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Brian Donegan  
#21 Posted : Monday, May 3, 2010 3:53:55 AM(UTC)
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It would be worth checking the output on a scope to be sure you are not getting oscillation. There is a lot of parasitic capacitance and inductance added there, not to mention antenna for picking up RFI/EMI.

I'm not saying it's not good and not possible, just use an abundance of caution.
NicMac  
#22 Posted : Monday, May 3, 2010 7:08:45 AM(UTC)
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Brian,
You are probably right even if I have not observed any abnormalities with different headphones or amps. Still sings like only a Buffalo can.
Anyway now I know which gain serves me best and I have no more use for this ugly construction :-)
Nic
kesgreen  
#23 Posted : Sunday, May 9, 2010 5:12:32 PM(UTC)
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I've just bought some Sennheiser HD 600 headphones and want to drive them from the Ivy III in a balanced setup. Most people seem to use 2 3-pin XLRs or 1 4-pin, with shield ground not used.

Would it be worth using 2 cables - 1 for each driver and each with the shield connected at the Ivy III end? I actually already used 2 lengths of Mogami 2893 to re-cable my Grados (both cables going into a 1/4" jack). Most seem to use 24AWG starquad and split it - using 2 cables makes the split unnecessary.

Either way I assume I connect the chassis XLR socket to the balanced outputs of the Ivy III? As a noob, I'm a little confused as to how connecting just the - and + of the balanced output is different to the signal and ground of the SE output. Also, why are XLRs always used? Could one not use 2 RCAs?
Russ White  
#24 Posted : Sunday, May 9, 2010 8:02:43 PM(UTC)
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HD600s already run two 2 conductor wires up to the cans. You just need to wire them to XLRs.
kesgreen  
#25 Posted : Sunday, May 9, 2010 9:21:51 PM(UTC)
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Thanks Russ but I'd like to keep the original cable for when I need to use them with a TRS plug (or if I sell them). I quite enjoy making cables anyway, plus I've already bought a pair of the Cardas plugs for the headphone end.
Beefy  
#26 Posted : Monday, May 10, 2010 4:26:31 AM(UTC)
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The best connection is single 4-pin XLR, no shield or ground connected.
Brian Donegan  
#27 Posted : Monday, May 10, 2010 4:37:05 AM(UTC)
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Quote:
Also, why are XLRs always used? Could one not use 2 RCAs?


You can really use any connector you want. The main reason for not using something like RCAs is to prevent connection errors later... if you connect a regular SE-input stage to you balanced outputs, it would typically connect the grounds, which in this case would actually be the balanced signal's - out, and that would be bad. A unique connector means no mistakes.

Quote:
I'm a little confused as to how connecting just the - and + of the balanced output is different to the signal and ground of the SE output.


SE outputs (typical RCA connectors for example) use one wire for signal and one wire for ground. Balanced signals (XLR connectors) use one wire for ground and two wires for signal, + and -. the two signal wires are identical, but 180-degrees out of phase. Picture a sine-wave, and call that the + signal. The - signal would look identical, but when the + goes up, the - goes down. Here's some additional reading: http://en.wikipedia.org/wiki/Balanced_audio
kesgreen  
#28 Posted : Monday, May 10, 2010 1:34:56 PM(UTC)
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Thanks for the info. guys.

I checked out the Wiki link although I find it a little complicated. None of it ever mentions headphones though. Surely headphones are just small speakers and you never hear of speakers being connected with anything other than speaker wire (OK I've never heard of anything else other than normal wiring or bi-wiring). I mean I've read a lot of posts on Head-Fi and I'm still not sure why driving headphones from balanced outputs is better.

Update: Just found a FAQ on the Headroom site which says that balanced headphones have this benefit:

Quote:
a significant increase of audio performance is heard due to the doubling of slew rate and power; the reduction of some distortion components; and virtual elimination of crosstalk at the headphones due to the common ground


There's some more stuff on there which I shall continue to read. Interesting...
Beefy  
#29 Posted : Monday, May 10, 2010 2:37:03 PM(UTC)
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I'll preface this by saying that in many cases I don't think that going balanced provides huge benefits, but......

kesgreen wrote:
I checked out the Wiki link although I find it a little complicated. None of it ever mentions headphones though. Surely headphones are just small speakers and you never hear of speakers being connected with anything other than speaker wire


Sure, but speaker wire is a pair of wires to each speaker. You don't run the ground from a single connection on the amp, to one speaker, then to the other speaker. But this is essentially what you are doing in unbalanced headphones.

kesgreen wrote:
Update: Just found a FAQ on the Headroom site which says that balanced headphones have this benefit:

Quote:
a significant increase of audio performance is heard due to the doubling of slew rate and power; the reduction of some distortion components; and virtual elimination of crosstalk at the headphones due to the common ground


This could be important with respect to the Buffalo.

Running balanced, each individual driver is powered by a single OPAMP. Plenty of power, and no unnecessary steps.

Running unbalanced, both drivers are powered by the same OPAMP. Less power, and the signal goes through this extra OPAMP.
Russ White  
#30 Posted : Monday, May 10, 2010 3:34:46 PM(UTC)
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The key idea is the shortest distance from source to your ears. When you are aiming for that you can't do better than DAC -> I/V -> Cans. When dealing with a balanced DAC that means a balanced I/V driving balanced headphones. :) I am so spoiled by this I spend most of my time listening this way.
kesgreen  
#31 Posted : Monday, May 10, 2010 5:18:55 PM(UTC)
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It all makes perfect sense to me now.

When I considered building the Buffalo II/Ivy III it was mainly to use as a DAC/pre-amp. It's just a great added bonus that it's a fully balanced headphone DAC/amp as well.

When I consider everything it can do, it just seems like better and better value for money.
zajin  
#32 Posted : Wednesday, May 12, 2010 3:32:32 PM(UTC)
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Hi all!
In my future buff II/IVY combo, I would like to have a headphone connector, although not balanced.
What would be the best way of connecting a 1/4" jack? +/gnd from balanced, or just take the signal from SE?

I will mainly use the DAC connected to an amplifier via SE, but it would be nice to be able to easily and directly connect my grado's from time to time :)
stringgz301  
#33 Posted : Friday, May 14, 2010 11:51:28 AM(UTC)
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Just to confirm my understanding (before I start ordering parts), if I add a volumite controller, I can then have a second set of wires coming from the single-ended IVY III terminals going to a headphone jack. If I do this, can I run separate headphones out of the IVY and my headphone amp at the same time?

Also, can I power the Volumite from the same Placid that is powering the BII and Toslink module?

Thanks
Brian Donegan  
#34 Posted : Friday, May 14, 2010 11:55:38 AM(UTC)
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stringgz301 wrote:
Just to confirm my understanding (before I start ordering parts), if I add a volumite controller, I can then have a second set of wires coming from the single-ended IVY III terminals going to a headphone jack. If I do this, can I run separate headphones out of the IVY and my headphone amp at the same time?


Yes.

stringgz301 wrote:
Also, can I power the Volumite from the same Placid that is powering the BII and Toslink module?


There is actually a four-pin header on the BII for connecting the Volumite. This provides power (3.3V) for the Volumite. You should not install the vreg on the Volumite and instead use a jumper between pins 1 and 3 of the vreg pads (details in the manual).
ericsphillips  
#35 Posted : Tuesday, May 25, 2010 11:34:07 AM(UTC)
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So what is the consensus on the output resistance (i.e. jumper or not) for a part-time amp-connected output and part-time headphone-connected output?

I am looking to have 3 output connectors: SE via RCA and TRS in parallel and Bal via 2 XLRs.

95% of the time the connection would be XLR to amp. Occasionally, i would unplug the amp, and connect my bal-cabled HD600s. The SE would be rarely used.

Seems like it would be best to leave the jumpers out?

kesgreen  
#36 Posted : Tuesday, May 25, 2010 12:52:47 PM(UTC)
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I reckon so. One day I might install a switch to act as a reversible jumper, but I'm using balanced HD600s without jumpering and they sound great - no problems whatsoever.

Edited by user Tuesday, May 25, 2010 12:53:24 PM(UTC)  | Reason: Not specified

Brian Donegan  
#37 Posted : Tuesday, May 25, 2010 12:55:14 PM(UTC)
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You could add the resistors, then wire two sets of outputs: one for headphones (to the resistor pads) and one for a pre (to the output termials), then leave them both live all the time.
kesgreen  
#38 Posted : Tuesday, May 25, 2010 12:57:53 PM(UTC)
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That's a great suggestion Brian, thanks. I just might give it a go.
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