Singxer SA-1 Review (Balanced Headphone Amp)

[Celty]

Hijack / thread pollution alert! Please take cover immediately for your own safety!

 

[Highvolt60]

More details, from Singxer's Taobao：

At the front stage output, the single-ended impedance is 22.5 ohms, and the balanced impedance is 45 ohms.

I think you mean 22.5k and 45k ohms input impedance !

 

[amirm]

No more discussion of the parts suppliers, etc. This is a review thread. Sidetracks are allowed for a post or two, not beyond.

 

[Highvolt60]

In fact, I am the designer of SA-1 from Singxer.
I am very happy that everyone is interested in SA1.
The design ideas of SA1 are different from other manufacturers;
Balance the input and output for maximum performance.
SA1 is based on a fully balanced design, from input to volume control (quadruple ALPS RK27 volume potentiometer), 4 identical amplifier circuits.
The potentiometer is manually selected to ensure channel balance at low volume.
Other manufacturers may convert the balanced input to single-ended, and the volume potentiometer just uses a clean 2-connect potentiometer.

thanks

Tom, can you provide me with details on the jumpers to bypass the AC input coupling caps ?
My source (Oppo UDP-205) is also AC coupled at the output (0.0mv dc).

Also is the 6.5mm output just in parallel to the positive out on the 4 pin balanced connector ?

Love the amp so far and have some 4 pin Neutrik XLR connectors on the way to convert one or more of my headphones !

 

[Argomedo]

Great review. I was waiting for it.

If i have an SMSL SU-9 and Drop THX 789 what differences should i expect if i replace the amp for the Singxer sa-1?

 

[Veri]

If i have an SMSL SU-9 and Drop THX 789 what differences should i expect if i replace the amp for the Singxer sa-1?

In all honesty? Likely absolutely none, the 789 is very good already. It has a knob that can get noisy, and it hasn't got the best crosstalk in lowest gain; both of which might be better on SA-1. On the other hand, 789 will have less of a performance loss at lowest impedance loads. Not a problem with SA-1 in lower gain though, but can become troublesome at high gain and high driving power. 789 also handles BAL in SE out, SE in BAL out better. SA-1 is optimal with balanced out as mentioned earlier in the thread. SE in SE out as measured by Amir seems fine from the looks of it, while with BAL in SE out Amir noticed more grounding noise. So all of this are things to keep in mind!

 

[doug2761]

Great review. I was waiting for it.

If i have an SMSL SU-9 and Drop THX 789 what differences should i expect if i replace the amp for the Singxer sa-1?

From what I understood from the review and measurements on this site of the Drop THX 789 vs the Singxer SA-1 it seems that if you are using unbalanced output that the performance of the Drop unit measures more consistently (perhaps better) than the Singxer. Both seem to me to measure fantastic. It would surprise me if you can hear a difference between either. I may be interpreting the measurements incorrectly but it seemed to me that the Drop unit measured more consistently regardless of RCA or balanced input and balanced or non balanced output. Archimago also reviewed the Drop THX 789 and both the Drop and the Singxer seem to have performance that's better than the DAC you will be connecting to it. This might be a good time to relax and enjoy the music. No need to do any swaps unless you desire to feed some neurosis.

 

[deafenears]

Drop has this available again, $539

https://drop.com/buy/singxer-sa-1-balanced-headphone-amplifier

 

[Celty]

Drop has this available again, $539

https://drop.com/buy/singxer-sa-1-balanced-headphone-amplifier

Damn you!

 

[JB5150]

Quite the statement. I'm pretty sure the A90 measures slightly better SE.

I said NOTHING about "measures better"
I DID say it is BUILT better, and SOUNDS better.
I dont use BAL in SE out.
I have other amps that I prefer for my Single Ended needs.
Maybe even some low SCORING amps
If Single Ended MEASUREMENTS are important, there are many higher SCORING amps on "the chart"

 

[tom.chen]

@tom.chen Which opamp does the SA-1 use on its input stage?

TI 's OPA1612

 

[tom.chen]

Thank you for this information and congratulations for your amp very appreciated in several reviews

Thank you for your encouragement, we will work hard to design more new products. Thank you all for your attention.

 

[tom.chen]

Tom, can you provide me with details on the jumpers to bypass the AC input coupling caps ?
My source (Oppo UDP-205) is also AC coupled at the output (0.0mv dc).

Also is the 6.5mm output just in parallel to the positive out on the 4 pin balanced connector ?

Love the amp so far and have some 4 pin Neutrik XLR connectors on the way to convert one or more of my headphones !

In any case, we don't recommend to use internal DC coupling, this is only for our test. We will consider removing this DC socket in the future.
There are only 4 amplifiers inside, and the three output sockets 6.35 4.4 XLR are all connected together.

 

[raif71]

In any case, we don't recommend to use internal DC coupling, this is only for our test. We will consider removing this DC socket in the future.
There are only 4 amplifiers inside, and the three output sockets 6.35 4.4 XLR are all connected together.

While you're at removing DC sockets in the future, bring the gain switch to the front of the unit, will ya

 

[aandres_gm]

I said NOTHING about "measures better"
I DID say it is BUILT better, and SOUNDS better.
I dont use BAL in SE out.
I have other amps that I prefer for my Single Ended needs.
Maybe even some low SCORING amps
If Single Ended MEASUREMENTS are important, there are many higher SCORING amps on "the chart"

Pretty sure your KEYBOARD is ACTING UP. Please check the CAPS LOCK key.

 

[Cortes]

Subjectivist view

 

[Highvolt60]

In any case, we don't recommend to use internal DC coupling, this is only for our test. We will consider removing this DC socket in the future.
There are only 4 amplifiers inside, and the three output sockets 6.35 4.4 XLR are all connected together.

Always best to have no AC coupling caps in the circuit path !
My Oppo has them already on the Balanced/Unbalanced outputs.
I have not opened up the unit yet, what type of caps are used for the 4 Electrolytic types (I see what look like 4 WIMA caps as bypass) ?
When I had the Oppo player in my hifi setup, I had the coupling caps bypassed.
When I moved it over to my headphone setup, I removed the bypass on the caps since the old head amp was DC coupled.

Thanks

 

[aravaioli]

Well, for me the SA-1 just did not work as expected and it will be sent back to Shenzhenaudio (unless someone in the UK wants to take it off my hands).
Although I trust Amir's measurements, I just can't understand why it drives even my Q701 with little to no headroom left. In all honesty I did not expect this even from my Arya but that is what I experience. My Violectric V200 which this might have replaced has A LOT of spare headroom left. For example, see photo, I listen the Arya with volume set at 12.30 o'clock while on the SA-1 am at 5. I just do not get it: how can it have 3.6W into 50 ohm?
On the subjective side, which I realise isn't that suited to this forum, the SA-1 does sound good. Fed balanced by an SU-1 the sound of the Violectric is a bit crisper than the smoother SA-1 and the soundstage is narrower than the SA-1. To my ears of course.

 

[Eldgrim]

Well, for me the SA-1 just did not work as expected and it will be sent back to Shenzhenaudio (unless someone in the UK wants to take it off my hands).
Although I trust Amir's measurements, I just can't understand why it drives even my Q701 with little to no headroom left. In all honesty I did not expect this even from my Arya but that is what I experience. My Violectric V200 which this might have replaced has A LOT of spare headroom left. For example I listen the Arya with volume set at 12.30 o'clock while on the SA-1 am at 5. I just do not get it: how can it have 3.6W into 50 ohm?
On the subjective side, which I realise isn't that suited to this forum, the SA-1 does sound good. Fed balanced by an SU-1 the sound of the Violectric is a bit crisper than the smoother SA-1 and the soundstage is narrower than the SA-1. To my ears of course.

Did you activate high gain by flipping all the switches underneath the unit?

 

[frankh]

Well, for me the SA-1 just did not work as expected and it will be sent back to Shenzhenaudio (unless someone in the UK wants to take it off my hands).
Although I trust Amir's measurements, I just can't understand why it drives even my Q701 with little to no headroom left. In all honesty I did not expect this even from my Arya but that is what I experience. My Violectric V200 which this might have replaced has A LOT of spare headroom left. For example, see photo, I listen the Arya with volume set at 12.30 o'clock while on the SA-1 am at 5. I just do not get it: how can it have 3.6W into 50 ohm?
On the subjective side, which I realise isn't that suited to this forum, the SA-1 does sound good. Fed balanced by an SU-1 the sound of the Violectric is a bit crisper than the smoother SA-1 and the soundstage is narrower than the SA-1. To my ears of course.

View attachment 130432

Have you set the SA-1 to high gain mode? The 4 switches are at the bottom of the amp. It's a weird way of switching to high gain but I guess Singxer has their reason for doing so.

PS: Didn't see Eldgrim's post before I post mine, sorry.