[LAU] Jacks and sockets - Was: Berlin Linux Audio meeting @ c-base 2018-10-09

[Tim]

On 10/07/2018 04:45 AM, Ralf Mardorf wrote:
> On Sat, 2018-10-06 at 17:36 -0400, Tim wrote:
>> On 10/06/2018 03:51 PM, Ralf Mardorf wrote:
>>> https://www.roland.com/us/products/gkc-5_10/
>>
>> Most folks become aware that even the best quality single-conductor
>>    (with shield ground) 1/4" guitar cables eventually break. It happens
>>    to all of them. Usually at the entry point to the plug, or in the
>>    plug itself.
> 
> Hi,
> 
> I confirm this and most likely anybody else does, too.
> 
>> Now take that hard-learned experience with a single-conductor cable
>>    and apply it to *thirteen* conductors. Guess what happens...
>>
>> (Jacks for these DIN type plugs are usually never a problem if
>>    secured and soldered properly. Usually far less trouble than
>>    other types of jacks.)
>>
>> Often, the cause of the cable's break is the plug's strain relief
>>    being too tight - ironically the very thing that is supposed
>>    to help prevent breakage in the first place.
>>
>> I can't be too harsh on this product for the price/weight range.
>> But yeah, buy TWO of them to be safe.
> 
> Hi,
> 
> the reason that I like to get more information about this Roland cable
> is, that there are a lot of less expensive 13 pin DIN cables available
> by the Internet and I do not only need a backup cable, I also want to
> get a shorter cable than those sold by Roland.
> 
> Some of the non-Roland cables seem to be without a locking mechanism,
> but other provide a locking mechanism, e.g. the CD changer cables. I
> wonder about the used cables. Are all cable cores of the original Roland
> cable audio cables or are the cores a mix of different kind of cables?
> Do other 13-pin DIN cables provide the same pin to pin connection as the
> Roland cable? Since we know that some elChepo audio cables are ok for
> 50 cm short cables, but 3 m long cables worsen sound quality, while more
> expensive cables are still ok for cables way longer than 3 m, I wonder
> what 13-pole cables are good and which are bad. When using the Roland
> cable for the "normal" guitar pickups, too, the sound quality of the
> audio signal from the "normal" pickups is good. Unfortunately there is
> no printing on the Roland cables. If I want to build my own cables, what
> cables and what jacks might be good?
> 
> My favoured electronic part dealer provides only one 13-pin din jack
> that fits, it's without locking mechanism and seemingly an elCheapo. The
> dealer calls it "monitor plug" and yes, my Atari SM124 has got a 13-pin
> din jack without locking mechanism, too. The dealer seems not to sell
> any 13 cores cables at all.
> 
> Ordering jacks and cable from perhaps different dealers + time exposure
> might not be worth the effort, to build a non-Roland cable, but perhaps
> ordering a CD changer cable could be a solution to replace an original
> Roland cable.
> 
> Regards,
> Ralf

Hm, I'm seeing wildly varying prices for the cables on ebay.
The originals seem... a little over-priced.
I can see why you'd be shopping around, I would too :-)
Best advice I would say is read any user reviews accompanying them,
  since they seem to be from people who actually use them for this
  specific purpose.

Usually I wouldn't worry about the locking mech, but in this case
  since one end goes into the guitar that would be important.
Most of the ones I'm seeing appear to have the lock.

Be sure to only look at ones that are for this Roland-compatible
  purpose. Other cables may be 13 pins but they may not be
  pin-compatible, and even if they are, the wires and shield may
  not be a good thickness, insulation, stiffness etc.
Especially those CD changer cables, may not be the right thing.
In those, some of the wires may be individually shielded which
  carry audio, and the other wires may be just control signals,
  so it's not really the right thing.

Randomly selected, this one for example promises to be pretty good:
https://www.ebay.com/itm/usa-seller-LOCKING-13-PIN-CABLE-SYNTH-ROLAND-GKC-3-VG-8-GR-VG-GK-2A-MOORE-10-FT-/281387018954

I was going to talk about the GKC wires carrying raw, weak un-buffered
  signals from the pickup... but it turns out that's *not* true !
Looky here, I found a schematic of the GK2/3 at the top of this page:
https://www.vguitarforums.com/smf/index.php?topic=73.0
And here is the VG-88 service manual:
https://elektrotanya.com/roland_vg-88_sm.pdf/download.html

According to those diagrams, the cable carries power,
  and *buffered* signals, and some up/down switches and
  volume control signals.

Therefore, some of the wires (the six pickup signals) might be
  individually shielded and the others not, with a master shield
  ground surrounding the whole lot.
Thus the cable core itself may be a special cable not easily
  found to buy. But I'm not sure, possibly a normal 13-conductor
  cable would actually be OK since the signals are buffered.

If you find such a wire and decide to attempt to make your
  own cable, some advice I can offer is to have a can of
  technician 'freeze spray' handy. Or a can of compressed
  air 'duster' (Dust-Off etc.) turned upside down will also do.
The reason is that when attempting to solder such tiny wires
  to such plug pins, you only have a few millimeters of exposed
  copper followed by a few millimeters of wire insulation before
  the wire disappears into the cable.
The heat from the soldering iron can *easily* melt that insulation
  and before you know it you have a mess of melted insulation on
  your hands and you'll have to cut the cable and start over.
So after each application of heat from the iron, be sure to
  immediately freeze the area to prevent the heat from traveling
  further down the wire melting the insulation.

Also you'd better have nerves of steel and steady hands
  soldering thirteen tiny wires to thirteen tiny plug pins.
It can be frustrating, I know.
Probably not worth the effort, I would buy a cable.

Tim.