Changing electrolytics

Hello, I have to change the 4 big electrolytics in the PS of my Threshold Sa/3.9e.

What brand do you suggest for best sound/reliability?



Nichicon is the standard.  Any good modern cap is going to be better, and a lot smaller than your originals.

For reliability check the temperature rating.  Get equal to or higher rated temps.  Higer temp ratings on caps are related to reliability and mean time to failure, so in the same amp, a 105 degree cap will last longer than an 85.

Cornell Dublier. That’s what was used by Jon Soderberg from Vintage Amp Repair on my 3.9e and 6e. Also should add IXYS rectifiers and updated Binding Posts.

I would try to find Cornell Doublier caps about the same diameter as the OEM Mallory’s. That will make fitment easier, using the same securing bands, etc.

Should be higher temp rating than the Mallory’s and try to stay with 10% of the max capacitance of the MMallorys.


FWIW, Mallory was bought/taken over by Cornell Doublier.

If those use the Mallory caps and you want to replace them in kind, CDE has picked up the line which is now the CGS series. Mouser has a 39,000uF in stock. These are tough to find without having to place a factory order (which is a minimum of 24 to 36  pieces and can costs thousands of dollars).

Nichicons have metric threads and may be a problem if other things screw into the caps. Kemet caps are cheaper, but they are fairly new and don't have a long track record and could cause problem later (as Mark Levinson 300 series owners found out the hard way with the Philips caps).

You can go smaller in diameter, but not bigger (or else the ground bar would have to be re-drilled). As long as the bottom plate is clean, it isn't too big of a job to put in a smaller clamp. Aslo, check how much play you have up and down -- or you may be stuck without a length option.

It seems most of the large size capacitors are very expensive. Adding further difficulty is locating ones in stock. Recently purchased some for a Hafler redo. Yikes. The price is sky high!

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Since you are saying "Big Electrolytics", you are most likely changing the filter capacitors of the power supply.  For those:

- Buy the ones with the HIGHEST temperature rating.
- Buy the ones with the HIGEST lifetime rating.
- Buy the ones with the HIGHEST ripple current rating.
- You CAN buy both the increased voltage and capacitance versions PROVIDED
  that if you have inrush current limiters such as impulse resistors and thermistors,
  their capacitance rating is NOT exceeded or they are very likely to explode at power on.

As an example, here is what I used in my own built amplifier (4 of them):

Note how they are rated at 20,000 hrs at 85 degrees C.  They are indeed expensive but remember that they are at the heart of the power supply.