Project Receiver Box Review (Pt.2) – Little Power House of an Amp

Introducing a Little Power House / Powering up False Start / Usability of the Receiver Box / Driving Full-Range Tower Speakers / Driving Inefficient Bookshelves / Green Cred for the Pro-ject Receiver Box / Concluding Remarks

Stock photo of the Pro-ject Receiver Box S from their spec sheet, but this is exactly what mine looks like.

Stock photo of the Pro-ject Receiver Box S from their spec sheet, but this is exactly what mine looks like.

Introducing a Little Power House

[This is Pt. 2 of the Review of the Receiver Box S. For Pt.1, please click here ]

Proponents of Class-D amplification (aka chip amps) are quick to point out that Class-D is not a “digital” amp. I suppose the idea that a little computer chip can sound as good as a bunch of large capacitors, heat sinks, power supplies with lots of wire and circuit boards, is a bit controversial. So they prefer to not call it what it is: a digital chip that approximates the analog sound. Now when well executed, that approximation is pretty darned close, but the problem is that it often isn’t well executed at all. This gives this whole category of amps a bad name and tends to make folks not want to call it a digital amp.

Pro-ject’s Receiver Box S could never be made that small and still deliver 25 watts of power without using a chip, so that is what it is. That said, unlike most of the lower quality stuff made in far away places, this amp is actually well executed; very well, actually. The sound still has a very Class-D character, though and it is not without its quirks, one of which resulted in a delay of a couple of months to get this article written, but it is still a nice little amp.

So let’s see how it performed.

Powering up False Start

One thing proponents of Class-D amps will swear up and down is that the technology is solid, that the amps are capable of incredible feats of performance, and that they are indestructible. That has not been my experience, especially with the many inexpensive amps I’ve tried. This one was also problematic. It worked fine for a couple of weeks and then, I plugged it in wrong, and poof, I bricked it. The fact is that Class-D amps are extremely sensitive because they have a single chip at the core and unlike the big iron, they have very few other parts to take the brunt of a mistake.

The manual nonchalantly states that one should plug the power cord into the back of the device first, connect it to the transformer brick that dangles on the second cord, and then plug that cord into the wall. Id did it in reverse order and after a very soft pop, it gave up all signs of life. It wasn’t entirely my fault. The transformer brick dangling from the back of my cabinet had loosened the connection to the Receiver Box S, so I naturally went to plug it back in… but I did not unplug the rest of the cable-brick chain before doing so. This is one big reason I hate transformer bricks, they cause problems just like this one.

Anyhow, the dealer went above and beyond the level of service I typically experience with inexpensive electronics (Amazon, are you reading this?), and offered to cross-ship a new unit right away. Three weeks later, a brand new little Receiver Box S arrived. I unpacked it that night, wrestled with the darned thing to get all the cables plugged in (see Pt.1), took care to plug the power cord in in the right order, and for good measure placed the transformer brick next to the receiver from now on. I grabbed my trusty Logitech Harmony remote  and I was back in the listening chair ready for some critical listening.

 Usability of the Receiver Box

The interface is pretty straight forward. The main < and > buttons are OK for changing volume, but I really would have preferred a rotating knob. Would it have increased production costs that much? Heck, I’d pay an extra $10 to have it. The display changes to show what the volume is when you push the buttons, but it does feel a little anemic at times. Pro-ject, please just add a rotary volume knob in the next version.

What is also annoying is that pushing the buttons sometimes moves the whole Receiver Box. The thing is not lightweight by any stretch and the cables dangling behind it help keep it steady too, but this is another negative consequence of using push buttons instead of a rotary knob. It was an issue every time I forgot to also hold the Receiver Box down with my other fingers.

The input button sits right next to the volume buttons and is labeled with a spacey-looking “ * ”. I occasionally pushed it by mistake with my big fingers, but labeling it “ * ” is also not intuitive. I realize Pro-Ject wants to make the interface international and not leave people in other countries out, but anyone who’s buying a stereo is going to know enough English to figure out the word for input. Heck even I can figure out what it means in Swedish, German, Italian, and I’m sure that the Japanese character for it would be pretty easy to recognize after a short while too. Sorry, but I’ve never considered “ * ” to mean “input.”

I’ve already mentioned (in Pt. 1) that the remote is irritatingly small and cheap-feeling. I also hate the squishy-snap type of buttons. It makes it hard to know when you’ve pressed the button. The layout also confusing with the “M” buttons surrounding the direction arrows. Figuring out how to set and erase FM station presets was a pain, and the manual was barely adequate. I did figure it out, but it wasn’t quick. Searching for stations was also a chore, mostly because of those irritating buttons. The rest of the remote is pretty self-explanatory, but it isn’t a conventional layout, either.

One final thought, although this is the case with many electronics, is that the display is small. In order to tune the receiver, you have to be very close to it so that you can see the station. Granted, the numbers are large-ish and screen real-estate is a factor on such a small box, but I would have preferred an even larger screen. LCD screens aren’t that expensive these days, so I really don’t think it would add that much to the manufacturing costs to add a larger screen. The rest of the info on the screen is even smaller, by the way. The tuned station and volume are reasonable big, but the other info is tiny.

Maybe I’m being unreasonably nit-picky about these little quirks. Or I’m just getting old, codgety and my vision is going. Or maybe they really are irritating quirks. I’ll go with the latter.

Driving Full-Range Tower Speakers

I like small electronics, and my current “reference” in the small department, is my British Musical Fidelity X-150 Integrated Amplifier. This little monster puts out a whopping 80 Watts of deep grunting power. It is a perfect match for anything up the chain that sounds bright. But to call it small, might be an understatement. Yes, like much of the Musical Fidelity gear it’s half-width, but it’s not really small and it was never going be concealed under the Pro-ject Receiver Box S. I’ve been using the Musical Fidelity amp with good results with my irritatingly hard to please Zu Audio Soul Superfly speakers. At 16 ohms a 1-watt headphone amp can drive the Superflys, but that can sound brittle. P.S. “Superflys” – how cool of a name is that for a pair of speakers – kudos to Sean Cassey & Zu for thinking of it.

Anyways, I know a tubed little SET amp would do wonders with the Superfly speakers, but I am thoroughly disgusted with the inverse relationship with power on the tube-side of this hobby: the lower the watts, the more expensive the amp. Screw that; so I have been intentionally boycotting tubes and trying to find a decent solid state amp – the Musical Fidelity seems to play nice with the Superflys. But how did the Pro-Ject do?

At just 25 watts, it’s obviously not as powerful. Actually, with my 16 Ohm speakers, that actually drops the power down to 12.5 watts per channel. The other problem was that Class-D amps don’t gel well with my Superflys. Actually very few amps do, but Class-D amps really don’t. Because Class-D amps are notoriously fast and the Superflys are too, this just makes for a very clinical sound with very little life to it. I won’t go so far as to say it sounds unlistenable, but it does tend to sound a bit boring, maybe even irritating, so much so that I usually listen to other gear. And that has been my experience with Class_D amps connected to the Superflys.

Weeeellll…. I’d like to say that the Pro-Ject Receiver Box S was different, but it wasn’t. It still sounded boring. That said, it sounded better than what I had heard from Class-D up to this point. The midrange was better fleshed out and the bass was nice and tight. Treble was OK, too. Granted it wasn’t Musical Fidelity quality sound by any stretch, but unless we are comparing them side by side (and who really does this except audio geeks, anyhow), the Pro-Ject Receiver Box S was doing pretty good. Time to try another speaker.

I also happen to have a pair of Sonist Audio Recital 3 speakers (review coming soon). These are stunningly beautiful speakers and I bought them because of the looks and the fact that the late Randy Bankert, who I had met at a few audio shows was a really nice guy. OK, they sounded decent at the show, too, but to be perfectly honest, it was the gorgeous solid wood cabinets that made me open my wallet, and boy am I glad I did. Those ribbon tweeters are amazingly smooth and such a joy to listen to when they are tasked with smoothing out bright sounding gear. They are also very sensitive speakers, so they do fine with low-power amps. Amazing speaker, really.

Sitting on the floor between these two beautiful and elegant rosewood towers, the “digital” Pro-Ject Receiver Box S was not only dwarfed in size but also completely out of its esthetic element. I doubt many people will pair these together, but the combination actually worked well. Even more so than with the Superflys, that little Receiver Box showed its mettle as the same bass and midrange played in the room. Imaging was there as well. The treble still a bit anemic, but it was an improvement, most probably because we were now comfortably in 8 Ohm territory and the Receiver Box S was more at home there.

This got me thinking, what if we went in the other direction and tried some hard to drive speakers? Class-D proponents are always talking up the chip’s power handling into lower resistances. Paul McGowan of PS Audio even told me once that you could short the terminals on his HCA-2 amp and it would just peacefully go into protection mode. I never tried this, but I did use it to drive Magnepan speakers and it never complained. It was a great match. Now I don’t have the Maggies anymore, but I do have some pesky British bookshelves that could give this little Pro-Ject a workout.

Driving Inefficient Bookshelves

Most every piece of “kit” (as the Brits like to say) that comes from the Isles, and harkens back to some past electronic glory, is hard to drive. Don’t know why, but it’s curiously common. Wharfedale’s China-assembled little 80th anniversary Dentons are no exception. The online reviews aren’t exactly positive, but I would venture to guess that this is because of a lack of power to drive the little monsters. Of course, they also have a dark character to them, also very British, which ironically makes them a poor match for anything also British. Naturally people are pairing the Dentons with British amps, and I can tell you as a fan of Musical Fidelity, Creek, and Rega, that has not been a good match in my home. Yes my Musical Fidelity X-150 has power, but not the synergy. So how would the Pro-Ject do with the Wharfedales?

In one word: wow!

Maybe it’s the pairing of tight-as-steel German engineering with broodish British wood, but this little Pro-Ject can inject some life into the stodgy Dentons. It also didn’t run out of steam when turning up the volume. Imaging improved and lo-and-behold, we had treble. While it wasn’t the ethereal angels playing trumpets in the sky above the Brandenburg Concerto, it was enough treble to wake up Miles’ Sketches of Spain. Very impressive indeed. To be frank, I had not been very happy with my Dentons either. Until I paired them with the Pro-Ject, that is. This combination actually works well, and I think I have found what the cold-fish Dentons had been missing: chips, digital chips!

At 4 Ohms, by the way, the Receiver Box S puts out an additional 5 watts of power, for a total of 30 watts. Granted this isn’t the doubling of power we see with much more expensive amps, but it’s certainly a welcome addition considering how little watts there are to go around in the first place. Let’s be honest, 25/30 watts of power isn’t going to blow the roof off of anything, but it’s quite a feat for a little 4x4” box. That it actually sounds good doing it is a big relief.

Also on hand, I have a pair of also tough-to-drive Pro-Ject Box 5 speakers (review coming). They also sounded quite good. Not in the same league as the Dentons, but with the Pro-Ject, they also sounded better than what I had heard before. This pairing is probably the one most people buying the Receiver Box S would choose, so that is what Pro-Ject engineers were going for. There is definitely something to be said for brand synergy. Nicely done.

Green Cred for the Pro-ject Receiver Box

The Pro-Ject Receiver Box S is tiny, which reduces its carbon footprint – it is cheap to ship, cheap to manufacture and it doesn’t take up much space. More indirectly, the small form-factor also reduces expenses and resources in other ways  – less and smaller cabling inside, smaller circuit boards, faster assembly, and a simpler design because there isn’t much room for complexity, anyhow. Those are all green values.

At just 4x4" it is certainly small, but don't let the size fool you, this little wonder packs a wallop!

At just 4x4" it is certainly small, but don't let the size fool you, this little wonder packs a wallop!

Because it is a Class-D amp, it also requires very little energy to play loud, even very loud. This type of amplification also doesn’t require a large transformer, thus also reducing size. Likewise, because all that power comes from a small chip, the Receiver Box S also produces very little heat. In my tests, I ran this little amplifier for hours on end, often at rather high volumes and it never became very warm – actually I think the LED display produced more heat. Yes, computer chips can get hot, and I’m sure I could make the Receiver Box S overheat in extreme conditions, but most people would never do this. Simply playing it loud, will not overheat this amp. Comparing the heat produced by my Musical Fidelity, the difference is striking – I can usually make that amp too hot to touch after just an hour.

The Pro-Ject is made in Austria and the Czech Republic. Some parts may come from the Far East, so I can’t give it a complete blessing on that front. However, it is a world better than the many little amps that hail from the East, such as the flashy stuff listed on eBay from companies like Topping, Kinter, Lepy, and others. While they may provide some functionality, the quality simply isn’t comparable. In addition to low quality, they are more often than not manufactured by companies with much poorer standards for worker safety, lower worker compensation, and lax adherence to the environmental regulations that are in place in Europe. Every time we purchase from companies in the Far East to save a buck, that savings comes at a high cost to the workers producing it. When purchasing Pro-Ject equipment, we are adding another layer of guarantees that the product is of higher quality and fairly produced.

Concluding Remarks

It’s rare to find so much good stuff inside such a small package. For those of us hunting for green gear, it’s usually with some hard-to-swallow compromises that we end up with the gear we keep. Pro-Ject has some fixing to do when it comes to the cable connections, the cheap remote, and the transformer brick. I’m not sure if there will be a version 2.0 of the Receiver Box S because it looks like the company is focusing on the larger upmarket 8”-wide format of the DS line and leaving the smaller, more affordable 4” wide format behind. I can understand economic realities, but this is a pity, because the smaller size does provide advantages such as being more green. This little receiver will fit anywhere, and considering how good it sounds, that’s a huge achievement.

Needless to say, I was thoroughly impressed. For a mere $400, you get a complete receiver with FM radio, presets, a remote, 25/30 watts of power, the ability to drive inefficient speakers, two analog inputs, all in a little 4x4” package you can fit on a CD rack. The sound quality is comparable to larger and more expensive gear, and runs circles around mass-produced stuff from Best Buy and Amazon. The Receiver Box S is perfect for a dorm room in, a tiny studio apartment on the lower East side or in downtown Amsterdam. You can hook up just about any standard speaker, even a 4 ohm one, and you’ve got a complete sound system. Should you need to, you can pack up the entire sound system into a backpack in a few minutes. That’s pretty amazing engineering and gets my respect.

Is it truly green? Well it’s not made in the USA, but it is a whole lot greener than much of the gear out there. Despite some of the design choices that Pro-Ject has made, I highly recommend this little power house of a receiver.

Pro-ject Audio Systems / Box Designs 
Receiver Box S (product link) 
MSRP $399, available in Silver and Black 
Available through various resellers including Needle Doctor, Music Direct, Audio Advisor, Crutchfield and various other retailers.