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Moscode 402Au Amplifier Review

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Service and Quality

Service is important when it comes to purchase of expensive, complex audio gear. In the course of the past twelve months I spoke with an embittered ex-distributor who couldn’t get the overseas manufacturer to respond to warranty service requests from customers. He was forced to abandon the company and absorb much of the costs of repairs himself. I have had the unpleasant experience of trying multiple units and finding them all to contain defects. I received outstanding customer support, but I simply became tired of malfunctioning units, so I switched to another brand.

What happens after the transaction is every bit as important as what is heard beforehand. There are responsiveowners and distributors, and there are unresponsiveones as well. I have had emails, interviews, phone calls etc. go unanswered. When that happens you can bet I develop a theory of how customers might be treated. I am hesitant to highly recommend a product without qualification if there is poor or no response from the manufacturer or distributor.

I mention this as I have encountered superior responsivenessfrom Moscode. I had received but not been able to begin using the amps until five days after their arrival.George is one of very few manufacturers who called me, not at review publication time, but early on, “… just to see how things were going with the amps.” In this particular situation that was a very wise move. I turns out that there was an issue with one of the amps. The left monoblock sounded absolutely shitty – completely unlistenable. All frequencies across the board were distorted to a point that even lyrics were unrecognizable. My first thought was that a tube was bad, but I worried since the distortion was, to my ear, likely not caused by a tube.

George had invited me to call him with any problems, and I felt he meant it. After I ran diagnostic tests to determine that in fact it was the left channel amp, I hesitatingly called him fairly late in the evening, later than I should have. But I wanted an answer as the problem was eating at me. George was frustrated as well, as he said he had never had an amp lose a channel as I had described. According to him, the design was fairly bomb proof.

Via phone, prior to returning the unit for repair, he had me remove the cover and check the rail fuses, which were all intact, deepening the mystery. As I scanned the interior looking for clues I saw it – the left lead from the torroid transformer was completely disconnected! I guess that wouldcause distortion. Our assessment was the locking connector had been pushed in just short of snapping tight and had wiggled out while in transit. George immediately admitted that it may have been an error on the assembly line, which also was logical.

Sometimes audiophiles forget that fallible humans make their gear, and they go ballistic if something is wrong. Woe be to the manufacturer who gives them a faulty unit! If one comes into contact with enough components over a lifetime at some point there will be transactional, shipping, build quality or service issues.

What do you think my impression would have been if George was unreachable or unresponsive? What if I had to sit with an inoperative unit for two weeks or a month? Some manufacturers and distributors seem unreachable despite repeated calls and emails. If I had a problem I might be stuck for weeks, and if you had the problem you might be stuck longer. I see a correlation between how a manufacturer or distributor treats the reviewer in terms of communication and the customer in terms of service. I weigh the responsiveness of the company liaison when considering how to recommend a product.

George has been responsive, even attentive, to my experience with the amps. I give higher than average marks to the company for its service. I would not be put off at all by the torroid connection mishap, as I am confident that a customer could easily reach help at Moscode and would obtain a solution efficiently. It turns out George was right, during the review period the amp has been bomb proof operationally. Beyond that, he has been a delightful wellspring of knowledge, as he has spent considerable time ensuring that I understand design and manufacturing principles behind it.

Inside the Moscode 402Au Amplifier

The “OTL/ESL Connection”

I enjoy it when combinations of daily activities, planned events, and the vagaries of life result in a new discovery. Little did I know when I visited with George at CES 2009, discussing a review of his 402Au, that I would be setting myself up for a bit of time travel; I would revisit an era in audiophilia when the OTL was the amplification system par excellence. I would like to say I had put “two and two” together, or better yet that I knew the history of Quad speakers and OTLs, but ignorance once again got the best of me. I’m simply blessed to have stumbled onto a similar combination again fifty years later!

Quad Electrostatic speakers were in development at approximately the same time as the OTL (Both in the late 1950’s). Quads have difficult, variable impedance, a true challenge to many amps. However, the Moscode was a big hit with the Quad, some said a match made in heaven, or at least state-of-the-art. Imagine an amp with stunning clarity matched with a speaker with famous openness and “honesty”. If only I had heard that combination. I am hearing a very similar combination. No, I do not have a Quad 2905, but I have something every bit as fantastic, the King Sound “the King” speaker, a simply masterful,full-range ESL under $10K (ESL fans will be very well rewardedfor checking out my review)!

Everything old is new again; at least that’s how I feel about the synergy between the Moscode 402Au amps and the King speakers. I have always adored the sound of panel speakers from the first moment I heard them. One piece of audiophile history I knew prior to reviewing was that the name Quad is synonymous with the mesmerizing beauty of the Electrostatic Loudspeaker, otherwise known as the ESL. Having heard the older models I can attest that they are magical in the midrange, and in their time a stunning accomplishment. Even now, decades after their introduction, the earlier Quad 57 and Quad 63 models have a loyal following despite their idiosyncrasies. Sometimes what you don’t know perfectly coincides with what you know, you just have to realize it! In ignorance I arranged a review of a combination of gear which mirrored that well loved older pairing, in this instance the Moscode 402Au and the King’s Audio “King” speaker.

No wonder George was excited when I told him about the King speakers! Actually, “hopeful excitement” might have best described his demeanor. He knew the history of OTL/ESL combinations and how immensely popular they were. Now, half a century later I was pairing the Moscode, the progeny of the OTL with a new breed of electrostatic speaker. Would the magic be found in this paring? Would the 402Au uphold the tradition of being a stellar amp for ESLs in particular?

I aver the King is the perfect speaker to put the Moscode amps through their paces. George has designed the 402Au to have a robust power supply, with capability of handling any impedance load supposedly.So, the fact that the King ranges from about 6 Ohms at 20Hz to about 1.8 Ohms at 20 kHz is no problem. These kinds of loads are a problem for some amps, case in point: the Azur 840W’s. While they handled the King speakers well enough in Mono Bi-Amp mode, their protection circuitry was tripped when set to Mono Bridged mode. The demand was simply too extreme, but thankfully, they were easily reset without consequence.

I found some good points of comparison between the Azur and the Moscode when both were in Bi-Amp mode powering the Kings.The Azur is an ultra pure solid-state amp. I have found it to be more clear and detailed than any Class D amp I have used to date. It has the capacity to “open up” the music like an upgraded CD player or turntable. On the other hand, the Moscode has a sense of tonal correctness and tremendous grunt in the bottom-end. I spent quite a bit of my time listening to the Ayon CD-2 player running directly intothese two sets of amps.The CD-2 has its own level control, so that one can streamline the rig and maximize the ability to hear the amp’s contribution.

The 402Au is an excellent argument for the benefit of tubes in an audio system for capturing the human element in music making. I enjoy the Azur amps very much and I feel they are a compelling choice for affordable SS amplification. However, as with most SS amps I have used, they trade some degree of warmth for detail. This, however, is where the Moscode 402Au excels. They brought a cashmere quality to a speaker constructed of Mylar and metal.

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