HE-500, LCD2, D5000, DT770, SR80, on a speaker amp (Emotiva mini-X A-100) Project
Feb 13, 2014 at 12:33 PM Post #3,197 of 3,819
  Lots of X-100 Mini users plug their headphones in direct and are happy with the sound quality. Give it a try before you decide to modify it. If you do decide to add resistors ben_r_ used 220 ohm resistors and was very happy with the results.

i have mine modded, direct hp jack on front of mini, works great with the he4, not so much with the magnums, to much hiss. Thats why io asked about using 150 ohm iems. Ill just try it
 
Feb 13, 2014 at 12:59 PM Post #3,198 of 3,819
Finally got the parts to make my version of the robinette box. It will feature 2x4 female banana (input/output), jack and xlr and a switch for attenuator/ no attenuator circuit. Do you think it will affect sq to use the attenuator circuit with he500 (assuming it is 12 dB preferred resistor network)? I have a little hiss with he500 and a tiny little bit with he-5le
 
Feb 13, 2014 at 1:03 PM Post #3,199 of 3,819
Finally got the parts to make my version of the robinette box. It will feature 2x4 female banana (input/output), jack and xlr and a switch for attenuator/ no attenuator circuit. Do you think it will affect sq to use the attenuator circuit with he500 (assuming it is 12 dB preferred resistor network)? I have a little hiss with he500 and a tiny little bit with he-5le


No, in fact IMO you SHOULD attenuate the signal if using the mini-X a-100 to drive headphones. Forget the external box though, put it all cleanly inside like I did!
 
Feb 13, 2014 at 1:42 PM Post #3,200 of 3,819
Internal box it is.. Will use it with other amps in the future :)
I have to get a new neutrik jack as the locking mechanism doesn't work in the one I've got, though. Very annoying..
 
Feb 13, 2014 at 1:50 PM Post #3,201 of 3,819
Internal box it is.. Will use it with other amps in the future
smily_headphones1.gif

I have to get a new neutrik jack as the locking mechanism doesn't work in the one I've got, though. Very annoying..


Just remove the locking mechanism. I have done it to several Neutrik locking jacks. Its just a red piece of plastic inside it.
 
Feb 13, 2014 at 2:38 PM Post #3,202 of 3,819
 
Internal box it is.. Will use it with other amps in the future
smily_headphones1.gif

I have to get a new neutrik jack as the locking mechanism doesn't work in the one I've got, though. Very annoying..


Just remove the locking mechanism. I have done it to several Neutrik locking jacks. Its just a red piece of plastic inside it.

Yeah, I see. Thank you! How do I go about it?
 
Feb 13, 2014 at 3:34 PM Post #3,203 of 3,819
davidsh, I have a pair of HE-500s that I used to test the Robinette Box with and as I said in the review I cannot detect a difference in sq when the resistor network is switched in and out (the volume has to be raised with the resistor network of course).
 
An assembly tip: Try to do as much soldering on the connectors as you can before mounting them in the box--especially putting the resistors on the network bypass switch. Pre-attach all the wires to the headphone jacks because it can get a little tight in there. Feel free to pm me with any questions and please write a review when you've got some listening time with it.
 
Feb 13, 2014 at 4:06 PM Post #3,204 of 3,819
  davidsh, I have a pair of HE-500s that I used to test the Robinette Box with and as I said in the review I cannot detect a difference in sq when the resistor network is switched in and out (the volume has to be raised with the resistor network of course).
 
An assembly tip: Try to do as much soldering on the connectors as you can before mounting them in the box--especially putting the resistors on the network bypass switch. Pre-attach all the wires to the headphone jacks because it can get a little tight in there. Feel free to pm me with any questions and please write a review when you've got some listening time with it.


Where is a link to the DIY on this "Robinette Box" you speak of? Id like to take a look at that.
 
Feb 13, 2014 at 4:15 PM Post #3,207 of 3,819
  Yea make an adapter like this (or buy one pre-made) one and you can plug your headphones into it:
 

I just want to mention that this type of adapter is perfect for the Mini-X, but it shouldn't be used on speaker amps with balanced (non-common ground) output as you can damage the amp. If your amp's black speaker terminals are connected to ground (you can verify this with a multimeter) then this type adapter is safe to use.
 
Feb 13, 2014 at 4:18 PM Post #3,208 of 3,819
  Very nice robrob. You should shrink that down, clean it up, make a few and sell em on your website and eBay.

 
Thanks Ben, I intentionally used a large box for the prototype to make it easier to assemble and troubleshoot but it's a labor intensive build and the parts cost is surprisingly high so I don't think I could sell many.
 
Feb 13, 2014 at 4:21 PM Post #3,209 of 3,819
  Link is here: http://robrobinette.com/RobinetteBox.htm
 
RBInside.jpg

Headphones and 'Amp Mode Switch' on left, speaker binding posts and 'Network Bypass Switch' on right.


@robrob,  I love the pic with the loading press in the right corner 
biggrin.gif
  You do your own loading much?  I still have my 50cal equipments to complete.  I've been loading the other calibers for years. 
beerchug.gif

 
Feb 13, 2014 at 4:27 PM Post #3,210 of 3,819
   
Thanks Ben, I intentionally used a large box for the prototype to make it easier to assemble and troubleshoot but it's a labor intensive build and the parts cost is surprisingly high so I don't think I could sell many.


I bet most of those connectors could be found in a right angle PCB mount version as well as the switches and the resistors which would make assembly A LOT easier if it were all soldered onto one board and the overall package would be very small. Find a metal project box that the board will fit in, get a local metal working company to cut the holes for you and a metal finishing company to anodize it or powder coat it and you could probably sell it for $100 as a nicely finished product. Yea who knows how long it would take you to move them, but it would be a fun project and maybe a good learning experience :)
 

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