DIY HE Adapter
Apr 12, 2013 at 2:59 AM Post #16 of 48
Hi,
Thanks for reply. I haven't try direct connection yet (becouse I'm still insecure).
I can buy sth from this shop:
http://www.loudspeakershop.eu/resistors-c-196.html
I was thinking about Duelund 10R10W or Mills MRA-12 8R2 or 15R for parallel resistor. But as far as I'm concerned in my situation (powerfull solid state amplifier) resisitor in series would more important to protect my HP. What other values it might have than original 25 Ohm 1/4W to still protect my headphones?
And how solid state amplifier would react to such high impedance (aprox. 50 Ohm) without big (for example 10W from additional parallel resistror) load (amplifier will be for example very warm?) If I connect he500 directly to taps?
What would be sympthoms of "overpowering" my headhones if I use them without any resistors protection? Headphones  will play probably very loud on lower volume levels but when I will know if it's to much for them before they will be damaged (will any distortion in sound appear first)?
Emil.
 
Apr 13, 2013 at 1:16 PM Post #17 of 48
Hi. I remember that feeling. But when I connected my HE-6 straight to the speaker outputs of my 100wpc Odyssey Cyclops Max ss integrated amp, with the volume control on zero, nothing happened. When I turned the volume control up, the sound qualilty was very good. I have used it like that for hours, with the volume control at about 25%,  
 
There was quite a bit of sibilance, though, so I bought the HE-adapter, jiggered some cables, and the sound quality became outstanding.
 
Then I hooked the HE-adapter up to my new Fi 421A SET with 4wpc, and ever since I have been enjoying the best music reproduction from CD that I have ever heard.
 
I bought some new resistors, too, Mills MRA-5 10R0 and Shinkoh 18R0 1w, but I haven't installed them yet.
 
Please let us know how your new resistors sound! 
 
Apr 15, 2013 at 4:24 AM Post #18 of 48
Of course I'll post my impressions but I also have a question about resistors in series. Most of users recommend  using 10W-12W Mills or Duelund resistor for paralell connection. Are there any recommendation of resistors in series? Should it be also non-inductive resistor? Can anyone post some examples?
 
http://www.soundlabsgroup.com.au/p/MU-MRESIST-10R-20W/10+Ohm+20W+MRESIST+Supreme+Resistor
Would higher power resistors be better for powerfull solid state amplifeirs?
E.
 
Apr 15, 2013 at 5:20 PM Post #19 of 48
Quote:
Of course I'll post my impressions but I also have a question about resistors in series. Most of users recommend  using 10W-12W Mills or Duelund resistor for paralell connection. Are there any recommendation of resistors in series? Should it be also non-inductive resistor? Can anyone post some examples?
 
http://www.soundlabsgroup.com.au/p/MU-MRESIST-10R-20W/10+Ohm+20W+MRESIST+Supreme+Resistor
Would higher power resistors be better for powerfull solid state amplifeirs?
E.

the resistors in series doesnt have to nonind, id say some allen bradley carbon comp resistors or some audionote tantalums. the mundorf m resist should be fine as the resistors in parallel.
 
 to be clear i am talking about an adapter that consists of one parallel resistor and one series resistor like the first post, i am not talking about the project 100 schematic. 
 
Apr 19, 2013 at 6:47 AM Post #20 of 48
Hi,
Thanks fo reply.
Yesterday I decided to connect my he-500 directly to my rotel rb1080 solid state amplifier (thanks for user Happy Camper). After first longer session I can say that I can hear slightly noise compared to the sound with HE-Adapter and the soud is louder. With adapter I was listening at -26 level and now -36 (range is from -80 to +12). And sound seems a bit brighter? Anyway I decided to start making my adapter with:
http://www.loudspeakershop.eu/mills-12w-15r-p-1435.html?language=en&currency=USD  or:
http://www.soundlabsgroup.com.au/p/MU-MRESIST-10R-20W/10+Ohm+20W+MRESIST+Supreme+Resistor
for paralell resistor.
Resistor in series I'll take sth like 1/4W 25Ohm and post my impressions later.
Emil.
 
Apr 19, 2013 at 3:56 PM Post #21 of 48
The adapters will attenuate, which does reduce noise. The standard adapters also reduce damping factor, which will give a slightly looser and darker sound. 
 
I'm thinking if I make another adapter, instead of a single 10ohm resistor in parallel I'll use two 5 ohm in series, then split off between the resistors for the headphone output. This should present roughly the same load to the amp, give attenuation, and maintain damping factor for the headphones. 
 
Apr 19, 2013 at 11:15 PM Post #22 of 48
Quote:
the resistors in series doesnt have to nonind, id say some allen bradley carbon comp resistors or some audionote tantalums. the mundorf m resist should be fine as the resistors in parallel.
 
 

 
I think that the quality of a resistor in series may actually be more important than the resistors in parallel.
 
The audio signal has to travel through the in-series resistor.
 
Induction would probably change the sound quality. It my not introduce distortion (noise) but it could impact other characteristics.
 
But in the end actual trial and error will decide the best results - given that different headphone and amp pairings will exist.
 
Apr 24, 2013 at 5:17 PM Post #23 of 48
How do I tell if a resistor is non-inductive?  Would a pair of these work: http://www.mouser.com/ProductDetail/Xicon/280-CR15-10-RC/?qs=sGAEpiMZZMtbXrIkmrvidNqDYkzv63xDQeKig%252b%252bO6x8%3d?
 
I am only using a 10W amp so I figure I don't need 20W resistors.  
 
I'm going to take a TA2020 board and attach a 4-pin XLR to the outs, bypassing speaker taps all together, but wanted to basically build the simple HE adapter into it.  Probably going to get a bunch of different values for attenuation if needed.
 
Apr 24, 2013 at 6:00 PM Post #24 of 48
Apr 27, 2013 at 4:38 PM Post #25 of 48
Quote:
solder dosnt matter, if you have a tube amp your gonna want some nice allen bradley carbon resistors (the audio not tantalums are good also) no ww or metal film for the ones in series.
 
for the 2 in parallel somthing above 8 ohms is better (matching dosnt matter this is all off of the 8ohm tap of your amp) i use 10 to 16 ohm resistors in parallel but they should be of high w disapation i use 20w resistors, the ones in series dont matter as much for w dissapation id say above 1/2 w is fine. 
 
so in all together for you amp id use 10 or 16 ohm resistors 20w in parallel, then for the ones in parallel depending on the gain of your amp and how much surface noise there is maybe around 36ohms or 56ohms or 100ohms depending how much hum and other noise are in the amp by itself the higher value the quiter everthing any of these should be atleast 1/2w.(most speaker amps have a bit of hum just due to the fact they wernt designed for headphone use and you dont hear the hum on speakers)
 
your idea of less things in the signal path wont help you much if you wanted the least stuff in your signal path just run your headphone straight into the taps of your amp, this adapter isnt required it just adjusts many of the things so its more suitable for headphone use.
 
for example i made one of these for my 2a3/45 tube amp i used 16ohm 20w resistors in parallel and in series i used 100ohm resistors. sounds amazing from my hifimans and my lcd-3.
 
if you have any more questions just pm me

 
Hey Spriggs, as I read back through this thread, I note that I forgot to tell you THANK YOU. Sorry 'bout that. You've been real helpful to everyone here. Way to go!
 
THANKS
 
I hope I get a chance to try my new resistors soon.
 
Apr 27, 2013 at 5:36 PM Post #26 of 48
Yes, thanks to everyone who has helped.  I have parts on the way to integrate this into an amp.  Taking a TA2020 tripath board and hooking it up just as a headphone amp through a 4-pin XLR out, just for giggles.
 
Jun 23, 2013 at 12:10 PM Post #28 of 48
OK so I have the Emotiva a-100 miniX..  It works just fine right off the speaker taps with the HE-6, HE-5LE, and the HE-4.  Some have reported hiss with the HE-500.  Now I would like to know using this amp with headphones like Denons, Audio Technicas and Grados.  If I buy the HE-Adapter - can it be modded and have the resisters replaced with better ones that will work with the before said headphones - and what resisters would that be?
 
Dec 11, 2013 at 9:36 AM Post #29 of 48
Here's a link to my Headphone Resistor Network Calculator webpage. It will help you optimize resistor values to match your headphones to your amp.
 
I also have a much more detailed and complicated network calculator spreadsheet.
 
Balanced Headphones Resistor Network:
Headphone_Resistor_Network_Preferred.jpg

 
Single-Ended Headphones Network:
Headphone_Resistor_Netwrok_Single-Ended_Preferred.jpg

 
After playing with resistor values an R2 value of 6 ohms 5 watts (wirewound) and R3 of 2 ohms 3 watts (wirewound) works well for almost any headphone & amp combo.
 
Jun 1, 2014 at 11:17 AM Post #30 of 48
Here's the layout diagrams for a basic headphone interface:
 
 

Basic Speaker Amp to Headphone Adapter - Single Ended TRS

Speaker_to_Headphone_Attenuator_TRS.png

This type of adapter is only for amplifiers that have their negative speaker terminals tied together (common ground).
 

Basic Speaker Amp to Headphone Adapter - Balanced Output XLR 4-Pin

Speaker_to_Headphone_Attenuator_XLR.png

This adapter will work with single-ended and balanced output speaker amplifiers.
 

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