I’m repairing a NAD M3 which requires a full recap. I’ve replaced pretty much all of the caps and came to the main filters, pulled out the filter caps I bought about 6 months ago and…. They don’t fit. I really should have paid more attention to the physical measurements.
The filter caps that are in the amp, which are all quite buldged, are snap-in and 40mm in diameter and 83mm in height. They are 22,000uF 80v. The caps I purchased are 27,000uF 80v and are 40mm in diameter, but 105mm in height. I’m so bummed.
I’m having trouble finding 40mm dia snap in caps that are 22,000uF (or higher). I could use the ones I have until I find some that are 80-90mm in height, but being at 105mm I won’t be able to put the top on the amp.
Anyone that might be able to find a good quality cap that will work, I would be eternally grateful. I’m stuck on this project until I find some and I have no choice, they have to be replaced.
Thank you,
Dan
The filter caps that are in the amp, which are all quite buldged, are snap-in and 40mm in diameter and 83mm in height. They are 22,000uF 80v. The caps I purchased are 27,000uF 80v and are 40mm in diameter, but 105mm in height. I’m so bummed.
I’m having trouble finding 40mm dia snap in caps that are 22,000uF (or higher). I could use the ones I have until I find some that are 80-90mm in height, but being at 105mm I won’t be able to put the top on the amp.
Anyone that might be able to find a good quality cap that will work, I would be eternally grateful. I’m stuck on this project until I find some and I have no choice, they have to be replaced.
Thank you,
Dan
Use these to find what you need. Choose the length as your maximum or less.
https://www.digikey.com/en/products/filter/aluminum-electrolytic-capacitors/58
https://www.mouser.com/c/passive-components/capacitors/aluminum-electrolytic-capacitors/
https://www.digikey.com/en/products/filter/aluminum-electrolytic-capacitors/58
https://www.mouser.com/c/passive-components/capacitors/aluminum-electrolytic-capacitors/
Oh yes thank you, I am able to search mouser and digikey, but they don’t have anything. I was hoping someone may know of another good source.
Dan
Here are some within your height limit at Mouser. No doubt DIgikey also has several.
Yes.
In principle, Electrolytics have become more efficient along time, so same capacitance at any given voltage takes less space.
Meaning you must search for capacitors with same pin spacing to fit current PCB; they will certainly be smaller than originals, so thinner, shorter, or both.
If they are less than 40mm, who cares?
They will fit anyway.
And I can´t imagine a reason for them being longer, unless you chose pencil thin ones.
Old Geometry rules still rule, if you pardon the pun.
Didn´t go through it, but I bet Rayma´s list contains a few suitable ones.
Again: your only "critical" dimension is pin spacing, all others are somewhat "flexible".
In principle, Electrolytics have become more efficient along time, so same capacitance at any given voltage takes less space.
Meaning you must search for capacitors with same pin spacing to fit current PCB; they will certainly be smaller than originals, so thinner, shorter, or both.
If they are less than 40mm, who cares?
They will fit anyway.
And I can´t imagine a reason for them being longer, unless you chose pencil thin ones.
Old Geometry rules still rule, if you pardon the pun.
Didn´t go through it, but I bet Rayma´s list contains a few suitable ones.
Again: your only "critical" dimension is pin spacing, all others are somewhat "flexible".
Thank you, you may have missed it in my first post, but I mentioned that I’m limited to a little more than 83mm in height, but the most important thing was that I could not go any bigger than 40mm in diameter, there is absolutely no room to go any bigger. That’s why I said I was having a difficult time finding some. Every capacitor in that cart you linked to is bigger than 40mm in diameter and unfortunately will not work.
As you can see they populated the board right up to the caps.
Dan
Maybe I’m not explaining this very well.
Won’t be able to find smaller and well that’s my problem, if I could find smaller than the originals I would. The caps from the M3 aren’t all that old, 2007-2008 I believe. If this was a ‘70s or ‘80s era amp I’m sure I’d have no problem. But the originals are 40mm and any I can find are either larger than 40mm in diameter and that unfortunately can’t work. There are some 27,000uF I found that are 40mm in diameter, but are 105mm long, which is too long and that’s what I have currently.
I did find some 22,000uF 80v caps that are identical in size to the originals, 40mm d and 83mm L, but look like they’re a year out from being in stock.
Dan
Let´s introduce some heresy here 😱
IF no one suitable appears, "downgrade" a little 😱
No 22000/27000uF physically suitable cap appears?
Ok, search for, say, a 16000uF pair.
Will the amp sound "worse" ?
Actually not.
In my book (and into that of a lot of people) that amp/supply is already way over the top, as far as capacitance goes.
See it another way: better "good" 16000uF than damaged already bulging dry high ESR blow/leak-any-day current ones.
IF no one suitable appears, "downgrade" a little 😱
No 22000/27000uF physically suitable cap appears?
Ok, search for, say, a 16000uF pair.
Will the amp sound "worse" ?
Actually not.
In my book (and into that of a lot of people) that amp/supply is already way over the top, as far as capacitance goes.
See it another way: better "good" 16000uF than damaged already bulging dry high ESR blow/leak-any-day current ones.
The form factor being small (smaller than comparable caps) should throw up a red flag. miniaturizing usually compromises service life. I can often find two Nichicons that are the same value/voltage/temp but the little one only rated 2000 hours instead of 3000, 5000, or 10,000. You may be better off with the smaller uF, as JM suggests.
why does it need a full recap ? 2007 amp... I would not worry before 2037/2040 ! Are they bumped on the top or do you see some wet leaks at the base !
So the closest I could find was 15,000uf, a 3000 hour CDE I believe. I was really hoping to see an 18,000 and then just parallel four 4,700uf caps and place them within the case where they would fit. I found some 35mm Kemet 20,000uF, bit look to all be special order….
So going from 44,000 to 30,000 per channel wouldn’t be the worst thing? I could always grab them and then also order the 22,000uF caps that will be available in a year and swap them when they come in.
Thank you,
Dan
Yeah they do seem small, the 15,000uF 80v caps I found are identical in size to these 22,000 and are only 3000. The 22,000 I did find are 2000 hour. The 27,000 I have now are 3000 hour. Kemet looks to make some nice long hour in these values, but being special order not easy to get. Wonder if there are any vendors that sell them? I’ll do some looking.
Thank you,
Dan
Yeah, they just used really garbage caps. All four of the filters are fairly extreme in their bulging. I measured the esr on all four last night and all were around .2 to .5 ohms which is way to high for a value this large.
I’ve been running into this all over the amp, I think I’ve pulled maybe a dozen that measure “okay”
Dan
I feel it is better to do a blanket recap if the ones fitted are not a well known brand, as the board is out, and there is little point in leaving a suspect device in place, which will cause issues sooner or later.
Put long life 105C caps, and standard not audio fool ones.
I do not think this built to price unit deserves those expensive ones, and their performance debates are foolish in any case.
Put long life 105C caps, and standard not audio fool ones.
I do not think this built to price unit deserves those expensive ones, and their performance debates are foolish in any case.
Yes, that is indeed what I am doing, a blanket recap. Even if a cap measured okay it still goes as every cap is “JH” brand except for four “Shanghai” branded caps. I pretty much used Panasonic FC everywhere, a few Nichicon PW as the FC value availability seems to be shrinking. So what I can’t get in FC anymore I get in PW or PM. I’m even replacing all of the SMD with through hole.
This unit is better than your average NAD, and better than quite a bit out there actually, but I get what you’re saying.
Dan
We’ll just double checked and those 22,000uF that are available in a year from now have a lead spacing of only 10mm on a 40mm cap lol. Those won’t work. I could solder small leads to reach the holes and then glue them down maybe. What a pain.
Dan
Dan
Can you make holes under the heat sinks for better circulation without removing them?
Or damaging tracks?
It may improve the air circulation.
Or damaging tracks?
It may improve the air circulation.
Well actually the heatsinks are external to the amp. I only have one channel in the amp here, but you can see what I mean.
Dan