Where's this extra cap go?

[TwoThirteen]

Hey guys,

I'm still a learning builder and I've gotten a used BHC that I'm rebuilding. I'm taking it step by step and very slowly, going to make sure I check every connection, re-solder a few parts, and such. I have the rest of the rebuild planned out but I'm not sure where this bad boy's supposed to connect. It's a WIMA 2.2uf MKS4 250. I bought some replacement (stock) nichicon caps so worse case scenario I'll just pop those on instead.

Is it a common mod to use one small film cap in addition to the 220uf 250v cap on 20u and 21u? (That's how it found its way to me, seems a bit odd, no?)

If any experienced modders would like to chat over discord to help with going over the build that would be really great too. 

https://imgur.com/0GPUcMS
It's only half on at the moment and needs soldered but that's the general position I found it in. What would you guys do in this case?

It does have a choke installed if that matters in this instance.

[Paul Birkeland]

Clip it out and throw it away.

[TwoThirteen]

Thank you! Useless stuff installed makes me question the rest of the build, soo this is only going to get more involved. I appreciate the expertise and commitment to helping us newcomers.

[Paul Birkeland]

You should show the rest of the build.  It's wired for 110V, so definitely check your line voltage when you can.

[TwoThirteen]

The other day I messed around and ordered the wrong Nichicon power caps.

I got these: https://www.digikey.com/en/products/detail/nichicon/UPW2E221MRD/589769

They are not the same as the stock ones that came on the amp, because they're labeled PW(M) and not CS(M). Looks like the ripple current is ~525mA. Not sure if any of these numbers matter much. Can't find the CS(M) stock ones listing to compare/contrast #'s to ask more specific questions.

I may have to try and attach the ones that came with it instead, but their leads are very small.

What do you guys think about using the ones I got off Digikey compared to the stock ones? Again, all expert advice very appreciated.

Thanks everybody. I'm just getting started, will update thread and post full build here soon.

[Paul Birkeland]

The actual stock caps we provide vary a bit depending on what's stocked.

UCY2E221MHD3 is what we would generally aim to provide with the kit, as it has the highest ratings and doesn't hit the base when laying down, but they have been sold out for a while and may not be available till Halloween.  There are a couple that appear to be genuine from a vendor I've used before on eBay here:
https://www.ebay.com/itm/313133110211

I wouldn't use the caps with the short leads, as they may be a bit of a challenge to work with.

As far as ripple current ratings go, it helps to know if that rating is at 120Hz or something higher like 10kHz.  A cap's lifetime rating is multi-dimensional with  the rated voltage, ripple current, ripple frequency, and operating temperature all coming into play.  As you move away from all those maximums, anticipated capacitor life increases rather dramatically. 

[TwoThirteen]

Hey Paul,

Thanks for supplying the power cap part # that's a huge help if I encounter any issues with the work I did. I got the short lead caps on, they just had to be put sticking to the side.

I'm still not finished with the build yet, as I want to find a way to clean up the soda can sized caps mounting system. Still have yet to paint, etc. If you guys want to eye the inner workings and offer any advice or notice any weird connections I'd really welcome your inputs/suggestions!

https://imgur.com/fARNgRg
https://imgur.com/aNoJMjY

[Paul Birkeland]

You have an Alps Blue pot with the wires soldered directly to the pins.  Eventually that will snap the pins off.  I would get an adapter PC board from eBay, mount that to the pot, then reinstall the wires onto that.  You could also get a different pot with solder lugs that won't have this issue.

If the current power supply caps can be reused, I would just do that.

The big caps tend to just not fit all that well in a 6x10 chassis (there's plenty of room in the Crack-a-two-a). 

There are some solder joints on there that could probably use a little more heat to flow out a bit better.

What is your incoming AC mains voltage?

[TwoThirteen]

Today I plan to re-solder most of the joints for improved flow and order some 3D printed big-ass-cap brackets found here: https://www.shapeways.com/product/984NM88BE/capacitor-bracket?optionId=61921483
I just think that it'll make transporting it around my house a bit safer, last thing I want is a cap getting loose and bashing into other parts, it's future-proofing in case I move, too. Only shitty thing about it is having to screw through the top deck but I'll probably find a way by flat-mount zip-tying through the bracket instead.

I did some research and I believe that original mystery cap was just a bypass cap. (some swear by them some think they're snake oil?)

I'll check voltage here in a bit, gonna get the joints cleaned up first.

[TwoThirteen]

It works! Sounds really good. Let the tube rolling commence.

[Paul Birkeland]

What was your line voltage?