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HE-500, LCD2, D5000, DT770, SR80, on a speaker amp (Emotiva mini-X A-100) Project - Page 202

post #3016 of 3639

Newbie here. Schiit Gungir --> Emotiva mini-X --> LCD-XC = beautiful music. Got my Emotiva today and now have the Gungnir hooked SE to the amp as well as balanced to the Mjolinir. Using the speaker tap cables made by Brian at BTG (great job Brian) and the overall sound is awesome and I am running the mini-X at less than 9 on the volume pot. Got a couple of holidays coming up so looking to do some A/B with the Mjolnir as well.

post #3017 of 3639

Did you hear any strange noise floor, hiss or something like that? I just ordered an Alpha Dog and could consider a powerful speaker amp as Emotiva Mini-X A-100 but in this thread look like over 50% people get hiss, noise ... Did Brian at BTG add some resistor into your speaker taps? Thanks.

post #3018 of 3639
Quote:
Originally Posted by punit View Post
 

I have a very basic electrical / engineering knowledge, so will be grateful if anyone can help me with the following. I plan to try my HE 500's from the 8 ohm speaker taps of the Cayin audio AT70 Tube integrated amp. I will use the Hifiman HE adapter & balanced HP cable. The links for all are as below :

 

 

http://www.cayinusa.com/Product_Name.asp?Category=26:56:40&types=1

 

http://head-direct.com/Products/?act=detail&id=104

 

http://head-direct.com/Products/?act=detail&id=146

 

Will there be any issues that i should watch out for or things should go fine ?

 

Thanks

 

You will be fine using the HE-Adapter box with your tube amp, although this if from your link, "HE-Adapter is not for any high or average efficiency headphones, such as HE-300 and HE-500."

 

The HE-Adapter is not an optimal design but does ok with 8.6ohms of effective speaker load and 4.4dB of attenuation when used with your HE-500s. You'd probably get better sound quality with just two 11ohm, 10watt wirewound resistors connected across the amp's + and - speaker posts. No soldering required, just bend the resistors' leads to make the connection. This will give your amp around 8 ohms of speaker load and no attenuation. Try this first if you can get another headphone adapter without a resistor network like the HE-Adapter. If you hear noise floor hiss or have too little volume knob movement you can add attenuation resistors in the two + headphone wires or better yet build a "preferred headphone resistor network" with 6 and 2ohm resistors for 12.4dB of attenuation or 7 and 1 ohm for 18dB.

 

P.S. Nice amp.


Edited by robrob - 1/13/14 at 7:07am
post #3019 of 3639

@robrob 

Can you draw a diagram of how to connect the two resistor per channel network to the amp terminals without soldering? I imagine you'd need to connect the headphone adapter with banana plugs, and the resistors in the bare wire part of the posts?

post #3020 of 3639
Quote:
 Can you draw a diagram of how to connect the two resistor per channel network to the amp terminals without soldering? I imagine you'd need to connect the headphone adapter with banana plugs, and the resistors in the bare wire part of the posts?

 

Someone posted a pic of that setup in this thread some time ago. Just bend the legs of the resistor so one leg drops into the bare wire hole in the amp's black speaker binding post, and the other leg drops into the hole in the red speaker binding post. Do the same for the other stereo channel. Then connect the headphone adapter using either the same bare wire hole or banana jacks.

post #3021 of 3639

Here's a pic from my website showing the 10ohm, 10watt, 1%, wirewound resistors across the speaker binding posts of the Robinette Box (11ohm resistor I linked to above would actually be slightly better than this 10ohm).

 

RobinetteBoxPanels.jpg

Speaker posts and 'Network Bypass Switch' on left. Right side is the front panel with 4-Pin XLR, 1/4" and 1/8" TRS headphone jacks, 'Amp Mode Switch' and oscilloscope output BNC jacks.

 

With the resistor network bypassed (switch up) and the external resistors connected this way you can connect to a tube speaker amp with the correct effective speaker load but no attenuation (which may or may not sound better than when using the standard L-pad 'preferred' attenuation network inside the box).


Edited by robrob - 1/13/14 at 10:12am
post #3022 of 3639
Ah, you are just talking about one parallel resistor per channel. At first I thought you meant your "preferred" network from the previous page. Is it possible to do that one without soldering?

I was thinking maybe this:

put R2 into each positive terminal's binding post
Put both R3 into the negative terminal between the two positive terminals, along with the ground wire (this is the one I am least sure about)
Use alligator clips on each channel's positive wire to clamp on R2 and one of the R3s (both sides)

Would that work?

EDIT: Like this


Edited by manbear - 1/13/14 at 10:08am
post #3023 of 3639
Quote:
Originally Posted by manbear View Post

Ah, you are just talking about one parallel resistor per channel. At first I thought you meant your "preferred" network from the previous page. Is it possible to do that one without soldering?

I was thinking maybe this:

put R2 into each positive terminal's binding post
Put both R3 into the negative terminal between the two positive terminals, along with the ground wire (this is the one I am least sure about)
Use alligator clips on each channel's positive wire to clamp on R2 and one of the R3s (both sides)

Would that work?

EDIT: Like this

 

Yes, that will work but I recommend you try the single parallel resistor first because you only need the resistor network if you need attenuation to solve hiss or volume knob problems.

post #3024 of 3639
Right now, I am just using series resistors on the positive terminals. It works fine, but I'm just curious. Would you say there is no sonic reason to try this preferred network if I am happy with hiss and volume knob travel currently? I am using the Emotiva BTW.
post #3025 of 3639
Quote:
Originally Posted by manbear View Post

Right now, I am just using series resistors on the positive terminals. It works fine, but I'm just curious. Would you say there is no sonic reason to try this preferred network if I am happy with hiss and volume knob travel currently? I am using the Emotiva BTW.

Most would argue the less you alter the signal the better but there is the possibility of moving toward your amp's 'sweet spot' volume level by adding some attenuation. The advantage of using the 'preferred network' is it adds attenuation while giving your amp its expected 8ohms of speaker load which may or may not improve the sound quality.


Edited by robrob - 1/13/14 at 10:31am
post #3026 of 3639

I can't seem to understand the difference of the preferred resistor network vs the straight attenuation. I understand that the speaker load will not be matched to what the Amp desires but wouldn't the crossing of the + and - terminals cause some interference? I guess since it is a single ended design it doesn't matter? 

 

Would there be a difference in SQ if both ways had the same attenuation?

post #3027 of 3639
Quote:
Originally Posted by robrob View Post
 

Most would argue the less you alter the signal the better but there is the possibility of moving toward your amp's 'sweet spot' volume level by adding some attenuation. The advantage of using the 'preferred network' is it adds attenuation while giving your amp its expected 8ohms of speaker load which may or may not improve the sound quality.

Thanks for answering my question before I ask it :P

post #3028 of 3639
Quote:
Originally Posted by Drsparis View Post
 

I can't seem to understand the difference of the preferred resistor network vs the straight attenuation. I understand that the speaker load will not be matched to what the Amp desires but wouldn't the crossing of the + and - terminals cause some interference? I guess since it is a single ended design it doesn't matter? 

 

Would there be a difference in SQ if both ways had the same attenuation?

 

It depends on the amp, the headphones and how good your ears are. The parallel resistor across the speaker terminals doesn't cause interference but it's possible it could alter the sound quality. This stuff is subjective so it's best to try different setups and let YOUR ears be the guide.


Edited by robrob - 1/13/14 at 10:51am
post #3029 of 3639

I noticed that on my Onkyo TX8050 network receiver which has resistors in series 390 ohms from the speaker taps to the headphone output jack on the front. I noticed that the bass is tiny bit softer(less tight) from the headphone output as compare to the headphones directly from the speaker taps. It may seems that adding resistors just in series may decrease the damping factor. Adding resistors in parallel might have less impact of the bass "tightness" and I would have to experiment a bit and see if I can hear what impact on sound is. I think that alot depends on the headphone and amps used.

post #3030 of 3639
Quote:
Originally Posted by john57 View Post

I noticed that on my Onkyo TX8050 network receiver which has resistors in series 390 ohms from the speaker taps to the headphone output jack on the front. I noticed that the bass is tiny bit softer(less tight) from the headphone output as compare to the headphones directly from the speaker taps. It may seems that adding resistors just in series may decrease the damping factor. Adding resistors in parallel might have less impact of the bass "tightness" and I would have to experiment a bit and see if I can hear what impact on sound is. I think that alot depends on the headphone and amps used.


 



The resistors definitely affect the damping factor, but this should only cause an audible change for dynamic headphones. What headphones are you using when you make this observation?
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