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The remote option is most unusual. It obviously doesn't add a motor to the master knob. Thus having the latter fully counter clockwise can't produce any sound no matter how vigorously one presses the up button on the wand or in dying hope observes the LED confirmation of the display which shows received commands. That's because the remote only operates "within a ±10dB window against the level set by the main volume, i.e. in 4 steps up and 7 down. There's an additional 20-30dB of attenuation or full muting with the wand's attenuate button." The plastic casing with its IR circuitry sits inside the wooden box buffered by simple foam squares all around. This leaves some play. Shaking the wooden case thus elicits a bit of inner movement. To be blunt, €900/$1.200 for this strange and functionally crippled contraption with tiny 9V switch-mode power supply is excessive. It also looks odd and adds two cables to the usual spaghetti salad behind the gear. It does however allow the amp to be installed out of sight whilst retaining a modicum of volume control.

For the obligatory inside tour one has to move beyond the four strategic box shields. If one does here's what the bird's eye view on the main board would show which is usually concealed beneath the biggest internal case.


Here we go straight to the 2-channel International Rectifier amplifier module. It piggybacks on SPEC's main board right in front of the low-pass filter air-core inductors and caps. The short flying leads from the main board to the output terminals leave via massive screw-down blocks. This termination method is far sturdier than the ubiquitous solder joints to a PCB. Its presence here indicates very high current flow at that precise juncture.


The dual-mono IR module runs two clocks per channel. The main board contains a three-pole external clock switch (likely an assembly feature to fix the precision trim pot setting) and a socketed International Rectifier version of the Japanese Tachyonix Corp. 3310 volume controller chip. The heat-sinked module accommodates three 78M12CT voltage regulators.


Next we see one of the two vertical boards which are usually ensconced in their own box shields as well. Here one comes eye to eye with two more of the special capacitors Shirokazu Yazaki talked about.

What follow now are closeups of the locking power rocker; the main volume control; the input selector; six capacitors wrapped in sticky ERS-type shielding cloth...

... two views of the Japanese power transformer from Kitamura Kiden which also supply Esoteric; and two views of the power supply section.


As this inspection confirmed, the RSA-M3EX is very far from just another ICEpower, Hypex, PowerSoft, Abletec, AnaLight or Pascal affair. Just so that plain fact wouldn't safeguard it from being compared directly to such 'off-the-shelf' D-class competitors.
Wyred4Sound mAMP [ICEpower] | Roksan Oxygene [Hypex]
For modified Hypex UcD400 with linear power supply and Lundahl input transformer I had the $5.000/pr AURALiC Merak monos on loan. For Pascal I had the modified S-PRO-based €3.250 Gato Audio DIA-250 with IR DirectFET output transistors like the SPEC. Both are from rather to very much more cost-effective. Both also offer considerably higher power. The Danish integrated even adds features like a 24/192 DAC with asynchronous XMOS-based USB, a beautifully legible dot-matrix white display and remote control over the amp's complete volume range.
AURALiC Merak | output section of Gato Audio's DIA-250
Well prior to any listening yet, the gavel thus came down hard on the RSA-M3EX's price and its very peculiar also very costly add-on remote control. Nothing like a bit of competition to keep things honest. With that out of the way, how about sonics? For that assessment I'd use two very different speakers - the soundkaos Wave 40 and the AudioSolutions Rhapsody 200.
The first is a 92.5dB Raal ribbon-augmented German 8-inch widebander in a complex Swiss tone wood enclosure with very short line/scoop loading and low-order filters. This is the type of speaker conventionally mated to low-power SET amps (or in my own case Nelson Pass' SIT-1 transistor equivalent). The second is a typical 'muscle-amp' speaker by virtue of a challenging impedance curve and seriously underdamped dual-port bass alignment. It thrives on high damping factor i.e. low output impedance. As a 5-driver 3-way with higher-order networks, the dual-woofer floorstander also responds well to power. To keep things honest against traditional amp topologies I'd use the aforementioned FirstWatt SIT-1 monos; Crayon Audio's CFA-1.2 which despite its medium power output handles the Rhapsody 200 beautifully and sonically can be thought of as a functionally and power-enhanced Bakoon AMP-12R; and the DC-coupled very affordable but boffo Job 225 which is a bit less refined but more powerful. You could say that the Japanese challenger had its work cut out for itself.