Review: PS Audio Sprout – Whose Bass?

The Sound

PS Audio Sprout vibrates between impressive and awesome. Assuming that your hydro is sorted, it perfectly drives any headphone or earphone you own. It packs such effortless power and current that I can run its volume nearly at 100% when driving Audio Technica’s sensitive ES7, which usually rattle like the Dickens when fed too much volume. Sprout blasts the ES7 with next to no IMD distortion better than most amps I’ve tried. And the resolution that it pops into the same headphones is nearly as good as an unloaded signal. Ditto the DT880/600. Ditto Earsonics SM2. Ditto the Oppo PM-2. In fact, there’s not a single headphone’s load under which Sprout suffers.

Sprout’s headphone amp pummels the DACmini PX in a number of key areas. First, it puts out amazing current into any Ω load. Next, no matter the load, the volume, the source material, or the bit-rate, its stereo detail and image barely contract.

To be fair, unloaded it manages a mere 68dB of stereo crosstalk from its headphone out (as measured through a Lynx Studio HILO). But even loaded with something crazy like an Earsonics SM2, that number drops by only 3 dB, or 5%. Most amps suffer crosstalk collapses of at least 15% under similar conditions. And only when driving the SM2 do distortion numbers ramp up to what some amps consider ‘normal’ levels.

Its output is as reliable as can be.

There is a catch, though, and that is: Sprout puts out next to no low-bass information. Anything under 100Hz is practically inaudible against higher-frequency signals. I’m talking about a precipitous drop from 100Hz to 50Hz of more than 3dB and -5,5dB at 20Hz. -5,5dB may not seem like much, but it is. If you’re into Bruce Springsteen, you’ll have to enjoy Born in the USA without its subtle bass cues. The good news is that most music we listen to, even stuff we consider ‘bassy’, has very little true audible sub-bass information in it. That is to say that this sudden drop in information may not even be audible for most of what you listen to. In fact, American Hip-hop, a genre most people think of as ‘bassy’, sounds virtually the same through Sprout as it does through similarly-voiced amps with linear bass responses.

Highs and mids are neutral, contrast into the mids and highs are great, as is post-bass dynamic range. Sprout is airy, clear, and pretty-sounding. Vocal timbre and clarity are perfect. Stringed instruments are weighty, percussion is clear, and spatial cues are effortless.

Which makes me wish that it spat linear signal from 50Hz on up. Why? Well, a lot of the EDM and dubstep I listen to actually drops below 50Hz. And most of my favourite headphones are either bass-light or bass-neutral, meaning that when fed by Sprout, they’re spritely. Interestingly, since the amp performs nearly flawlessly no matter the load, cutting bass response below 100Hz was a conscious decision. And, noting how airy and clear Sprout sounds, I get it. But I’d be happier choosing that cut myself than it being part and parcel to Sprout’s sound signature.

How about loudspeakers?

On paper, PX’s Class-A 50 watt/channel amp betters Sprout. But in use, Sprout handles low-Ω bookshelf and living room speakers far better. Even when watching movies, Sprout dishes out clearer dialogue, and a lot less crosstalk between lows and highs. Of course, just like its headphone out, Sprout’s power amp section is sub-bass shy. Of course, most bookshelf speakers won’t even hit 70Hz without a major dip in frequency response, so Sprout isn’t losing anything. And it handles impedance swings better than the PX, ensuring contrast and detail levels are high all while avoiding the worst distortion.

It is a GREAT power amp.

Why PX?

So why would you choose the DACmini PX over the Sprout? Build for one. It’s a bit more solid. It’s also way easier plug into and out of. If you’re not into wood, it’s matte metal will do you good. Oh, and while it has trouble driving low-Ω loads, it nails a flat 20 – 20.000 Hz frequency response as both a pre-amp and a high-impedance load amp. Then there’s optical, which for some reason, Sprout lacks. If you’ve got an TV, or basically most decent HiFis from like the 1990s on, optical’s there. And while optical has a host of problems, cutting it out isn’t a solution. Finally, it comes with an AC/DC converter that obviates the worst ground hums.

Why Sprout?

It’s easy: Sprout’s headphone amp is better, and so its its loudspeaker amp. It’s got glorious bluetooth. Yeah, you can say goodbye to wires. Your mates can come over and sync to Sprout in a jiffy. It drives loads both large and small, nearly to perfection. And, it costs 200$ less.

End Words

While obviously a design decision, Sprout’s hard high-pass filter will put off some listeners. But apart from it – and if you’re flat is perfectly wired – it is nearly a bulletproof design. Great drive for both speakers and headphones, great clarity, space, and contrast. As long as you don’t count on fiddling much with its back panel, and especially if you love Bluetooth as much as I do, Sprout is gold.

It just works.

If Sprout is this capable at 800$, I can only imagine of what PS Audio’s BKH Signature Amplifier at can do.