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Headphone Jack Installed (Read 2363 times)
tubenvy
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Posts: 3
Headphone Jack Installed
08/03/10 at 23:38:02
 
Just added a headphone jack to my ZKit1. Thought I would give this a try since I haven't heard of this being done yet with the ZKit1. It sounds amazing with the Grado SR80 headphones I am using. I did this by adding a 100 ohm 2W resistors to the positive side of the left and right outputs and standard wire leads to both negative outputs. These leads were then soldered to their respective places on a regular chassis mount, Radio Shack (Yes, you read correct- please don't hold this against me- it was for the sake of research) headphone jack. This kit makes a outstanding headphone amp. I would be interested to here other members observations of this Mod.

Mods:
-CCE Mod
-Alps Blue Velvet Volume
-DIY HVAC foil tape interconnects and speaker wire insulated with packing tape (sounds crazy but sounds good....ears are the judge-wonderfull detail)
-DIY heavy gauge power cord
-Hum Mod (quiet as a ghost)


Equipment:
-ZKit1 in custom wooden enlosure
-NAD 512 CD
-Grado SR80 headphones
-Fostex 108EZ speakers in custom horn cabinets
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« Last Edit: 10/03/10 at 03:21:34 by tubenvy »  
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Alan H
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Posts: 63
Re: Headphone Jack Installed
Reply #1 - 08/14/10 at 13:38:53
 
Great to know this.

I would have liked to build a headphone option in from the start - rather than now wondering if I can easily add it after assembly.

So I'm hoping info like this headphone option (and the CCE mod, and hum solutions below) will make their way into the ZKit1 Assembly Instructions.

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FLAC via Ethernet-over-Mains
Squeezebox 3
Valab 6N Solid Silver Coax
GD-Audio DAC19 DSP
Decware SE84DIY (V-Caps + CCE mod)
Solid silver / teflon cables
Scotmoose Sachiko FE206En Horns
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Havlaz
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Posts: 4
Re: Headphone Jack Installed
Reply #2 - 09/10/10 at 06:04:42
 
Noob question - any danger in trying this with the SE84C+ ?

thanks

Eitan
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tubenvy
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Posts: 3
Re: Headphone Jack Installed
Reply #3 - 10/03/10 at 03:28:59
 
Should be OK. SE84C+ is the same setup. You can connect the headphone jack and associated wires/resistors to your speaker outputs on the outside of the cabinet to test or go ahead and solder leads to the speaker outputs inside the cabinet and mount the jack into the metal amp enclosure. You will need to drill a 1/4" hole to mount the headphone jack.
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Raduschka
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Posts: 210
Re: Headphone Jack Installed
Reply #4 - 01/15/11 at 16:04:04
 
Hi tubenvy,

I followed in your footsteps and installed a headphone jack (from Radio shack yes, for the time being) because the zenkit turned out a little underpowered for my triangles. I prefer my Jolida 801a for now. The main issue I have with the zen kit is a loud hum that I can't resolve. I installed 2 X 200ohm resistors in the same way you described and the hum almost disappeared (along with the relative volume reduction). I am listening for sound degradation (I have a pair of akg 701) but I can't find any, at equal loudness, just a welcome reduction in hum.
I am a complete novice and don't understand much of what I am doing, can you please explain the use of resistors in that particular place? I have never heard of that yet. And how important is it that they be rated at 2watts? Are there different qualities, should I bother to order more expensive ones?
Thanks a lot
Raduschka

------------------

cayin tube output cd-player
Triangle Antal speakers  91db
Jolida 801a 2x70 w
silver teflon interconnects
diy power cables
black diamond cones
monster power 1600ht power cleaner
akg 701 headphones
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« Last Edit: 01/15/11 at 16:23:03 by Raduschka »  
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tubenvy
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Posts: 3
Re: Headphone Jack Installed
Reply #5 - 02/05/11 at 02:40:30
 
For the headphone mod, you should be using (qty 1) 100ohm resistor per channel, not (qty 1) 200ohm resistor per channel as you have described. Also, your hum problem can be solved by adding a length of solid core wire (i used small gauge telephone wire) from the ground tab of each RCA input to the respective ground on the volume pod. I had the same hum issue but, even through headphones, my amp is now as quiet as a church mouse. The hum mod is described in the following post:

http://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1257041114/0.
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Evo
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Posts: 53
Re: Headphone Jack Installed
Reply #6 - 02/19/11 at 09:39:03
 
Hi Tubenvy,

Sounds like a good idea. I have young children so to be able to use the zkit1 as a headphone amp would be a bonus. I also want to use mine to drive speakers on occasions too. I was wondering about installing a switch contact headphone jack, but my knowledge of electronics is rudimentry. My understanding of how these things work is that as the headphone jack goes in it cuts the connection to the speakers. The conntections are signal - headphone jack - speakers as I understand it. If I put a 100R resistor in the signal path before the headphone jack the won't I also have put the 100R resistor before the speakers when they are connected? Or am I wrong?
If anyone can tell me how to do this properly i.e my the zkit1 a headphone amp that mutes the speakers when I plug headphones in, please let me know. Would love to try it,

Matt
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