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Old 15th October 2011, 09:31 PM   #21
Wolfsin is offline Wolfsin  United States
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Quote:
Originally Posted by sgrossklass View Post
Even a common ground connector does not necessarily spell disaster though, as long as its resistance is less than about 1% of minimum driver impedance. (Example: HD590, ~1 ohms vs. 100 ohms.) 40 dB of channel separation should be plenty on cans if even 12 dB of imbalance already is painful and vinyl gets along fine with <30 dB.
I calculated -72 dB for a 12 foot common ground connection with HD-600s. It would take nearly five hundred feet of common ground to exceed your 1% rule of thumb. I am willing to ignore crosstalk issues, at least for Senns, especially for the balanced case in which all four conductors are insulated from one another.

OK, at a practical level, GAC-3 should perform identically to GAC-4. That is the NULL hypothesis against which most testing will be performed. Intellectual honesty argues for a test against the ideal as well. There the NULL hypothesis will be that GAC-3 cannot be distinguished from Mogami 3106 by listening only to Sennheiser HD6x0s.

Fair enuff?
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Old 16th October 2011, 05:13 AM   #22
qusp is offline qusp  Australia
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forget the shield, its pointless, just adds capacitance and serves no real purpose imo. it causes more problems than it solves given there is no way to connect it to ground at both ends. but if you must the mogami is a good choice. sorry I've been flat out, haven't had time to go through your emails thoroughly

Last edited by qusp; 16th October 2011 at 05:15 AM.
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Old 16th October 2011, 10:22 PM   #23
Wolfsin is offline Wolfsin  United States
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Glad you've been busy, qusp. The Aussie economy must be running ahead of ours.

I have been reacting to the initial post in this thread suggesting that balanced headset cables need be expensive. It would take a terrible amount of EMI for a shield to be of any value and crosstalk is not an issue unless, as sgrossklass pointed out, your cans resistance is very low.

So where's the expense? It could, for some headsets, be tricky to alter the wiring. Certainly that is no issue with HD580, HD6x0, or HD800 as the cable unplugs easily. My dog provided a ready supply of cables with everything intact except the stock mini connector which is right where the four conductors meet. The temptation to solder on a TA4F connector was simply too great although soldering thru the red and green lacquer was difficult. Paint remover dissolved that.

The total expense in that case amounted to less than ten dollars including both the female TA4F and the male TA4M panel mount mate. The real expense came in balancing the complete chain of components from bits thru TA4M :-(
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Old 22nd October 2011, 07:03 PM   #24
Wolfsin is offline Wolfsin  United States
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As promised, I cabled the HD600s using GAC3, three conductors within double copper shielding. The shield and white attach to the left can and the brown and green to the right. The GAC3 was chosen over the two GAC4 cables for its PVC flexibility, despite the slightly higher (but still negligible) capacitance. Rather than a 'Y' I looped the cable across the headband incurring nearly 2ns delay in one side :-) Now I can remove the cans using only one hand.

Honestly I can detect no difference between this cable, Mogami dual twisted pairs separately shielded, and the "modded for balance" stock cable, despite using the somewhat pricey Cardas connectors, solder, and flux. Basically I believe electrical characteristics for such a short - 4 meters - cable in a quiet EMI location to be irrelevant as noted in earlier posts.

What is important is usability, strength, flexibility, and DIY price. Gotham GAC3 was and is my clear cloice.
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Old 22nd October 2011, 07:40 PM   #25
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Smile NULL Hypothesis

Wolfsin,

You must be a little bipolar being both the Experimental Group and the randomly assigned Control Group in the A X B testing. I am not blind, however I do see double.
LOL!
Did you note any impressions comparing your custom balanced cables to the stock out of the box Sennheiser cable?
Worth the effort? Sound Wise?

DT
All just for fun!
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Old 22nd October 2011, 10:06 PM   #26
Wolfsin is offline Wolfsin  United States
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Heh. "You must be a little bipolar" -- worse, fully retarded!

I had, at one time, three sets of Cardas connectors. When Lew at Gotham suggested I try three, my reaction was why not. Had forgotten how little I enjoy soldering cables. When the cables arrived I noted the difference in flex and inquired about it. It was largely due to the jacket material but the GAC3 had one fewer conductors so I chose it and soldered it together.

At first I noticed a big difference but quickly realized that I had wired the connector in a manner that reversed the left and right. I will continue listening and switch back to the modified stock cable at some point for more comparisons. The mod allows bridging / balanced connections to left and right by replacing the mini phone plug with a mini xlr 4 pin.

Since taking on this comparison I have read more re the bridge / balance controversy and reconsidered the difficulty of A-B testing that required a headset cable switch. I cannot even test the original cables because I have no SE headamp. Hence my bipolar state.

Conveying how something sounds to anyone else is difficult. I went balanced (bridged) a couple of years back by wiring a pair of stereo discrete preamps across each can. Difficulties with non-zero DC, blocking caps, etc. caused me to try a different pair of preamps but experimentation was interrupted almost a year ago. Recently I noticed that the original discrete preamps had been reved twice and included an attenuator. It seemed worthwhile to rebuild the discrete preamp to see if caps had been the issue. Well, something had changed for the better and then, in reviewing my work just prior to the interruption, I noticed an error. With all caps gone and the attenuator allowing me to adjust for a hearing imbalance, I moved the system to a whole new plateau.

I am now completely balanced from bits thru four BB1704 DACs thru discrete (JC-2 like) preamps thru HD600s. I never imagined redbook could sound this good. Then this thread caught my eye. Building a cable seemed neither difficult nor costly compared to the other work (or so it seemed).

My belief that to twist (as in conductors) is human but to balance (bridge) is devine has led me on this quest. Many other changes / mods have made a difference in how music sounds. Changing the cable in the headphones has not :-(
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Old 23rd October 2011, 05:38 AM   #27
qusp is offline qusp  Australia
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well tbh mate, you've only marginally improved the cable, but hey their your ears, however i gather you've been expecting not to hear a difference from the beginning
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Old 23rd October 2011, 08:21 AM   #28
rsdio is offline rsdio  United States
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It seems that nobody (in this thread, at least) has pointed out that headphones are speakers. Have any of you heard of someone trying to make balanced, shielded speaker cables? I don't see how regular balanced cables would make sense unless you have active headphones of some kind. Speaker drivers are inherently passive devices (they certainly do not have semiconductors in them). I don't even think that coaxial cables are appropriate for headphones. Wouldn't you want zip cord, ideally?

Quote:
Originally Posted by Wolfsin View Post
The history of bal<->unbal is littered with hums, screeches, and worse between components, but allow me to point out that cans are not a component in the traditional sense. They are more like an MC cartridge, i.e. inherently balanced, while being capable of rejecting common noise.

Please help me discard this idea before I go off and build one if I am "thinking inside the cable" and missing something important.
I would say that headphones are somewhat similar to an MC cartridge, but exactly like speakers.

Quote:
Originally Posted by sgrossklass View Post
One of the more important points in wiring them up unbalanced is keeping the returns separate for as long as possible, as return resistance common to both channels degrades channel separation. Stock cables for the usual suspects (HD5x8, HD6x0, various AKGs etc.) implement that already.
On this point, I totally agree. Again, comparing to speakers, we don't connect the ground leads together on our stereo cabinets and then bring a single wire back to the amp - that would be atrocious.

Basically, it seems obvious to me that the ideal wire for a pair of headphones is a pair of zip cords. No coaxial shield; no shield at all.

Microphonics are an obvious issue, as I'm sure we've all heard the problem in real life. Not only the electromagnetic aspect of microphonics, but even just the mechanical coupling of cable to earpieces. If tapping on the cable makes a sound in your ear (without power applied), then you're possibly going to be distracted by that during use.

It seems to me that the most important issue is to consider the type of headphone amplifier. If you have a complementary/push-pull output stage on your headphone amp, then balanced really makes no sense because the ground is common to the speakers and the active circuits. But, if you have balanced single-ended stages on your headphone amp final outputs, then balanced cabling would make more sense. Of course, zip cord still works just fine for balanced single-ended, especially if you aren't trying to shield the cable.
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Old 23rd October 2011, 11:07 AM   #29
qusp is offline qusp  Australia
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remember i can't see you
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Old 23rd October 2011, 02:51 PM   #30
Wolfsin is offline Wolfsin  United States
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i>>Have any of you heard of someone trying to make balanced, shielded speaker cables?

Actually most speaker wire intended to run any distance is twisted. It is the shield that is pointless, as qusp pointed out above. The twist is what provides the noise immunity.
In the case of headphones the cable is usually so short and the EMI so small. that even zip cord, if the conductors could be twisted, might be OK.

The first great leap in quality occured for me when I severed the common connection on my HD600s at the chewed off plug. I then added a second JC-2 like preamp and BRIDGED each of the cans. Using the stock cable with a 4 pin miniXLR. Thinking the cable might matter I tried Mogami stereo microphone cable. It made no sonic improvement whatever.

My conclusion was that bridging made a big difference but was it the additional drive capability across each can or severing of the common conductor? I tried using ever higher driving capability -- a pair of LME49600s on each side in push-pull mode (won't call it balanced) -- and that made it marginally better.

Wiring with GAC3 improved usability but made no sonic improvement vis-a-vis Mogami or the original cable for me. That doesn't mean others might hear a difference.

The terms balanced, bridged, and differential are all causing a great deal of pain, I agree. The near impossibility of performing A-B when headphone cable is involved had not occurred to me until faced squarely.

As soon as I can build 'the wire' (bal-bal) I will carefully relisten. I genuinely hope to hear a difference.
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