Capping unused RCA output and input sockets
Printed From: Graham Slee Hifi System Components
Category: And the rest
Forum Name: Audio System Set-Up
Forum Description: Discussions about getting the best from your system (Digital section now moved)
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=2579
Printed Date: 27 Mar 2026 at 12:44am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: Capping unused RCA output and input sockets
Posted By: Sidman
Subject: Capping unused RCA output and input sockets
Date Posted: 06 Jun 2015 at 8:22pm
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What are other members views on using caps on unused sockets. Other than keeping out dust is there really an advantage in preventing unwanted RF interference. There are many suggestions that plain or shorting caps should be used and I have had caps supplied with a Salisbury made amp, but I could not say that it made any difference if they were used or not. ------------- Listen to the music, not the gear! |
Replies:
Posted By: Graham Slee
Date Posted: 06 Jun 2015 at 8:42pm
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If you're interested in preventing RF interference the articles here (http://www.compliance-club.com/keitharmstrong.aspx) are truly state of the art! Before you can get to view it however, you need to register - a simple process. ------------- That none should be able to park up and enjoy the view without a smartphone and the knowledge in how to use apps |
Posted By: Ash
Date Posted: 06 Jun 2015 at 8:50pm
Think I might just buy a desktop Faraday cage to put my Majestic-Solo in and be done with it. 
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Posted By: Graham Slee
Date Posted: 06 Jun 2015 at 9:10pm
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Shouldn't be any need for that if you buy products from businesses who care about electro-magnetic compatibilty (EMC). There are right ways, and there are wrong ways or imaginary ways in which the customer is easily conned depending on the marketing prowess. Unfortunately those who invested their profits into getting EMC right (or at least starting to take the proper actions) will find they're the losers, and the clowns who don't care will be those who succeed financially. Why? Simple! The consumer doesn't give a damn - they're only interested in marketing spin, valves, boastful specifications, cosmetics and price! ------------- That none should be able to park up and enjoy the view without a smartphone and the knowledge in how to use apps |
Posted By: Ash
Date Posted: 06 Jun 2015 at 9:12pm
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Uhhhh, not quite what I had in mind... |
Posted By: Ash
Date Posted: 06 Jun 2015 at 9:27pm
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You're somewhat right Graham; the consumer is often their own worst enemy. Your products have design considerations to considerably reduce long wavelength electromagnetic radiation from getting through to the electronics. But as you say, you can't stop it all, just reduce it as much as possible. A Faraday cage would reduce it even further, especially if a customer was using CuSat50 interconnects instead of Lautus. ?? Anyway, I've kinda gone on a tangent again...
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Posted By: DaveG
Date Posted: 07 Jun 2015 at 8:54am
I've used those things on unused RCA inputs and noticed no difference whatsoever, other than they keep the dust off!  ------------- Dave Michell Gorbe + HR PSU -> Cadenza Bronze -> SME V -> Elevator -> Accession -> Proprius -> B&W CM6 s2 | Cusat 50 & Spatia cables -> 
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Posted By: Graham Slee
Date Posted: 07 Jun 2015 at 9:27am
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The truth is at http://www.compliance-club.com/keitharmstrong.aspx but I doubt anybody is interested in the truth. The truth isn't snazzy. ------------- That none should be able to park up and enjoy the view without a smartphone and the knowledge in how to use apps |
Posted By: Ash
Date Posted: 07 Jun 2015 at 10:27am
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Take Graham's Majestic for example. Three coaxial inputs, an RCA input pair and RCA output pair. For now, I'll just ignore the other connections like the large hole pair of the balanced output. So the coax and RCAs are like tiny antennas, I guess. But Graham isn't stupid; he's got 40 years of experience in dealing with EMI from sources such as radio. I assume that the outer surface of these contacts are all at case potential (linked to the chassis with almost no resistance between them)?? So they are just a continuation of the metal case. The inner holes have a diameter of maybe between 1-2mm?? So what would be the probability of long wavelength radiation actually falling directly on the inner metal surface, through such a small gap?? Then the electronics would have to have some kind of sensitivity to this type of signal for there to be an audible effect?? Diffraction theory and Young's slits experimental findings would provide an explanation here Graham?? Sod it, it would be easier to just put the whole system in a small metal fine-mesh Faraday cage and just have a tiny opening for the cables to leave from.
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Posted By: Sidman
Date Posted: 07 Jun 2015 at 12:38pm
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This is from one one of the online articles that prompted my question. 'First up is the generic nickel coated RCA caps. These caps are the cheapest one could find and they do bring down the noise floor of your system if all the un-used RCA input/outputs are covered. However, the lowered noise floor does come at a price. The sound takes a turn towards the darker end of the tonal palette, this is good for balancing overly bright or forward sounding systems. On more tonally balanced systems, the darkened effect also seemed to rob away some of the high frequency sheen, and "air". Transparency also drops a few notches if one uses too many of these. Use them only on RCA tape loops or monitor outs.' I think I agree with DaveG in that in my experience caps seem to keep out dust rather than make a difference to the sound. But maybe our ears are not what they should be!! ------------- Listen to the music, not the gear! |
Posted By: Graham Slee
Date Posted: 07 Jun 2015 at 12:52pm
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Sounds like Rainbow Foil to me. Maybe doing things the right way wasn't for me. Perhaps I should have BSed you instead. Just think of the following I could have had?  I think your ears are exactly what they should be!!! I truly hope you all keep your sanity... As Genesis penned regarding the victims of the unscrupulous "we will rock you rock you little snake, we will keep you snug and warm"  ------------- That none should be able to park up and enjoy the view without a smartphone and the knowledge in how to use apps |
Posted By: Ash
Date Posted: 07 Jun 2015 at 1:17pm
| If you were full of BS Graham, I wouldn't still be here. I may not have your level of education and abilities but I am allergic to BS if it clearly doesn't make any sense. |
Posted By: Sidman
Date Posted: 07 Jun 2015 at 6:42pm
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Graham, are you saying that you have no strips of rainbow foil on your LP labels, no cream on your cables and no green edges on your CDs? I must confess to not having rainbow foil or magic cream but I do still play the odd CD with green edges! Despite all this I will say that the best improvement to my system came from installing a humble Gram Amp 2 Special Edition. (You could say this was more than a Slee...t improvement over the Belt..ing ideas of some audiophiles.) Thank you, Graham, for you answer to my original question. I will add one of your headphone amps to my set up soon and forget the gimmicks. ------------- Listen to the music, not the gear! |
Posted By: BAK
Date Posted: 07 Jun 2015 at 9:47pm
Free Sign up @ http://www.compliance-club.com/Free_Registration.aspx?artid= - http://www.compliance-club.com/Free_Registration.aspx?artid= Then click on... http://www.compliance-club.com/keitharmstrong.aspx - http://www.compliance-club.com/keitharmstrong.aspx There is a lot of info there... another whole encyclopedia in itself! IEC, EMC, EU are all referenced. The first pdf by Keith Armstrong is as far as I got today... grounding of cables is better than not. If needed to eliminate ground loop hum, try a Parallel Earth Conductor (PEC), with noise testing, he shows it is better than leaving the shield not connected at the input to the next stage. The first pdf by Keith Armstrong is at... http://www.compliance-club.com/pdf/Bondingcableshields.pdf - http://www.compliance-club.com/pdf/Bondingcableshields.pdf after sign up. Quote: "Reference #3: IEC 61000-5-2:1997 Electromagnetic compatibility (EMC) – Part 5: Installation and mitigation guidelines – Section 2: Grounding and cabling recommends directly bonding cable shields at both ends using 360 RF bonding techniques... It also recommends using a 'Parallel Earth Conductor' (PEC) with a lower impedance than the shields, where necessary, to divert a large proportion of the power-frequency ground loop currents away from the shields. A PEC can be a dedicated conductor, or it can be new or existing metalwork, as long as it is bonded to the frame/chassis/enclosure of the equipment at both ends of the cables concerned (effectively in parallel with their shields)." He also gives balanced cables testing and some balanced XLR connector examples. ------------- Bruce AT-14SA, Pickering XV-15, Hana EL, Technics SL-1600MK2, Lautus, Majestic DAC, Technics SH-8055 spectrum analyzer, Eminence Beta8A custom cabs; Proprius & Reflex M or C, Enjoy Life your way! |
Graham Slee wrote:Posted By: LOINER
Date Posted: 09 Jun 2015 at 7:21pm
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I use" Shorties" in my unused RCA inputs but I cant say whether they make any difference or not I never bothered to do a before and after comparison ------------- STUART SOLO ULTRA LINEAR DIAMOND EDITION LAUTUS DUAL MONO 1.5M INTERCONNECTS GRAM AMP 2SE |
Posted By: Richardl60
Date Posted: 10 Jun 2015 at 3:06pm
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Hi whilst I have no direct experience I am aware of someone who has tried the 'shorties' and uses them though unsure what or how big the benefits are or whether EMI related or not. If EMI is considered an issue (which is presumably why Graham uses screened interconnects I think), is there any reason why Graham doesn't use screened mains cables? Not sure on the Spatias as they may or may not be but presumably if interference is polluting the interconnects then it will for mains and also to the speakers?? I have never had the inclination to try such caps, though may do one day . . ..usually on tial or return though my desire to listen to music perhaps currently outweighs my potential desire to tray another widget! Cheers Richard
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