Output Capacitor Upgrading Questions

[Paul Birkeland]

Well, you take out the 2.9K resistors that attach to 7 and 9 when you install the Speedball.

[manther]

Ah, thats right. Thank you.

[JLDub]

Hey everyone, I'm sure this has been covered before somewhere, but I've done a bit of searching and can't find a super definitive answer.

I was wondering if it's okay to upgrade to output caps with a microfarad rating a little below 100 like these:
https://solen.ca/products/capacitors/fast-capacitors-250v-pa-series-metallized-polypropylene/pa9100/
Or if I should really use the other with a 100uf rating minimum.

Honestly I'd like to use the 91uf 250v Axon true caps but partsconnexion's selection stops at 43uf. https://www.partsconnexion.com/axon-true-cap-film-capacitors.html
I'm going to contact them tomorrow to see if they can get higher values ordered and if not then I'll probably just stick with the solens. I've pretty much come to conclusion that everything around this price range is going to offer similar performance (Audyn, Solen, Dayton, Erse PulseX, Jantzen, etc) so I'm more focused on price/value and physical size/ease of install.

Thanks

[JLDub]

Bump.

[Paul Birkeland]

Give it a shot and let us know how you like it!

[JLDub]

Whoop! Will do. FYI, according to partsconnexion, Axon is no more. So I'm going with the 91uf Solens straight from CA.

[elmoe]

I noticed this picture in a different thread as a way to mount the capacitors:

https://bottlehead.com/smf/index.php?action=dlattach;topic=6030.0;attach=5468;image

Is this safe to do? It looks like a hole was punched in the plate, and a screw was inserted then locked in place with a nut. It was then used to solder the caps to directly and wired where necessary.

[Paul Birkeland]

Is this safe to do? It looks like a hole was punched in the plate, and a screw was inserted then locked in place with a nut. It was then used to solder the caps to directly and wired where necessary.

That's an insulated turret.  Here's an example:
https://www.mouser.com/ProductDetail/Keystone-Electronics/11511?qs=sGAEpiMZZMsg%252Bek5lc7F5m87vzA%252BVXoK

This is a very, very good way to mount big capacitors, but that's $25 worth of parts to serve that purpose.

[JLDub]

Very interesting! Cost is definitely a factor. I still haven't picked up any upgrade caps but someone mentioned automotive Velcro as it has a much higher temperature rating. Can be found on Amazon. I figured I would start there.

[elmoe]

That's an insulated turret.  Here's an example:
https://www.mouser.com/ProductDetail/Keystone-Electronics/11511?qs=sGAEpiMZZMsg%252Bek5lc7F5m87vzA%252BVXoK

This is a very, very good way to mount big capacitors, but that's $25 worth of parts to serve that purpose.

Thank you!

[Love Rhino]

This was a great thread and I learned a lot about upgrading the crack!  I was wondering if I were using Sennheiser hd800 headphones, or similar 300+ resistance headphones, what would be the lowest uf I could get away with replacing the output caps?  I would of course like to avoid noticeable roll of in audible sound.  I was looking at a chart that made it seem that 33uf would be ok, and that would open up my options in cap choices quite a bit.  Stick with higher uf around the 100 mark, or....?   

Thank you!

[Paul Birkeland]

I would of course like to avoid noticeable roll of in audible sound.

If we assume the HD-800 is a 300 ohm headphone, then I'd stick with 100uF, but the HD-800 is not a resistive device. The HD-800 is ~450 ohms at 20Hz, which would lead me to recommend ~70uF.

If you don't care about 20Hz response but 30Hz is OK, then you could go down around 60uF. 

IMO, 33uF is too small.  You can certainly buy a selection of Dayton film caps in 33uF, 47uF, 68uF, and 100uF values, then do some listening tests.

[mcandmar]

These 82uf popped up on eBay recently, might be of interest.  Seller has a whole range of oddball cap sizes which might suit some for speaker crossovers.

https://www.ebay.co.uk/itm/333019020505

https://www.ebay.co.uk/itm/332828562969

[Love Rhino]

Thanks!  I like the look of the clarity caps.  I actually am going to try some Russian KZK 100uf white line caps.  I might have to get creative to get them to fit, but luckily I live next door to a woodworker so I can recruit him if I need more space.  They're not as large as many of the Mundorfs, however.

[Love Rhino]

Does anyone have a recommendation of some 470uf caps to replace the first couple PS caps?  I've been seeing quite a few 'nichicon' but not a lot else, and i'm looking for something not too expensive that would still be an upgrade.

I was thinking of  changing out the first two 220uf PS caps with 470 caps, and then using a film cap for the last PS (I have a choke installed so I could get away with lower uf).