Coupling Cap Polarity

From: dangerda–(at)–arthlink.net
Subject: Re: Q!!-Re Replacement Capacitors
Date: 16 Mar 1999 00:00:00 GMT
Content-Transfer-Encoding: 7bit
X-Posted-Path-Was: not-for-mail
X-ELN-Date: 16 Mar 1999 15:54:54 GMT
X-ELN-Insert-Date: Tue Mar 16 07:55:10 1999
Mime-Version: 1.0
Reply-To: dangerda–(at)–arthlink.net
Newsgroups: rec.audio.tubes

Hi Steve,

We’ve had some discussion on this topic recently.

Some caps are marked to show which terminal is connected to inner
foil, which is connected to outer foil.

The consensus seems to be that, in principle, if you orientate the cap
such that the outer foil is to the lower-z node, you may provide some
shielding of the inner foil from radiated/coupled electromagnetic
noise and interference. It would make sense for the seller to tell
you to hook the inner foil side to the load, as the source is usually
lower-z than the load, so the cap would provide more effective
shielding if orientated in that manner.

I presume that’s what you mean when you say “orient the inner foil
towards the output side of the circuit”.

Regards the effects of HF roll-off being dependent upon orientation of
a non-polarized cap, that is something I’m not familar with.

In my experience measuring HF roll-off at audio frequencies it depends
primarily upon the first order impedance of the devices, and to a
lesser extent is dependent upon the loss mechanisms in components like
capacitors and inductive devices. I suppose in some cases the loss
mechanisms might be orientation specific, but this would be a second
order effect, and probably of very small magnitude. The simple test
would simply be to measure the HF poles with the caps orientated in
both directions, and determine if there actually is a measurable
difference that has a real effect upon the audio properties of the
circuit.

Regards,
Dangerdave

>On Mon, 15 Mar 1999 17:04:42 -0500, “Pinky & The Brain” wrote:

>Looking to shed some light on the “replacement capacitor” subject as it
>applies to a Dynaco PAS-3. I recently purchased a set of 22 polypro
>replacement caps for my unit and was informed by the seller that upon
>installation I should orient the “inner foil” (right) side towards the
>output side of the circuit in all cases to avoid “rolling off” the High
>Frequencies I never realized that polypropylene tubular caps were “polarity
>sensitive”. Does anyone have any input on this matter? Any and all responses
>welcome!
>
>TNX
>
>Steve
>

 

Buy the Book!

I cleaned up my tab for Sonny Boy's Help Me and made it into a short book. There's a Kindle version for 99 cents, and if you buy the paperback you get the Kindle free.

Playing "Help-Me" In the Style of Sonny Boy Williamson II: A step by step, note for note analysis of some of Sonny Boy's Signature Riffs

I also write Science Fiction, so you can sample some of my best stories. Also available in Kindle format.


Error Message Eyes: A Programmer's Guide to the Digital Soul
 

Line 6 POD HD400 HD 400 Multi Effects Guitar Pedal Amp Simulator

$125.00 (1 Bid)
End Date: Friday May-24-2019 18:25:49 PDT
Bid now |
Webster Electric Co. Amplifier Model 63-1930's

$375.00
End Date: Friday May-24-2019 19:11:44 PDT
Buy It Now for only: $375.00
Buy It Now |
Vintage Acoustic Model 220 Amplifier Made In USA

$299.49 (0 Bids)
End Date: Friday May-24-2019 19:38:59 PDT
Buy It Now for only: $399.99
Buy It Now | Bid now |
Korg Kross Keyboard EX 61key workstation new model w/PCM Silver Blue trim/Amp

$649.99
End Date: Friday May-24-2019 20:16:12 PDT
Buy It Now for only: $649.99
Buy It Now |
JWD Davis Model DA-10 Pro Audio Power Amplifier. Cnx

$132.25
End Date: Friday May-24-2019 20:39:03 PDT
Buy It Now for only: $132.25
Buy It Now |

 

The JT30 Page Popular links

I began collecting data about the microphones used by blue harp players before there was an internet. I began organizing it into JT30.com in the late 1990s. I accumulated more stuff than I remember. This is some of it.

Street Theory

A Harp Player’s Guide to Music Theory

Learning Harp

Picking Up Blues Harp

A guide to learning to play Blues Harp

Microphone Information

Usenet Articles


Harp Amps

I've been collecting Harp Amps for a while. This is the old Harpamps.com website. There is lots of information here. Here a coupld of links.


Harp Tab

A collection of songs and riffs that I’ve worked out over the years, plus some libraries of stuff I’ve converted to tablature. I’ve included most of the notes and instructions that helped me when I was learning to play blues harmonica.

Basic Riffs Simple harp tabs for songs Blues riffs and phrases.

Harp-L Archives 1992 to 2002


1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003

Harp Frequently Asked Questions