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Audio GD SA-31 head amp/ preamp . A powerfull Head Amp with Diamond Difference design . - Page 23

post #331 of 433
Manatwork, I refer to the synergy, not the ability to drive. How well do they synergize, both being warmish.

Clemmaster, I can't decide whether or not I'll go balanced with the hd650 over the next 2-3 yrs. I also have an RS1i which I'm sure I'll never balance, if that helps.
post #332 of 433

I have just bought a brand new Audio GD SA-31 (not SA-31SE) Headphone amplifier at a bargain price.  After burning it in for more than 50 hrs I carried out an audition with three of my headphones, i.e.  Audeze LCD-X (with Toxic cable Silver Widow),  Senn HD800 (with Toxic cable Black Widow) and Hifiman HE-500 (with Toxic cable Black Widow).  I was disappointed by the overall performance of this SA-31 as it is not ear friendly when compared with my other three headphone amplifiers, i.e. Yulong A18; Fidelity Audio HPA-200SE and Hifiman EF-5 (modded – see this link:  http://www.head-fi.org/t/711004/hifiman-ef-5-headphone-amplifier-mods-and-rolls).

 

From my knowledge I have the feeling that it should not be the fault of the circuit design or the components being used.  I suspect that the output impedance of SA-31 might be too low as I found it did not perform well with high impedance headphones.  The music was laid back and though it appeared to have more space I found that it was unreal and artificial. The music was not at all three dimensional.

 

With that in mind I inserted two 33 ohm resistors in series to the L and R of the headphone output socket with a view to adjusting the output impedance.  Well, as I have expected the result is really excellent.  For best performance I put the gain to High and it performs much better than using Low gain setting.  The music is cleaner, with better sound staging and with better musical separation.  The artificial space has disappeared.  I have tried Warm 1 and Warm 2 settings but IMHO I still prefer without any warmth being added.  Now the SA-31 performs almost the same as Yulong A-18 and Fidelity Audio HPA-200SE which cost almost double the price.

 

I have uploaded two photos to show how to add the two 33 ohm resistors for reference.  If you have tried it out you may wish to confirm if my finding is correct.  

 

post #333 of 433
Quote:
"From my knowledge I have the feeling that it should not be the fault of the circuit design or the components being used.  I suspect that the output impedance of SA-31 might be too low as I found it did not perform well with high impedance headphones.  The music was laid back and though it appeared to have more space I found that it was unreal and artificial."

 

1. Both of your Planar-Magnetics are Low-Impedance. So, exactly what Headphones are you referring to? 

 

2: A low impedance output should be beneficial to Any Headphone, not just low impedance types. Inserting a 33 Ohm resistor into the signal should not- theoretically at least- bring any improvements to sound quality. And it certainly makes no sense that it should impart a somewhat Laid-back quality to the music. In fact it should be the exact opposite...

 

Best,

 

Leonel


Edited by rocksteady65 - 5/5/14 at 9:57pm
post #334 of 433

In my experience the SA-31 needs plenty of burn-in, more so than any other amp, DAC or headphone I've owned. Perhaps the resistors are helping that process along (in addition to changing the output impedance and how the amp interacts with headphones)?


Edited by Utopia - 5/5/14 at 1:39pm
post #335 of 433
Quote:
Originally Posted by rocksteady65 View Post
 

 

1. Both of your Planar-Magnetics are Low-Impedance. So to what exact Headphones are you referring to? 

 

 

HD-800.

 

Irrespective of what the theory are, my ears told me that there are actual improvements, in particular, to HD-800 after adding the 33 ohm.

post #336 of 433
Quote:
Originally Posted by inter voice View Post
 

HD-800.

 

Irrespective of what the theory are, my ears told me that there are actual improvements, in particular, to HD-800 after adding the 33 ohm.

There are similar opinions for 43 ohm of the Sennheiser HDVD800, e.g.:

 

http://www.head-fi.org/t/605444/sennheiser-hdvd800-headphone-amplifier/1830#post_10174212

post #337 of 433

I have asked Kingwa on the same question and here is his reply:

 

"Series the resistors will increase the output impedance, maybe the bass is less   cause the high and mid become more than bass. But in the design, the SA31 is except (may be a typo and should be "expected") sound warm and smooth , not neutral." 

 

That might be the reason of having better sound as I can hear clearer mid range and highs, but the bass has not reduced though.

 

IMHO the SA-31 sounds better to my ears with the resistors put in series but that could be my preference only. 


Edited by inter voice - 5/6/14 at 2:38am
post #338 of 433

Strange that it is the low impedance causing the poor sound with the HD800's because I love my Master-6 ( 1ohm output impedance) with the HD800's.

 

Interesting solution though.


Edited by nigeljames - 5/6/14 at 2:40am
post #339 of 433
Quote:
Originally Posted by nigeljames View Post
 

Strange that it is the low impedance causing the poor sound with the HD800's because I love my Master-6 ( 1ohm output impedance) with the HD800's.

 

Interesting solution though.

Well I am not saying SA-31 is not good.  When I first heard the music from the SA-31 it was quite alright to my ears.  As I have other three headphone amplifiers I have the benefit of A/B testing them one by one in minute details using three different headphones, i.e. HD-800; LCD-X and HE-500.  My prefer headphone amplifier in its order is Yulong A18; Fidelity Audio HPA-200SE; Hifiman EF-5(modded) and then SA-31.  BUT after adding the series resistor the SQ of SA-31 has changed and now it almost performs the same as Yulong A18.  As to the headphones I prefer HD-800 for classical music while LCD-X for jazz and vocals.   HE-500 is not to my liking.

As I mentioned before it is only my personal preference.


Edited by inter voice - 5/6/14 at 3:26am
post #340 of 433
Quote:
Originally Posted by inter voice View Post
 

Well I am not saying SA-31 is not good.  When I first heard the music from the SA-31 it was quite alright to my ears.  As I have other three headphone amplifiers I have the benefit of A/B testing them one by one in minute details using three different headphones, i.e. HD-800; LCD-X and HE-500.  My prefer headphone amplifier in its order is Yulong A18; Fidelity Audio HPA-200SE; Hifiman EF-5(modded) and then SA-31.  BUT after adding the series resistor the SQ of SA-31 has changed and now it almost performs the same as Yulong A18.  As to the headphones I prefer HD-800 for classical music while LCD-X for jazz and vocals.   HE-500 is not to my liking.

As I mentioned before it is only my personal preference.

That is an interesting finding given most people find they prefer the HD800 with a lower output impedance.  However, as King-wa stated, the artificial sense of space is by design.  I had the HD800 and the SA-31 before and felt it was an odd match with it as well but not necessarily bad though.  I moved to a Burson Soloist after that, and preferred it with the HD800's.  

 

If you have a chance to listen to the Soloist, you may like it based on what you've said.  I felt the Soloist specifically had a more realistic presentation of soundstage and imaging of instruments.

post #341 of 433
Quote:
Originally Posted by Clemmaster View Post
 

 

Do you have any plans on going balanced with these?

If yes -> NFB-6: less warm, should work better with the dark 650s.

If no -> SA-31: works better single ended, no question.

 

Note: I own the SA-31 and used to own the NFB-27 whose headphone amp section is of the NFB series (somewhere between the NFB-6 and Master-5/6/8).

I consistently favored the SA-31 with all my headphones. This includes the Mad Dogs 3.0 single ended, which is the closest (in sound signature) to the HD-650. Even though it should have worked better with the brighter NFB-27, it wasn't the case. The SA-31 is that good.

 

Edit: forgot to say that all my headphones = Hifiman HE-500, HE-4, HE-5LE, Fostex TH-600, AKG Q-701. They all are on the bright(ish) side of the force.

 


I might go balanced, but I can't stomach the cost of balanced HD 650 cables except these: http://www.amazon.com/Upgrade-Version-balance-ZY-002-2-5M/dp/B00A2QJLY8/ref=sr_1_1?ie=UTF8&qid=1399695912&sr=8-1&keywords=sennheiser+HD650+xlr+cables

What do you think?

 

Also, I have an RS1i, which would be harder to balance, given that I'd need to ship them to the person doing the mod. Also this leaves me less flexibility if I'm travelling, since I couldn't lug my balanced rig with me.

 

Kingwa only says the NFB-6 is slightly more neutral (note the newer version is a bit warmer based on user feedback), while the SA31SE is more musical. My only worry is they will make the HD650's bass bloat more, and then I can no longer use it for metal/rock etc. Any comments on that?

post #342 of 433
Quote:
Originally Posted by Vandal View Post
 

 


I might go balanced, but I can't stomach the cost of balanced HD 650 cables except these: http://www.amazon.com/Upgrade-Version-balance-ZY-002-2-5M/dp/B00A2QJLY8/ref=sr_1_1?ie=UTF8&qid=1399695912&sr=8-1&keywords=sennheiser+HD650+xlr+cables

What do you think?

 

Also, I have an RS1i, which would be harder to balance, given that I'd need to ship them to the person doing the mod. Also this leaves me less flexibility if I'm travelling, since I couldn't lug my balanced rig with me.

 

Kingwa only says the NFB-6 is slightly more neutral (note the newer version is a bit warmer based on user feedback), while the SA31SE is more musical. My only worry is they will make the HD650's bass bloat more, and then I can no longer use it for metal/rock etc. Any comments on that?

I am sure you're aware that you can reterminate both those headphones for very little (under $20 shipped)- they are both 4 wire cables (Grado is more than 4 but easy).

It is easier than you think unless you feel it has to be magic wire rather than stock.

SA31 will no add bloat to anything, only a bit more warm than neutral from my experience.

post #343 of 433
Quote:
Originally Posted by tim3320070 View Post
 

I am sure you're aware that you can reterminate both those headphones for very little (under $20 shipped)- they are both 4 wire cables (Grado is more than 4 but easy).

It is easier than you think unless you feel it has to be magic wire rather than stock.

SA31 will no add bloat to anything, only a bit more warm than neutral from my experience.

 

Where can I get them reterminated for that price? Would be wonderful if you could let me know.

post #344 of 433
By your own hand with solder gun and solder and a little research.
post #345 of 433
Quote:
Originally Posted by Vandal View Post

Where can I get them reterminated for that price? Would be wonderful if you could let me know.

See how to DIY it here.
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