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post #2236 of 2580

Hey fellas, need to verify my plan here:

 

I'm building a new balanced cable for my HD650s, to be terminated in a 4 pin XLR. Eventually I'll be buying a balanced amp and want to be ready for that. For the time being, however, I only have a single-ended amp and need to build an adapter as well (female 4 pin XLR to TRS). 

 

Basically, I'm 99% sure this is correct, but I'm going to use Mogami W2534 quad-conductor cable, but I'm not sure what to do with its shield. The TRS obviously has the 2 tabs and the arm but the 4 pin XLRs have the 4 pins and a Ground tab. Do I run a floating shield on the main headphone cable only, and ignore the shield on the adapter? See my diagram below... Thanks!

 

post #2237 of 2580

Ignore the shield completely man, the 4 wires will be used on the 4 pins of the XLR connector. L+, L-, R+, R-. Then wire the xlr connector on your adapter the same way as the one on the end of the cable, but connect both ground wires from that to the single ground on the 3.5mm connector.

post #2238 of 2580
Quote:
Originally Posted by cCasper TFG View Post
 

Ignore the shield completely man, the 4 wires will be used on the 4 pins of the XLR connector. L+, L-, R+, R-. Then wire the xlr connector on your adapter the same way as the one on the end of the cable, but connect both ground wires from that to the single ground on the 3.5mm connector.

 

Ok, sounds good. Thanks!

post #2239 of 2580

So after a long long while, I finally gotten my parts. I have a few questions about constructing the cable. Sorry if the questions had been asked before. The said cable will be like this :

3.5mm plug (http://www.redco.com/Amphenol-KS3PB-AU.html) --> quad conductor cable(http://www.redco.com/Mogami-W2893.html) --> Y-split --> male 3pin mini XLR(http://www.redco.com/Redco-TA3MB.html) --> female 3pin mini XLR(http://www.redco.com/Redco-TA3FB.html) --> headphones

 

1. Should I ignore the shield?

2. At the 3.5mm plug, since the cable is quad, that means i have to solder L+ conductor for the left channel and R+ conductor for the right channel and the R-&L- to the ground, right?

3. At the 3pins mini XLRs, since I will split the cable into 2, so 2 conductors go to each mini XLR. So I only use the L+/L- & R+/R-?


Edited by graphidz - 7/15/14 at 12:29am
post #2240 of 2580

graphidz so is this a 3.5 to dual mini xlr 3 pin male cable?   and your headphone has two mini xlr 3 pin female ports?  is this your t50rp?

post #2241 of 2580

Yes

Gonna make one

Yep, my T50RP

post #2242 of 2580

I think what I did was I followed this convention for the colors:

Source Plug end = shielding + black + clear/copper soldered to ground (sleeve)  ,  red soldered to right+ (ring) , blue soldered to left+ (tip)

 

I was going to solder the spiral shield to the shield part of the plug only on one side, the source side.. for you the 3.5mm..  but I got lazy and I only soldered the black and clear conductors to the shield.  it works fine but I think technically you'r;e supposed to attach the spiral shield to that side too..  I was going to cut off like 3/4 of the spiral and then twist the rest to make it small enough to fit on the shield.. but like I said I got lazy.. you should try it though.. 

 

and then for the two 3 pin mini xlr male plugs I think you'd just use red for R+ on the plug for the right headphone cup, then L+ for the left headphone cup.. and then R- and L- can be the other two conductors, I don't think it matters what colors you use but here's the convention I used:

 

Headphone end = red soldered to right + (positive)  , black soldered to right - (negative)  ,  Blue soldered to left + (positive) , clear/copper soldered to left - (negative)

 

and on the headphone side I don't think you connect the spiral shield at all...  

 

here's a pic of the 3 pin xlr pins, note I think the top two numbers would be reversed when looking at the plugs from the back?

Warning: Spoiler! (Click to show)

Pin # 1 does not need to be connected to ground for headphone use, just leave it disconnected.

Many headphone amps have a pair of 3-Pin XLR connectors. For the Left XLR connector you connect the L+ to Pin 2, L- to Pin 3 and the cable shield to the XLR connector's ground lug. Connecting the cable shield to the ground lug will provide RFI noise protection for the cable. Pin 1 does not need to be connected to ground for a headphone cable (it's there for microphones and other audio gear). The Right XLR connectorwould be R+ to Pin 2, R- to Pin 3 and the cable shield to the ground lug.

If you wish to use one headphone cable and Y the cable to the XLR connectors and/or the ear cups I recommend using Canare Star Quad or Gotham Mini Quad cable. Remove the rubber outside layer and shield for the cable Y, you'll need about 17 inches for the ear cup Y and around 6 inches for the XLR Y. Unravel the 4 conductor wires and then twist them into right and left pairs going to the ear cups and/or XLR connectors. You can cover the cable split with a couple inches of heat-shrink tube to dress up the cable. I also recommend heat-shrink for the XLR end of the cable Y to enhance the grip of the XLR connector's strain relief clamp.


Edited by uncola - 7/15/14 at 3:08am
post #2243 of 2580
Quote:
Originally Posted by uncola View Post
 

I think what I did was I followed this convention for the colors:

Source Plug end = shielding + black + clear/copper soldered to ground (sleeve)  ,  red soldered to right+ (ring) , blue soldered to left+ (tip)

 

I was going to solder the spiral shield to the shield part of the plug only on one side, the source side.. for you the 3.5mm..  but I got lazy and I only soldered the black and clear conductors to the shield.  it works fine but I think technically you'r;e supposed to attach the spiral shield to that side too..  I was going to cut off like 3/4 of the spiral and then twist the rest to make it small enough to fit on the shield.. but like I said I got lazy.. you should try it though.. 

 

and then for the two 3 pin mini xlr male plugs I think you'd just use red for R+ on the plug for the right headphone cup, then L+ for the left headphone cup.. and then R- and L- can be the other two conductors, I don't think it matters what colors you use but here's the convention I used:

 

Headphone end = red soldered to right + (positive)  , black soldered to right - (negative)  ,  Blue soldered to left + (positive) , clear/copper soldered to left - (negative)

 

and on the headphone side I don't think you connect the spiral shield at all...  

 

here's a pic of the 3 pin xlr pins, note I think the top two numbers would be reversed when looking at the plugs from the back?

Warning: Spoiler! (Click to show)

Pin # 1 does not need to be connected to ground for headphone use, just leave it disconnected.

Many headphone amps have a pair of 3-Pin XLR connectors. For the Left XLR connector you connect the L+ to Pin 2, L- to Pin 3 and the cable shield to the XLR connector's ground lug. Connecting the cable shield to the ground lug will provide RFI noise protection for the cable. Pin 1 does not need to be connected to ground for a headphone cable (it's there for microphones and other audio gear). The Right XLR connectorwould be R+ to Pin 2, R- to Pin 3 and the cable shield to the ground lug.

If you wish to use one headphone cable and Y the cable to the XLR connectors and/or the ear cups I recommend using Canare Star Quad or Gotham Mini Quad cable. Remove the rubber outside layer and shield for the cable Y, you'll need about 17 inches for the ear cup Y and around 6 inches for the XLR Y. Unravel the 4 conductor wires and then twist them into right and left pairs going to the ear cups and/or XLR connectors. You can cover the cable split with a couple inches of heat-shrink tube to dress up the cable. I also recommend heat-shrink for the XLR end of the cable Y to enhance the grip of the XLR connector's strain relief clamp.

 

Basically what I had initially concluded too, but wasn't confident enough. Reading this helped me too :
http://robrobinette.com/BalancedCable.htm#Other_Balanced_Headphone_Connectors_
Thanks for the advice

post #2244 of 2580

Another question, if I want to use the shield to the mini XLR's ground lug, is it OK if I make a braid together with the conductors (as in 2 conductors+1 shield twisted into a wire)?

Or don't bother with it and just cut it altogether


Edited by graphidz - 7/15/14 at 9:41am
post #2245 of 2580

For the redco mini xlr, I don't think there's a ground lug..  I think maybe the metal strain relief  clamp is the part you're supposed to clamp to the spiral shield.  You could do that, but I've read it's best only to attach the spiral shield on the source side, the 3.5mm plug..  

edit:  ok yeah if you look at the picture in the pdf on the bottom right.. it says you crimp metal strain relief tabs closer to the plug to the spiral shield.. and the second strain relief tab should be over the insulator..  

edit 2: I realized once you split the starquad cable for the dual mini xlr, might be really hard to maintain the spiral shield.. heh I'd just be lazy and not attach it on the headphone side

http://www.redco.com/files/MINI_XLR_Assembly_instructions.pdf


Edited by uncola - 7/15/14 at 11:43am
post #2246 of 2580
Hi there. I've seen in some pics, like the one below, where people are using 4 wires for doing their interconnects. Is this purely from a looks perspetive? Also I would assume then that they terminate two wires on the positive and two on the negative. That sound about right?

500x1000px-LL-3cd5424d_2013-10-1423.37.55.jpeg
Edited by Orihalcon - 7/15/14 at 1:33pm
post #2247 of 2580
Quote:
Originally Posted by Orihalcon View Post

Hi there. I've seen in some pics, like the one below, where people are using 4 wires for doing their interconnects. Is this purely from a looks perspetive? Also I would assume then that they terminate two wires on the positive and two on the negative. That sound about right?


That is correct. The braid is nice and everything stays together well. The downside is, that it doubles your wire costs.
post #2248 of 2580

It also throws out shielding but that isn't usually a big issue.

post #2249 of 2580

Hi!

 

Has anyone opened an Apple Lightning to USB camera adapter? Since it has capabilities that the standard usb cable doesn't have, I guess it must contain another chip in the female USB A end?

 

I recently bought an iFi Nano iDSD, and it works like a charm with the Touch 5G running iOS 7.1.2. I had an idea about breaking a Lightning to USB camera adapter open and unsolder the female USB A end from the chip and replacing it with a male USB B connector...

 

What do you guys think?

post #2250 of 2580
Quote:
Originally Posted by Orihalcon View Post

Hi there. I've seen in some pics, like the one below, where people are using 4 wires for doing their interconnects. Is this purely from a looks perspetive? Also I would assume then that they terminate two wires on the positive and two on the negative. That sound about right?

Looks, and that many smaller wires are easier to bend than thicker ones. If you have thick wires with a small system like the Stack, or like mine, the wires can move or weigh down the equipment or won't bend enough to allow the plugs to go in.

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