• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Which audio electrolytics in tube voltages -- Your comments please !

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Howdy,

I need to get some electrolytics with value/rating 220uF@200V. I can't find a US source for anything Elna has.

Can someone recommend another model? How about the Muse brand?

Are there afoordable film caps that could be used? If a circuit specifies a certain value of electrolytic, can a smaller film cap be subbed? How would that affect the circuit?

Hopefully your comments will inform a lot more DIYers than just me.

Thx!
 
IMO Panasonic, Nichicon, and United Chemicon are fine capacitor manufacturers (and I have used all of them in amp projects with no problems). I would avoid eBay purchases of lytic caps due to fakes, unless you are reasonably sure that they are genuine.

Here is a decent pick: Digi-Key - 565-1439-ND (Manufacturer - EKXG201ELL221MM25S)

In response to if the cap can be subbed with a lower capacitance film, cap - it depends on the circuit.
 
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I need to get some electrolytics with value/rating 220uF@200V. I can't find a US source for anything Elna has.

Can someone recommend another model? How about the Muse brand?

Are there afoordable film caps that could be used? If a circuit specifies a certain value of electrolytic, can a smaller film cap be subbed? How would that affect the circuit?

The main consideration is to obtain capacitors with the same capacitance, at least the same voltage ratings, and with at least the same ripple current rating. (The internal impedance may also be a consideration if it is in the power supply, but it's difficult to comment on that specifically).

If the capacitor is in the direct signal chain then using a smaller value will most likely reduce your frequency response. If it is in your power supply then using a smaller value will most likely increase the ripple on the high voltage, perhaps substantially. Neither of these are likely to be good things.

You can place capacitors in parallel and add the capacitance value. Example: two 120 microFarad capacitors in parallel equals one 240 microFarad capacitor.

Recently I have had fine results with Rubycon capacitors in my preamplifier power supply (example: Farnell part number 1547017). I would echo the voice of others in recommending that you avoid e-bay capacitor purchases. Consider buying your caps from the main distributors as their quality is usually very high.

: )
 
This is a important issue as electrolytic caps have the shortest life expectancy in a tube amp and the physical location becomes important. Keep lowest in chassis with plenty of ventilation.
I try to use those for SMPS (switchmode power supplies) have lower ESR; some versions rated at 105°C,;
Rule of thumb-> life expectancy halves for each 10°C rise.
I've also used good quality electrolytics in lieu for expensive tanatalum types without any sonic differences.

richy
 
Richy reminds us of an important design point about short lifetimes of electrolytics. This is the reason I don't buy them from ebayers - they go stale with age, and stale caps sound bad.

As well as choosing a cap with adequate voltage rating, be sure to check the ripple current rating, if the cap is the first one after the rectifier. The lifetime is much shorter if you get that wrong!

Use the Duncan Amps Power Supply designer-2 to find out the real value of ripple current in your amp. If you're too lazy to do that, just double the value of dc current your amp draws at max signal and you have the ripple current. You need about 500mA rating for a 50W amp.

Axial Caps rarely have enough ripple current rating for first cap duty. Snap-in types usually offer the best choices there.

The Nichicon VX series sounds good for preamps. Elsewhere I like the Panasonic TSHA or TSHB or TSUP series. I use the Samwha HJ series in guitar amps, and the sound of these low cost parts please my customers.
 
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