Singxer SA-1 Review (Balanced Headphone Amp)

[caocaolatre199x]

I purchased the sa-1 about a week ago and it still hasn’t come in (and likely won’t for several weeks since I’m in the US) and I was wondering if anyone has purchased one recently that can confirm whether the amp still has the jumper pins. I know SingXer said they would remove the pins in a future revision, but I would like to know if they are still present on current models. If not I am going to either return it or cancel my order and just go with the Jotunheim 2.

I just received it 3 days ago, I could recognize a few small changes on the circuit board but the jumpers still exist. Rest assured.
However I don't understand what the use of DC jumpers mean? What will happen in the circuit when plugging the jumpers? I also want to try this but some people say it might ruin my headphones. So what do I have to do to avoid broken headphones? Can it be used with low impedance IEM or not?

 

[Roland68]

I just received it 3 days ago, I could recognize a few small changes on the circuit board but the jumpers still exist. Rest assured.
However I don't understand what the use of DC jumpers mean? What will happen in the circuit when plugging the jumpers? I also want to try this but some people say it might ruin my headphones. So what do I have to do to avoid broken headphones? Can it be used with low impedance IEM or not?

What changes did you see on the board?

The jumpers are not in the circuit but in the signal path of the inputs.
This only bridges the coupling capacitors at the inputs that filter out the DC component in the signal. The DC protection circuit is in front of the headphone outputs and has nothing to do with the jumpers.

Please note that you have to remove the guarantee seal (but apparently you already have) and do the whole thing at your own risk.
However, you should definitely measure the DC component at the outputs of your source device beforehand.

 

[Veri]

I just received it 3 days ago, I could recognize a few small changes on the circuit board but the jumpers still exist. Rest assured.
However I don't understand what the use of DC jumpers mean? What will happen in the circuit when plugging the jumpers? I also want to try this but some people say it might ruin my headphones. So what do I have to do to avoid broken headphones? Can it be used with low impedance IEM or not?
View attachment 150872

Skipping the DC protection takes it out of the signal path, but is obviously risky if your input source has some DC offset. It that gets to the amplifier and then headphones there could be damage. But some people on YouTube videos claim it sounds better..

 

[Snoopy]

Some people seem to have removed the mod again since it sounds "fatiguing".

To Me the SA 1 sounds already pretty impressive as it is. No reason to risk damaging my headphones and voiding the warranty

 

[Roland68]

Some people seem to have removed the mod again since it sounds "fatiguing".

If that's true, then that would explain why such abstruse high capacities were used as coupling capacitors, and with such a low dielectric strength. That would be a kind of sound tuning.

I will listen carefully to my Singxer SA-1 at the weekend, with and without coupling capacitors.

 

[Roland68]

Skipping the DC protection takes it out of the signal path, but is obviously risky if your input source has some DC offset.

At this point it should be said very clearly that a source device with a significant or problematic DC output is either really bad or broken. But of course that's just my personal opinion.
The coupling capacitors at the inputs are installed, among other things, because the developer never knows what kind of device is being clamped in front of it. It can also be defective.

 

[Veri]

At this point it should be said very clearly that a source device with a significant or problematic DC output is either really bad or broken. But of course that's just my personal opinion.
The coupling capacitors at the inputs are installed, among other things, because the developer never knows what kind of device is being clamped in front of it. It can also be defective.

Yes it's true. It shouldn't happen. But from what I've read, as an example, the ESS9068 powered Gustard X16 apparently outputs DC on power off. It's for these kinds of defects that DC protection is in place anyways, better safe than sorry.

 

[caocaolatre199x]

What changes did you see on the board?

Try comparing with the manufacturer board image provided, a few capacitors are added (or moved from the bottom up), I don't know. Or simply the use of higher quality components such as gold plated jacks, ..

 

[godmax]

Try comparing with the manufacturer board image provided, a few capacitors are added (or moved from the bottom up), I don't know. Or simply the use of higher quality components such as gold plated jacks, ..

View attachment 150944

Still looks identical to me besides the QC PASS sticker For differences in components Singxer would have altered their pcb layout version, but V1.3 on both images.

 

[Roland68]

Try comparing with the manufacturer board image provided, a few capacitors are added (or moved from the bottom up), I don't know. Or simply the use of higher quality components such as gold plated jacks, ..

No, everything has stayed the same, except for the gold-plated 6.35 headphone jack.
The 8 blue components next to the heat sink are 1 ohm resistors. The 4 components under the SMPS are inductors, only visually different.

 

[Veri]

The 4 components under the SMPS are inductors, only visually different.

Right.

 

[Snoopy]

Did someone already do a clear case mod or something for headphone amps? I think this thing looks seriously beautiful inside .

 

[caocaolatre199x]

The 8 blue components next to the heat sink are 1 ohm resistors

In the area of blue resistors, 2 capacitors have been added to next group of 2 resistors, look closely.

 

[Roland68]

In the area of blue resistors, 2 capacitors have been added to next group of 2 resistors, look closely.
View attachment 150963

You're right, I didn't see that. These are missing from my SA-1.
Under certain circumstances these are the ones that sit under the heat sink between the transistors of mine. The imprint "Singxer SA-1 V1.3" is in a different place on me than on the two shown. So a third execution.
What is the serial number of your SA-1?

 

[Kahntraband]

When mine comes in I will try the direct coupling mod. I measured the XLR outputs of my RME ADI-2 DAC FS and when running it had a DC offset of 1 to 3 mV. When off the DC offset jumps around between 10 to 30 mV. This is to be expected since it’s not outputting anything. I don’t expect any damage from 3 mV of DC, so the mod should be harmless. I will eventually report back on whether removing the capacitors from the signal chain does anything to the sound or if Currawong is just hearing things.

 

[tom.chen]

At present, the jumper of SA-1 has not been removed.
Jumpers are used for testing.
We do not recommend using DC Direct couple.
Although SA-1 also has stable and safe DC protection circuit.

 

[Forsaked]

In the area of blue resistors, 2 capacitors have been added to next group of 2 resistors, look closely.
View attachment 150963

Looks like that my 5 weeks old SA-1 is the same revision:

 

[caocaolatre199x]

Looks like that my 5 weeks old SA-1 is the same revision:

View attachment 152133

Right. However, your transformer has a better paint. If what to say to this manufacturer, I want to say that they should clean up the dust from the motherboard and components before fitting the shell. I removed the shell and lost my warranty just because I saw inside a lot of dust, and wanted to consider it.

 

[raif71]

Dust can come in through the side openings of the amp. Also, I'm worried that ants, spiders or other bugs go inside via the side slits and make a home in the amp

 

[caocaolatre199x]

Dust can come in through the side openings of the amp. Also, I'm worried that ants, spiders or other bugs go inside via the side slits and make a home in the amp

When this amp was only 1 day old at my house, I was unhappy because I could see a lot of dirt through the gap of the case.