Electrolytic cap question

[VintageCharlie]

i would send you the 220uF for the cost of shipping (i think cheapest shipping would be 5-6$), but maybe you can get it off a store cheaper if you get it along with other bits, as 6$ for a modern cap is quite expensive. Not sure if i can part with the Erie - i have to dig in my stash.

[kevrockitt]

I undersatand. Let me know asap if you want to sell the erie and how much. I will take the sprague though. Think it all over so I can paypal the cash to you. One or both, it's all good. Thank you so much for all your kindness!

Kevrockitt

[Roe]

I'm using some NOS japanese caps that look almost like the grey RS caps

[kevrockitt]

I did come across an erie NOS 250uf 50v. Would that be a suitable alternative to a sprague 220uf 50v cap?

[Roe]

low voltage caps seems to sound better at the cathode

[kevrockitt]

The Metro manual for the 50w kit reccomends 220uf 50v at that position on the board. So I am wondering if the 250uf would be ok if the voltage were still 50v. I also have access to a 220uf 40v NOS cap. What do ya think?

[Roe]

The Metro manual for the 50w kit reccomends 220uf 50v at that position on the board. So I am wondering if the 250uf would be ok if the voltage were still 50v. I also have access to a 220uf 40v NOS cap. What do ya think?

first, a 220uf cap will often measure 300uf. second, the difference between 250 and 220 is negligible both theoretically and practically. third, the actuall voltage is barely 2v, so a 6v cap is more than sufficient. forth, low voltage caps may actually sound better. finally, the construction of the cap is sometimes more important than the uf and voltage ratings (older caps often have the right sound)

[kevrockitt]

Great info!!!! Thank you!
Kevrockitt!!!

[demonufo]

It's certainly would ring true for a 6V cap to sound better than a 50V cap, since it will have much lower ESR in theory.
Some people may actually prefer the sound of a higher ESR cap though. For instance, take those that have been playing amps with knackered filter caps for years (now I'm not saying that all old caps are knackered and have high ESR though ) and have gotten used to their amps. Some of thes people are actually disappointed with the tonal change that new caps bring.
I'd follow Roe with this one.

[kevrockitt]

Ok guys...how do I test NOS caps and more importantly I would I reshape a cap properly?

[Roe]

no need to form these caps. you can measure it but usually they're fine

[kevrockitt]

Would that be because they recieve such low voltage passing through them at the cathode position?
I'm learning new stuff about building amps everytime I log in here.

Thanks
Kevrockitt