Aleph3 recap

[grimberg]

I have bought Elna Silmic II from this site: Handmade Electronics Indexpage

If it is not too much trouble, please post more pictures as you take your Aleph 3 apart. That kind of image is hard to find.

[Dukja]

No problemo! My mind was just playing dumb on me. I was always thinking the wrong one that ZM referred to. Some people in other rare disciplines (not mine) use m for micro, hence the confusion.

I only noticed on the darkened spot after I took the photo with flash light. I was wondering what was going on there. Thanks for the explanation. I will take a good look later.

So is that patch under NTC thermistor still good and only re-solder is needed? Why would that spot accumulate heat?

Thanks for the good info. I am learning.

[Dukja]

Originally Posted by grimberg

I have bought Elna Silmic II from this site: Handmade Electronics Indexpage

If it is not too much trouble, please post more pictures as you take your Aleph 3 apart. That kind of image is hard to find.

Thanks for the link. That was where I found out of here.

I certainly can post more photos later if this is not against any rules. And it is quite a job to take out all the necessary screws without a good Allen wrench in my lab.

[Zen Mod]

Originally Posted by Dukja

....

So is that patch under NTC thermistor still good and only re-solder is needed? Why would that spot accumulate heat?
...

inspect traces visually ; I presume they're still good ( it's PL product )

NTC is heating during operation , and transfering heat to pcb ; that's why you always see long legs on NTC

[Dukja]

Thanks, ZM. I'll check on it. I have also seen some metal clips on transistor to assist heat dissipation. Would it be good idea to put something like that on NTC if it was so hot? I'll also take an IR measurement next time to see what's the operation temperature of it.

It seems 22mF are very common and anything above that is more expensive and much less choices (for size and spec). Anyone has good sources to recommend?

Thanks!

[6L6]

Thermistors will run in excess of 100C. Be careful not to touch it while it's on!

What are the dimensions of the filter caps. (Height and Diameter are the important ones...)
There are going to be a good number of choices from Digi-Key and Mouser.

[Zen Mod]

digikey

part No. P6895-ND for 22mF/25V
P6921-N for 22mF/35V
P6898-ND for 33mF/25V
P10012-ND for 33mF/35V

check by your self - maybe I didn't found cheapest ones

panasonic 22000uF/25V - Google претрага
panasonic 22000uF/35V - Google претрага
panasonic 33000uF/25V - Google претрага
panasonic 33000uF/35V - Google претрага

in any case - my (as always ) modest opinion is that this amp is well worth spending money on even much costlier caps ; not Audiophool ones , but decent ones with decent price
dunno - maybe Papa can tell what they're using these days in PL products

[Dukja]

Thank you both!!

Originally Posted by 6L6

Thermistors will run in excess of 100C. Be careful not to touch it while it's on!

Wow! that is super hot. Does the design of that NTC requires to reach that temperature to work correctly? Will putting on mini-heatsink on it distort its functionality? That seems to be safer for the PCB board.

Originally Posted by Zen Mod

digikey

part No. P6895-ND for 22mF/25V
P6921-N for 22mF/35V
P6898-ND for 33mF/25V
P10012-ND for 33mF/35V

Yes, I checked Digikey and Mouser but was using 40V as the minmum rating. I guess that I can relax a little bit. The original Panasonic caps has 25V rating anyway.

It seems that I can only use the "through hole" and "snap in" types with that board. The snap-in has two leads for mechanical mounting and I just snip off those, right?

[Zen Mod]

use through hole

don't cool NTC - it needs to be hot for proper function

[Dukja]

I just use the IR thermometer to take the temperature on the NTC. Actually the temperature on NTC was abut the same as the 22mF caps. However, the square pad where the black wire connected to was as hot as 240F. That temperature quickly rose up or drop down when I turn on or off the amp.

That 240F seems to be too much. I suspect that the pad was bad so the resistance across the pad was too large and hence very hot spot there. Maybe I should jump a wire from black to yellow wire and to the leg of NTC (to bypass the pad) just to see if my theory is valid?

Or whatelse could be the issue for such high temperature on pad? And is OK to keep running it like that?

Thanks a lot for your keen eyes and help!!