Good capacitor for Gainclone?

[maxw]

I am going to make a gainclone but I am not sure how to choose a good capacitor for good sound quality. I have made a PIMETA headphone amp and know some good brands like Elna starget/cerafine , Panasonic FC series etc but I see some gainclones here seem to have big exotic looking ones

I am wondering what are some good brands and model that is available via RS components or Farnel/newark.
And where did you get yours if they are not readily available?
How do you pick them?

I got 5 of these today from a scrap metal yard for $2.
Written on them:
Roe brand
ELKO - EYM/A
10,000MFD -10/+50%
100V-
-40...85 degrees C
433/3.85
W-Germany
Pic attached

Any good?
(I have searched for this model/brand)
Thanks

[thomas997]

Many people here will tell you to go for something between 1000-2000uF.

Blackgate or similar expensive capacitors.


I would try the ones you have out, but also try something with a lower capacitance (panasonic, BC, anything decent). Then decide which sound you like best.


Personally I have some 5k and 20k uF ones, when I finish off my amp I will test to see which sound better. I dont really want to go buy exotic anything at this point.


Oh yeah and make sure you test those out as well. Connect a resistor in series and measure the voltage across it (should drop to very low), or measure the current? I have found both methods from searching this forum.

[zagisrule!]

The more capacitance you have in the supply the better...it just takes up more room.

If those caps are still good they are fine. Blackgates and other similar "magic" capacitors are nothing but a waste of money IMO. Especially in the power supply, the "sound quality" of a capacitor is insignificant.

The gainclone has few/no capacitors in the actual audio path...therefore why should you drop $25 or more on your 1000uF Blackgate when it is not even in the audio path (where it matters )? And therefore can not affect the actual audio signal at all?

Bottom line is that your caps are more than adequate and if you decide you don't want them and they work I'll buy them.






-Matt

[Dr. ODD]

I think these are fine old Roederstein caps. They have a good "Reputation"
The question is how old they are, and if they are still allive. The age might be describt in the 6th line, but I am not sure! Maybe you cold measure them before using.

PS: I think you made a realy fine catch at the scrap yard

[jean-paul]

Originally posted by zagisrule!
If those caps are still good they are fine. Blackgates and other similar "magic" capacitors are nothing but a waste of money IMO. Especially in the power supply, the "sound quality" of a capacitor is insignificant.

The gainclone has few/no capacitors in the actual audio path...therefore why should you drop $25 or more on your 1000uF Blackgate when it is not even in the audio path (where it matters )? And therefore can not affect the actual audio signal at all?

Pretty controversial opinion. You underestimate the importance of a good PS ( as some manufacturers do so rest assured ). When you think in currents you'll see that a PS capacitor is *in* the audiopath.

Panasonic FC is a good choice and cheaper than BG. When the Roederstein caps are more than 10 years old I would not use them considering the low prices on new quality caps. If you're on a budget and decided to use them anyhow please leave them at a low voltage ( 5V or something ) supply with a large resistor ( 1M, 470 kOhm or so ) in series for a day or so. Then turn up the supply to 20 V and leave it for a day like that. If there are any signs of "leaks" in the rubber seal at the top I would advise you to discard them. Do not forget to discharge the cap with a 100 Ohm resistor before using it.

!!! Connecting old electrolytic caps that have been stocked/not used for a long time directly at their rated voltage may let them explode, you've been warned !!!

When stocked for a longer time oxidation can occur in the cap. Letting them charge on a low current will remove the oxidation. BTW, they are long life types as can be found here:

http://www.ecomal.com/pdf/ALUCaps.pdf

[Mark25]

Originally posted by jean-paul

!!! Connecting old electrolytic caps that have been stocked/not used for a long time directly at their rated voltage may let them explode, you've been warned !!!

This is worrying! I recently aquired some old long life RIFA peh 63v 3300uF electro's from Baco. datecode BA1 ??. worst case supply is 52v. what do you think JP?

[jean-paul]

I don't know why the manufacturers like to use unreadable datecodes. I don't know what to think of BA1, sorry. Maybe the datasheet explains how the BA1 datecode translates into an understandable date ?!?!

Just use the technique as described and you'll be able to use them in most cases. I never use electrolytic caps older than even 5 years in my gear but that's just me. Above 10 years is too old, I've learnt my share with caps Nowadays I only buy them when I need them which unfortunately is not a 100 % guarantee that you receive recent made parts. Always check what you get, I once received caps made in the year I was born !

Stocking of electrolytic caps is only interesting if they can be bought for low prices and if you think you'll be really using them in the near future. Also long life parts of MIL quality can be bought without doubt if they're new/unused and produced not too long ago.

The prices of new ones when bought cleverly at the right shop is too low for wanting to use doubtful parts ( doubtful in the sense of not knowing how old it is ).

Some reading on lifetime of electrolytic caps:

http://www.svalander.se/shoppen/pdf/...fe_factors.pdf

[Mark25]

thank-you for the useful informative post JP.

[maxw]

Originally posted by jean-paul
I\The prices of new ones when bought cleverly at the right shop is too low for wanting to use doubtful parts ( doubtful in the sense of not knowing how old it is ).

I think you are right. These could have been out in the weather for weeks before I got them, I think I'll just get some new ones. I can use one of these as a paper weight

Thanks heaps for the advice and information guys, much appreciated