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diy student 5th September 2001 06:32 PM

I'm building an Aleph 3 that calls for 8x 22,000uf caps I have a choice of either 30,000uf caps or 10,000uf caps at my disposal. Assuming that I'm going to use a total of 240,000uf does it matter which size I use. Will 3 10,000uf caps generally add about 3 times the distortion of 1 30,000uf cap? Thanks for your time.

Freddie 5th September 2001 08:24 PM

I would go for the cheapest alternative.
If 3*10000uF is cheaper than a 30000uF I would use 3*10000uF.

I am collecting parts for my Aleph 30, and I will probably end up with 22 * 10000uF, with a 50amp diode bridge and a 600VA toroid transfomer per channel.


/Freddie

Jakeh 6th September 2001 10:08 AM

Look up the specs of your particular caps, generally a bank of smaller caps will have lower ESR.

Xavier 7th September 2001 05:30 AM

Multiple Capac. in Parallel (vs) Single Capacitor
 
Please remember the following points when selecting Capacitors

1. The life of a Capacitor depends on its core temperature, usually around 85 - 105 C max.

2. The temp. itself depends on the ripple current of the capacitor.( ripple current varies with the value and voltage rating of the capacitor.)

3. Exceeding the ripple current of the capacitor increases temperature and therefore reduces life considerably.

4. Using Ohms law, if multiple capacitors of same working voltage are operated in parallel, then ripple current is evenly distributed amongst them and therefore increasing their reliability and life.

-XL

dutch diy 10th September 2001 08:24 PM

multiple caps
 
Multiple caps offer one additional advantage:
Putting a small resistor (0.1 Ohm or so) in series with the cap keeps the in-rush current to a more managable size.

Switching on my dual-mono JLH (4*22000 uf) does produce a visible glitch on a a lightbulb which is connected to the same wall-socket.

Chad 20th September 2001 04:28 AM

I'm building an amp that has a 50-0-50 transformer 300va that after the rectifier will be +70 and -70 rails. I am wonder about caps. I can get four 10,000uf caps rated at 125v or four 26,000uf caps rated at 250v for the same price. A local shop has four of each surplus. I know more uf value is good for a psu but, I'm wondering if the 250v caps will be okay on the 70volt rails?

Thanks in advance, Chad


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