Singxer SA-1 Review (Balanced Headphone Amp)

[Roland68]

I bought this amp in Sweden EU. can I open the box and legally return it for repair under warranty.

In any case, you can lose the voluntary guarantee if you remove the seal.

Since it is not an upgradeable device (like a e.g. a PC) the legal guarantee of 2 years will remain in place, but this can have two consequences.
1. In the event of a defect, can you be required to prove that you are not at fault for the defect!
2. The removal of the seal can fundamentally reverse the burden of proof of the guarantee and you must provide this.

But that's just the legal situation and it's always "to be right doesn't mean you get it".

 

[MalinYamato]

Without the mod, has anyone so far found any issues with this amp that requires you to send it for repair? I will measure the output voltage of my dac to make sure it's OK then do the mod hoping there are no other unlreated issues that may pop up...the thing will arrive tomorrow.

 

[wric01]

Modded with silver wire jumpers. Hyperdetailed. Is it just me or do all sa1 have this hissing noise at the end of the volume pot 4-6 oclock for all high gain on. Anyways i found the solution Gain switch 1 low 2 high 3 low 4 high , no more noise at full volume.

 

[MalinYamato]

Modded with silver wire jumpers. Hyperdetailed. Is it just me or do all sa1 have this hissing noise at the end of the volume pot 4-6 oclock for all high gain on. Anyways i found the solution Gain switch 1 low 2 high 3 low 4 high , no more noise at full volume.

sounds weird! what does each gain switch represent and do specifically?
The following parts will arrive tomorrow and I'll use those jumpers to bypass four of the caps (or whatever they do to improve the sound 10% as one reviewer explained). The cable is a balanced RCA to XLR which I will use to connect a Khadas Tone 2 Pro as DAC to the SA1 amp. I hope the conductivity of those jumpers is good enough not to degrade the signal.

 

[Roland68]

Modded with silver wire jumpers. Hyperdetailed. Is it just me or do all sa1 have this hissing noise at the end of the volume pot 4-6 oclock for all high gain on. Anyways i found the solution Gain switch 1 low 2 high 3 low 4 high , no more noise at full volume.

You know the SA-1 has 4 individual power amps that should have the same gain setting?
Especially if you use it with balanced headphones.

 

[Roland68]

sounds weird! what does each gain switch represent and do specifically?
The following parts will arrive tomorrow and I'll use those jumpers to bypass four of the caps (or whatever they do to improve the sound 10% as one reviewer explained). The cable is a balanced RCA to XLR which I will use to connect a Khadas Tone 2 Pro as DAC to the SA1 amp. I hope the conductivity of those jumpers is good enough not to degrade the signal.
View attachment 187334View attachment 187335View attachment 187336

The gain switch switches the two different amplification stages (high gain/low gain). With the SA-1, all switches should always be in the same position.

Did you buy the Khadas cables with the balanced RCA connectors for the Khadas Tone 2 Pro?

For the SA-1, I would recommend letting it run for a week to rule out defective components.
The jumpers only bridge the coupling capacitors that filter the inputs of the Singxer SA-1 to DC.
Before you bridge these jumpers, you should first measure with a 1 KHz sine signal DC at the output of the source device (Khadas Tone 2 Pro). Before and with a bridged jumper also at the headphone output of the SA-1. If you use another source, you have to repeat the whole thing, don't forget.

 

[MalinYamato]

The gain switch switches the two different amplification stages (high gain/low gain). With the SA-1, all switches should always be in the same position.

Did you buy the Khadas cables with the balanced RCA connectors for the Khadas Tone 2 Pro?

For the SA-1, I would recommend letting it run for a week to rule out defective components.
The jumpers only bridge the coupling capacitors that filter the inputs of the Singxer SA-1 to DC.
Before you bridge these jumpers, you should first measure with a 1 KHz sine signal DC at the output of the source device (Khadas Tone 2 Pro). Before and with a bridged jumper also at the headphone output of the SA-1. If you use another source, you have to repeat the whole thing, don't forget.

thank you for the advice, will do so.
yes, those are the Khadas proprietary cables with their unique balanced RCA cable to a balanced XLR -- their own invented balanced RCA
solution.

 

[Roland68]

thank you for the advice, will do so.
yes, those are the Khadas proprietary cables with their unique balanced RCA cable to a balanced XLR -- their own invented balanced RCA solution.

Perfect, you seem to mean it really seriously.
Nice equipment

 

[wric01]

You know the SA-1 has 4 individual power amps that should have the same gain setting?
Especially if you use it with balanced headphones.

That maybe but that noise at 4-6 oclock is noticeable , try it yourself with no music playing it's a dead giveaway but most with hearing damage here can't hear it.

 

[MalinYamato]

SA1 arrived today
Raspberry PI 4 runs Volumio3 which feeds Khadas Tone Pro 2 DAC which feeds the Singxer amp through a balanced cable. I wrote a Python program that displays information about bitrate, bit depth, songs,etc, and that allows me to control the device through 4 push buttons.
Currently, it displays a Qubus stream at 3216 bits per second, 96 kHz, 24 bit.

 

[Snoopy]

That maybe but that noise at 4-6 oclock is noticeable , try it yourself with no music playing it's a dead giveaway but most with hearing damage here can't hear it.

I have mine in high-gain. Max. Volume with the DAC in dacmode. No hiss at all with my focal Elegia and DC Aeon 2 Noire (balanced)

 

[MalinYamato]

I am on high gain and after two days I like the sounds with no hiss at all, BUT where is the power? I need to turn the volume knob to 12 o clock to get a decent sound to my phones. Not that I need the power, but considering the over-kill spec, I was expecting a much louder amp.

I compare this EUR 500 amp with my EUR 340 Zen Can Signature HFM V2, which has analog EQ settings to boost the bass where it lacks on HFM phones such as Sundara. The improvement is slight and I cant wait to get the 10% improvements by the DC bypass mod...

 

[Veri]

I am on high gain and after two days I like the sounds with no hiss at all, BUT where is the power? I need to turn the volume knob to 12 o clock to get a decent sound to my phones. Not that I need the power, but considering the over-kill spec, I was expecting a much louder amp.

It's the non linear pot, it only gets loud at the very end of the range. If you max it it will likely be LOUD, no?

 

[MalinYamato]

It's the non linear pot, it only gets loud at the very end of the range. If you max it it will likely be LOUD, no?

Yeaaa, I am not at all used to this kinda pot. It is not linear at all but exponential as you explain, and gets very loud at the very last stage of the volume knob.The component that implements this pot is huge when looking inside the amp and perhaps they have worked hard to get it this way instead of putting an ordinary linear potentiometer... Why?

 

[Snoopy]

I am on high gain and after two days I like the sounds with no hiss at all, BUT where is the power? I need to turn the volume knob to 12 o clock to get a decent sound to my phones. Not that I need the power, but considering the over-kill spec, I was expecting a much louder amp.

I compare this EUR 500 amp with my EUR 340 Zen Can Signature HFM V2, which has analog EQ settings to boost the bass where it lacks on HFM phones such as Sundara. The improvement is slight and I cant wait to get the 10% improvements by the DC bypass mod...

Make sure it's really set to high gain. All four switches on the bottom have to "click" audible.

And are you using balanced?

I'm at 2-3pm with my Aeon 2 Noire on high gain. If your DAC outputs 4v or more it should be plenty loud

 

[MalinYamato]

Make sure it's really set to high gain. All four switches on the bottom have to "click" audible.

And are you using balanced?

I'm at 2-3pm with my Aeon 2 Noire on high gain. If your DAC outputs 4v or more it should be plenty loud

It's all balanced from DAC to amp from amp to phones.

 

[Veri]

It's all balanced from DAC to amp from amp to phones.

Then the SA-1 is at its best specification in that set-up should sound good. But yes, the pot is a bit of an oddity.

 

[MalinYamato]

...did the mod after testing it unmoded for 2 days, so now I cannot return this thing. I am stuck with it.
I measured DCs on the balanced pins and it was less than 5 mv so I felt confident doing the mod.
Yes, the sound improves quite a bit more than what I expected actually

 

[Kitarist]

...did the mod after testing it unmoded for 2 days, so now I cannot return this thing and must keep for life.
I measured DCs on the balanced pins and it was less than 5 mv so I felt confident doing the mod.
Yes, the sound improves quite a bit more than what I expected actually
My Argons are very power-hungry, thus I run with the gain set to high.

What exactly improved? Is there any explanation why does this mod "improve" the sound?

 

[MalinYamato]

What exactly improved? Is there any explanation why does this mod "improve" the sound?

hard to describe, not much of the bass improved, but the upper mid and treble improves giving it more detail, space, more 3D -- it's now a new better amp, kinda magic what this mod could do! You should not ask me why it improves, I just did as others suggested me to. My ears are very musical but I am a nobody when it comes to tech.