Class A and USB Powered? 
No thanks, lol.
Class A needs power to actually be Class A. At least the sAp-1 plugs into the wall.
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Yeah the USD doesn’t work but once you plug it into the wall it does. I guess it might be a little too DIY for some.
Yeah it’s just weird that they don’t even include a power supply. I also tend to trust SMSL more than Douk Audio, which is known for their useful but sometimes too cheap stuff. 
Looks interesting, not sure how much I would trust TO-92 packages (the transistors in the output stage) to handle higher-ish power.
The sAp-1 is interesting to me because I tried (and failed) to DIY an amplifier around the same chip it uses (Ti TPA6120A2). So I could take a look inside to see where I went wrong.
Dive in, let us know what you think. It is my toilet/bath amp (welcome to my world) and it is appropriate to to 58x. Form factor and build is awesome. I think I paid $42? Silly.
Am going to wait for one to be available for cheap in the EU.
Zeos finally reviewed it. Didn’t say much except it was more powerful than what it said it was. No comparisons because he said he had nothing to compare it to at 50$ (he got it for 50$). Also said it is not class A… but… it’s kinda like it.
TL,DW: if you want “crispness” get the JDS Atom, if you want smoothness, get this.
The sAp-1 (like the RNHP, L30, A90, and many more) is based on the Texas Instruments TPA6120A2
From the spec sheet:
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Really? Wow, I didn’t realize the Topping was using this TI chip as well. I thought they had some proprietary in-house design (“Nested Feedback Composite Amplifier”), but I just went and looked at the teardown again and sure enough, TPA6120A2 on the Topping amps. I should know better than to take marketing buzzwords at face value… I really should know better… I’ll never look at my L30 the same again, it’s just the cheep trailer trash cousin to my RNHP (Topping L30 go round the outside 
)
This is a good reminder that amps (and DACs) are much more than the sum of their parts. But this does raise an interesting question, what are the most common chipsets used in headphone amplifiers? Clearly the TI TPA6120A2 is popular. I’m sure there’s only a handful of IC solutions in use, as their design and manufacturing is very specialized and expensive.
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NE5532 is a very common Op-Amp in audio applications. Can find that in anything from cheap headphone amps to thousand dollar mixing desks.
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Since Zeos did not even bother comparing the sAp-1 it to the Atom, here’s my review… compared to my JDS Atom and my Liquid Spark. Just click the little 
's. 
Also, it’s not Class A… but Class AB. 
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16:50 Minute mark in the video…
“There is no protection circuit in there because a protection circuit will ruin the [?]” (points at capacitors) “like these here capacitors are protection circuit and you can bypass them with jumpers”
WHAT
THE
FUCK?
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what the hell is he even talking about.
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Capacitors preventing the headphones from, well, exploding. Something about this:
And apparently some shitty amps don’t even have these capacitors… cough L30?
With Capacitors, you can AC couple while blocking DC, yes.
The fun begins with the characteristics of capacitors (ESR, ESL, etc.)
I am not one to tell if capacitor coupled is better (sound wise) or worse than DC coupled. Having capacitors (if quality component and correctly sized) in the path between the output stage of the amp and headphone will certainly save your from L30-like incidents.
Having a DC-offset on the output is suboptimal, having large DC currents flow through voice coils is BAD (because melting and 
)
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Yeah well, TL,DR: the Singxer is a “special” amp with the low-high gain switches on the bottom of the amp (scratches head) and I think bypassing the capacitors will just disable the low-gain switch kinda like with the BasX A100 (different beast I know) and just give you all the powah.
…and all the risks associated with it. But yeah, that’s off-topic.
Edit: Zeos’s point was, even if he paid 50$ for the sAp-1, it’s well made, so it has these capacitors. Still, full price is 100$, and he should at least have compared it with the Atom and the Liquid Spark… but I’ve done it instead, I guess. 
Putting in jumpers in the SA-1 and A-100 are very different things.
In the A-100, the jumpers are like taking off the throttle limits.
In the SA-1, the jumpers are like…
Well, let me draw a picture:
Capacitors (oversimplified) work like a pair of Tanks with Pistons in them connected via a Balance.
The left tank is accessible to the amplifier. It can take water out of it or put some in. Doing so makes the piston move thereby pulling or pushing water through the turbine (the headphone).
Even if the amp happens to work like a broken tap and trickle water into the left tank (or leak out of the tank), the piston can only move so far before bottoming out. The turbine can still wiggle back and forth (wanted movement!).
The jumpers are like moving the bucket to the right tank. This now takes the sloppiness of the pistons out of the equation, which is good! However having a leaky tank (or dripping tap) will now have the turbine spin (unwanted movement).
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Nice. Thank you very much for this explanation and drawing.
Gold star for your electro-mechanical analogy! Your headphone model has both an “R” (narrow passage into and out of the turbine), an “L” (turbine has a moment of inertia giving it an inductive reactance), and a “C” with the water tanks on the input and output. Love it!
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For your information.