Replacement Filter Caps

[Spica]

I'm looking for replacement caps for a 20 year old Cary amp. The filter caps fit
through access holes in the amp and are 1100uf 450v with a diameter slightly less
than 2". Cap height is not an issue.



Although I found a replacement (CBE) at Mouser.com that fits the bill, it's a non-stock
item requiring a minimal purchase of 16 units.



So my question is, can I use a different value cap without blowing up the rectifier?
As usual, thanks for any recs or suggestions.

[Fred[_12_]]

A friend went through this a year or so ago when he wanted to recap his 25 y.o. SS amp.
He contacted Cornell Dubilier and they put him in touch with a distributor who had 4 of the
caps he needed in stock. The contact info is on their site.

You can always replace the rectifier with something a little better if necessary. If the
original rectifier isn't a fast recovery type, that should be done anyway.

Fred


"Spica" > wrote in message ...

> I'm looking for replacement caps for a 20 year old Cary amp. The filter caps fit
> through access holes in the amp and are 1100uf 450v with a diameter slightly less
> than 2". Cap height is not an issue.
>
> Although I found a replacement (CBE) at Mouser.com that fits the bill, it's a non-stock
> item requiring a minimal purchase of 16 units.
>
> So my question is, can I use a different value cap without blowing up the rectifier?
> As usual, thanks for any recs or suggestions.

[[email protected]]

On Mar 1, 11:48*pm, "Fred" > wrote:
> A friend went through this a year or so ago when he wanted to recap his 25 y.o. SS amp.
> He contacted Cornell Dubilier and they put him in touch with a distributor who had 4 of the
> caps he needed in stock. *The contact info is on their site.
>
> You can always replace the rectifier with something a little better if necessary. *If the
> original rectifier isn't a fast recovery type, that should be done anyway..
>
> Fred
>
>
>
> "Spica" > wrote in ...
> > I'm looking for replacement caps for a 20 year old Cary amp. *The filter caps fit
> > through access holes in the amp and are 1100uf 450v with a diameter slightly less
> > than 2". *Cap height is not an issue.
>
> > Although I found a replacement (CBE) at Mouser.com that fits the bill, it's a non-stock
> > item requiring a minimal purchase of 16 units.
>
> > So my question is, can I use a different value cap without blowing up the rectifier?
> > As usual, thanks for any recs or suggestions.- Hide quoted text -
>
> - Show quoted text -

Let us hope their capacitors are under 20 years old...

[Fred[_12_]]

wrote:
> On Mar 1, 11:48 pm, "Fred" > wrote:
>> A friend went through this a year or so ago when he wanted to recap
>> his 25 y.o. SS amp.
>> He contacted Cornell Dubilier and they put him in touch with a
>> distributor who had 4 of the caps he needed in stock. The contact
>> info is on their site.
>>
>> You can always replace the rectifier with something a little better
>> if necessary. If the original rectifier isn't a fast recovery type,
>> that should be done anyway.
>>
>> Fred
>>
>>
>>
>> "Spica" > wrote in
>> ...
>>> I'm looking for replacement caps for a 20 year old Cary amp. The
>>> filter caps fit through access holes in the amp and are 1100uf 450v
>>> with a diameter slightly less
>>> than 2". Cap height is not an issue.
>>
>>> Although I found a replacement (CBE) at Mouser.com that fits the
>>> bill, it's a non-stock item requiring a minimal purchase of 16
>>> units.
>>
>>> So my question is, can I use a different value cap without blowing
>>> up the rectifier? As usual, thanks for any recs or suggestions.-
>>> Hide quoted text -
>>
>> - Show quoted text -
>
> Let us hope their capacitors are under 20 years old...

Indeed; in my friend's case, the caps he was after had only been in their
catalogue for a couple of years. They were the largest value in one of the
largest sizes they made, something like 170,000 ufd at 100vdc. The four
he bought cost him over $600, but he thought it was worth it to bring his
Krell up to date. And when I heard the results, I had to admit it sounded
damn near as good as a decent triode tube amp. ;-)

BTW, Cornell Dubilier caps do have date codes. The ones my friend bought
were about 3 months old.

Fred

[[email protected]]

On Mar 2, 12:12*pm, "Fred" > wrote:
> wrote:
> > On Mar 1, 11:48 pm, "Fred" > wrote:
> >> A friend went through this a year or so ago when he wanted to recap
> >> his 25 y.o. SS amp.
> >> He contacted Cornell Dubilier and they put him in touch with a
> >> distributor who had 4 of the caps he needed in stock. The contact
> >> info is on their site.
>
> >> You can always replace the rectifier with something a little better
> >> if necessary. If the original rectifier isn't a fast recovery type,
> >> that should be done anyway.
>
> >> Fred
>
> >> "Spica" > wrote in
> >> ...
> >>> I'm looking for replacement caps for a 20 year old Cary amp. The
> >>> filter caps fit through access holes in the amp and are 1100uf 450v
> >>> with a diameter slightly less
> >>> than 2". Cap height is not an issue.
>
> >>> Although I found a replacement (CBE) at Mouser.com that fits the
> >>> bill, it's a non-stock item requiring a minimal purchase of 16
> >>> units.
>
> >>> So my question is, can I use a different value cap without blowing
> >>> up the rectifier? As usual, thanks for any recs or suggestions.-
> >>> Hide quoted text -
>
> >> - Show quoted text -
>
> > * * * * *Let us hope their capacitors are under 20 years old....
>
> Indeed; in my friend's case, the caps he was after had only been in their
> catalogue for a couple of years. *They were the largest value in one of the
> largest sizes they made, something like 170,000 ufd at 100vdc. *The four
> he bought cost him over $600, but he thought it was worth it to bring his
> Krell up to date. *And when I heard the results, I had to admit it sounded
> damn near as good as a decent triode tube amp. *;-)
>
> BTW, Cornell Dubilier caps do have date codes. *The ones my friend bought
> were about 3 months old.
>
> Fred- Hide quoted text -
>
> - Show quoted text -

Thanks God! Seems the price has really crept up lately. Market
must be very small,I guess.

[Patrick Turner]

On Mar 3, 4:12*am, "Fred" > wrote:
> wrote:
> > On Mar 1, 11:48 pm, "Fred" > wrote:
> >> A friend went through this a year or so ago when he wanted to recap
> >> his 25 y.o. SS amp.
> >> He contacted Cornell Dubilier and they put him in touch with a
> >> distributor who had 4 of the caps he needed in stock. The contact
> >> info is on their site.
>
> >> You can always replace the rectifier with something a little better
> >> if necessary. If the original rectifier isn't a fast recovery type,
> >> that should be done anyway.
>
> >> Fred
>
> >> "Spica" > wrote in
> >> ...
> >>> I'm looking for replacement caps for a 20 year old Cary amp. The
> >>> filter caps fit through access holes in the amp and are 1100uf 450v
> >>> with a diameter slightly less
> >>> than 2". Cap height is not an issue.
>
> >>> Although I found a replacement (CBE) at Mouser.com that fits the
> >>> bill, it's a non-stock item requiring a minimal purchase of 16
> >>> units.
>
> >>> So my question is, can I use a different value cap without blowing
> >>> up the rectifier? As usual, thanks for any recs or suggestions.-
> >>> Hide quoted text -
>
> >> - Show quoted text -
>
> > * * * * *Let us hope their capacitors are under 20 years old....
>
> Indeed; in my friend's case, the caps he was after had only been in their
> catalogue for a couple of years. *They were the largest value in one of the
> largest sizes they made, something like 170,000 ufd at 100vdc. *The four
> he bought cost him over $600, but he thought it was worth it to bring his
> Krell up to date. *And when I heard the results, I had to admit it sounded
> damn near as good as a decent triode tube amp. *;-)
>
> BTW, Cornell Dubilier caps do have date codes. *The ones my friend bought
> were about 3 months old.
>
> Fred- Hide quoted text -
>
> - Show quoted text -

I'd only re-cap an amp's electro's if there was real evidence the old
caps had reduced capacitance or had signs of getting too hot for too
long.

But if the replacements have higher capacitance then the charge up
current can be higher for longer and the existing mains fuse may
blow. If the original caps were say 1,100uF, and you went to say
4,700uF then you could limit inrush currents by using a 20W resistance
of say 10 ohms in series with diode outputs and the caps or have a
more elaborate series resistance with mains of perhaps 50 ohms x 40W
and when the rail voltage reaches 70% of final value the resistance is
shunted by a relay acting after a timer circuit. This circuit must
always go through the slowed charge up delay time even if the amp is
turnd off, then on again after only a second.

One might also use diodes with better current ratings. In a 300W SS
amp I built in 1996 I used 2 x 100,000uF 75V for + and - 70V rails. I
have 240V mains here and I used a delayed charge up circuit with 100
ohms in series with mains to power trans. 120V mains might need only
50 ohms.
In my amp, I could turn it off, and it would run for 25 seconds from
the stored charge in the 200,000uF I have.
But the delay circuit would always work even after turning off then on
again fast. I recall I used 35Amp rated bridges for the diodes. These
were plain simple bridges, not fancy fast recovery diodes which don't
make any difference to the sound.

The purpose of the delay reduced the need for a high value mains fuse.
The mains fuse needs to be low enough to protect against excessive
mains input current if the amp is making too much power into a load
too low or if there is a some other fault which draws lots of current
which might always be less than the in rush charge current to such
large caps.

Patrick Turner.

[kartinkent]

The bass is not as tight as it used to be but still sounds very good and a hum has
developed, but you need to be very close to the drivers to hear it. The hum was
never there before and considering the 20 year old age, I just think it's time to
refresh the caps. I find it hard to believe that 20 year old electro caps are still
performing up to spec.