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DIY: Emotiva mini-X a-100 Headphone Amp Mod Guide - Page 2

post #16 of 37
Thread Starter 

Added a new pic showing the HE-500's on the Woo Audio single headphone stand all on top of the blacked out and modded Emotiva mini-X a-100.

post #17 of 37
Quote:
Originally Posted by ben_r_ View Post
 

Thanks guys.

 

Also, if there is anything else youd like me to talk about that I might have missed or other pictures youd like to see let me know here and Ill see what I can do. I will be getting up a pic of the amp powered on as well as one with my new Woo Audio headphone stand thats coming holding the HE-500's but anymore pic of the inside and I probably wont be able to do as I dont want to open this amp up anymore unless I absolutely have to.

ben_r: A Fantastic job, which has left me in awe and gotten me intimidated at the same time. Now (since any process involving drilling a chassis or messing with the insides of an amp scares the bejeezus out of me), if I were to opt for the adapter option, can I add the attenuation by simply installing standard attenuators at the input points on the mini-x (DC-1 out ===>> Mini-x inputs)?  Also is the adapter in the pic available for sale, or did you make that yourself?  I have posted a similar question to you on the Emotivalounge, so excuse the repetition.  It is just that my Hifiman He-500 will be delivered any day from now, and I would like to have the amp ready to do it justice.

Thanks...

post #18 of 37
Thread Starter 
Quote:
Originally Posted by sahmen View Post
 

ben_r: A Fantastic job, which has left me in awe and gotten me intimidated at the same time. Now (since any process involving drilling a chassis or messing with the insides of an amp scares the bejeezus out of me), if I were to opt for the adapter option, can I add the attenuation by simply installing standard attenuators at the input points on the mini-x (DC-1 out ===>> Mini-x inputs)?  Also is the adapter in the pic available for sale, or did you make that yourself?  I have posted a similar question to you on the Emotivalounge, so excuse the repetition.  It is just that my Hifiman He-500 will be delivered any day from now, and I would like to have the amp ready to do it justice.

Thanks...


You could definitely put the attenuation resistors inline with the adapter cable I pictured and avoid messing with the amp itself entirely. I built the one shown in the review though I have seen others on eBay while not as nice looking still offer the same function. One with attenuation resistors in line would more than likely have to be a custom job that someone would have to build for you or you build it yourself.

post #19 of 37
Quote:
Originally Posted by ben_r_ View Post
 


You could definitely put the attenuation resistors inline with the adapter cable I pictured and avoid messing with the amp itself entirely. I built the one shown in the review though I have seen others on eBay while not as nice looking still offer the same function. One with attenuation resistors in line would more than likely have to be a custom job that someone would have to build for you or you build it yourself.

I have attempted to use a Sherbourn LDS 2 150 (https://www.audiogeneral.com/sherbourn/lds2_75_brochure.pdf), which I have purchased brand new, as a headphone amp, but the results are mixed:  The amp outputs sounds normally through line output into my He-500s, but that sound is understandably anemic (as line outputs sound are typically supposed to be, if I have understood my readings correctly).  I have been trying to use the speaker outputs on the amp for my headphones using the "Art HeadTAP" ("ArtCessories Headphone tap [http://www.sweetwater.com/store/media/ARTcs_Specs0303_HeadTAP.pdf]), but I am not able to get any sound to my headphones this way, for some reason that I cannot fathom.

 

The speaker outputs on the LDS 2150 accept only bare wire connections (instead of banana plugs, as the mini-x does), so in order to connect it to the Art HeadTAP, I use 20 awg speaker wires that are connected to two 1/4 pins (for L & R channels), which I then connect to the Art HeadTAP via a Radioshack  Y-Adaptor (http://www.ebay.com/itm/like/261437616347?lpid=82)..

 

When I power on the amplifier with the speaker output connections configured this way, the LDS (Load Detection system) LED flashes orange in order to indicate either that there is a problem with the speaker connections, or with the "impedance of the connected speakers" (but there are of course no connected speakers:  there is the Art Headtap, and if everything is working correctly, my headphones).

 

Again, my headphones works well with the amp in conjunction with the the Art Headtap, when connected to the Line outputs on the amp.  The problem I have outlined above occurs only when I am attempting to use the speaker outputs on the amp. I have spoken to customer support at both Emotiva and Art Headtap, and they both seem to think there is no reason why the speaker outs on the amp should not work well with the Art HeadTAP as desired, so I must be doing something the wrong way. If you have any suggestions or questions, kindly let me know.

post #20 of 37
Thread Starter 
Quote:
Originally Posted by sahmen View Post
 

I have attempted to use a Sherbourn LDS 2 150 (https://www.audiogeneral.com/sherbourn/lds2_75_brochure.pdf), which I have purchased brand new, as a headphone amp, but the results are mixed:  The amp outputs sounds normally through line output into my He-500s, but that sound is understandably anemic (as line outputs sound are typically supposed to be, if I have understood my readings correctly).  I have been trying to use the speaker outputs on the amp for my headphones using the "Art HeadTAP" ("ArtCessories Headphone tap [http://www.sweetwater.com/store/media/ARTcs_Specs0303_HeadTAP.pdf]), but I am not able to get any sound to my headphones this way, for some reason that I cannot fathom.

 

The speaker outputs on the LDS 2150 accept only bare wire connections (instead of banana plugs, as the mini-x does), so in order to connect it to the Art HeadTAP, I use 20 awg speaker wires that are connected to two 1/4 pins (for L & R channels), which I then connect to the Art HeadTAP via a Radioshack  Y-Adaptor (http://www.ebay.com/itm/like/261437616347?lpid=82)..

 

When I power on the amplifier with the speaker output connections configured this way, the LDS (Load Detection system) LED flashes orange in order to indicate either that there is a problem with the speaker connections, or with the "impedance of the connected speakers" (but there are of course no connected speakers:  there is the Art Headtap, and if everything is working correctly, my headphones).

 

Again, my headphones works well with the amp in conjunction with the the Art Headtap, when connected to the Line outputs on the amp.  The problem I have outlined above occurs only when I am attempting to use the speaker outputs on the amp. I have spoken to customer support at both Emotiva and Art Headtap, and they both seem to think there is no reason why the speaker outs on the amp should not work well with the Art HeadTAP as desired, so I must be doing something the wrong way. If you have any suggestions or questions, kindly let me know.


Without digging too far into it, my best guess is that the collections of cables and adapters your using, especially those that have their own internal resistors in them) are collectively "showing" a load to the amp that its not happy with and thats why your getting the LDS tripped with all that stuff connected. Just my best guess. That LDS setup theyve got in that amp (as well as other stuff depending on how it was designed) might not make it an optimal option for this type of headphone setup. If it were me Id sell it and pick up the Emotiva unless youre using the Sherbourn for something else.

post #21 of 37

Your intuition seems largely correct: I just spoke with the Art HeadTap folks, and they tell me that the headtap generates no impedance load at all... However, there is a microprocessor unit on the Sherbourn amp that requires a minimum impedance load of 3.0 before it would allow the amp to connect to the speakers. So that could explain the problem. Still I am wondering why the amp cannot see the 38 ohm impedance load of the He 500 when it is connected.  I am also wondering whether the amp would work if I were to attach actual speakers to it first. The Emotiva folks say the Mini-x does not have either the Load Detection System or the Microprocessor Unit functionalities, so I might just end up going with the Mini-x as you suggest.  A little sad, since the Sherbourn amp looks like one champ of a performer.

 

This is from the amp's manual:

 

"An embedded MPU (Micro Processing Unit) ensures that the amplifier cannot be ’overdriven’, and the LDS (Load Detection

System) ensures that all speaker connections must be good before the amplifier is connected to the speakers."

 

It seems that these two functionalities are just "too much of a good thing" for my present purposes.

post #22 of 37

I'm guessing there is a short between a + channel and ground somewhere in your wiring bundle. I don't think it's a lack of load. If you have a multimeter connect a set of headphones and check the resistance between L+ and ground and R+ and ground on the speaker end of your interface cables. One or both probably read 0 ohms.


Edited by robrob - 4/25/14 at 12:09pm
post #23 of 37
Quote:
Originally Posted by robrob View Post
 

I'm guessing there is a short between a + channel and ground somewhere in your wiring bundle. I don't think it's a lack of load. If you have a multimeter connect a set of headphones and check the resistance between L+ and ground and R+ and ground on the speaker end of your interface cables. One or both probably read 0 ohms.

Thanks Robrob: This is definitely interesting, but I do not have a multimeter, so I cannot perform the test you have described.  On the other hand, I have ordered a set of professionally made raw wire to 1/4" speaker cables, which are coming down the pipeline, so I should be able to test them out and find out whether the problem with the connection is my own faulty wiring.

post #24 of 37

Excellent work Ben R. I went ahead and did the mod pretty much identical to how you did with the same caps and all. Trouble is, I increased the noise floor to high for my liking as compared to just using the speaker taps. I started with just twisted copper braiding, and then re-routing the wiring. That didn't work.

 

Next I ordered a piece of Mogami shielded quad cable and that didn't solve it. Just too much noise entering the lines. So, I have a great looking jack on the front but the cable is disconnected internally.

 

The external taps with banana plugs does work just fine. I've been specifically using HE-500, K712 Pro, and my new Beyer T1 with the MiniX.......such an impressive pairing with all of them.

 

Quite a stellar amp easily besting my other fleet of amps. Thanks for the great post!

post #25 of 37
Thread Starter 
Quote:
Originally Posted by Grado77 View Post
 

Excellent work Ben R. I went ahead and did the mod pretty much identical to how you did with the same caps and all. Trouble is, I increased the noise floor to high for my liking as compared to just using the speaker taps. I started with just twisted copper braiding, and then re-routing the wiring. That didn't work.

 

Next I ordered a piece of Mogami shielded quad cable and that didn't solve it. Just too much noise entering the lines. So, I have a great looking jack on the front but the cable is disconnected internally.

 

The external taps with banana plugs does work just fine. I've been specifically using HE-500, K712 Pro, and my new Beyer T1 with the MiniX.......such an impressive pairing with all of them.

 

Quite a stellar amp easily besting my other fleet of amps. Thanks for the great post!


Wow that sucks. I have zero noise on mine through the headphone output until the volume is dang near all the way up. Sorry that didnt work out for you. You did use the resistors for attenuation right?

post #26 of 37

Is anyone here familiar with the Matrix M-Stage HPA-1 (2012 version with LM4562) amp's performance  with the He-500s?  I am specifically looking at this unit which is currently on e-bay.  If it is a good match I wouldn't mind purchasing it, but I would like to be sure of its performance with the He-500s in comparison with the Emotiva mini-x.  Here is the unit:

 

 

http://www.ebay.com/itm/Matrix-M-Stage-Headphone-Amplifier-LM4562-Ships-from-USA-/161307853328

 

Any helpful assessments would be highly welcome.

 

Thanks

post #27 of 37
Quote:
Originally Posted by ben_r_ View Post
 


Wow that sucks. I have zero noise on mine through the headphone output until the volume is dang near all the way up. Sorry that didnt work out for you. You did use the resistors for attenuation right?

 

Sorry for the long delay. I wrote "caps" in my prior post but meant resistors. I used the same exact resistors as you and soldered them the same way. Just wish I didn't have that noise problem.

post #28 of 37
Quote:
Originally Posted by robrob View Post
 

I'm guessing there is a short between a + channel and ground somewhere in your wiring bundle. I don't think it's a lack of load. If you have a multimeter connect a set of headphones and check the resistance between L+ and ground and R+ and ground on the speaker end of your interface cables. One or both probably read 0 ohms.

It turns out you were right... It was just a question of bad wiring. I got a well-made adaptor, and now the sherbourn LDS 2 150 is driving both my he-500, and my Senn hd600 quite swimmingly...  I do not even need the headphone tap I bought anymore, since I'm experiencing no noise at all.  Still since the Sherbourn seemed to be making the HD 600 shine a bit more colorfully than the He 500, I caved and went for the mini-x itself, which is also firing on all cylinders...  I have also quickly figured out that the question of amp/headphones compatibility is rather tricky and unpredictable in many ways.

 

Thanks to everyone who chirped in...

post #29 of 37

I just got a mini-X that I am using for speakers. Is there a way to do this mod so that when the headphones are not plugged in the audio will be routed to my speakers and once headphones are plugged in the audio will be routed to the headphones only? 

 

Or this this mod only really valid if you are using the mini-X for headphones only?

post #30 of 37
Thread Starter 
Quote:
Originally Posted by jasonb View Post
 

I just got a mini-X that I am using for speakers. Is there a way to do this mod so that when the headphones are not plugged in the audio will be routed to my speakers and once headphones are plugged in the audio will be routed to the headphones only? 

 

Or this this mod only really valid if you are using the mini-X for headphones only?


Well the way I built it was more for just using it as a dedicated headphone amp. However I would imagine through some creative use of some sort of switching TRS jack you could accomplish what you are describing. Most people doing that from what I have read use an external switching box to go back and forth between the two outputs. Personally Id want it all self contained though.

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