XLR connections for Virtue + headphones

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HiFlight

XLR connections for Virtue + headphones
« on: 8 Feb 2011, 03:30 pm »
As I have found my Virtue 2.2 to be an outstanding amplifier for powering my HE-6, K1000 and K340, all very difficult to drive headphones with conventional headphone amplifiers, the following information may be of interest to other DIY users of this type of headphone.
 
WARNING!!!   UNDER NO CIRCUMSTANCES SHOULD YOU ATTEMPT TO USE A 1/4" OR 1/8" STEREO JACK OR PLUG WITH A TRIPATH-BASED AMPLIFIER. THIS WILL CAUSE $$$$$ DAMAGE TO YOUR AMPLIFIER.  THE HEADPHONES MUST BE WIRED AS IF THEY ARE SPEAKERS, IN OTHER WORDS, 4 COMPLETELY INDEPENDENT LEADS TO THE AMPLIFIER TAPS. [/]

As Tripath-based amplifiers are not able to safely power headphones utilizing a common ground, it is necessary to "balance" them by wiring them in the manner of speakers, with independent ground returns.  The use of XLR connectors makes this a fairly simple operation.  Below is the wiring schematics most commonly used for balancing phones using either 3 or 4-pin connectors.  While there is no absolute industry standard for this type of connection, the AKG K1000 pretty much sets the standard and is that which is reflected below:

The Neutrik connectors are all numbered by the pins, so it makes them easy to identify.   On the 4-pin XLR connector, the basing is as follows:
        Pin 1 = L + 
        Pin 2 = L-
        Pin 3 = R+
        Pin 4 = R-
       
        If you are facing the front of the female plug (viewing the holes) with the locking notch at the top, numbering is clockwise, with the first hole to the right of the locking notch being #1.   
        Note that the male is numbered opposite, but when they face each other, the numbers match up.
               U                                                              U
        4           1  = Female connector                 1         4  = Male connector
          3     2                                                         2    3
       
       
       
       
        On the 3-pin XLR, basing is as follows: 
        Pin 1 = NC or shield
        Pin 2 = Pos
        Pin 3 = Neg




       
       
       
The locking notch on the 3-pin XLR is not shown on the diagram, but it is at the top between the 1 and 2 pins.  Also, wire color might not be Red and Black. 

Although this is not a difficult DIY project, for those who do not feel comfortable with soldering this type of connection, I would be willing to make up an adapter to match a balanced headphone to the Virtue speaker taps.

Ron       
« Last Edit: 20 Feb 2011, 11:45 pm by HiFlight »

virtue

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Re: XLR connections for Virtue + balanced headphones
« Reply #1 on: 8 Feb 2011, 06:23 pm »
Ron - thank you so much for posting.  We're seeing a lot of sales to balanced headphone listeners these days ;-)  I apppreciate your know-how and for letting folks know about the synergy.  Could you post a picture of the finished dongle and the neutrik XLR connector part number?

HiFlight

Re: XLR connections for Virtue + headphones
« Reply #2 on: 9 Feb 2011, 08:37 pm »
If building a dongle to match the 4-pin XLR female connector used on most balanced phones, the Neutrik part number is:
NC4FX-BAG

If your phones are terminated with the 3-pin XLR connectors instead of the single 4-pin connector, the Neutrik part number would be:
NC3FXXB (2 req.)

The picture below shows the finished adapter with the 4-pin XLR.

Ron





Jason T

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Re: XLR connections for Virtue + headphones
« Reply #3 on: 20 Feb 2011, 08:18 pm »
Guys
so you know and fully understand. (reiterating on Rons post)
our amps have dual bridged chips in them which CANNOT share a ground.
do NOT use a 3pin xlr plug with unbalanced headphones on our amplifier it could blow a channel.

simply put if your headphones aren't fully balanced and don't offer a 4 pin plug with separate grounds per channel please do not use them on our amps.
Your amplifier will not be warrantied under these conditions.

virtue

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Re: XLR connections for Virtue + headphones
« Reply #4 on: 20 Feb 2011, 10:25 pm »
To make this more concrete, if the output of the amp ever goes through a 1/4" or 1/8" headphone jack adapter (some headphones ship with them) ... Kapow, game over.  We had one customer blow up their amp and we replaced it. Next customer, we won't be as generous.

Enjoy this combination, but with responsibility please.  If you don't know what we're talking about here in this thread, buy a dedicated headphone amp!

mamba315

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Re: XLR connections for Virtue + headphones
« Reply #5 on: 24 Feb 2011, 10:24 am »
Great thread!  I think I'm about order the Audeze LCD-2's and I definitely want to try them on my battery powered M901.  Audeze seems willing to make whatever cable I need, so perhaps a balanced cable with 4-pin XLR termination is the way to go.  Then get 3 adapters: 3.5mm TRS, 6.35mm TRS, and speaker wires.  That'd cover all the bases, from iPhone to head amps to the Virtue.  Would be pretty sweet!

Audioclyde

Re: XLR connections for Virtue + headphones
« Reply #6 on: 1 Nov 2011, 04:57 pm »
Am I understanding correctly, that basically can't use a Sensation amp to drive my Grado RS-2's?  (other than the pre outs, which may not have enough drive). Or is there a potential work around?

Thanks,

Randy

eclein

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Re: XLR connections for Virtue + headphones
« Reply #7 on: 1 Nov 2011, 05:58 pm »
Hifiman now makes an adapter for amps like my 2.2 so balanced phones can be used. I forget the part number but its $99 and takes speaker outs and turns them into a balanced male connector in a nice case, i have one on order.
http://www.head-direct.com/Products/?act=detail&id=104
 the link above should be the page on the site that shows the HE adapter...
« Last Edit: 1 Nov 2011, 07:26 pm by eclein »

trungkien

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XLR connections with difference pin position
« Reply #8 on: 24 Mar 2013, 06:40 pm »
dear all,
please help me for this misunderstood : my XRL IC between Accuphase amp and Wadia CD player ,on  Accuphase  is pin 2 is + , pin 3 is -,and on the Wadia  is Pin 2is + and pin 3 is -.
Is there any problem if I use XRL IC to connect them? should I have to change to RCA or change PIN position?
I try to find on internet but no information .
Thank you very much>
Trung Kien