Singxer SA-1 Review (Balanced Headphone Amp)

[amirm]

My home insurance and any other insurance won't cover (in the EU) if you use prohibited appliances and similar. That's for sure (and it makes sense).

Can you quote the specific section that says so? Tons of people say the same about US but it simply is not true. Insurance is to cover for such "accidents." Homeowner cannot be expected to look for such marks and know the implication thereof. The company may get in trouble for shipping unsafe and illegal products but I doubt very much that owners are penalized as such.

 

[amirm]

@JohnYang1997 , is the issue with the unbalanced output being taken from one leg of the diff path real? I think @amirm said he couldn't see any degradation. Can you guys confirm pls?

No, I said there was degradation but nothing like what Wolf showed:

I tried testing with XLR input and 1/4 HP out (measured balanced) and got fair bit of ground loop dropping SINAD by a few dB (not shown). Not sure if this is instrumentation issue or design.

 

[gvl]

Confirmed by the designer that the unbalanced is taken off one branch of the balanced input. The intention was to get best performance out of balanced output. And it does. But that's not the whole story. There can be distortion being cancelled in balanced output and the grounding design is not very good. So it's a complex issue in fact. But you know...

What happens with RCA inputs? Do they get converted to balanced first and then one branch is taken for the 6.3mm again? The RCA in 6.3mm out test looks good here.

 

[JohnYang1997]

No, I said there was degradation but nothing like what Wolf showed:

The degradation is with load. Could you do a distortion vs power with unbalanced output like before, please?

 

[JohnYang1997]

What happens with RCA inputs? Do they get converted to balanced first and then one branch is taken for the 6.3mm again? The RCA in 6.3mm out test looks good here.

It's ok without load. Distortion rises with power like shown in the 33ohm distortion vs power graph. Without load it's like what Amir showed.

 

[amirm]

The degradation is with load. Could you do a distortion vs power with unbalanced output like before, please?

All my headphone amp reviews have a 600 ohm load for the dashboard (ignore the AP footnote that says otherwise). But sure, let me see if I can find the time....

 

[Veri]

All my headphone amp reviews have a 600 ohm load for the dashboard (ignore the AP footnote that says otherwise). But sure, let me see if I can find the time....

Thanks Amir!! Sorry for the hassle I'm buying one so any extra info is very much appreciated haha.

Have a nice week-end everyone!

 

[gvl]

It's ok without load. Distortion rises with power like shown in the 33ohm distortion vs power graph. Without load it's like what Amir showed.

Hopefully can be confirmed here. If so the Magnius seems like a much better deal.

 

[Veri]

If so the Magnius seems like a much better deal.

Magnius isn't exactly better when using from its single-ended TRS output it's easier to forgive though since it's only $199, compared to the SA-1.

 

[gvl]

Magnius isn't exactly better when using from its single-ended TRS output it's easier to forgive though since it's only $199, compared to the SA-1.

Hopefully we'll see loaded TRS results here to make the final call.

 

[Ralf Stocker]

Not sure if using switching power supplies is a good idea. I recently had them and they caused problems. Others were broken.

 

[Veri]

Not sure if using switching power supplies is a good idea. I recently had them and they caused problems. Others were broken.

Topping A90 also uses those meanwell supplies. So far, very few issues I've seen with A90 so from what I see, hear and experienced owning one, these switching supplies are totally fine, if the design around them is good.

 

[PeteL]

Actually, a ton of plastic molding goes on in the USA, too.

Many kitchen appliances, washers, dryers, air conditioners, and other household electronic and electrical goods are manufactured in the USA and they are price competitive. However, unless you are talking about “high end” consumer electronics, then far and away there is not much consumer electronics production in the USA. The only notable exception I can think off of the bat is the Macintosh Pro.

Was this not clear that I was not talking about consumer electronics? I took the time to put in bold what I was talking about, and explain further that I was specifically talking about semi-conductors components i.e. : commonly called chips. I also tought that my first comment was self explanatory, when a contributor stated that the US do almost no electronic parts, I jokingly made a reference to the Silicon Valley.

 

[davidvilla]

Amir about the position of the switches in phonitor X "Maybe we skip this generation until they figure out the switch needs to be in the front" "The circuit can be laid out to allow the gain switching to be in front without lengthening the circuit path. Alternatively a relay can be used to change the gain wherever it needs to be"
Amir about the poitionof the switches in Singxer SA-1 "suspect they went this way to minimize PCB path lengths and hence improve noise figure. Performance over functionality!"
Sorry, I dont understand

 

[raif71]

Think I'm gonna order the SA-1 and test it in all my uses. If it has grounding issues it goes back. On paper it looks like a pretty fine amp though. @amirm pretty late to be asking things, but any chance you tested its pre-amp capabilities? wonder how it does vs A90.


Yeah, see previous discussion. It is AB for the most part. But can still be biased into class A at 'normal' listening levels really. Depends how much you push it. On the other hand, what does it matter?

I'm using both headphone and pre-amp function of the Singxer SA-1. The xlr out is connected to Eris X5 XT monitors and so far, I'm enjoying what I hear. Plenty of power out of the pre-amp (E5 XT both at slightly above 50% volume)

 

[tom.chen]

More details, from Singxer's Taobao：

Large balanced output power:
16Ω 10000mW
32Ω 5500mW
68Ω 3100mW
120Ω 2000mW
600Ω 380mW

Single-ended power: the corresponding balanced output power divided by four.

SA-1's Class A model:
Balanced 16 ohm load: below 500mw;
Balanced 32 ohm load: below 1000mw;
Balanced load of 68 ohms: below 3000mw;
Balance the load above 68 ohms: almost all power is Class A;

SA-1 headphone amplifier gains:
1. Single-ended input, single-ended output: low gain is 0db, high gain is 11db;
2. Single-ended input, balanced output: low gain is 6db, high gain is 17db;
3. Balanced input, single-ended output: low gain is -6db, high gain is 5db;
4. Balanced input, balanced output: low gain is 0db, high gain is 11db;

LOW-Z is low-impedance mode, HI-Z is high-impedance mode:
Low-impedance output impedance is 1.4 ohms (balanced) and 0.7 ohms (single-ended);
High-impedance output impedance is 11.4 ohms (balanced) and 10.7 ohms (single-ended);

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

Usage suggestions and precautions:
1. Based on the SA-1 is an amp with a fully balanced design concept, it has made the greatest optimization for total balance. Therefore, the recommended way to use it is: balanced input and balanced output, followed by single-ended input and balanced output.
2. If you need to use single-ended, it is recommended to use single-ended input; it is not recommended to use balanced input, single-ended output.
3. For high-sensitive headphones such as earplugs, high gain mode is not recommended.

 

[tom.chen]

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.chen]

Thank you very much for the review of amirm.
SA-1 uses op amps from TI and the transistors from ON Semiconductor.
The 4 code switches at the bottom are from ALPS.
We test every ALPS potentiometer to meet our requirements.

 

[Veri]

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

Congrats on the great performing product

 

[Deleted member 31750]

I was thinking the usual XLR in, 6.35mm out for almost all the tests. They omitted the half branch of the XLR when using 6.35mm out, similar to Magnius essentially. And when loaded the performance also degrades a lot with 6.35mm out. View attachment 129593View attachment 129594
Usually a differential amplifier is needed to do the summing which adds a bit of noise.

Same amplifier, same test, different results. How this is explained?