extrusion search". Then try to match up your heatsink with one of theirs. They have a lot of extrusions so you should be able to.get very close if not exact. This is what I did with mine and it was almost exact.
I would like to say your heatsinks will be large enough, but its best to determine it based on their actual ratings and not what someone "thinks" is going to be enough.
Thanks! Will do that. I see a lot builders use rods ( i hope that is the right name for it, bit of a language barrier for me) to connect the heatsinks together. Is this the best way? I get it is handy because you can fix the top and bottom plates to them. But in terms of heat transfer , the beat way? Or does a strip of aluminium have the same effect.
Not, single sided boards
Yes, one heatsink per channel
heatsink is CM e not MM
best regards
It looks like the heatsink backing plate is at least 10mm thick if not 12.5mm so heat spreading is probably not as much of a concern. However if I had such large heatsinks and I was designing a board to be used on them. I'd put the mosfets sticking horizontally off of the ends, two on the left and two on the right. If you did it this way you could even possibly add a third mosfet on each side to create an Aleph 5 in the future if you so desired. Always keep your options open. 😀
It's not as straightforward as I thought on a stock Aleph 3 circuit board. I opened it up and the input differential pair has 2 4-pin IRFD1040...a daughter board might be needed to accommodate 2 2SJ74s and maybe add Source resistors to somehow lower their Vds.
I can't find that part number. You sure they are not like these IRFD9210's. They look like 4 legs but are actually 3. I know that the irfd9210 was used in some of the Pass designed adcom products from back then.
You're right that's wrong, I think it's this...Vishay - MOSFETs - IRFD9010, SiHFD9010 - Power MOSFET I don't remember seeing a "2", too bad I didn't snap a pic. Yes, two pins are the Drains acting as heatsink also.
I dug up the Aleph 3 service manual I printed 10 years ago and they're labeled 9110. Most likely NP used this family of fets throughout the Aleph's production life...including those at Adcom.
Nelson,
Is there a variant of this that applies to the Aleph 5? I see that you say it needs to be low wattage, but the five isn't so far away.
Is there a variant of this that applies to the Aleph 5? I see that you say it needs to be low wattage, but the five isn't so far away.
you can use both iterations even on Aleph Million
in case of input JFets - you must shield them from excessively high PSU positive rail - say from +30V , with simple cascoding
plenty of exact schmtcs floating around
in case of input JFets - you must shield them from excessively high PSU positive rail - say from +30V , with simple cascoding
plenty of exact schmtcs floating around
Do you think I can use those Toshibas at Aleph 2 with out any mod to replace the IRFP type🙂
Thank you
Yes you right, IRF for LTP
If I can use the mentioned Toshiba probably that would be an improvement over the IRF type.
I do have some on hand.
Greetings