different kind of cable thread (maybe?) - DIY unbalanced 'interconnect' strategy & tactics

mhardy6647mhardy6647 Posts: 18,397
edited April 7 in DIY, Mods & Tweaks
I am interested in folks' opinions and experiences with respect to rollin' your own
unbalanced ("RCA" plug) audio cables for line-level use.
  • Favored type (brand/model and/or configuration) of cable?
  • Favored RCA plugs (brand/model)
  • Shielding scheme (if any)

you know, stuff like that.

I've been reading a little (e.g., Rane note 151, rane.com/note151.html) and just getting myself completely confused.

As a potential way to break my analysis paralysis, I figured it couldn't hurt to ask about
some empirical experience (is that redundant?)... but I'll definitely settle for some conjectural opinions.

Thanks.
"It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

"Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

"Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)

Comments

  • delkaldelkal Posts: 245
    I am very proud of the 999 silver interconnects I made, Its a very simple design. Pure solid silver wire in a teflon tube. Cut it to size and solder on a mid priced RCA. I didn't have any true high end interconnects to compare it to but the improvement from my mid priced interconnect was noticed immediately first time I tried them. I also made a matching pair with mil spec silver coated hookup wire with teflon insulation. They also sounded good but I have mostly been using the pure silver ones.

    I used this site as a guide. The only problem I had is I couldnt figure out how to secure the teflon tubes securely in the RCA body (they are slippery!). You don't want to pull these cables out by the wires. The pair I made look similar to these.

    pbd9ptyypw5x.jpg

    laventure.net/tourist/cables.htm

  • msgmsg Posts: 4,197
    edited April 7
    I like the Douglas Connection "kits" I ordered from Doug. So far I've only managed to get one set made, but I think they sound pretty good.

    I used the Furez FZ162AA Analog IC. I'd probably look at some Mogami shielded stuff as well.
    a36zwm0whrc7.jpg
    I like locking RCA connectors. Doug has a bunch of different ones.
    I used the DC Locking RCA; $12.50/pr. These are affordable and work well enough, but I prefer the locking functionality of other connectors a smidge better. These ones don't get quite as tight as I'd like, but there's a little trick to help that a bit.
    06qfusvpi2bb.jpg
    (Just picked up some Furez R10BCS Silver Plated Copper Core to use to refresh the connectors on my Technics SL-1200); $35/pr
    l7h6io4dc915.jpg
    Also picked up some time ago some Parts Express Locking RCA Connectors; $20/2pr. These are similar to the Vampire Wire ones, though I've not handled the VW's personally.
    am00d8g2wft7.jpg

    I once tried to bulk order some GLS Audio Locking RCAs, which look similar to the Parts Express ones, but the connector is thin and cheap, so back those went. With this style of locking connector, I was trying to find something similar to the ones MIT uses, but couldn't really find them. Most will be gold plated brass core, but I think Ideally I'd want gold plated copper core. WBT makes some, but spendy. Watch out for fakes on Ebay.

    Check out RCA Cables and Connectors at The Cable Company
    and at Parts Connexion.

    Re: shielding, for me, as I was "taught", I go with the shielding terminated along with the ground to the body of the source side connector only, and trim and tuck the braid on the destination end. I was reading that some companies don't use shielding, and instead rely on conductor geometry for interference rejection? Dynamique is a company that does this, iirc?

    Here's a link to my ugly first build with embarrassing solder work. Yeesh. Haven't done any serious critical listening with these. Was mostly just for the project fun with some nice quality materials.
  • pitdogg2pitdogg2 Posts: 10,227
    delkal wrote: »
    The only problem I had is I couldnt figure out how to secure the teflon tubes securely in the RCA body (they are slippery!).
    How about color coordinated shrink tubing with adhesive??

    Works..... still remove by RCA as you should always anyway.
  • KennethSwaugerKennethSwauger Moderator Posts: 6,530
    Low capacity RG62A/U and Pomona 6881 RCA plugs. Also Switchcraft SWC-3502A RCA plugs work fine.
    "And the house you live in will never fall down
    If you pity the stranger who stands at your gate" G.Lightfoot
  • msgmsg Posts: 4,197
    Ken, that's coax, right? How do you wire/build it with a single conductor?
  • mhardy6647mhardy6647 Posts: 18,397
    edited April 8
    msg wrote: »
    Ken, that's coax, right? How do you wire/build it with a single conductor?

    Are you asking coax for unbalanced I/Cs? Center conductor is "hot" (center pin); braid (shield) is "return" (outer connector) is the usual way IMO/IME (ahem, it's what I do). I

    Coax makes nice signal cables but (at least the cables I've used) are stiff and somewhat tedious to work with in the real world. I will admit that I've never (knowingly) encountered RG62, though :p

    92 ohm cable... it appears.

    Thanks to all for the input so far; I much appreciate [email protected]!
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • KennethSwaugerKennethSwauger Moderator Posts: 6,530
    I don't believe the characteristic impedance will make any difference except for digital device connections. It is the cable's geometry that caught my attention, the center conductor is held in the middle of a flexible plastic tube by a spiraling plastic form. The air between the conductor and the centering tube is the dielectric material (air has a good reputation for sound quality when used as a dielectric). This cable is used in scientific and test equipment when low capacitance is needed. Also early computer network connections.
    You have to use a little care to maintain the shape of the cable when attaching the RCA's ground return so as not to change the relationship between the conductor and the supporting structure. Of course any coaxial cable needs this care when attaching any kind of connector.
    "And the house you live in will never fall down
    If you pity the stranger who stands at your gate" G.Lightfoot
  • pitdogg2pitdogg2 Posts: 10,227
    Low capacity RG62A/U and Pomona 6881 RCA plugs. Also Switchcraft SWC-3502A RCA plugs work fine.

    Ken made some of these for me a few years back. It surprised me how well this cable worked.
  • delkaldelkal Posts: 245
    Low capacity RG62A/U and Pomona 6881 RCA plugs. Also Switchcraft SWC-3502A RCA plugs work fine.

    RG62A/U coax is the only wire I know of that used a copper coated STEEL conductor. Most "experts" say you need to use the purest copper or silver availible and to avoid all ferrous material like the plague .

    But I can't argue if it works. The "experts" don't know everything.

    https://catalog.belden.com/techdata/EN/9269_techdata.pdf
  • pitdogg2pitdogg2 Posts: 10,227
    edited April 8
    delkal wrote: »
    Low capacity RG62A/U and Pomona 6881 RCA plugs. Also Switchcraft SWC-3502A RCA plugs work fine.

    RG62A/U coax is the only wire I know of that used a copper coated STEEL conductor. Most "experts" say you need to use the purest copper or silver availible and to avoid all ferrous material like the plague .

    But I can't argue if it works. The "experts" don't know everything.

    https://catalog.belden.com/techdata/EN/9269_techdata.pdf

    Many (most) coax is now copper coated steel. This that Ken used was 100% copper. I believe his was an much older stock because when i tried to find some to buy i ran up against the fact i could no longer find 100% copper. Canare and a few others still make 100% copper coax and it costs more of course unfortunately none is RG62a/u
  • machonemachone Posts: 971
    I used Mogami w2549 microphone cable with Neutrik gold RCA's.

    The Mogami has very low capacitance and a great shield.
    The Neutrik have superior strain reliefs and the ground makes contact before the center pin.
    I connected the shield to the case on one end only (the source I think?).

    https://www.parts-express.com/mogami-w2549-neglex-long-run-microphone-signal-cable-1-ft--103-1012

    https://www.parts-express.com/neutrik-nf2c-b-2-profi-professional-rca-plug-pair--092-114
    Mojo Audio Joule v5>>Quantum Byte w/JRiver 21 and Fidelizer>> Starlight 7 USB >> Marantz SA 8005>> Equinox 7>>
    ModWright SWL 9.0 SE Signature >>Equinox 7>>
    Hafler DH-500 Amp+ (Musical Concepts PA-6 Elite Mod) >>Belden 5000 10 ga cables>>
    SRS 2.3TL (Fully Modified)...SDA-1A (Fully Modified with Dimensional Tweeter Delete)
    1KVA Dreadnought
    Pioneer PLX-1000 Turntable - Shure SC35C/N35X - V15III/VN35HE
    Yamaha TX-540 Tuner...Sony BDP-S570

    Separate subpanel with four dedicated 20 amp circuits.
    1. Amplification 2. Analog 3. Digital 4. Video

    "All THAT IS LOST FROM THE SOURCE IS LOST FOREVER"
  • msgmsg Posts: 4,197
    Yeah, I was wondering how a cable like this is physically terminated.
    I presume in this case, the shielding has to be terminated on both ends, whereas a 2-conductor cable, the return (not ground; dehr me) is the second conductor, and then the braid only terminated on the source side?

    I don't know how noise/interference gets into a cable, so this has me wondering
    1. How coax sounds when used as an analog IC constructed as above wrt noise rejection, and
    2. How digital cables built from coax are constructed/terminated.

    Good info up there on the build design/geometry, Ken. Neat to see what goes into selection of the wire, other uses, etc.
    mhardy6647 wrote: »
    Are you asking coax for unbalanced I/Cs? Center conductor is "hot" (center pin); braid (shield) is "return" (outer connector) is the usual way IMO/IME (ahem, it's what I do).
  • mikeyb128mikeyb128 Posts: 2,735
    delkal wrote: »
    I am very proud of the 999 silver interconnects I made, Its a very simple design. Pure solid silver wire in a teflon tube. Cut it to size and solder on a mid priced RCA. I didn't have any true high end interconnects to compare it to but the improvement from my mid priced interconnect was noticed immediately first time I tried them. I also made a matching pair with mil spec silver coated hookup wire with teflon insulation. They also sounded good but I have mostly been using the pure silver ones.

    I used this site as a guide. The only problem I had is I couldnt figure out how to secure the teflon tubes securely in the RCA body (they are slippery!). You don't want to pull these cables out by the wires. The pair I made look similar to these.

    pbd9ptyypw5x.jpg

    laventure.net/tourist/cables.htm

    A friend of mine builds RCA’s similar to this design, and they sound dam fine. They sound almost as good as name brand cables in the 900 range.
    2 channel:
    Bryston 4B3, Bryston BDA3, Cary SLP05, Shanling CDT1000SE with parts conneXion level 2 mods, Nottingham analogue ace space 294, soundsmith Carmen MKii, Zu DL103 MKii, Ortofon MC 20 MKii, Dynavector XX2 MKii, Rogue Audio Ares, Core power technologies balanced power conditioner, Akiko Corelli power conditioner with Akiko Audio HQ power cable, Nordost heimdall 2, Frey 2, interconnects, speaker and power cables, Focal Electra 1028 BE 2, Auralic Aries Femto, Black diamond racing cones, ingress audio level 1 roller blocks, JL Audio E110 with Auralic subdude, Primacoustics room treatments.
    Theater:
    Focal Aria 926,905,CC900, SVS PB ultra x2. Pioneer Elite SC85, Oppo BDP93, Panamax M5400PM, Minix neox6, Nordost Blue heaven LS power cables.

  • delkaldelkal Posts: 245
    If you do have a shielded cable one end MUST be terminated. If not the shield can act as an antenna and pick up interference. With shielded speaker cables (not sure about interconnects) you only want to have the shield grounded to the source end. Supposedly bad thing happen if you terminate the shield at both ends. Ever wonder why you have directional speaker wires when the AC current just moves back and forth? This is why.

    Unless you live next to a radio tower or are using extremely long runs I think shielded interconnects are over hyped. They add capacitance to the wire.
  • mhardy6647mhardy6647 Posts: 18,397
    msg wrote: »
    Yeah, I was wondering how a cable like this is physically terminated.
    I presume in this case, the shielding has to be terminated on both ends, whereas a 2-conductor cable, the return (not ground; dehr me) is the second conductor, and then the braid only terminated on the source side?

    I don't know how noise/interference gets into a cable, so this has me wondering
    1. How coax sounds when used as an analog IC constructed as above wrt noise rejection, and
    2. How digital cables built from coax are constructed/terminated.

    Good info up there on the build design/geometry, Ken. Neat to see what goes into selection of the wire, other uses, etc.
    mhardy6647 wrote: »
    Are you asking coax for unbalanced I/Cs? Center conductor is "hot" (center pin); braid (shield) is "return" (outer connector) is the usual way IMO/IME (ahem, it's what I do).

    The Rane technical note I referenced (I think) in the first post is well worth reading -- even though it may make one's brain hurt if taken too fast. Mine did. :#
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • mhardy6647mhardy6647 Posts: 18,397
    FWIW -- I think that we've made our own lives more difficult in terms of keeping (analog) signals clean and quiet by the immense amounts of EMI and broad-band RFI "hash" that we've added to our environments with cell phones, WiFi, Bluetooth, etc., etc., etc.

    Yeah, I am old and crotchety -- about some things, at any rate. :|
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • FestYboyFestYboy Posts: 2,525
    One could always install a Faraday cage around the rack... IR remotes wouldn't be affected, but any data streams from an outside source would need wired in or have an external antenna (outside the cage) installed.
  • mhardy6647mhardy6647 Posts: 18,397
    mzp5rmrzd5ie.png
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • delkaldelkal Posts: 245
    mhardy6647 wrote: »
    msg wrote: »
    Yeah, I was wondering how a cable like this is physically terminated.
    I presume in this case, the shielding has to be terminated on both ends, whereas a 2-conductor cable, the return (not ground; dehr me) is the second conductor, and then the braid only terminated on the source side?

    I don't know how noise/interference gets into a cable, so this has me wondering
    1. How coax sounds when used as an analog IC constructed as above wrt noise rejection, and
    2. How digital cables built from coax are constructed/terminated.

    Good info up there on the build design/geometry, Ken. Neat to see what goes into selection of the wire, other uses, etc.
    mhardy6647 wrote: »
    Are you asking coax for unbalanced I/Cs? Center conductor is "hot" (center pin); braid (shield) is "return" (outer connector) is the usual way IMO/IME (ahem, it's what I do).

    The Rane technical note I referenced (I think) in the first post is well worth reading -- even though it may make one's brain hurt if taken too fast. Mine did. :#

    I did make it (mostly) thru your link and it did make my brain hurt a bit..........But it did answer my previous post. For shielded interconnects you want the ends of each shield to be connected to the chassis of each component (see pin 1). This makes a lot more sense than dumping all of the interference the shield picks up into the RCA neutral.

    Eureka! All you have to do is connect a wire to each end of the shield and connect that to a screw on each components chassis. Instant balanced connection! I have no clue why interconnect manufacturers don't do this.

    j2yg1tiv8dpk.png



    http://www.rane.com/note151.html
  • mhardy6647mhardy6647 Posts: 18,397
    edited April 8
    grounding is an art and a science (maybe even a philosophy or religion) all to itself.

    I am still at the man-ape* scratching at the dirt with a sharp stick stage of understanding proper grounding. :neutral:

    5ztblzqy4rgg.png

    _____________
    * I mean, of course, person-ape.


    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • delkaldelkal Posts: 245
    edited April 8
    mhardy6647 wrote: »
    grounding is an art and a science (maybe even a philosophy or religion) all to itself.

    I am still at the man-ape* scratching at the dirt with a sharp stick stage of understanding proper grounding. :neutral:

    5ztblzqy4rgg.png

    _____________
    * I mean, of course, person-ape.


    Go ahead and do it........Throw that bone up in the air and see where you end up.

    Don't let the other monkeys keep you down.
  • mhardy6647mhardy6647 Posts: 18,397


    match_space.gif
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • voltzvoltz Posts: 4,948
    The Doctor is always on Call and here to serve!

    Rock on Crazy Diamond!
    2 ch- Polk CRS+ * Vincent SA-31MK Preamp * Vincent Sp-331 Amp * Marantz SA8005 SACD * Project Xperience Classic TT * Sumiko Blue Point #2 MC cartridge

    HT - Polk 703's * NAD T-758 * Adcom 5503 * Oppo 103 * Samsung 60" series 8 LCD
  • ken brydsonken brydson Posts: 7,010
    HT/Main- Panny 50" G10 Plasma, Pioneer SC-1222k AVR, Panny DMP-BD60 BDP, Polk LS90 mains, CS350LS center, LS/fx side surrounds, LS50 surround backs, SVS 25-31PC+ sub, Harmony One

    Office Rig- Marantz 2252B, Denon 2910, Kenwood KD2070 TT, Polk RTA 12B's/ RTA8t
  • delkaldelkal Posts: 245
    mhardy6647 wrote: »

    match_space.gif

    There you go..........now you are thinking!
  • delkaldelkal Posts: 245
    edited April 8
    delkal wrote: »

    I did make it (mostly) thru your link and it did make my brain hurt a bit..........But it did answer my previous post. For shielded interconnects you want the ends of each shield to be connected to the chassis of each component (see pin 1). This makes a lot more sense than dumping all of the interference the shield picks up into the RCA neutral.

    Eureka! All you have to do is connect a wire to each end of the shield and connect that to a screw on each components chassis. Instant balanced connection! I have no clue why interconnect manufacturers don't do this.

    j2yg1tiv8dpk.png



    http://www.rane.com/note151.html

    Maybe I was inspired too but I did a little more thinking about my previous post. If you ground both ends of a shielded RCA interconnect you will NOT get a balanced connection. The above schematic shows 2 op-amps in the pre (giving reverse phase signals) going to one op amp in the amplifier (that "decodes" / combines them).

    Grounding both ends of the shielded RCA interconnect to each components chassis will still work though. But only for the signals picked up by the interconnect. It seems like something trivial to try and it has to be much better than grounding these signals into the audio path,

  • machonemachone Posts: 971
    https://www.venhaus1.com/diysilverinterconnects.html

    Here is one without a shield that looks interesting.
    Mojo Audio Joule v5>>Quantum Byte w/JRiver 21 and Fidelizer>> Starlight 7 USB >> Marantz SA 8005>> Equinox 7>>
    ModWright SWL 9.0 SE Signature >>Equinox 7>>
    Hafler DH-500 Amp+ (Musical Concepts PA-6 Elite Mod) >>Belden 5000 10 ga cables>>
    SRS 2.3TL (Fully Modified)...SDA-1A (Fully Modified with Dimensional Tweeter Delete)
    1KVA Dreadnought
    Pioneer PLX-1000 Turntable - Shure SC35C/N35X - V15III/VN35HE
    Yamaha TX-540 Tuner...Sony BDP-S570

    Separate subpanel with four dedicated 20 amp circuits.
    1. Amplification 2. Analog 3. Digital 4. Video

    "All THAT IS LOST FROM THE SOURCE IS LOST FOREVER"
  • mhardy6647mhardy6647 Posts: 18,397
    machone wrote: »
    https://www.venhaus1.com/diysilverinterconnects.html

    Here is one without a shield that looks interesting.
    That does look cool, thanks for sharing the link.
    I like the topology -- not sure I'd go with silver wire, but that's a personal bias thing, you know? :|


    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
  • msgmsg Posts: 4,197
    Doc, in the interest of helping keep you on track with your projects/goals/life's desires, howsabout an update? :# B)
  • mhardy6647mhardy6647 Posts: 18,397
    heh, been doing too much garden prep (and pickup-truck-purchase equivocating). :)
    That said, some free time is on the horizon; thanks for the kick in the... well... you know.

    :)
    "It's like watching a roomful of people who couldn't get through college algebra discussing the flaws of quantum physics theory. I guess it could be fun, but it's ultimately a waste of time." -- seen on audiokarma

    "Some amps run on self bias, some amps run on fixed bias. But his amps run on confirmation bias." -- seen on audioasylum

    "Writing about hifi is like dancing about architecture" -- paraphrasing some wag (possibly Frank Zappa)
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