[Allanmarcus]

Question about wiring, i got the sommer cable peacock for my hd800.
I plan to wire it for balanced, and use an adapter for unbalanced amp.
if i got this correct, i would wire the shield of each cable to the ground tab on the xlr, wire the red/white cable to + and -, and on the headphone side only wire the + and -, and not solder the shield?
then for the trs jack adapter (would use same cable), i would wire the shield on the xlr female side, but don't wire it on the trs jack? attach left and right minus to sleeve of the trs jack.

talking about this cable: https://www.rapidonline.com/sommer-cable-sc-peacock-mkii-speaker-cable-549508

i'm using neutrik jacks for everything else (XLR male, XLR female, TRS male)

I would not connect the shield at all on any of the connectors.

If you think you must, due to high EMI, then only connect the shield to the ground/shield tab on the male XLR, then connect the shield to both the female XLR's ground/shield tab, as well as the shield of the 1/4 plug of the short adapter cable you are making.

The idea is for the shield to act as an antenna for any EMI, and for any such current to "drain" into the ground (earth) of the device you are plugging into. If you don't connect the shield to the ground/shield tab on the female XLR connector, there will be no way for the EMI to drain from the main cable, through the adapter.

But really, if you snip the shield on both sides and just worry about conductor wire, you will be fine.

 

[Bubblejuice]

This is a pretty noob question but, just to be absolutely sure, I'll ask it anyways. I feel like I'm not using the right words to look this up online. But... I am going to cut a cable in half, and add a 3.5mm female on one end and add a 3.5mm male on the other (to make a cheap removable cable).

Which leads do I wire to which? (I can't seem to figure it out with diagrams on google, especially when it comes to the female jack).

Here is the picture of the connectors:

http://imgur.com/a/VikfG

Thanks you!

 

[Bubblejuice]

Penmarker:

2 x right x hot
2 x right x common
2 x left x hot
2 x left x common

Perfect symmetry, except 4 wires in this case are connected to ground.



Bubblejiuce:
I didn't suggest checking continuity, I suggested checking resistance, there is a difference. I has a cable with no continuity between hot and ground, but did have resistance. There was a channel imbalance. Turned out I had a defective plug.

"Reflow" a solder joint means to apply the hot soldering iron to the solder joint again to reheat the solder to liquid state again, and possibly adding a tad more solder, then remove the iron and let the joint cool naturally. This procedures makes sure the joint is good and that a good contact is make. There is no way you can look at a joint and know it's good.

Ohhh, that makes more sense. Thank you very much! I don't know what it means lol, but I thought they were the same thing. I'll go ahead and check that too. It feels wrong taking it apart since I spent so long building it, but I'd rather have a properly functional cable and a little more experience.

I am new to soldering, but I watched a good video series from the 80s that was recommended to me. Only one of the joints had excess solder. The rest are not bad (not great since I'm still new though).

However, I may as well ask now, my lead free solder was taking forever to melt at 217C, so I ramped it up to 500C which melted the solder pretty quickly. Could this mess with the solder/leads? (I didn't touch the iron to the leads for more than 1 second at a time).

Also, could using a heat gun at 120C over a wire mess with anything about it? There was a lot of heat shrink to shrink on this wire, I tried to not hold it on each part for very long at one time, but some parts like the jacks just retained heat for a bit since they are metal. And the mogami wire isn't very thick.

 

[Bubblejuice]

I hope it is true, I said it lol. We generally teach people the first day of soldering what a solder joint should look like so it really does not take a lot of experience to learn shiny from dull but I do understand what you are saying. Companies like Bottlehead have to provide info to cover any level of experience. I have seen some of their "expert" advice and most is quite sound. We generally teach people to do it correctly so they do not have to go back over it. I built two crack amps, Dynaco equipment, an oscilloscope, fm radio, cap meter, and designed and built my own electronics but everyone has to start somewhere. I do this for a living as well as a hobby. It is never a bad idea to tell someone what a result should be like and I have posted plenty of pictures of proper solder joints.

Companies like Kester do the same thing, they post photos of what a solder joint should and should not look like. If you learn some basics and do it right the first time there is little need to go back and reflow solder. Think about it, even if you do that, it is a good idea to have a basic concept of what the end result should look like.

I am not trying to give you a hard time Allan, I just looked at the statement "There is no way to look at a solder joint and know if it is good or bad."

I recently repaired an amp that someone was going to toss by just looking at the solder joints. (I got it free and it is a very good amp.) I only hit those I knew were bad and left the good ones alone. Soldering is a very basic part of electronics and not a hard thing to learn to do, and to learn to do well.

I watched an old video series on it. It was super informative. I understand what a good joint looks like, but I still need quite a bit of practice to get that type of joint every time. There's so many little things I do that I'm not sure if I'm doing correctly though when I solder. I guess that comes with the territory.

 

[Paladin79]

I have been pretty busy but I will try to list some basic techniques for soldering when time allows.
Now on to shielding.

EMI is a factor but so is RFI in any audio circuit containing speakers. (Headphones are in a sense tiny speakers.)
I use shielding whenever possible, even on RCA auxiliary cables. Why?

There are major things that can interfere with electronics, some are natural, some are man made.

In the world we live in, we can get interference, particularly RFI from desktop and Laptop computers, microprocessors, switch mode power supplies, phone chargers, microwave ovens, light dimmers, magnetic lines of flux from the earth, WI-FI, cordless phones etc, etc. etc.

We are now faced with more such EMI/RFI than any time in human history I would think. Analog as well as digital transmissions are out there. Some can come through at high audible levels, some at lower but if you have shielded cable and the choices is to hook up the shield properly or leave it off, I would say hook it up, by all means!!!!!!

I own an RF meter but they are not that common. Here is an easy way to test for RFI/EMI. Get a portable transistor radio with an AM dial. Tune it between stations (white noise) and then move it toward electrical outlets, surge protectors , computers, etc and see if you get a hissing sound. This is a cheap and easy way to test for RFI/EMI.

There are some good AC outlet strips out there with good EMI/RFI protection but there are also some that come from off shore where they do not worry much about FCC regulations. In my downstairs where my audio set up is located, I count 9 things that can produce EMI/RFI. I know about this stuff. I worked with switch mode powers supplies, integrated circuits and such and continue to work with RF circuitry on a daily basis.

Now you need not worry about shielding if you do not have a computer near by, or a phone charger, or have Wi-Fi, or live on the planet earth then you should be fine without shielding. Twisted pair is a form of shielding but, how good is it when you are manually twisting wires together? I generally use braided cables outdoors away from the electronics in my downstairs. My lighting, camera system, thermostat, computer, TV, all work from wi-fi and yes we have a microwave oven and light dimmers lol. A simple thing to remember is, twisted pair is good, shielded twisted pair is better. Now it is fun to braid cables and they look neat and they do have some shielding but if asked about star quad cable and there is a shield there, you are certainly not improving things by not hooking it up, and more often than not you are more susceptible to EMI/RFI, that is not opinion, that is fact.

 

[1yay1]

I would not connect the shield at all on any of the connectors
[...]
But really, if you snip the shield on both sides and just worry about conductor wire, you will be fine.

Then why not use the shield as - and the twisted pair as +?

 

[Paladin79]

Generally you use a shield for what it is intended for, a shield. By combining a twisted pair you eliminate their benefits in this case if they go to the same point. You can get the signal there but that is not the best way to do it using the cable you are using. Sorry for the quick answer but we are getting ready for cinco de mayo.

 

[Allanmarcus]

Then why not use the shield as - and the twisted pair as +?

Technically, that would work. The impedance and capacitance of the shield is likely difference than the conductors, so that might have some deleterious effect on sound. Any EMI/RFI being picked up by the shield is much more likely to be transferred to the transducers, so that might not sound good.

All I was saying is that when making the cable adapter, you want to connect the shield on both ends so the shield from the main cable can drain, assuming you connect the shield from the main cable to the shield/ground lug on the XLR connector.

I read some anecdotal reports of disconnecting the shield on an XLR cable made the headphones sound better. This was one guy here at head-fi, and long enough ago that I cannot remember the thread.

I've made a dozen or so cables. Some with shield, some without, some without the shield connected, some with it connected. I cannot hear any difference. YMMV.

 

[1yay1]

I'll just keep the shield unconnected then, like you suggested, seems easiest.

 

[Paladin79]

I have known of people who cannot tell MP3's from 24/192k so if you cannot hear it, build it any way you want I guess lol.

I personally cannot see paying the prices I pay for dac, amp and headphones and then putting anything in the path that would lessen the quality but then some folks are happy with Beats hooked to MP3's on their phones. If you cannot hear it, you cannot hear it.

I do this for a living and have to make sure people in recording studios and such are not getting sub standard product, a DIY'er has the freedom to do anything they wish. Your equipment, your ears. More power to you.

 

[Allanmarcus]

sorry to bother with this again, but I have another question. I will be making this switch box. 1 set of RCA inputs (from the DAC) to 6 RCA outputs. I will run balanced mic cable between each RCA jack and the switch, connecting the hot to deck 1 (the deck closest to the shaft), and the ground to deck 2. Do I connect the shield for each wire to ground on the RCA side? What do I connect to the switch side shield to, if anything? Or do I join all the shields in the middle, and heat shrink that?

Whoops! Sorry, I meant to send this as a PM. I got confused.

 

[Paladin79]

sorry to bother with this again, but I have another question. I will be making this switch box. 1 set of RCA inputs (from the DAC) to 6 RCA outputs. I will run balanced mic cable between each RCA jack and the switch, connecting the hot to deck 1 (the deck closest to the shaft), and the ground to deck 2. Do I connect the shield for each wire to ground on the RCA side? What do I connect to the switch side shield to, if anything? Or do I join all the shields in the middle, and heat shrink that?

I would just attach shield to the ground to the RCA side and not to the switch side. The reasoning is, if you connect both grounds to shields you are creating a loop that will act as an antenna. The shield is in place and I was always taught to shield the source side, which is indeed the RCA connection. I also found this method used
when talking about internal shielding on amps, if I can locate that article I will post it (it has been months since I read it.) I build all RCA aux cables this way when using microphone cable, two conductors and shield ground and I am very pleased with the results. Item number four below is what I am referring to. There are a lot of people out there I rarely listen to but Bruce Heran has always made sense to me and I find his info to be sound and reliable.

I believe somewhere in this article he mentions twisted pair is good, shielded twisted pair is better. This is what bugged me when advice was given not to connect the shield at either end on star quad wire, Maybe you do not hear a difference now but in the right circumstances you may well hear it. If I measure it and know it is there, I would just as soon eliminate a problem that my ears might not pick up so easily.

http://diyaudioprojects.com/Technical/Grounding-Shielding/

• All grounds do not go directly to the chassis.

• Absolutely avoid having any ground conductor handling both signal and power returns.

• Avoid multiple ground paths for the signal (ground loops).

• Use only one end of the shield inside equipment.

• Do not connect the chassis directly to the signal or power supply grounds. Isolate it with a type X2 capacitor and parallel resistor.

• All grounds must eventually interconnect at a single place. Use a central ground connection for all three common types of grounds. I prefer this to be at the input jack location.

 

[Speedskater]

The idea is for the shield to act as an antenna for any EMI, and for any such current to "drain" into the ground (earth) of the device you are plugging into.

EMI current does not drain into the ground (earth). This current is only interested in returning to it's voltage source, if a shield is a handy path back to it's voltage source then of course it will take it.

* * * * * * * * * * * * * *
The real go-to experts on this subject are:
Neil Muncy
Jim Brown
Henry Ott

 

[Paladin79]

Allan means well and there are much nicer ways to describe what he was saying other than "dumb". A lot of these folks are doing their own experimenting with braiding wires and what they are creating are aesthetically beautiful and for their own usage.
He takes the time to try to help others and like any forum, some things need to be taken with a grain of salt. I have heard of Muncy and Ott but am not familiar with Jim Brown, I will have to check him out sometime.

 

[Allanmarcus]

It's my understanding that headphones and amps are so low impedance that shielding the wire really doesn't add any value. Even so, my recommendation was to connect the shield to the ground lug for the main headphone cable, and to connect the shield to both connectors on the adapter.

My comment was that if the shield is not connected, it will likely make no difference. i stand by that solely based on personal experience.

I't certainly possible that connected an unshielded cable to cheap sound card might cause a problem. Also, a fairly long cable might pick up noise.