different kind of cable thread (maybe?) - DIY unbalanced 'interconnect' strategy & tactics
mhardy6647
Posts: 26,986
I am interested in folks' opinions and experiences with respect to rollin' your own
unbalanced ("RCA" plug) audio cables for line-level use.
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.
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.
Comments
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.
laventure.net/tourist/cables.htm
I used the Furez FZ162AA Analog IC. I'd probably look at some Mogami shielded stuff as well.
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.
(Just picked up some Furez R10BCS Silver Plated Copper Core to use to refresh the connectors on my Technics SL-1200); $35/pr
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.
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.
Works..... still remove by RCA as you should always anyway.
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
92 ohm cable... it appears.
Thanks to all for the input so far; I much appreciate [email protected]!
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.
Ken made some of these for me a few years back. It surprised me how well this cable worked.
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
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
SRS 2.3TL (Fully Modded)...Velodyne Optimum 8 subwoofer
1KVA Dreadnought
Marantz SA 8005
Pioneer PLX-1000 Turntable - Shure SC35C/N35X - V15III/VN35HE
Yamaha TX-540 Tuner...Sony BDP-S570
Sony PS4
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"
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.
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.
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.
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.
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.
Yeah, I am old and crotchety -- about some things, at any rate.
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.
http://www.rane.com/note151.html
I am still at the man-ape* scratching at the dirt with a sharp stick stage of understanding proper grounding.
_____________
* 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.
Rock on Crazy Diamond!
HT - Polk 703's * NAD T-758 * Adcom 5503 * Oppo 103 * Samsung 60" series 8 LCD
There you go..........now you are thinking!
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,
Here is one without a shield that looks interesting.
SRS 2.3TL (Fully Modded)...Velodyne Optimum 8 subwoofer
1KVA Dreadnought
Marantz SA 8005
Pioneer PLX-1000 Turntable - Shure SC35C/N35X - V15III/VN35HE
Yamaha TX-540 Tuner...Sony BDP-S570
Sony PS4
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"
I like the topology -- not sure I'd go with silver wire, but that's a personal bias thing, you know?
That said, some free time is on the horizon; thanks for the kick in the... well... you know.