- электролиты менять все точно. Их там совсем немного, и они неполярные.
Я б поставил ... хотя бы вот такие: ECAP NP (К50-6), 47 мкФ, 35В 105°C
Jim Williams на гирслатце писал что биполярные/неполярные хуже обычных электролитов - у них "мутный, темный" звук. Он рекомендовал померять в том месте напряжение - и поставить обычный полярный в соответствии с полярностью напряжения, шунтированный полипропиленом Wima MKP-2 0.01uf для улучшенного воспроизведения высоких частот и быстрых фронтов/импульсов:
-- Non-Polar (Panasonic SU)?
JW: You will want to remove the
bipolar caps, they are very dark sounding. I would use the Panasonic FM or Rubycon Z series unless you want to blow $5 a piece for the Rubycon Black Gates. I would also increase the values a bit for a better low end. Doubling the value extends the low end by one octave.
First measure the voltages on each side of the bipolar cap.
Place the polarized cap with the + pin towards the positve voltage. If you go with 50V caps, up to 10 volts of reverse voltage will be tolerated by the polarized cap. Next, use a small bypass cap across them to allow the air to get through and minimize the dampening of the slow electrolytic caps. A Wima MKP-2 .01uf/250v fits nicely on the rear of the pcb.
JW: Most of those are Panasonic bipolars that are very slow and clogged sounding. First, measure the offsets off each opamp or hybrid amp stage.
Replace the bipolars with polarized caps with the polarity adjusted for the polarity of the dc offsets.
-- Nichicon Muse Bipolars?
Too dark and slow. They are not long life
105 degree rated, they are common 85 degree caps and will not last in the hot interior of a tube guitar amp. Black Gates are a far better choice if you require bipolar electrolytic caps. Remember, every bipolar electrolytic cap is actually 2 caps wired in series. If you need to install a bipolar cap,
a better way is to use the 105 degree long life, low impedance FM or HE or ZL caps by using two in series with the + pins connected to each other. If you want to get wiggy, add a resistor from the + supply to add a bias voltage to the junction of the + pins of the caps. Then place a small value polypropylene film cap across the - pins of the caps.
JW: How did you test THD on electrolytic caps? I run them through my Audio Precision and I still scrape the analyzer's residual distortion.
My experience with
all of them including the Black Gates is they absorb transients and damp pulses, that's easy to test and see. This is why
I recommend a fast high voltage polyprop film cap as a bypass, that passes what the electrolytics absorb.
Do try the tests with the HQ film bypass, it will lower distortion at higher frequencies. Bob Pease at National Semi has done articles about the effects of various caps, it's an interesting read.
See also:
2 cents. First, older electrolytic caps are not very good, period. They are large, leak, have ESR and DA problems. They damp transients. There are new formulations available that are marketed as tantalum replacements, these are the Rubycon ZA/ZL, the Nichicon HE and the Panasonic FM series...
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Can anyone describe in what terms of sound quality an older piece of gear might improve from re-capping? I hear about it sometimes on restoring older g
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