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?
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
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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 :-(
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 :-(
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.
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.
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!
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!
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 :-(
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 :-(
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?
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.
I would say that headphones are somewhat similar to an MC cartridge, but exactly like speakers.
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.
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.
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.
Lots of choices here (available through Digikey): http://www.switchcraft.com/Documents/conxall_catalog.pdf#page=12
I've used them for balanced connection with phono cartridge, also for power connectors between supply and amp chassis.
Sheldon
I've used them for balanced connection with phono cartridge, also for power connectors between supply and amp chassis.
Sheldon
Haven't compared them with anything. Lots of choices and they work well. Just offered them as an option.
Sheldon
Even more thanks, then, Sheldon. I am still waiting for a suggestion of what cable to use. I agree that the shield is not needed, that the cables must be sufficiently rugged to handle some abuse, that low resistance is a virtue (though solid silver izExcessive IMO), and that a pair of single conductor coax is the work of the devil himself. You know what I have tried. You know I am unwilling to pay boutique prices.
To limit my exposure, and to suppress foolish suggestions, I have put a few conditions on the following offer, which is one time only. Here is the offer. If you have a cable you believe will sound superior AND you have HD6x0 Cardas compatible cans AND you will wire a bridged TA4M connector to your gear, suggest that cable in this thread. If selected you agree to send me six feet of that cable. I will supply another pair of Cardas connectors and a TA4F, build the cable, listen to it and then ship it back to you for your opinion.
If there is more than one suggestion, I will break all ties with considerations of group feedback. The cable will then be shipped from one to another of all those who suggest a cable type not chosen, each paying the postage to the next within one week of receipt. Anyone breaking this chain will . . . If this needs modification, please let ne know.
Keep in mind that qusp lives on the other side of this planet so whoever listenz just before him might go broke
To limit my exposure, and to suppress foolish suggestions, I have put a few conditions on the following offer, which is one time only. Here is the offer. If you have a cable you believe will sound superior AND you have HD6x0 Cardas compatible cans AND you will wire a bridged TA4M connector to your gear, suggest that cable in this thread. If selected you agree to send me six feet of that cable. I will supply another pair of Cardas connectors and a TA4F, build the cable, listen to it and then ship it back to you for your opinion.
If there is more than one suggestion, I will break all ties with considerations of group feedback. The cable will then be shipped from one to another of all those who suggest a cable type not chosen, each paying the postage to the next within one week of receipt. Anyone breaking this chain will . . . If this needs modification, please let ne know.
Keep in mind that qusp lives on the other side of this planet so whoever listenz just before him might go broke
What you've documented so far makes sense. Separating the wire for left and right probably makes more of an improvement than changing the wire to more expensive types.
I agree that balanced, bridged, and differential can be confusing. Sometimes they are equivalent. I would be tempted to design a hand-made headphone amp using Nelson Pass' super-symmetry, because that performs better than simple bridged amplifiers. That's because noise on one channel is inverted on the other and canceled out on the speaker, and this sort of thing cannot happen with two independent amplifiers that are bridged. But, I suppose it's a lot of trouble to build your own headphone amplifier just to get a fully balanced circuit from DAC to headphones. I suppose there are headphone amps out there which are about as good, but I also imagine that Nelson's patent is stopping anyone from building a super-symmetric or "X" headphone amp.
In any event, please continue to report your findings. Now you've inspired me to replace these noisy (default) headphone output circuits that I have, even though I rarely use them...
Great thought, rsdio. It turns out Russ White has done the heavy lifting for us right here on DIYaudio when he proto'ed the TP IVY. Nelson Pass agreed it was SuSy and it is only $79 as a kit. The best part is that its balanced outputs are sufficiently powerful to drive most cans directly. I have not yet assembled the kit but will before EOY.
Nice! Can you provide a link to that, or the title of the thread? I tried searching for Nelson Pass, Russ White, TP IVY and SUSY headphone but couldn't find any headphone amplifiers after a couple of pages of search results.
I would be very interested in looking over a SUSY headphone amp circuit!
Hi rsdio. For a couple of minutes, before Google rescued me, I thought I might have dreamed that one up! First, NP re SuSy.
http://www.diyaudio.com/forums/pass-labs/113874-discrete-super-symmetric-i-think-opamp-i-v-etc.html
Then from the IVY III manual (IVY III being the current rev of the proto being discussed in the link above):
The IVY-III can easily drive most headphones (even down to 16Ω) when used as a balanced headphone driver along with the Volumite or similar digital volume control. The SE outputs are not capable of as much power, but can still be used for most headphones. It is recommended that if you wish to drive headphones you use jumpers for R25/R26 and/or R27-R30, which will allow for better damping factor. The OPA1632 can drive up to 150mA, giving you plenty of power for almost any headphone listening situation. It is recommended when driving power amps to always use the output resistors, especially with very capacitive cables.
Note that this is a non-IV (since the WM874x DAC has voltage outputs) but also a real-IV since the ESS DAC has current outputs that just happens to be capable of driving cans A quick read of tthe entire manual will either cause palpitations or gastric distress!
The IVY Balanced Line Stage
Twisted Pear has a twisted naming scheme for its kits. The proto got called Ballsie but, frankly I think NashvilleNavyNife would have caused less confusion.
http://www.diyaudio.com/forums/pass-labs/113874-discrete-super-symmetric-i-think-opamp-i-v-etc.html
Then from the IVY III manual (IVY III being the current rev of the proto being discussed in the link above):
The IVY-III can easily drive most headphones (even down to 16Ω) when used as a balanced headphone driver along with the Volumite or similar digital volume control. The SE outputs are not capable of as much power, but can still be used for most headphones. It is recommended that if you wish to drive headphones you use jumpers for R25/R26 and/or R27-R30, which will allow for better damping factor. The OPA1632 can drive up to 150mA, giving you plenty of power for almost any headphone listening situation. It is recommended when driving power amps to always use the output resistors, especially with very capacitive cables.
Note that this is a non-IV (since the WM874x DAC has voltage outputs) but also a real-IV since the ESS DAC has current outputs that just happens to be capable of driving cans
A quick read of tthe entire manual will either cause palpitations or gastric distress!The IVY Balanced Line Stage
Twisted Pear has a twisted naming scheme for its kits. The proto got called Ballsie but, frankly I think NashvilleNavyNife would have caused less confusion.
Wow! 37 discrete transistors in a single channel? Is all of that really necessary? I guess I've been spoiled by the Zen articles which might have only 6 or 7 transistors per channel in the most complex designs. This also appears to be a current input preamp, so you may need to adjust. But, don't take my comments too seriously, as I haven't spent much time analyzing this. If I look at it longer, I may see that he's combined a preamp stage and amplifier stage together, but I had a hard time reading the schematic with the disjointed pieces.
If you want to start small, maybe try one of the Zen amps, but dial down the output current from the typical 2 A or 6 A to 150 mA or less. Then, if you like where things are heading, maybe you could try Russ White's circuit.
If you want to start small, maybe try one of the Zen amps, but dial down the output current from the typical 2 A or 6 A to 150 mA or less. Then, if you like where things are heading, maybe you could try Russ White's circuit.
If TP had called it SuSyPre, the headamp with BOTH voltage and current inputs it might have been more descriptive. Part of the complexity is the analog filters. I think 'the wire' by opc may be just the ticket but diverged because of your SuSy thought. I am attempting to simplify from quad BB1704s to quad WM874x DACs but that is really off in the weedz.
I want to create bits to cans balanced/bridged pipelines so I can mix and match to see what is important and what is not. The topic of this thread treads periously close to religion and politics but my goal is not controversy but lowcost simplicity. If, in the end I find an SE solution, that wood be even better. For now however I need to keep left and right channels entirely separate so I can play with wave shaping immediately following the DAC.
As regards my headphone cabling offer, the silence is deafening!
I want to create bits to cans balanced/bridged pipelines so I can mix and match to see what is important and what is not. The topic of this thread treads periously close to religion and politics but my goal is not controversy but lowcost simplicity. If, in the end I find an SE solution, that wood be even better. For now however I need to keep left and right channels entirely separate so I can play with wave shaping immediately following the DAC.
As regards my headphone cabling offer, the silence is deafening!
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