Electrolytic capacitor replacement

I want to swap out a couple of electrolytic caps with higher quality caps, also electrolytic. The ones I am looking at are all physically bigger than the ones I am replacing, and consequently the leads don’t fit the board. The rubicon’s I want to bin are have a diameter of around 3/4’ and the caps I’m considering are between 1’ and 2’. The big issue I have is the lead spacing.

I’m considering using a spacer between the pc board and the cap giving enough room for the leads to bend enough to fit the board. I have space on the board to fit a larger cap, but not enough to mount the caps on their side. The caps new will need to sit “upright”.

Id appreciate it if somebody has figured an eloquent solution for this.

Elegant would be more eloquent. Ditch the board. Hardwire direct. That's what I did. See the last couple pics on my system page.
Elegant would be more eloquent.
Well played!
When I swapped in a monster film cap for the power supply electrolytic, I couldn’t fit the cover back on. Now I leave the cover off. Sounds better anyway with the metal gone.
pauly there a LOT of great electrolytics that are the same size.

Do you mean taller or wider. It is always per application but how many are there and what is it your recapping?

Vishay, Mallory, Cornell Dubilier, Panasonic, 25 more at least..

Radial right, not axial?

If the caps are snap in, then…..

Simple. Solder leads to the cap that are long enough for you to mount it at whatever angle etc… you need. Be sure to keep these lead outs as short as possible and place heat shrink over the lead outs between the cap and the board to prevent any possibility of a short.

The lead outs should be the proper gauge, solid core copper, to fit inside the solder pads. Usually 18 gauge is fine, but be sure. You can thin the lead outs before applying the heat shrink to prevent oxidation. Or use tinned copper, solid core conductors as used on most film caps.

If the cap fits over the solder pads with no need to angle, the lead outs will not allow you to seat the cap perfectly flush on the board. That’s ok, just use a product like Soundcoat vibration damping sheets, with adhesive on one side, cut a small piece or two to fit between the cap and board. It’s not conductive and adds that next level of OCD attention to the details 😊

Just saw this comment by you….

”I’m considering using a spacer between the pc board and the cap giving enough room for the leads to bend enough to fit the board. I have space on the board to fit a larger cap, but not enough to mount the caps on their side. The caps new will need to sit “upright”

This is fine. Use the suggested Soundcoat between the cap and board if you like.

Are you using the Audio Note KAISEI caps? Great caps! 

Yep, taller & wider (diameter). I’m sticking to the same value. I’m looking at 47uF/400v. 

Yep, radial, if that means both leads exiting on the same end.  😂🤣

Are you using the Audio Note KAISEI caps? Great caps!

I’m looking into kaisei caps - the value I’ll need to get has snap on connectors -> 50uF/500v. They have a 50uF/350v with leads but I’m uncomfortable going down to 350v given the board specifies 47uF/400. The actual caps are 47uF/450v so …

I was also looking into Mundorf MTubes, but if anything they’ll be more challenging to mount than the kaisei. 
I was also thinking of drilling holes in the PC board that match the cap spacing and the routing the leads to the existing holes underneath the board. I’d need to glue the caps in place with some non conductive epoxy. 
I’ll look into Soundcoat . Never heard of it before.

Careful drilling holes if the board is double sided etc…! Also, sometimes a ground plane is located close to the solder pads. You could cause a short.  Soundcoat is sold at Parts Connextion and Sonic Craft I think. Sonic Craft used to sell it. I use the stuff all the time in my mods/upgrades.

Have you used glue on PC boards before? I'm worried an epoxy may be too much and you end up with a hole in the board when you want to change later on. A friend of mine used a glue gun but that is way to much heat for my liking. 
No need. If you solder the leads properly from under the board, then you can tension the leads strong enough so the cap rests securely on top of the precisely cut Soundcoat pads. This is all you need.

If you don’t want to do that, then hot glue always works and comes off fairly easily without damaging the board should you need to remove the cap. I don’t like using any kind of goop for this sort of thing, but that’s me.

You could also use double sided tape pads in place of the Soundcoat material.

I’ve taken a peek inside my 2A3 monos, and over there I have all the space in the world for cathode bypass caps. I was wondering if you have tried Solen PB caps for cathode bypass? 
I’m thinking they’re film, which beats an electrolytic all day long, and they’re very inexpensive. Size is not a problem. 

Please make sure you measure the ESR and compensate accordingly.  Lowering the ESR, especially with caps that go towards the ground (even order filter components, zobel, etc. ) have have a significant impact on the impedance curve.
This is for an amplifier. I have replaced those Solen caps before. I have never liked Solen caps however. They are OK in a power supply, but they are slow and dull sounding. Why not Clarity CSA?

Why not Clarity CSA?

I wasn’t aware of the Clarity caps.

Honestly, after posting I saw VH makes both a 47uF ODAM and 47uF OIMP, so I had been thinking of going for one or the other. The Clarity is about half the price of the VH audio caps, so that’s probably the more sensible choice.

Sorry I misread.  I dislike solens a great deal as well.  :)
Jeez, the Clarity caps aren't really small are they? Wow. 


I’ve put the Clarity in a cathode bypass position on a driver tube and it sounds very good. It added a ‘gentle’ but detailed quality. Thanks for advice; good call as always!

You mentioned Solens are ok in a power supply. I’d love to use Clarity but they are just too big. Is it worthwhile to swap out the cheap electrolytic with Solens?

Also, would it be worth looking into using large value Solens bypassed by a smaller Clarity - Lets say a 51uf Solen and a 10uF Clarity? I’m talking power supply decoupling caps.

Please confirm the cap value needed and the voltage realized in your power supply. 
Here are my two favorite film caps for power supplies,

- Clarity TC 600v. They have a 50uf Kelvin style and 55uf regular dual lead. Many other values.  No bypass cap needed. 

- Mundorf Tubecap - many values.  Smaller and good. No bypass cap needed 


Yep, I keep uF the same (or close) and voltage I'll either go up or at least keep the same. 

Sizewise I cannot swing Clarity or Mundorfs. At a pinch I can squeeze in Solens, but as you mentioned they're not very good. If they aren't an improvement over electrolytics, I won't bother. 

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If needing to stick with Electrolytics, then I use these! These may fit….

Mundorf HV Mlytic - use these all the time

Audio Note Kaisei - these will most likely fit.They can get pricy. Very good. 

Thanks, I’ll look into them. I’ll probably go for one of the three prong MLytics. Given the cost of the kaiseis, I’ll use them on cathode bypass positions only. On a power supply the cost would run up pretty fast. 

Reading between the lines, you really don’t like Solens, do you? 😂🤣
Let me clarify something I should have said earlier. The Solen caps, or any film cap, will sound better than 95% of the electrolytics out there in a power supply. I gave you other film choices better than Solen. I thought the Mundorf tube caps were no bigger than Solen? 
If the Solens fit better than the Mundorf Tubecap,  then you can use them. Both the Mundorf MLytic HV and Solen film caps are good choices for your power supply. You can decide based on price and space. If you use the Mundorf  Mlytic HV or HV+, then add a film bypass cap. 
Got you. I am interested in using film for both better sound and reliability. I’m going to try and see if I can squeeze Mundorf Tubecaps in. 
The 30uFs are rectangular and if I can superglue them against the sidewall I’ll get them enough of them in. Maybe. 

Ok, short of taking a hacksaw to my chassis, I cannot use Tubecaps. I think I’m going to have to settle the Mundorf Mlytic. Do recommend bypassing them? 

I want to use the 50+50uF three prong. The ODAM is a little too expensive for bypassing - I need to replace 4 caps per amp. I’m a little under spec, the current electrolytic are 56uF. What would you recommend?
You can measure what’s in there and see what value they really are. Electrolytics can vary up to 20% depending on spec.  You can ask Sonic Craft to match the caps as close to 55uf as possible. 
Yes, use bypass caps for sure. You can use a cap like Audience Auricap XO, Clarity CSA, and Jantzen Superior Z. Make sure they are high enough voltage for your circuit. 1-3 uf or so is fine. 
I generally use Nichicon capacitors in power supplies, etc.  Clarity if I have to.  Then Mundorf.

I prefer V-Caps to the other capacitors.  I generally do not find a need to use by-pass capacitors.  Some people use them all the time.  I have not found that they are a big improvement over other changes.
Happy Listening.
Elegant would be more eloquent. Ditch the board. Hardwire direct. That's what I did. See the last couple pics on my system page.

:-) correct on both.  But wait, there's more.
I often drill holes in the existing PCB that match the leads, and use copper solid wire to hard wire it.  use adhesive ot hold the cap firmly in place.

Now, in what what are the new one's "superior".  If not larger, you are barking up the wrong tree. On a relative basis 'lytics suck -- all of them. Use the world's cheapest film cap in parallel and it will still b 10X better.  I suspect one is already there. if not shame on them.  I means really shame on them.
I ought to have added, what i define as "superior" are the characteristics that affect sound quality, specifically both frequency and phase linearity. They are dissipation factor and dialectic absorption. Both are often on the datasheet. ’Lyics range from bad to worse. Films range from good to excellent, and are way more stable. But they are vastly less size efficient (small values in big packages) and so are only usefully applied in parallel to handle the frequencies that are most affected.
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On Klipsch Choprus speakers there is a little dinky 68uf electrolytic which does not last as long nor sound as good as an Audyn 68uf poly cap. Of course the size is 20 times larger at least.

  I take the old electrolytic off and reuse the holes in the PC board for the new cap leads. I have to mount it on top of the board pairs with hook and loop tape and then a cable tie over cap and tape for extra security. I have to extend the leads to reach the PC board holes with good tined buss wire which is then insulated with teflon sleeves and the bare joints where the buss wire is soldered to the cap lead wires is protected by heat shrink tubes.