Moon by Simaudio 230HAD headphone amplifier

Headphone amps and amp/DACs
Simaudio Moon 230HAD
Moon by Simaudio 230HAD headphone amplifier

More than a year ago Hi-Fi+ favourably reviewed Moon by Simaudio’s superb Neo 430 HAD headphone amp/preamp/DSD DAC and found it to be a world-class product—one even the most particular headphonistas could happily embrace as a benchmark component. In practical terms, the only drawback with the Neo 430 HAD was that its £3,800 asking price placed it beyond reach for a number of otherwise passionate and sound quality-conscious headphone enthusiasts. What was needed, some thought, was a headphone amp/DAC similar in overall sonic characteristics to the 430HAD, but that would sell for a more manageable price. Happily, Moon by Simaudio had this very idea in mind when they created the Neo 230HAD headphone amp/DAC, which sells for £1,500.

How did Moon by Simaudio achieve such a dramatic reduction in price without cutting significant sonic corners? As is always the case in such design plans, the answer lies in deciding exactly where and how acceptable compromises can be made. If we take the original 430HAD as a starting point, then here are the cost-reducing changes Moon implemented in developing the 230HAD.

First, Moon decided that unlike the 430HAD, which features a fully balanced amplifier, the 230HAD instead would incorporate a single-ended only amplifier. Along with this decision came a concomitant choice to roll back the 230HAD’s power output specifications to what might be described as a ‘moderately powerful’ level—this in contrast to the 430HAD’s prodigious 8 Wpc (!) output capabilities.

Second, Moon elected to scale back the size (though not the quality) of the 230HAD’s power supply, which in turn meant the 230HAD’s circuitry could fit within a half-width chassis as opposed to the full rack-width chassis used for the 430HAD.

Finally, Moon utilised a traditional high-quality motorised-Alps volume potentiometer, in contrast to the sophisticated optical encoder-controlled 530-step attenuator of the 430HAD, which was itself derived from the company’s Evolution-Class products. The use of a potentiometer is a significant cost saving, even if it comes at the expense of the stepped attenuator’s ultimate transparency and ability to maintain tight inter-channel balance.

Taken together, these choices made good sense in that the sensitivity ratings of many top-tier headphones have steadily been climbing in recent years, meaning that as a rule there is less of a premium on sheer headphone amp power output than there used to be. The one potentially significant trade-off, though, is that the 230HAD’s 115dB signal-to-noise ratio is not as good as the 430HAD’s tomb-quiet 120dB signal-to-noise ratio—a difference partly attributable to the single-ended vs. fully-balanced circuitry of the two models, but also attributable (I suspect) to the 230HAD’s somewhat less beefy power supply.

On the digital audio side of things, it appears the 230HAD and 430HAD use similar if not identical DAC sections. The DAC sections of both units can handle PCM files at 16-32 bits/44.1 – 384kHz, and can decode DSD64, DSD128, and DSD256 files. Quoted frequency response, bandwidth, and distortion figures for the two units’ DAC sections are essentially the same, which is good news for prospective 230HAD buyers.

Then, as a final cost-reduction measure, Moon has configured the 230HAD so that it deliberately eliminates all non-essential features from the 430HAD, thus making the ‘junior’ model as simple and affordable as possible. For example, where the 430HAD had user-adjustable master gain settings and provided built-in user-selectable crossfeed circuitry (designed to provide a more three-dimensional, outside-the-head listening experience for headphone users), the 230HAD foregoes both features. Likewise, where the 430HAD sported extensive home automation-orientated features such as a 12V trigger output, an IR sensor, an RS-232 control port, and Simaudio’s SimLink system, the light and lithe 230HAD omits all of the above.

In theory, either the 430HAD or the 230HAD can be used as primary preamplifier/DACs in speaker-based hi-fi systems. In practice, though, it’s clear the 430HAD stands more as the versatile, audio rack-mountable, full-featured preamp/DAC/headphone amplifier, whereas the 230HAD presents itself as the streamlined, ‘everything-you-need-and-nothing-you don’t’ desktop model that likely will be used primarily for headphone listening.

With that said, however, here is an interesting factoid to consider. If you compare the performance specifications of the 430HAD and 230HAD side by side, you will discover that—apart from noise and power output specifications—the two units appear virtually identical. On paper, then, it would seem the 230HAD and 430HAD share a significant amount of sonic ‘DNA’, despite the obvious differences between the two. But this raises a key question: Are these seeming similarities borne out in real-world listening tests? In a word, yes, they are.

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