[borrego]

  Thank you for the above post. The information is very useful but it is things like this that may make me return my SA-31SE when I receive it this week.
I was really excited for my new amp but I am now a little apprehensive. I am rubbish with all kinds of DIY and I prefer things to work as intended from the start.
 
Has anybody else had a similar experience?
 
Cheers.

 
If you do not find any problem with your SA-31 then there is absolutely no need to worry. Just enjoy the amp.
 
I am a DIYer and knowing the SA-31 has a really good circuit design just makes me want to make sure everything is rightly done so I can have it reaching its maximum potential. I actually considered buying the SA-31 circuit board from audio-gd's DIY shop and built my own SA-31 (http://item.taobao.com/item.htm?spm=a1z0d.6639537.1997196601.32.oqgKBR&id=520377979177). So I did do some research on the SA-31 circuit design and key assembling steps.

 

[Robert777]

No. It is an awesome amp. No mods needed imo

 
 

  Yep. It's great. After all these years I still have mine and can't resolve to selling it...

Thank you. I am excited again. 
 
Cheers.

 

[Robert777]

I received this amplifier a few days ago and I am very impressed.
I purchased the last unit from a dealer in France and it also come with the remote control as standard.
It also came with some circuit boards in bubble wrap which I have no idea what to do with.
I am using my HP-A8C as a DAC, connected to the SA-31SE, feeding my Fostex TH900 and TH500rp headphones.
 
I would say the Audio-gd amp adds a clarity, separation, detail and effortlessness to the sound.
The improvements are only subtle, as I think they are with most things at this level, but they are welcomed.
I now find myself getting drawn into the music much more than when running directly from the HP-A8C, which I still think is a beautiful product.
The Audio-gd has me head banging, toe tapping and smiling before realising.
 
Highly recommended.
 
Cheers.

 

[inter voice]

  A FIX SHOULD BE DONE FOR EVERY SA-31!!!
 
I have owned the SA-31SE for a few days. While I like its sound, I do find a few problems with my unit:
 
1. The amp takes a long time to "warm up": I find it needs up to 2 hours to have its sound signature to settle down. And it is with my EPA-007 stacking over it
2. Even after warm up, it sounds lean. The bass and overall dynamic lack quite a bit
 
I know the SA-31 circuit is base on the discontinued/earlier audio-gd SA100/SA100i/SA200 integration amp. I recall reading something before from audio-gd's Chinese DIY forum saying there is usage of temperature compensation transistors in the SA300 poweramp circuit design (the SA300 is the balanced version of the SA100/SA200). The temperature compensation transistors should be placed/pressed to the headsink shared by the output power transistor.
 
 
Thus I suspect the problems I have the SA-31 is because of improper contact between the temperature compensation transistor and the aluminum back plate heatsink shared with the output power transistors.
 
 
Results after the fix:
1. The amp now only needs about 20mins to "warm up" and have the sound signature stabilized.
2. More bass, and more dynamic sounding signature. My SA-31 finally sounds "properly".
 
I strongly recommend all SA-31 owners to apply the fix.

 
Thank you for the finding and I have done similar mods to my SA-31 using metal clips and hard plastic pressing strips. Silver contact greese is applied between the 2 transistors and the heat sink to ensure best thermal transmissions.  It only took me 20 minutes to complete this simple task. I can confirm that now the SA-31 stabilizes much quicker with this mod being in placed.  Thanks.

 

[heybaroo]

I have to thank this thread - I've moved into head fi from regular hi fi as small spaces and small children have dictated drastic changes. I've been trying to replace a Cayin tube amp matched to Dynaudio bookshelves for a fraction of the cost and this thread led me to the SA-31. I found one on Gumtree, did a lot of research, and this thread was the tipping point. Thanks very much! I started out with my Jaycar Digitech/Brainwavz HM5/Fischer Audio FA-003 clones and thanks to another thread moved on to the Fischer FA-011s. They need some proper amping which this has in spades. I had the jumpers in for the FA-003 clones but with the FA-011s the jumpers are out and more detail is in as they are quite v-shaped in signature. Unbelievable combination for under AUD600! I'm using a Fiio X1 as the source with flac and some some lossy files and have almost approached my previous $5,000 setup soundwise...has anyone else tried this combination? I know both are a bit long in the tooth but I'm an analogue man at heart...
 
Really good preamp as well - very, very impressive for the price point.
 
Anyway, thanks again for helping me find this amp!

 

[conquerator2]

I still scratch my head as to why this baby was ever discontinued. I keep looking for a similarly priced amplifier to this day to outperform it, but it isn't easy 

 

[heybaroo]

I still scratch my head as to why this baby was ever discontinued. I keep looking for a similarly priced amplifier to this day to outperform it, but it isn't easy 

Hear hear... I'm thinking about upgrading my headphones (of course) and an going to hang on to the SA-31 as I think it should drive just about anything well... I've started doing a bit of research on the HE-6 and just read your review on it from a few years ago. How do you think the SA-31 would go driving it? On paper, it should be hope but I've read about people using 160W amps on them. Of course this is into 8 ohms and the SA-31 does 10W into 40 ohms... just curious.

 

[heybaroo]

Oops, fine,not hope...

 

[conquerator2]

Hear hear... I'm thinking about upgrading my headphones (of course) and an going to hang on to the SA-31 as I think it should drive just about anything well... I've started doing a bit of research on the HE-6 and just read your review on it from a few years ago. How do you think the SA-31 would go driving it? On paper, it should be hope but I've read about people using 160W amps on them. Of course this is into 8 ohms and the SA-31 does 10W into 40 ohms... just curious.

You're right, it technically should suffice.
But with the HE6, you are better off with speaker amplifiers. They provide the most power and the HE6 really likes that.
Again, can't know until you try and you can always get a cheap vintage speaker amp to suit them 

Regardless, I would exercise caution when buying the HE6. It has the potential to reward you, but you have to commit it.
I wouldn't buy the HE6 again for many reasons, power hungry being just one of them, though there are many happy owners with testimonials of brilliance 

 

[Clemmaster]

The SA-31 is fine for any Hifiman planar except the HE-6. It sounds shrill with it.
 
It's the only headphone that I preferred on the NFB-27 built-in amp, because it is more beefy (less "powerful" on paper, but it has a beefier power supply). For any other Hifiman, the SA-31 was my go-to amp.

 

[conquerator2]

It's been consistently my  go-to amp for every headphone. It's not dead-flat neutral, it has a certain character, or coloration that won't suit every headphone but it's a damn good and versatile amp that powers virtually anything. There's nothing quite like it on the market today IMO 

Dunno what I'll buy when it breaks 

 

[borrego]

Hear hear... I'm thinking about upgrading my headphones (of course) and an going to hang on to the SA-31 as I think it should drive just about anything well... I've started doing a bit of research on the HE-6 and just read your review on it from a few years ago. How do you think the SA-31 would go driving it? On paper, it should be hope but I've read about people using 160W amps on them. Of course this is into 8 ohms and the SA-31 does 10W into 40 ohms... just curious.

 
The circuit design of the SA-31 originated from the SA-100, which was an integrated speaker amp from audio-gd. So you can be sure the SA-31 has enough power to drive the HE-6.
 
The SA-31 sounds "Shrill" not because it lacks power, but because its temperature compensation transistors were not touching the heatsink plate properly. See my "laundry clip" mod a few pages back for the fix.
 
With the "laundry clip" fix in place, the SA-31 sounds like a good neutral, powerful tube amp.

 

[heybaroo]

Thanks folks, all of the above has just reinforced how happy am with this amp. It should pair up quite well and drive almost anything I am likely to own in the next several years, perhaps even the HE-6 with borrego's mod. Amazing purchase for AUD250. I have read that it has a real synergy with the HE-500, and I am very keen to hear a HD-650 with it as well...

 

[Pharmaboy]

Don't know if anyone is still following this thread, but I just have to weigh in on the Audio GD SA-31SE.
 
I bought mine from a Head-Fi bud about 6 weeks ago, around the same time I got a new ZMF Ori. Those are incredible headphones that do everything rather differently & better than I'm used to. They sound spectacularly good through the SA-31SE. But oddly enough, the Ori made it harder to figure out what this amp can do (studying 2 unknown variables is harder than just one).
 
I've been trying the Ori on other HP amps in house, and can confirm it's an amazing headphone, regardless of source. But it was only tonight that I finally listened to other headphones on the SA-31SE--2 inexpensive Chinese closed-back designs I've had for a number of months...I know their sound well, or thought I did.
 
Listening to one of them now on the SA-31SE, and it's striking to hear this inexpensive-but-good headphone scale right up with the SA-31SE. For the first time with the Marantz MPH-2, I'm hearing richly detailed midrange, full of subtle positional nuances and great finesse in the sound of percussion. It sounds so good. Got the same basic result with the Yenona Adapter Free DJ headphones...they both sound like themselves, but greatly improved. I'll try the Philips Fidelio X2's tomorrow.
 
Suddenly it's very clear that the SA-31SE is absolutely the equal of the Ori. Each produces great note separation, finesse, and detail, top to bottom, with zero brightness or "sheen." I have other amps that hit harder & a touch lower in the bass, and have somewhat more impactful dynamics overall. But I've never heard another amp even come close to the SA-31SE in the subtle sonic areas of soundstaging and microdynamics. For example, the SA-31SE is easily the best amp I've ever heard for percussion...all kinds of percussion.
 
I am so lucky to have found this amp. BTW, my DAC is the equally superb Audio GD NOS 19. I'm guessing the SA-31SE has unusual synergy with this DAC.
 
(life is good!)

 

[Mike Nee]

   
I've been trying the Ori on other HP amps in house, and can confirm it's an amazing headphone, regardless of source. But it was only tonight that I finally listened to other headphones on the SA-31SE--2 inexpensive Chinese closed-back designs I've had for a number of months...I know their sound well, or thought I did.
 
(...)
 
I am so lucky to have found this amp. BTW, my DAC is the equally superb Audio GD NOS 19. I'm guessing the SA-31SE has unusual synergy with this DAC.
 
(life is good!)

 
Hi, have you heard theirs NFB-1AMP? Or maybe you know of any comparison between SA31SE and NFB-1AMP?
 
On their main website Audio GD specifies four different USB interfaces:
a) USB-32
b) Amanero combo 384
c) Xmos U8
d) Xmos U208 (since Nov 2016)
Is there any consensus regarding the above in the meaning of "best audio" performance?