Elna cerafine bypass??

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My arcam alpha 7SE have an output coupling capacitor - a 10uF electrolitic Elna cerafine. In my tweaks i've tried to bypass it with a polyester 100nF Philips capacitor. It's a shame that I can't get rid of those coupling capacitors...but without them:5V offset :hot:

I've made some listenings with and without the bypass capacitor and I just can't decide:

With bypass capacitor: sound seems a bit more treble extended but I don't really precise if it's just extra distortion/harsh or is in fact extra revelations...
Yeah...I know metal film capacitor would be the best but low €€€ present! :dead:

Thank you for your time.
 
Ok :)

Thank you VS.

I see you are also Portuguese. Where do you get those kind of capacitors? And by the way : how the hell can you distingue between polyester and metal film??... (felling dumb :D )

I really thought that a metal film capacitor is something like a multicap, or those cousins- costing around 90€?!?!?!?

Thank you for your Time...
 
Well, yes and no...

The multicap is a metal film cap, but what VS suggest is that you use a metalized polypropylene film cap. The difference is a metalized film cap is manufactured by depositing metal onto a plastic and then wound. The metal film caps are made using two (or more) layers of film, plastic and metal.

Generally the film types are more expensive, but are considered to be better performers (something to do with pinhole noise in the metalized variants, i can't remember exactly right now). Polystyrene is considered to be the worst (AFAIK) of the plastic dielectrics, and polypropylene among the better.

MKP (metalized polyprop.) types are generally a good cost/performance compromise, if you don't feel like shelling out the $$ for film caps. Also there are "standard" non-audio manufacturers of film types that won't cost you an arm and a leg. The special audio brands are sometimes insanely expensive by comparison. Wether it might be worth it i cannot say...

Check out Walt Jung's How to pick Capacitors, part 1 ; part 2 it is very informative. It might be a tad on the technical side, but you don't have to understand everything that's said (i sure don't ;)) to get a good guideline for picking capacitors. The end of part 2 sums it up pretty good, so skim the first part if you're not interested.

/Andreas
 
Re: Ok :)

audiocrow said:
Thank you VS.

I see you are also Portuguese. Where do you get those kind of capacitors? And by the way : how the hell can you distingue between polyester and metal film??... (felling dumb :D )

I really thought that a metal film capacitor is something like a multicap, or those cousins- costing around 90€?!?!?!?

Thank you for your Time...


Hi ! Yeah, a Portuguese fanatic ;)

Well, regarding to your questions, a polyester capacitor is also a film capacitor ! MKT is a comum label present in the capacitor package meaning "Metalized Polyester".

You could buy a MKP "Metalized Polypropylene" capacitor by as low as 1 euro or even 80 cents, however a good audiophile "version" will cost you much more, in general above 10-20 euros, and it depends on the voltage - choose a high voltage type since it gives a better sound (>200V, 400 or 630V preferred). With a very reasonably price you could chose one of these (Mundorf) starting at: http://www.schuro.de/mcap.htm.

If you want to spend as little money as possible go just to a good
electronic shop and ask for a Polypropylene Capacitor (MKP) and test it right away!

Regards,
VS

PS: where do live ?
 
VS said:
Regular one's that you can find "easly" in Portugal .....http://www.wima.com/navig/pr.htm


Hi Nuppe,

Do you agree with this classification ?

1st - MKP
2nd - Polystyrene
3rd - MKT (or MKS)
4th - Electrolytic

I'm definitely no authority on the subject, but yes, I think that about sums it up. If MKP or Polystyrene should be first i don't know, but both are supposed to be very good. Polystyrene
are harder to get hold of though.

/Andreas
 
Hi,

Ops...the first is really Teflon !

Ok, in fact there is some discussion about polystyrene and polypropylene...but the "first" is disappearing and also I never see any document stating that is was best than polypropylene…

Do you have any "source" document ?
 
Mr. Rowland words

I read that in a Portuguese magazine called "audio" some years ago. I'm will seek my atttic and translate it...if I find it!

In those words He also talked about impedance adaptation in sources, cables...etc (all about His "obcession" about tranformers....a good one I must agree in my modest opinion)

I just have to find that damm magazine...:confused:
 
about voltage dividers using resistor

well...practically you will in fact have less signal comming out from the source, but you are also adulterating the output impedance.
Unless you have a 0pF+1000Mega-ohm input impedance pre-amplifier it's a wordefull and ALMOST perfect trick...

If you increase the output impedance of a source the tranfer of the extremes of the frequencie will be highly adulterated due to the capacitance of interconnet cables (loss in low frequencies) and in pream internal capacitance(loss in high frequencies)...so...

What I really need it's a perfect solution...nothing more ;)

I really thing that just altering the gain of the pre amp I'll get the nirvana...

Please correct me if I'm wrong.
 
Re: Sorry...awnswer in wrong topic

audiocrow said:
That passive idea it's good....I'll have to give a try

See that way.

1-You have ~2volts out from your CD.

2- Your amp need less than 1 Volt for full output.

3- There is no amplification without distortion and noise (even if low)

Then, why to use a pre , that amplifies the 2 volts from the CD 3 or 5 times (sometimes more) attenuate this excess gain and only put the same 1 volt at the amp input.

Can this manipulation ,do anything good, or it will only increase distortion and noise...
 
Tube_Dude said:


Quoting my Philips Components and Materials Data Book

Polystyrene Tan (tangent of the loss angle)at 10 KHz- less than 5X10^-4

Polypropylene Tan at 10 Khz - less than 10X10^-4

Polyester Tan at 10Khz - less than 110X10^-4


In fact in depends pretty much on the capacitor manufacter.
For instance see this page: http://www.wima.com/navig/pr.htm

Their polypropylene film foil cap (FKP) has even a dissipation factor lower that the lowest value that you have stated, 3x10^-4 ! So I guess your source is not so actual as you would like...
 
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