Tweakers' Asylum

Yes, go for it.

69.156.196.162

cheap-Jack

In Reply to: RE: Wima film cap instead of BP or tant? posted by Zombie on June 19, 2007 at 23:28:01

Hi.

As suggested below, film caps, being non-polar are always better than bi-polar 'lytic caps & tantalum caps.

In my SS phonostage (for MM cartridge) I built only a couple months back, the design required 4.7uF I/P cap & 10uF O/P coupling cap. I've used (metallized) polyeser film caps, some no-name makes built similar to WIMA.

Since it only comes max 2uF (50V) a piece, so I had to parallel a few of them to add up the right capacitance. I zing-yang parallelled them to reduce the ESR, ESL (equivalent series resistance/inductance), etc of the caps.

The overall sonics of the RIAA phonostage sound pretty gratifying:-
vibrant, very transparent, & muscial. Surely the polyester film coupling caps help deliver such decent sound.

c-J

Follow Ups:

RE: Yes, go for it. - Zombie 07:35:22 06/20/07 (7)
Great. Thank you for sharing your experience.
These Wimas are only 5 mm's wide and are therefore at least physically suitable as I have a ready-made RIIA.
- Try to do what I did if space permits !!! - cheap-Jack 08:03:38 06/20/07 (6)
  Hi.
  
  Try to zing-yang parallel two caps of half the capacitance instead of using only one single cap for coupling signal paths - if room is available.
  
  Why? A capacitor is a complex AC network comprising its self-inductance, series resistance Rs (e.g. transfer resistance btwen the mult-layer metellized film electrodies), insulation resistance Ris, & its capacitance C.
  
  So by zing-yang (reverse direction connecting) parallelling two caps of half capacitance will substantially reduced the ESR/RSL inside the caps.
  
  So order 2x 2.4uF caps for I/F, & 2x5uF for O/P coupling.
  
  c-J
  - Why care about esr in coupling caps? - Slider 09:38:08 06/20/07 (5)
    The reactance of the cap would be far above the esr at any frequency of interest. But I tend to agree with fmak, Wima's aren't very good for this application. The only ones that really sound great are the MP3 series with epoxy impregnated paper dielectric, but they are very big and best used for applications where you only need about 0.1uF. Your best bet, and just my opinion, is to go with a tightly wound cylindrical cap, the higher the voltage the better. Some of the better made mylar types sound more neutral than the more exotic plastics, just because they are wound tighter and more uniformly due to the stronger plastic, which helps to keep the core from generating as much mechanical vibrations.
    - Sonics is subjective - cheap-Jack 12:02:38 06/20/07 (4)
      Hi.
      
      I did not say WIMA sounds good or not as I never used them. I am quoting the metallized polyester film caps of some no-name brands, with shape & built like WIMA, do sound pretty nice in my projects. So a brandname like WIMA should not sound so lousy as it is recommnened for coupling application.
      
      Take it or leave it is up to the readers.
      
      Why argue on ESR or ESL or what not? As long as they can be both reduced by ying-yang parallelling the caps, why not try it?
      
      c-J
      - I thought Wimas were stacked film caps - nightdoggy 19:02:46 06/21/07 (3)
        
        In Reply to: RE: Sonics is subjective posted by cheap-Jack on June 20, 2007 at 12:02:38
        
        as opposed to the more inductive wound type.
        Tension should not be an issue with them.
        doggy
        
        They do make stacked film caps ... - Slider 21:43:30 06/21/07 (2)
        
        In Reply to: RE: I thought Wimas were stacked film caps posted by nightdoggy on June 21, 2007 at 19:02:46
        
        ... but most of the encapsulated ones in the plastic boxes are wound, and then flattened. The stacked film are often worse sounding, possible because the layers of film are not under any tension or pressure so can easily move. They are only held together by electrostatic charge. Both have about the same inductance if they are the same size since the inductance is mainly due to the size.
        
        Stacked film - nightdoggy 10:17:06 06/25/07 (1)
        
        In Reply to: RE: They do make stacked film caps ... posted by Slider on June 21, 2007 at 21:43:30
        
        is inherently low inductive. I thought they were all stacked and then potted.
        Wound film takes up a lot more room. They are inductive too. Panasonic makes a lot of low inductance wound models.
        
        wound isn't really any more inductive - Slider 11:47:48 06/25/07 (0)
        
        In Reply to: RE: Stacked film posted by nightdoggy on June 25, 2007 at 10:17:06
        
        The construction is almost the same with a layer of schoopage on each end to join the conductive deposit on every other layer. The path length is the same, and the inductance is primarily a result of the lead spacing.

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.

This post is made possible by the generous support of people like you and our sponsors:

Atma-Sphere Music Systems, Inc.