Hardware Reviews

Moon 340i D3PX


 Even if we like to style ourselves as purists, and in the main regard audio separates as the only way, there is still a lot to be said for the well-conceived all-in-one box. Take the Moon 340i D3PX for example. No, the product name doesn’t trip off of the tongue very elegantly, but this integrated amplifier which has a built-in DAC and a phono stage – and outputs a claimed 100 Watts into eight Ohms and double that into four – is positioned as an exemplar of functionality and value.

The 340i D3PX doesn’t cost a huge amount of money, all things considered. And, as I discovered during the time I had it in my system, it has proper sonic credentials. Buy a 340i D3PX, add some speakers, a turntable, a streamer and a few cables all of decent but not excessive provenance and, some of us might say, job done.

Readers who’ve looked at my brief bio here on The Ear will know that I am all about two things: audio as a means to a musical end, rather than an end in itself, and value with a capital V. Thus informed, they will immediately understand how I approached this evaluation of the Moon. Can we buy better sonics? Of course. But no-one who has fished in the high-end audio pond for any length of time can fail to have noticed that the law of diminishing returns is only too real. 

The question is, for the price does the 340i D3PX provide enough of what truly matters in music reproduction to hold our interest. We can buy the Moon configured just as a straightforward integrated amplifier for the grand sum of £4,100. In this configuration it is called the 340i X. But when it’s only a further £800 to add the DAC and a phono stage as factory-installed options it’s hard to see why many people wouldn’t do so, particularly as both add-ons are priced so keenly. The extra money, by the way, also adds D3 (DAC) and P (phono) to the product name, thus we end up with 340i D3PX.


The 340i D3PX is quite a lump, getting on for 15kg in weight and is 42.9cm wide (nearly 17 inches). On the back are four single-ended inputs, and a pair of XLRs for pseudo-balanced connection. If the optional phono stage is on board, then leads from a turntable must be connected to single-ended input No 4. The DAC has three S/PDIF inputs and a single USB inlet. In addition to a mains socket and four speaker binding posts there is a 12V trigger socket, and two sockets for Moon’s SimLink inter-component signalling scheme. There’s an RS-232 port for custom automation or integration via a DB9 connector, and both variable and fixed RCA preamp-outputs.

On the front panel is the rotary volume knob – more of which later – a red multi-dot display, buttons to allow inputs to be selected, as well as mute and standby, a quarter inch headphone socket and a mini socket for personal media players. A remote control is also provided. Aesthetic appreciation is in the eye of the beholder; the review sample had a black front book-ended by bulbous silver cheeks, if it was my money I’d have the all-black variant.

Sound quality
It’s when we first turn on the 340i D3PX that things begin to get more appealing. The review sample, according to John Carroll of distributor Renaissance Audio, was un-used. He said that it would take around three days of being powered before beginning to sound as intended, with complete burn-in predicted after around 350 hours of use. Moon advises leaving the amplifier powered all the time. The 340i D3PX consumes 27W on standby and 29W on idle.

That it required time to settle was not in doubt; out of the box it sounded bass-heavy and rather closed in, so I set it to one side, powered and with a FM tuner connected. When I returned to it thirteen days later the Moon sounded much more like it, with a satisfactorily wide and even subjective bandwidth, tightly controlled bass, and strong transparency. Over further time it continued to improve, gaining transparency, richer tonal colour, improved dynamic texture and more sweetness at the top end.


Using it to amplify the output of my Denafrips Terminator Plus DAC and PS Audio Stellar phono stage, and driving 90db efficient PMC MB2se speakers, the results were surprising… in a good way. I occasionally listen in my four by six metre room at peak SPLs of 90dB plus. My reference Bryston 4B Cubed power amplifier, delivering some 300 Watts per channel, does it without breaking a sweat. On some recordings the experience transcends the purely aural and becomes properly physical too, the low end massaging body parts other systems can’t reach.

The 340i, with some 200 Watts fewer per channel, proved that it could almost match the Bryston for slam and low-end reach, and while the fins on the side of the Moon did get hot to the touch after a few hours of this kind of treatment, the conclusion had to be that not all Watts are necessarily the same. Yes, I know that last comment is arrant scientific nonsense, but I offer it in a tongue-in-cheek way to make the point that while the 340i may not have such impressive on-paper bragging rights, it can still make a very entertaining and satisfying go of things, driving the room plenty loud enough, thank you, without compression or clipping. With such a strong performance on tap, it almost feels like ingratitude to mention a minor blemish, but the 340i’s volume control is a little idiosyncratic; it is very aggressive, over the first 45 or so degrees of rotation going from no sound at all to, in my room, almost  too much. This will of course vary with loudspeakers however.

There’s a good measure of dynamic agility and texture to go with the pyrotechnics; leading to a degree of transparency than is uncommon at this price point and actually quite a bit above. The 340i threw the windows wide open on familiar performances, allowing the household to hear spatial, tonal and dynamic details that might be lost in the mix when using lesser amplification. The 2011 album from the Tingvall Trio, Vagen, entranced all over again when I used the Moon to amplify the feed from the Denafrips DAC. On some tracks we heard subtle cymbal work that had not been obvious before, while the location in the sound stage of the three instrumentalists was drawn with confidence, both side to side and front to back, overall with more specificity than we had heard with some other amplifier combinations, a few costing quite a bit more than the 340i.

Similar gains in resolution were heard when playing Slowly Rolling Camera’s album Juniper, for example on track three where Mark Lockheart’s tenor sax was rendered with very satisfyingly breathy dynamics, and warm, naturally blatty tonal density. The 340i’s designers have also quite clearly paid close attention to the matter of timing, using short signal paths and other measures to give the amplifier a snappy impulsion that drives music forward and makes listening sessions an exercise in foot-tapping engagement rather than detached ennui. In this important yet often misunderstood element of musical reproduction I’d put the 340i right up there with the best. Yes, it really is that good.


I wanted to try my vinyl rig into the on-board phono stage. Six screws undone, 340i lid off, toothpick in one hand and user manual in the other, it was the work of no more than five minutes to click the 340i’s DIP switches to achieve the correct impedance for my Soundsmith Paua II moving iron cartridge. There’s a useful range of adjustment available – 10, 100, 475 and 47k Ohm resistance, and 0, 100, 330 and 430 pF capacitance, with a choice of four gain settings from 40 to 66dB, as well as both RIAA and IEC equalisation. Changing the settings is not the kind of thing you’d want to do every day, but the average owner is probably only going to do it once, and in which case the required hands-on action is unlikely to be viewed as particularly onerous.

Settings established, the onboard phono stage proved to be more than competent. The same went for the DAC board, built around an ESS SABRE 9018K2M delta-sigma chip. It does DSD up to 256, PCM to 384kHz, and makes a perfectly satisfactory fist of both. There’s no doubt in my mind, though, that the integrated pre- and power amplification elements of the 340i are the sonic stars of the overall show. Fed by the Denafrips Terminator Plus and the PS Audio Stellar, as an amplifier the 340i proved able to live comfortably with the relatively more exalted company.

That’s not to criticise the DAC and phono modules: they are what they are; honest, entry-level functionality provided at a frankly bargain-basement price. If all-in-one convenience and cost-paring are the aim, then, I think, we’d be daft not to specify them. As a complete package therefore, the Moon 340i D3PX offers buyers a compelling ratio of price to performance. It thoroughly deserves a strong recommendation.


Type: integrated stereo amplifier with phono stage and DAC
Analogue inputs: 3x RCA, XLR, 3.5mm minijack 
Phono input: MM/MC with variable loading
Digital inputs: 2x coaxial, Toslink optical, USB
Max DAC resolution: 32-bit/384kHz, DSD256
Analogue outputs: tape out RCA, pre-out RCA 
Bluetooth: none
Headphone output: 6.3mm jack
Speaker outputs: 5-way binding posts
Power Output: 100W into 8 ohms; 200W into 4 ohms
Dimensions (HxWxD): 89 x 429 x 376mm
Weight: 13kg
Warranty: 1 years (10 years with registration)

Price when tested:
amplifier £4,100
DAC and phono stage £800
Manufacturer Details:

T +1 450 449-2212


integrated amplifier/DAC/phono


Kevin Fiske

Distributor Details:

Renaissance Audio Ltd
T +44 (0)131-555-3922

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