Postscript to Audio Note M10 Line Signature preamplifier Review

At some point after my Audio Note M10 review is written, a reviewer has to make the decision whether to purchase the review sample or return it to the manufacturer. For me, this is generally a fairly straightforward process as, other than with respect to digital pieces, I seldom make changes to my system. In this particular instance, the decision was very difficult. On the one hand, the M10 Line Signature was clearly and by a rather appreciable margin the single best preamp that I had ever had in my system. In all honesty, it does things that I would not have thought were the province of a preamp. On the other hand, its price is comparable to that of a Mercedes SL-450. At some point during this deliberation, the M10 Line Signature began to develop low-level noise in one channel. Here it would have been very easy for the manufacturer to provide new tubes and then try to troubleshoot the problem over the phone. To their credit, Audio Note asked that I return the control section of the preamp to the factory so that they could run a complete diagnostic and ensure that something more serious was not happening. They promptly arranged for DHL to pick up the unit and, at their cost, airfreight it back to London. Although they quickly determined that a tube was at fault, they wanted to keep the unit and burn it in to ensure that the problem did not recur. Given that I was taking a break from work to visit a friend in California and attend the inaugural LA Audio Show, this seemed like a good plan. Two weeks later, the factory contacted me to arrange return shipping. At this point, Peter told me that while the unit had been at the factory they had decided to replace the 20-step attenuator (actually a multiple silver contact switch with discrete resistors at each position) with a new design that allows 36 steps, which they feel is sonically superior.

Shortly thereafter, I received the “modified” unit and installed it in my system. The sonic attributes described in the initial portion of this review remain true of the modified unit, but some further improvement in the sound is apparent. The new volume controls are everything that I could have asked for and more. The additional range of adjustment is more than adequate for my needs and, as a side benefit, I believe that the new attenuators result in a further slight reduction in distortion, an even lower noise floor, higher resolution, and a more natural presentation of bass. Note that I am not saying more bass or even better-controlled bass, as those areas have always been strong points of the unit.  In this instance, I am thinking more natural and more of one piece with the midrange and highs.

One of the things that I find most beguiling about the M10 Line Signature is its ability to take recordings that in the past I would have found unexceptional and somehow breathe life into them.  Don’t misunderstand, exceptional recordings still are exceptional; however, I am beginning to realize that many recordings that I might have passed over in the past are truly enjoyable. On another note, the bass being produced is exceptional both in terms of control and slam. Again, records that I do not remember as ever having real bass now are surprising me with their bass content.

While I am relatively certain what my decision would have been even without the new volume controls, it was another point in favor of keeping the unit long term.  In the end, I put my money where my mouth had been and wrote the check.

Copy editor: Dan Rubin