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HE-500, LCD2, D5000, DT770, SR80, on a speaker amp (Emotiva mini-X A-100) Project - Page 215

post #3211 of 3792
Well, just the parts cost me 50-60$. The box I ordered is pretty small also..
Thank you for the tips Rob! As of now I have only got access to a poor soldering iron of the cheapest kind so it will sure be a hassle.
post #3212 of 3792
Quote:
Originally Posted by koiloco View Post
 


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

I really enjoy reloading and I have a 50 BMG press out in the garage but I haven't invested in the dies and primer tools needed since I moved to a place where 50 BMG ranges are rare. My primary press is a Dillon RL550 with the auto case loader. I used to be a law enforcement officer so I got tons of free 40 S&W brass so that's what I reload more than anything else.

 

My gun related stuff is here if you're interested: http://robrobinette.com/M16_4-Way_Selector.htm There are links at the top of that page to a suppressor build and other stuff.

 

Here's a pic of the Dillon press with 300 Blackout:

Tube.jpg 


Edited by robrob - 2/13/14 at 2:27pm
post #3213 of 3792

Actaully, the box I ordered is only 4.72 x 4.06 x 2.09

 

It might be a tight fit, especially if I want to upgrade and add more circuits, but I like it as it looks nice and has a good size.

 

post #3214 of 3792

@robrob, awesome!  I love Dillon catalog with the pretty ladies on the cover with their index finger correctly placed.  :D

If you do ever complete your 50bmg loading set up and wanna load some rounds, let me know.  I still have about 2000 once fired LC brass.  In CA, I have to reform the brass to 50DTC before loading since 50BMG is not legal in CA anymore.

post #3215 of 3792

Hi everyone,

 

Thinking about getting one of these for my new HE-500. Unfortunately i have no access to soldering; is there any CON to sonido's "20$ connection to the emotiva" ? I am thinking of pairing them in this method, unless someone is willing to make the cable for me, which i will be glad to pay for!

post #3216 of 3792
Dunno who, but some cable makers charge around 50$ for an adapter
post #3217 of 3792
Quote:
Originally Posted by psychoplast View Post
 

Hi everyone,

 

Thinking about getting one of these for my new HE-500. Unfortunately i have no access to soldering; is there any CON to sonido's "20$ connection to the emotiva" ? I am thinking of pairing them in this method, unless someone is willing to make the cable for me, which i will be glad to pay for!

 

Someone, I believe in this thread, showed how to source a headphone socket that used screw down wire connections to build a headphone to speaker amp cable adapter with no soldering required.

post #3218 of 3792
Quote:
Originally Posted by psychoplast View Post
 

Hi everyone,

 

Thinking about getting one of these for my new HE-500. Unfortunately i have no access to soldering; is there any CON to sonido's "20$ connection to the emotiva" ? I am thinking of pairing them in this method, unless someone is willing to make the cable for me, which i will be glad to pay for!

 

 

Quote:
Originally Posted by davidsh View Post

Dunno who, but some cable makers charge around 50$ for an adapter


Yea when I made mine:

 

 

It was about $30 in parts alone not including the shipping for them and the tools and know how to put it together. Course I used nice and expensive components and you could probably put one together for cheaper if you wanted to but who wants cheap audio gear?! ;)

post #3219 of 3792

At the very cheapest you could probably make one for $5 and just stick bare wire into the binding posts. But moving up into some sturdier components, add the bananas, some wire not from the hardware store, some sleeving, some braiding... $50 isn't too far off:

 

adapter: banana post to 4-pin XLR; 4-wire braid stranded copper and sleeved

post #3220 of 3792

Single-Ended Amplifier Speaker Out Adapter

 

If your amplifier has common ground output (L- & R- speaker terminals connected to ground) you can easily make an adapter to connect your normal unbalanced headphones to the amp's speaker terminals. Simply purchase a headphone extension cable (can be found on eBay) and cut off the male TRS plug. Then strip back the cable to expose the two center conductors which are L+ and R+ and the metal shield which is the combined (common) L- and R-. You can twist the shield strands into two wires to connect to the amp's negative speaker terminals but since the black speaker terminals are connected together to ground you really only need to connect the cable's shield to one negative speaker terminal. Connect the L+ wire to the amp's left red speaker terminal and the R+ to the right red speaker terminal. You also have the option to put banana plugs on the wire ends if you want. Once completed plug your headphone cable into the adapter cable's female TRS connector.

 

Unbalanced (Single-Ended Amp) Adapter Wiring

 

Female TRS Socket                               Amplifier Speaker Terminal

Tip              L+                                         Left Red

Ring            R+                                         Right Red

Sleeve      Combined L- and R-               Either Left or Right Black

 

Only 3 wires are really needed because on a single-ended amp both black (-) speaker terminals are connected together to ground. Just connect the TRS Sleeve wire to either black speaker terminal.

 

TRS Jack to 2 Conductor Cable

TRS_Pinout.jpg

The cable's metal shield is the common ground and gets connected to one or both speaker negative terminals.

post #3221 of 3792
Quote:
Originally Posted by kas49 View Post
 


Robrob, To refresh your memory, this was your response to post #2866.   I finally got my act together and added a 40ohm 5 watt resistor to both the + lines.  I used 5 watt 40ohm 1% Ohmite Wirewound Resistos from Mouser.  Result is better, but I still have a slight hum.  I assume I should next try 72 ohm resistors?  Also, do you have a recommendation for a better resistor?  And finally, kind of a dumb (and rookie wiring) question--Is there a special way to connect the resistors to the wire?  I just wrapped the exposed wire around them so that it touched both metal ends of the resistor (and then soldered where the wires touched, covered the resulting mess with shrink wrap and then connected the remaining wire to a banana plug.  It isn't pretty, but I assume it should work.  Thanks for you continuing help and patience


Robrob (and others fussing with the slight hum).  Just to close the loop on this.  You suggested in post #3098 of this thread that I try 100ohm resistors to eliminate the hum. I got them, but before I cut off the 40 ohm resistors to replace them with the 100ohm ones, I first decided to cut the wires through the shrink wrap to make sure that the signal was definitely going through (rather than around) the resistors.  Bingo!  Hum eliminated.   Thanks so much for your help.  I am now really loving my Aune T1 /Emotiva a-100/HE 500 set up.  It really sings and there is no more annoying hum during quiet passages.

post #3222 of 3792

Hi, all, does it matter whether R3 is upstream or downstream of R2? (I've got my R3 on the amp-side of R2 and it sounds fine, but I'm not sure that I'm protecting the output transformer on my tube amp like I should be.) 

 

And thanks for the simplified chart, Rob. It's just what electron-illilterates like me need.

 

Quote:

Originally Posted by robrob View Post
 

Here's an updated chart, it's part of my Headphone Network Calculator Spreadsheet:

 

post #3223 of 3792

R3 after the R2 is what's known as an L-pad which is essentially just a voltage divider. The amp sees the combined load of R2 + R3. (technically R2 + R3//Z, where Z is the headphone impedance). The headphone sees an output impedance of R3. You'll want relatively beefy resistors for both (ie: high wattage resistors).

 

If you have R3 before R2, then the amp essentially sees a load of R3. This is the config that comes in the Hifiman adapter box. Works well for planars, but a little more finicky with dynamics. R3 needs to be beefy, but R2 typically does not.

 

Both configs will protect the amp and present relatively stable loads.


Edited by Armaegis - 2/14/14 at 11:31am
post #3224 of 3792
Yes, it matters. You should move them around. Now, the amp sees a 2 ohm load.
post #3225 of 3792

I've been getting quite a few PMs about the Robinette box. I think it's stemming from this thread. I will consider making a 'batch' of 5-10 to keep costs down if there is enough interest for this box :beerchug:

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