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Old 6th February 2004, 02:31 AM   #11
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Hi,

Quote:
and since many people, thorsten included, suggests using film caps instead of electrolytics, so i'd like to give it a shot.
Since it's for the PSU you'll probably require large values at high voltages?

Consider paper in oil caps such as ASC. I think Partsconnexion carries them, probably a number of others too.

A major source of unwanted colouration are the cathode bypass caps.
Black Gates can perform miracles in this position but they're not cheap.

Cheers,
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Old 6th February 2004, 04:32 AM   #12
arnoldc is offline arnoldc  Philippines
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hi frank,

right now my amps use Black Gate capacitors for bypass, MIT RTX or Jensen or Auricap coupling capacitors, a mix of Sprague Atom, Nichicon Muse, Audio Professor (47uF x 2) one PSU related parts.

i just wanted to hear an amp without any electrolytics in it. so i'm progressively replacing the electrolytics on my Gordon Rankin Bugle 45.

it actually becomes more expensive with these Solen PPEs!

cheers!
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Old 6th February 2004, 04:55 AM   #13
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Hi,

Quote:
right now my amps use Black Gate capacitors for bypass, MIT RTX or Jensen or Auricap coupling capacitors,
Personnally I leave those as they are.

Quote:
a mix of Sprague Atom, Nichicon Muse, Audio Professor (47uF x 2) one PSU related parts.
You could replace all those with either one of the following:

BG
ASC PIO
SOLEN SCR.

Out of which I think the ASC is an excellent choice and may be the cheaper way to go.
They last for ever anyway...

Cheers,
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Old 6th February 2004, 09:19 AM   #14
arnoldc is offline arnoldc  Philippines
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thanks frank, time to deal with steve m of angela again
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Old 6th February 2004, 01:36 PM   #15
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Default Re: Thorsten, what film capacitors do you use?

Konnichiwa,

Quote:
Originally posted by arnoldc
Metallized Polyester, Polyester Foil, Polystyrene Foil, Metallized Polycarbonate, Metallized Polypropylene, Polypropelene Foil

Does that mean any of these will fit your description of "film" capacitors?
They all are "Film Capacitors", yes.

How a "Film Capacitor" sounds results from a wide range of parameters, many of which are poorely researched. I know Metalised Mylar Capacitors that reliably sound better than certain axial (rolled, no case) Metalised Polypropylene Capacitors.

Simple blanket statements like "Teflon is best" and "Mylar sucks" miss the point totally. For example, typhical "axial" rolled capacitors as often found in coupling (including boutique types) tend to sound bad in many positions, simply because of microphonics. Often a cheap plastic encased cap will sound better.

For powersupplies I recommend Metal or plastic can encased capacitors, ideally oil filled, as this will severely cut microphonics. The dielectric quality becomes almost irelevant, especially with oil-filled types (check the dielectric constant of mineral oils...). Using the common Solen Axial types is an almost surefire way to sonic disaster.... Often indutrial "Motor Run" and "Lightning Phase Compensation" types have excellent sonic behaviour, thanks due to their "industrial strength" construction and oil filling.

In other cases available size and required values impose limits. In cathodes you are often limited to use Mylar, simply because a few 100uF in Polypropylene Capacitors do not come cheap. Wherever "limited quality" capacitors are that show at least good (anti) microphonic behaviour you can get a lot back with correct bypassing. Capacitors are a big topic and ideally their use is minimised and the quality maximised.

So, in the end the key issues I'd look for have more to do with mechanical construction and materials (eg certain magnetic steel encased Teflon Foil & Film Cap's sound rather worse than capacitrs in plastic cases) and it is often desirable to "sacrifice" a Cap or two from the kind you intend to use to the audio gods by dismembering them, to see how connections are made, how tightly they are wound and so on before comitting to use them (listening tests, ideally "bypass" type also help).

Sayonara
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Old 6th February 2004, 02:49 PM   #16
marz.tv is offline marz.tv  Sweden
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Default the mystery cap

I have a bunch of these, that I've used as coupling caps in many great sounding projects. Appr. 3cm length, with grey epoxy or glass ends.
What are they? Some kind of paper in oil, right? How old are they?
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Old 6th February 2004, 03:51 PM   #17
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Default Re: Re: Thorsten, what film capacitors do you use?

Quote:
Originally posted by Kuei Yang Wang
For example, typhical "axial" rolled capacitors as often found in coupling (including boutique types) tend to sound bad in many positions, simply because of microphonics.
hi kyw, are capacitor microphonics similar to tube microphonics?
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Old 6th February 2004, 04:24 PM   #18
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I've never heard a mylar sound as good as even a cheap polypropylene, as long as the latter didn't incorporate magnetic materials and/or use stranded leads.

However, that reminds me of a bypass test a friend and I once did of some boutique metallized polypropylene cap (one of the original 'wondercaps' about 10uF, 310 VDC) that happened to have copperweld leads. The 3" of leads, once cut off the capacitor and listened to by themselves, added several times more audible degradation than the capacitor with the leads cut off 1/4" from the body did and both of us could reliably hear this.

The signal passing through the capacitor was line level and the ambient SPL averaged only in the mid to upper 80 db range during this listening test.

IAC, my overall experience with capacitors has led me to use electrolytics only when absolutely necessary, which means as (film bypassed) supply filters at the output stage of a power amplifier such as my DC coupled OTL or for filament supplies. Otherwise, I have used polypropylenes or better for everything around an audio path in stuff I've built since about 1980, except for a couple of low value polystyrenes which I couldn't easily find higher quality dielectric equivalents of. If I can get an air dielectric cap in a circuit, I'll use it.

For that matte, differences in dielectric quality have led to to replace all the Solo foil inductors in a speaker xover with Goertz? Why? Because the Goertz's polypropylene film sounded much more neutral, detailed and less 'hot' than the (either polycarbonate or mylar, I forget exactly) film used for the Solo chokes.
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Old 6th February 2004, 04:55 PM   #19
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Hi,

Quote:
hi kyw, are capacitor microphonics similar to tube microphonics?
Similar, yes.
I do feel that most filmcaps are quite O.K. in this respect.
Ideally, if you saw one in two, the inside would look like a monolythic block of metal.

The worst offenders are often electrolytics...


Quote:
(one of the original 'wondercaps' about 10uF, 310 VDC) that happened to have copperweld leads. The 3" of leads, once cut off the capacitor and listened to by themselves, added several times more audible degradation than the capacitor with the leads cut off 1/4" from the body did and both of us could reliably hear this.
That's why I nicknamed them Wondercraps...

Cheers,
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Old 6th February 2004, 05:13 PM   #20
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marztv:

Does a refrigerator magnet tend to stick to any part of them?
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