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A SiNGXeR SA-1 Class A Headphone Amplifier & Preamp Review: w/ Drop/Massdrop THX AAA 789 comparison.

Hey all! Welcome back to The Neighborhood! Today we’re looking at the SiNGXeR SA-1 Class A full Balance Headphone Amplifier. This became a highly requested review by channel viewers, and luckily APOS audio was able to supply me with a unit for review. So, without yammering on too much, let’s get InToit!

The SiNGXeR SA-1 is a pretty straight forward device in that it is Class A, a black metal box, and a fully balanced headphone amplifier. Footprint wise, it’s about the size of my 789, and looks relatively similar as well. In addition to a 4-pin XLR balanced output, a 4.4mm balanced output, and a 6.35mm unbalanced output, there is a volume knob, a power indicator, and three toggle switches. The first toggle switch toggles the device between off, preamp, or headphone amplifier modes. The second toggle switches between XLR and RCA input, and the third toggle switches between Low-Z (low impedance mode) and Hi-Z (high impedance mode). There are also high and low gain switches on the bottom of the chassis.

However; like the high and low impedance switch, throughout most of my testing, I noticed limited differences between high and low gain performance on this device. So, I left the Hi-Z switch and the high gain switches engaged in most instances. The only exception to this rule was with low impedance dynamics (for both IEMs and headphones alike), which were livelier and more dynamic in their presentation with the Low-Z mode toggled. Planar dynamics were generally less effected. All IEMs, even the sensitive ones, had black backgrounds even on high gain, which was surprising, but also begs the question as to the point of the low gain implementation? Nevertheless, the low gain is reported as 0 db and the high gain as plus 11 db.

The back of the box features RCA and XLR inputs and outputs for preamplifier usages, a main power switch, and a connection for your standard power cable. This device only outputs as a variable preamplifier and there is no way to bypass the preamplification stage and utilize it as a line out. No remote was included for preamplifier features, as the toggles and switches indicate, this is a purely manual device.

Regarding the SA-1’s sound, the circuit is class A, and it sounds like it (although I've been informed by another reviewer, "Skedra," that it is actually Class A, biased into A/B, but internal documentation provided by SiNGXeR does not support this [so take from that what you will...]). Overall, the presentation is very clean, with a hint of warmth and certain amount of analog feel to it. If I had to describe the tones in a few words, those words would be “elegant” and “silky smooth.” Dynamics I found to be sufficient, but somewhat soft in their overall delivery. Extensions in each direction were good without any form of harsh conveyance. The sound has a reference quality to it, but depth and dimensionality could only be described as average to slightly above average at best. As can occur in the case of some reference level gear, on certain songs peripherals and vocals were more forward than I would expect from the track- resulting in a more intimate presentation or closed-in experience. To summarize, the sound is somewhat reference, but also tilted towards warmness and intimacy.

Ironically, as I know most of you will interested in the SA-1 primarily as a headphone amplifier, I actually enjoyed this device most as a preamplifier. As such, I think it was an oversight by SiNGXeR not to include a remove, at least for volume adjustments. Even though most will likely buy this for use as a headphone amplifier in a desktop environment, it did sound good enough as a preamplifier to be used in a speaker setup as well. Given this, I’d call the lack of a remote as a miss opportunity by SiNGXeR here.

With regard to its ability to drive a load as a headphone amplifier, this thing seemed to top out with around a 300 Ohm headphone, with something like say the Sennheiser 6XX. And, while I was able to drive the 6XX both in balanced and unbalanced operation, it sounded notably fuller when ran off of the balanced connection of the SA-1.

Given the SA-1’s form factor and utility, the likely comparison here is with the THX AAA 789, a device that as it turns out is about half the cost of the SA-1 and also, as it works out, about twice as powerful as the SiNGXeR, even if the SA-1 is constructed slightly better. In other words, the SA-1 has about as much power as the 789 does in single ended operation, and about half-as-much as the THX amp does in balanced operation. This was pretty consistent across headphones. For example, the Beyerdynamic DT880 SE 600 Ohm variant performed similarly in balanced operation on the SA-1 as it did when being driven unbalanced by the 789. Notably neither device pushed these cans particularly well, but the 789 did have more power behind it in balanced operation than the SiNGXer did.

In sonic comparison to the THX AAA 789, the SiNGXeR delivers slightly larger images within its sonic picture, with a fuller sound, a thicker and warmer tonality, and bolder, more forward character. Individual notes sound more “deadened” or “flattened-out.” They have less of a leading edge, but also a hazier quality to them. The staging is slightly smaller in comparison, as well, but separation is more apparent. Having said that, in the end, these devices are more similar than they are different, and it will likely come down to personal preference, which one prefers, rather than one being objectively better than the other. Still, the SA-1 was less hit or miss regarding its ability to synergize with my particular headphone collection, and paired better across a variety of devices. For example, the Aeon Open X sounded just “so,so,” or underdriven, on the 789, yet became gloriously alive on the SiNGXeR. And with IEMs, the SA-1 provided a more transparent, blacker background with less interference in comparison to the 789, even when the SA-1 was permanently set operate in high gain.

Ultimately, as one picks their favorite reference amplification flavor between the two, it will be up to that specific buyer to justify the price difference between the SA-1 and the 789; as I’ve already said, these devices are more similar than they are different. Yet, to the right person, with the right head-fi stable of gear, the SA-1 might be just what the doctor ordered to complement their setup. So even though I’m sticking with my 789 given the $320 dollar price difference between the two, I might end up choosing the SA-1 for myself if price were no object. And with that, I’m out for now.

*Thanks to Apos Audio for sending in the SiNGXeR SA-1 for review (affiliate link):

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