Tonearm cable mini DIN - RCA structures

[Dunbar]

During the past few years I have made quite a few tonearm cables for my personal use and for friends (and by this I mean that I used bulk cables with different arrangements and finished them accordingly). All this time I looked for a comprehensive guide or diagrams that can illustrate the possible arrangements available for DIN to RCA connections and highlight their benefits and weaknesses. I did not have much success. Assuming that there are a few people with a similar interest here, I decided that it would be nice from my side to contribute with some diagrams that illustrate some of the possible arrangements for DIN to RCA tonearm cables.

If however, someone feels that something is wrong with any of them please feel free to correct me and express your opinion. Also, I think that your views on which are the most appropriate arrangements and why, would be very welcome by all of us here.

P.S. Sorry for the quality of the diagrams. I just hope that they are capable of explaining what's going on. Actually, I started creating them just to illustrate in another thread, a ground issue I have in one of my cables. Also, note that I have not tried yet the 3rd option of the twin cable. I just thought that it seems interesting and rather beneficial in the ground arrangement of the cable.

[rkay5]

Hi,
Thanks for posting this as it's helpful as I have made two tonearm cables and your drawing will help my when I make more.

[bpbutler]

I prefer the last of your "balanced twin cable configurations".

1. It permits true differential inputs, and the use of twisted pair for common-mode noise rejection.
2. It preserves the single-point ground principle at the amplifier.
3. By only grounding the shield at one end, the shield cannot carry current, and thus remains an equipotential Faraday cage around the signal carrying wires.

My critiques of the others:
Unbalanced configurations
#1 probably works if the negative phono input is grounded at the amp.
#2 the ground wire carries all the EMI that's picked up by the TT chassis. That noise is now coupled onto your signal wires.

Balanced/twin configurations
#3 probably works if the negative phono input is grounded at the amp. If you have a true differential input, this probably won't work as well.
#4 isolates the shields at one end, which is good, but any noise on the ground lead is coupled onto the shields. You don't have single-point-ground in this configuration.
#5 is what I usually build, and it seems to work well for me.

Balanced/quad configurations
#6 is about the same as #1 or #3. You don't have any isolation between L and R channel, but at low signal level, that's probably not that big a deal.
#7 has the same issue as #4
#8 you're using the shield as an EMI conductor, which I don't think is good. Better to have those currents flow through a separate wire, and keep the shields free of current.

Caveat: I haven't tried any of these except for #1 and #5, so I can't guarantee that you or someone else doesn't "hear" something better in the others. I'm basing my analysis on general grounding principles we use in RF comm.

[Dunbar]

Thank you for your responses guys. That was quite an interesting evaluation bpbutler and I agree with many of your observations.
I should have numbered each of the structures to make referencing easier.
In general all of the above structures do work.
The two coax/unbalanced structures are used as standard in most of the stock turntable/tonearm cables (i.e. No2 is used in stock Rega arms). Although you wouldn't want to use them with your MC cart, they do function but they could certainly be improvements by switching to a “balanced” structure.
Structure 3 is also used in most of the industry and DIY “twisted pair balanced” phono cables. It does have obvious weaknesses (mainly by connecting the shield with the return signal conductor) and I am not sure why it is used more often than No4 and No5. Most probably, some manufacturers and DIYers try to replicate the structure of some interconnect cables where the shield is connected at one of the RCA ends and fail to make proper use of the external ground lead which gives the freedom to drain the noise the shield has picked up away from the signal conductors.
Structure 4 is a very efficient way of using the ground and shield but I can also see the additional benefits of structure 5 where the shield not only is isolated from the signal paths (send and return) but also for the ground path and at the same time creates a single ground point at the control centre (I.e.amp/pre-amp).
Quad structures:
Structure 6 is may cause some problems. There is a small loop created by connecting the same shield to the return paths of both channels. You can avoid this by disconnecting it from one of the channels only. Overall it is not a great approach and it is only illustrated here for refference. It will work but can be improved by using structures 7 and 8. Structures 7 and 8 are very similar. 8 however seems to be better suited by reducing the distance of the ground path and preserving the flow of energy on the shield (interference) towards the control centre (rather than first towards the tonearm plug and then back to the pre-amp). This is also the one I tend to use in most of my cables and it is extremely successful.
I find that there are many advantages in using a signle run of quad over double run of twin. These have more to do with the conductor structure itself and the fact that both channels share the same environment and shielding rather than with the efficiency of the ground arrangement.
However, having taken, bpbutler's suggestion about the No5 on board, I will add another quad design that carries the same principles as No5 (as well as put all the structures together and numbered in order to facilitate any further discussion).

[Dunbar]

Here are the diagrams again (numbered this time)with the addition of No8 and having removed the less efficient quad structure that had the shield connected at both rca ends.

[Steerpike_jhb]

For the record, these audio /phono connectors are not 'mini DIN' connectors, they are standard DIN size. Mini DIN is what S-VHS video uses:

[Dunbar]

Sorry for the confusion. By mini DIN, I mean the standard 5-pin connector used in most of the tonearm cables including many versions of Linn, SME, Jelko, Roksan and many more. I believe that the correct term used for this type of connectors is JIS (also often called Tiffany) but in most occasions you will find them as DIN tonearm connectors.
These connectors are supplied by a small number of companies (most well-known being: Cardas, Atlas, SME, Furutech, Clearaudio, Van Den Hull and a few others).
This is probably also they reason they are so expensive compared to all other types of audio plugs.

[bpbutler]

Actually, my understanding is the so-called "DIN" connector used for tonearm connections is not a DIN connector in any way, shape, or form. Someone apparently called it a DIN connector because it resembles the mini-DIN connector in your picture. However, it is not plug compatible with the DIN connector. Which is unfortunate, because it makes it hard for us DIY types to get hold of the appropriate mating connector.

Correct terminology is probably to call it a "tonearm connector".

[Dunbar]

I am not sure of the origins and exact history of this connector. "Tonearm connector" seems to be the most appropriate term (although there are other types of connectors used as tonearm connectors as well. It certainly is not a DIN connector. However, the terminology DIN (which normally refers to the German origin type of connectors) has been adopted by the majority of the manufacturers and suppliers and one will usually find it in the name of the model/connector. In some other parts of the world is described as JIS to be identified as a Japanese standards connector. The origins seem to be Japanese but the connector is different from all other JIS types as well. Apparently it was initially manufactured by Denon Parts for a number of Japanese tonearm manufacturers and was used exclusively in the analogue industry.

The exclusive use of the connector for tonearms means that the overall demand for it is quite low and its price unreasonably high. On the other hand a typical tonearm connector uses materials of much higher quality than the typical DIN (which could perform exactly the same function); usually gold plated OFC pins instead of nickel and brass, Teflon insulation instead of cheaper plastics with high dielectric involvement, machined aluminium housing instead of molded plastic one.
Still quite expensive for DIY.

[Steerpike_jhb]

However, it is not plug compatible with the DIN connector. Which is unfortunate, because it makes it hard for us DIY types to get hold of the appropriate mating connector.

With a simple mod, you can make a compatible MALE plug, that will go into the Grace arms, not sure about other brands.
Buy a standard (and cheap, as in a dollar or less) FEMALE INLINE 5-pin DIN SOCKET (180 degrees). And a MALE D-Donnector (as used on conputer RS232 ports etc). Cut open the D-connector and take out its pins. Push the thick end (solder end) of the D-conn pins into the DIN socket, and you'll end up with a 5-pin DIN MALE plug, good for tone-arms.

The same will probably work to make a female tone-arm socket, if you used the gold tulips from a female D-Connector, but I have not tried it.

[zharca]

Apart from the pins being a different size (0.90” dia x 0.245” long) they are on a different pcd, 0.25”, spaced 60°, so I don’t think it’s a good idea to use the din body as it will probably strain the other connector a bit.

On the cables, I use the layout of No 4 and No 7 for one-piece tonearm cabling. Just substitute the arm for the DIN. The advantage of 4 is that two separate cables can be more flexible than 4-in-one, important for suspended decks.

This method is also useful where the arm board is metal, connecting the arm to the turntable ground, in which case the ground wire can be left unconnected to stop a possible loop.

A two-cable version of 7 would also be the way that a "real" balanced XLR cable would be connected, with the ground to pin 3.

[Steerpike_jhb]

Apart from the pins being a different size (0.90” dia x 0.245” long) they are on a different pcd, 0.25”, spaced 60°, so I don’t think it’s a good idea to use the din body as it will probably strain the other connector a bit.

Then the two Grace arms I have are something different to yours. They match the DIN connector exactly, BUT for the pins being thinner than DIN's.

[coolmaster]

DIY rewired Rega RB300 tonearm and stock LP12 to MC step up.
After some attempts with other structures, found #5 to be best suited for near or zero hum, saving only the individual screen star grounded to LP12 sub chassis earth point. If I had used the stock Rega cabling, I would have to ground the MC SUT negative points to earth via earth lift switch at the SUT.
Note: My LP12 have a renewed power cable (obviously better quality than something from 3 decades ago) with ground wire at mains plug. I believe older models are 2 wire mains and not AC mains grounded.
My tonearm external cabling is a high quality shielded microphone cable.
Mr Dunbar, thank you for this topic. Its a very interesting, infomative and helpful topic.