h_a said:
Hi,
Yes. 4 cores connected to the 4 cartridge pins. Personally I'd use
a single quality 5-pin DIN pug / socket rather than two XLR's.
The overall shielding is used as the earth for the turntable / arm / cartridge case.
The case of the DIN would connect to what for 2 phono sockets
would be the additional earthing post.
4-core with individual full screening.
http://www.maplin.co.uk/module.aspx?TabID=1&criteria=core&ModuleNo=136&doy=5m1
I always use this for a stereo tone arm lead terminating in a DIN plug.
🙂/sreten.
Hi,
the nice attribute to DIN and XLR is the ground making first on insertion and breaking last on extraction.
The very thing that is bad with RCA.
the nice attribute to DIN and XLR is the ground making first on insertion and breaking last on extraction.
The very thing that is bad with RCA.
Well about the same I want to use, single cable with 4 cores, 2 cores are separately shielded - and I want to use a single 5 pin XLR plug!
@sreten: sorry I don't fully understand...cable shielding is connected to tonearm mass, but NOT to amp, right? Better no double mass connections to avoid ground loops, right?
But the DIN plug case is connected to what then? Just to amp case? Same as the 2 minus signals from the cartridge?
The earthing post usually connects tonearm to amp enclosure, so I somehow don't understand that.
Please let me understand that!
Thanks a lot to all for your help!! Cheers, Hannes
@AndrewT: Neutrik makes some nice RCA plugs, where the mass connects first...
@sreten: sorry I don't fully understand...cable shielding is connected to tonearm mass, but NOT to amp, right? Better no double mass connections to avoid ground loops, right?
But the DIN plug case is connected to what then? Just to amp case? Same as the 2 minus signals from the cartridge?
The earthing post usually connects tonearm to amp enclosure, so I somehow don't understand that.
Please let me understand that!
Thanks a lot to all for your help!! Cheers, Hannes
@AndrewT: Neutrik makes some nice RCA plugs, where the mass connects first...
Hi,
Seems a five pin XLR will do the job also.
A normal amplifier has an earth post and 2 x phono inputs.
The phono earths should be used for the cartridge current only.
Any other earthing of the turntable should be via the earth post.
I don't understanding the sheilding of the cable described.
🙂/sreten.
Seems a five pin XLR will do the job also.
A normal amplifier has an earth post and 2 x phono inputs.
The phono earths should be used for the cartridge current only.
Any other earthing of the turntable should be via the earth post.
I don't understanding the sheilding of the cable described.
🙂/sreten.
h_a said:
If you're going to go that route, try an unshielded cable first, using a simple quad braid. A quad braid is essentially two interwoven twisted pairs, with one pair on one plane, and one pair on another plane at 90 degrees to the first. Use each of the two twisted pairs per channel.
Use small gauge wire, 28 or 30 gauge, and something that doesn't have real thick insulation. Stranded would work, but I like solid core. Wirewrap wire or magnet wire is readily available.
For the ground, just use a somewhat heavy gauge wire, 16 or 18 gauge, separate from the braid, and run it straight from the ground on your turntable to the ground post on the phono amp.
You can use a 4 pin XLR if you want, but I think XLRs are much better suited for hooking up 1,000 watt power amps to inefficient speakers than hooking up phono cartridges to phono amps.
I'd use a 4 pin Redel, but mini-DIN would be less expesive and more readily available.
se
Steve Eddy said:
Yes, wirewrap wire should work well. The advantage of making the cable yourself is that you can put a tighter twist on each pair. I use twisted pair in a braid screen for each channel, then another braid screen over the top (to hold the two pairs together). I use the braid as my ground wire - it has a nice fat cross-section and low resistance (which is what you want). Another advantage to using wirewrap wire is that the insulation will withstand the heat required to soak the ends of the braid with solder to get a good connection and stop fraying. (I solder another bit of wire to the end of the braid rather than attempting to solder the braid directly to the pin of the DIN plug.)
Very few moving coil cartridges connect one side of the signal to their body. Shures connect to the body, but it's not difficult to cut the thin foil connection, some Ortofons connect but the plastic mount insulate it from the arm.
AndrewT said:
As far as I know, only 3-pin XLR is designed so that the ground pin (i.e. pin1 according to the standard) is connected first.
All, it may not be such a bad idea to consider using a 9-pin D connector (pins1&6 for the first channel and pins 5&9 for the second). D-connectors are not expensive and, IMO, make an excellent choice for a quality, durable connection.
Regards,
Milan
Hi,
I have just pulled my stock of 5pin female XLR and they consistently have pin1 longer than the rest.
In any case the shell will contact first.
The Dplug/sockets have lots of spare terminals for multiple returns/grounds if they must be kept separate until they reach a central audio ground.
I have just pulled my stock of 5pin female XLR and they consistently have pin1 longer than the rest.
In any case the shell will contact first.
The Dplug/sockets have lots of spare terminals for multiple returns/grounds if they must be kept separate until they reach a central audio ground.
AndrewT said:
You've got me intrigued now.😉 I'll have to check this out myself on Monday when I'm back in the lab.
The shell is not necessarily connected to the audio ground. Sometimes, it is not even made of electrically conductive material (e.g. plastics). Those interested to learn more about XLR interconnections may find the following comments helpful:
http://www.aes.org/standards/b_comments/comments-draft-aes48-xxxx.cfm
Regards,
Milan
Hi,
the non conducting shell type of XLR usually have a conducting spring connected to the main shell casing(at the securing screw).
However this spring will probably not connect the ground before the pins make contact due to the spring being shorter than the shell.
Moamps,
can you post the AES draft doc showing the plug/socket standard?
the non conducting shell type of XLR usually have a conducting spring connected to the main shell casing(at the securing screw).
However this spring will probably not connect the ground before the pins make contact due to the spring being shorter than the shell.
Moamps,
can you post the AES draft doc showing the plug/socket standard?
AndrewT said:
I'm afraid I cannot post any AES standards, due to copyright restrictions. They can be purchased online, though, at: www.aes.org/publications/standards .
However, there is an IEC Standard defining the wiring of XLR connectors: IEC 60 268-12. The EBU recommendation based on that Standard is available here:
http://www.ebu.ch/CMSimages/en/tec_text_r50-1998_tcm6-4749.pdf
Hope this helps,
Milan
EC8010 said:
Do you really think that shielding is really necessary? I've had my cables, which are unshielded, used in few analogue systems, both from turntable to phono amp and from MC step-up to phono amp and no one has had any noise problems with them.
Since the main culprit is magnetic field coupling at power line frequencies, and since the permeability of copper is about the same as that for air, I don't see that a braided shield would be of much use for that unless it was made from some high permeability material.
I've found that the best way to protect against magnetic field coupling short of high permeability shielding materials is twisting/braiding and keeping the loop area as small as possible.
Have you tried going unshielded and just using the braid separate from the cable to make the ground connection?
se
AndrewT said:
I have some 3 pin Deltrons here and the pins are all the same length. However on the female, the sockets for pins 2 and 3 are inset further back from the pin 1 socket.
What's the situation with your females? Er... 😀
se
OK, may we agree then that only 3pin and 5pin female XLR connectors have pin1 a bit longer, unlike other DIN and XLR female connectors? 🙂
Regards,
Milan
Regards,
Milan
Belt and braces...
I hadn't really thought deeply about what the braid did (if anything). I figure that there are just so many ways that RF and hum can creep into a system that if it's possible for me to do something that might slow them down, then I'll do it (it's so much harder to fix things after the event). With MC cartridge impedances, we're mostly concerned with EM induction, so a copper braid doesn't do much (don't forget eddy currents, though). With a MM cartridge impedances, ES induction becomes more significant, and although the transformer will reject much of it, why rely on balance when losses through screening can be easily added?
I count rewiring a pick-up arm as one of the most horrible jobs, so when I decided to make up a new cable, it was for keeps. As I recall, it took about two days of effort because of the machining necessary to make a new housing for the base of the arm to grip the cable and allow the arm wires to be connected to it.
Steve Eddy said:
I hadn't really thought deeply about what the braid did (if anything). I figure that there are just so many ways that RF and hum can creep into a system that if it's possible for me to do something that might slow them down, then I'll do it (it's so much harder to fix things after the event). With MC cartridge impedances, we're mostly concerned with EM induction, so a copper braid doesn't do much (don't forget eddy currents, though). With a MM cartridge impedances, ES induction becomes more significant, and although the transformer will reject much of it, why rely on balance when losses through screening can be easily added?
I count rewiring a pick-up arm as one of the most horrible jobs, so when I decided to make up a new cable, it was for keeps. As I recall, it took about two days of effort because of the machining necessary to make a new housing for the base of the arm to grip the cable and allow the arm wires to be connected to it.
Re: Belt and braces...
Yeah, there would be some eddy current losses, but it's dependent on frequency and material thickness and I wouldn't think you'd get much benefit down at power line frequencies.
Fair 'nuff.
My ultimate goal is to locate my listening room inside a Faraday cage with the only AC being the music signal. Someday maybe. 😀
Ouch! I haven't owned a turntable for about 20 years now. I've been eyeballing them for a while now, but maybe I'll forget about them for a while yet. 😀
se
EC8010 said:
Yeah, there would be some eddy current losses, but it's dependent on frequency and material thickness and I wouldn't think you'd get much benefit down at power line frequencies.
Fair 'nuff.
My ultimate goal is to locate my listening room inside a Faraday cage with the only AC being the music signal. Someday maybe. 😀
Ouch! I haven't owned a turntable for about 20 years now. I've been eyeballing them for a while now, but maybe I'll forget about them for a while yet. 😀
se
Re: Re: Belt and braces...
As you say, but the most popular valves for RIAA front-ends are VHF/UHF tuner front-end valves like 5842 etc. And to get low noise, they operate with minimal grid-stopper resistors, so we really don't want a sniff of anything creeping in that might be (badly) demodulated and turn up in the audio band.
Steve Eddy said:
As you say, but the most popular valves for RIAA front-ends are VHF/UHF tuner front-end valves like 5842 etc. And to get low noise, they operate with minimal grid-stopper resistors, so we really don't want a sniff of anything creeping in that might be (badly) demodulated and turn up in the audio band.
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