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HE-500, LCD2, D5000, DT770, SR80, on a speaker amp (Emotiva mini-X A-100) Project - Page 203

post #3031 of 3607
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?

Adding a resistor in parallel is almost like adding another speaker at the same outputs, so you are not adding any noise just additional load at the speaker outputs in this scenario.

post #3032 of 3607
Quote:
Originally Posted by john57 View Post

Adding a resistor in parallel is almost like adding another speaker at the same outputs, so you are not adding any noise just additional load at the speaker outputs in this scenario.

If the amp WA so a push pull topology and I was trying to keep the setup balanced would it be a different answer? (curious noob)
Thanks
post #3033 of 3607

Would be the same, since the output terminal is still the same (4 banana jacks) for both single ended and balanced amplifier. 

post #3034 of 3607
Quote:
Originally Posted by Drsparis View Post


If the amp WA so a push pull topology and I was trying to keep the setup balanced would it be a different answer? (curious noob)
Thanks

The answer remains the same. You just have to be careful when using amps that do not use common ground is the exception.


Edited by john57 - 1/13/14 at 1:27pm
post #3035 of 3607
Quote:
Originally Posted by manbear View Post
 
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?

The Shure 940 and the Fostex T50 shows this effect of adding resistors in series in different ways. The Shure show more effect with the bass and the Fostex more with the treble which surprised me. I am using the pure audio mode on the TX8050. One of my reference tracks test for bass response and bass clarity is Also sprach Zarathustra. The Timpani should be very crisp and the reverberation should make it sound like playing in a large hall not in a small room.

post #3036 of 3607
Quote:
Originally Posted by LoveKnight View Post

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.
No noise or hiss. I am sure Brian did not add any resistor to the taps but I'll double-check.
post #3037 of 3607
Quote:
Originally Posted by robrob View Post
 

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).

 

Warning: Spoiler! (Click to show)
RobinetteBoxPanels.jpg

 

 

Looks nice, Rob. I have found a shop where I can get the Mills MRA12 for parallel only setup. I am thinking about modifying my HE adapter with your 6+2 network for 12dB attenuation. Which resistors would you suggest from this webshop?

http://www.hificollective.co.uk/catalog/-c-61_62.html

post #3038 of 3607
Quote:
Originally Posted by Anda View Post
 

 

Looks nice, Rob. I have found a shop where I can get the Mills MRA12 for parallel only setup. I am thinking about modifying my HE adapter with your 6+2 network for 12dB attenuation. Which resistors would you suggest from this webshop?

http://www.hificollective.co.uk/catalog/-c-61_62.html

 

I am not a hi-fi parts aficionado so I only have experience with Vishay-Dale and Mills resistors for critical audio circuits. I'd go with whatever brand you like of 6ohm 5watt 1% wirewound and 2ohm 3watt 1% wirewound resistors. 

post #3039 of 3607
Quote:
Originally Posted by robrob View Post
 

I am not a hi-fi parts aficionado so I only have experience with Vishay-Dale and Mills resistors for critical audio circuits. I'd go with whatever brand you like of 6ohm 5watt 1% wirewound and 2ohm 3watt 1% wirewound resistors. 

 

I found some cheaper Jantzen resistors. They make 2ohm and 6.2ohm, both 5W wirewound. I guess that would be fine right?

post #3040 of 3607
Quote:
Originally Posted by john57 View Post
 

The Shure 940 and the Fostex T50 shows this effect of adding resistors in series in different ways. The Shure show more effect with the bass and the Fostex more with the treble which surprised me. I am using the pure audio mode on the TX8050. One of my reference tracks test for bass response and bass clarity is Also sprach Zarathustra. The Timpani should be very crisp and the reverberation should make it sound like playing in a large hall not in a small room.


That's interesting. My previous amp was a tube amp with rather warm bass, so coming from that reference point I've been pretty impressed with the bass clarity of the Emotiva. Perhaps I should do a more critical comparison with and without resistors. So far, I've found that losing the noise floor is worth any trade-offs of using resistors. 

post #3041 of 3607
Quote:
Originally Posted by Anda View Post
 

 

I found some cheaper Jantzen resistors. They make 2ohm and 6.2ohm, both 5W wirewound. I guess that would be fine right?

As long as their tolerance is 1% or less. You want good matching resistors so you don't end up with a volume difference between channels (although 5% of 6 ohms = crazy low resistance difference).

post #3042 of 3607

Great. Thanks! :beerchug:

 

It's these: http://www.jantzen-audio.com/superes-resistors/

For members in EU: You can get them cheap from http://www.audiohobby.eu/ or http://www.europe-audio.com/ :) 

post #3043 of 3607

If you don't want to spend the cash on 1% resistors but have a multimeter on hand, just get a few 5% and match them yourself.

post #3044 of 3607
Quote:
Originally Posted by Armaegis View Post
 

If you don't want to spend the cash on 1% resistors but have a multimeter on hand, just get a few 5% and match them yourself.

 

+1 Just measure them with a multimeter. Good chance you'll get a pair that match for less money.

post #3045 of 3607
Quote:
Originally Posted by manbear View Post
 


That's interesting. My previous amp was a tube amp with rather warm bass, so coming from that reference point I've been pretty impressed with the bass clarity of the Emotiva. Perhaps I should do a more critical comparison with and without resistors. So far, I've found that losing the noise floor is worth any trade-offs of using resistors. 

Originally I was going to get another DAC but I looked at the two channel receivers with digital inputs and it made more sense from a cost and features perspective.  First I had the Onkyo A-5VL but the bass from the speaker taps was quite muddy to my ears and no where as clear with the Mini-X I return it. Then I decided to get the Onkyo TX8050 but cancel the order since Amazon lowered the price at $199 at 4:30am for a brief time. I just got lucky and the TX850 has very good sound quality and a low noise floor to boot. The TX8050 has two TI DAC's depending on which digital input I am using. The TX8050 is a 2011 model still on sale and Onkyo just came out with the eighth firmware bug fix for it. By using DLNA Gizmo from J.River I have all the graphics color display to control the TX8050 remotely as desired. The TX8050 was cheaper to get than the XDA-2. For now I have the Mini-X connected to it by using the TX8050 pre-outs. Surprising I am also getting a lower noise floor from the Mini-X as well. The TX8050 has a more fuller mid-range sweeter highs especially with the violins. The  Mini-X has  thinner sounds and the violins sounded a bit more steely. The differences are not huge. I might sell the Mini-X after I finished the evaluation and setup of the TX8050. As far tube amps goes I still enjoy my Little Dot VI+

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