"Absolutely brilliant": Passion For Sound Reviews the Singxer SA-1

Note: This article is based upon the video "Singxer SA-1 Balanced Headphone Amp Review - Better than Jotunheim 2?” made by Passion For Sound on their YouTube channel and is printed here in partnership with Passion For Sound. The review was originally posted on March 11th, 2021. Edits have been made for clarity and length.

We sent Passion for Sound the Singxer SA-1 Fully Balanced Amplifier to get his thoughts.

“This amp should absolutely be on your shopping list,” he said on his YouTube channel. “I think it’s absolutely brilliant and totally worth the $600 USD.”

Watch the video below or scroll on for the edited transcript. 

Intro

I think that the Singxer SA-1 is a marvelous amplifier. I think it’s absolutely brilliant and totally worth the 600 US dollars. Before I get to the comparisons, though, I just want to share two more things. 

Output Quality: Balanced vs Single-ended

The first thing I’ll talk about briefly is the output quality from the balanced versus the single-ended outputs. It’s not quite on par. What I found was that moving from the single-ended output to the balanced output, the XLR, even when matched on volume, had a much better sense of clarity. The separation of the sounds and overall width in the soundstage is better.

The single-ended output is still good. It’s not a bad sound whatsoever, but you can definitely hear the difference in the two.

What that means is that it’s using both sides of the circuit. It’s pushing a positive and negative voltage, so you’re getting the full power and dynamics that the amplifier has to offer. My assumption would be that the single-ended output--much the same as some other, cheaper balanced amplifiers on the market--is using jut half of the amplification circuit, and therefore you’re not getting the full quality that it can deliver.

I can’t stress enough that the single-ended sound is still very good, it’s just that balanced is where you’re going to hear what the Singxer SA-1 is really capable of. 

Output Impedance (“Z”) Switch

The other thing I want to talk about now is to swing back around to this output impedance switch. The output impedance of the Singxer SA-1 is 0.7Ω through single-ended or 1.4Ω through balanced, which is normal. So balance normally has twice the output impedance because it’s twice the same circuit. By switching to the High Z or high output impedance mode you’re adding just 10Ω to the output. So now it goes up to 10.7 or 11.4Ω, which is a fairly modest increase.

I’m used to high output impedance amplifiers being things like output transformers, tube amps, where you’re having output impedances of 80 to 150Ω, in some cases even into the 200Ω range. So to just go up by 10Ω to me seems a little bit redundant. I don’t get the point. As you’ll see on screen, it does make a very slight difference to the tonal characteristics of lower-impedance headphones, but it’s very, very minimal, and maybe that’s the idea. Maybe it’s just to add a tiny bit of warmth to those particular headphones, but I haven’t found it making enough difference that I’d bother with it too often.

Singxer SA-1 vs Schiit Jotunheim 2

Let’s talk about some sound comparisons. Having already said that, I think the SA-1 sounds fantastic, and also knowing that it’s smooth and clean and refined, let’s see what that means in the context of other amplifiers, starting with the Schiit Jotunheim 2, which is a $400 USD amplifier, making it $200 USD cheaper than the SA-1.

My initial impression was that I thought maybe the Jotunheim 2 was the better amp. It’s got a slightly more engaging tonality, something through the mid-range that it does where it’s not necessarily coloring the sound, but it’s got a presentation to it, or maybe a timbre to it that’s really engaging and fun. The SA-1, on the other hand, is probably just a touch more neutral. But they’re quite similar amps in that they’re smooth and they’re rich, but they’re still resolving and detailed.

Once I got the volumes right, though, and I worked through a number of different headphones, what I found was that when you’re using headphones with any sense of resolution and clarity in the upper minds, what you’ll hear from the two is that the Jotunheim 2 can get just a little bit rough in the upper mids in comparison to the SA-1. The SA-1 sounds beautifully smooth throughout, no matter what I drove with it and no matter what volume I had it at. The Jotunheim 2, on the other hand, at normal listening volumes, with some headphones, did start to sound just a little bit harsh on some of the upper mid-range.

In isolation, the Jotunheim 2 is not bad, it’s just that the SA-1 shows a level of refinement that’s just a touch higher. I’m guessing that could come down to things like component choices and parts choices, where that slightly higher budget means they might be using a more expensive capacitor or resistor or whatever the component might be in parts of the chain.

To be really clear, I think we’re spoiled for choice in having either the Jotunheim 2 or the SA-1 available to us at such affordable prices. Because you’ve now got two amplifiers with plenty of power for almost any headphone you can imagine and also fantastic sound. If your budget’s limited, the Schiit Jotunheim 2 is an absolute killer product, but if you’ve got a bit more budget, the Singxer SA-1 is even better. Both have a very similar sense of soundstage, which is to say it’s not huge but it’s good. They provide good resolution, fairly good separation of sound, and a decent sense of depth. The SA-1 pulls ahead slightly on resolution and detail-retrieval, but it’s really, really close, and so that led me to a comparison with my trusty Soloist behind me. 

Singxer SA-1 vs Burson Soloist 3XP

Anyone who’s watched the channel for a while will know that I adore the Burson Soloist 3XP. I think it’s one of the best solid state amplifiers on the market today at any price that I’ve heard. And so the SA-1 really had its work cut out for it.

What I found in putting them side-by-side was that the SA-1 has a slightly wider soundstage, which is pretty impressive. It doesn’t layer quite as deeply, though. The Soloist is very good at providing depth in the soundstage and layering in the soundstage, whereas the SA-1 is a little bit flatter. It’s not dead flat. It’s much better than some of the op-amp based designs I’ve tried, but it’s not quite as good as the Soloist, which does set a very high bar.

The general tonality of the two, unlike the Jotunheim 2 and SA-1, which were very similar, there’s a definite separation between the Soloist and the SA-1. The SA-1, as I’ve already mentioned, is a bit richer and smoother-sounding. I’m not going to say it’s thick or warm, but it’s rich and smooth, whereas the Soloist is a bit more clean, a little tiny bit more analytical, but never getting into any harshness. It’s a smooth but very neutral amp.

The SA-1, though, I would say, is a smooth and slightly richer-sounding amp. I can honestly say, listening to both, I can’t decide which I prefer in terms of tonality, because I like the richness and smoothness of the SA-1. It’s engaging and enveloping in much the same way the Jotunheim 2 is. The Soloist, though, has its benefits in that neutrality, meaning that it’s incredibly resolving and incredibly transparent, and that’s really, for me, the thing that separates the Soloist from the SA-1. It’s the levels of detail and the resolution that the Soloist is able to pump out.

The Soloist manages to produce a coherent sound, a sound that is made up of all sorts of textural nuance, little subtle spatial information that gives you a sense of where all the instruments are coming from in the soundstage. It just does that all magnificently, whereas the SA-1 does it well, but not quite at the same level.

If I can steal some feedback that I received from Robert, who was the one that sent me the SA-1 after he bought himself a Soloist, he felt like the Soloist really brought the music to life compared to the SA-1. And I felt much the same. As I listened to it, I could really understand what he meant.

The SA-1 is a fantastic-sounding amp. It’s absolutely brilliant, particularly for the price, but it doesn’t quite reach the levels of something like the Soloist that just absolutely invigorates the music with a sense of detail and energy and a lifelike presentation, in a way that the lower price tags just can’t do. That shouldn’t be a sense of shame for the SA-1, because we’re talking about $600 versus $1,100. So nearly twice the price. 

Conclusion

So if you’re in the market for a fantastic balanced amplifier and/or a preamp in that sort of six to seven hundred dollar USD range, and you’re looking for a beautiful, smooth, articulate sound, this is going to tick all those boxes.

I think, for me, as much as I love the Jotunheim 2, I’d highly recommend anybody that has the budget to spend should absolutely go for the Singxer SA-1, the biggest reason being the usable volume range is so much better. It’s also got the 4.4 output, which I think is a bonus and really the only drawback I can find with it is the gain switches are on the bottom. Unless that’s a deal breaker for you, this amp should absolutely be on your shopping list.