Moonriver 404 = Midrange Magic


The Moonriver 404 (retail $3,500, inc. remote control. optional DAC and phono stages) has recently received a running change/upgrade and all I can say is that while the amplifier before was great. With the lowering of the noise floor, increase in dynamics; a lot of micro-detail is allowed to shine through the music. Spent the week alternating between the Graham LS6 and the LS5/9 and all I can say is WOW !

On Afie Jurvanen's fourth Bahamas album - Earthtones (2018) we find the guitarist/songwriter joined by the stunning rhythm section of Pino Palladino and James Gadson. With decades of legendary albums to their individual credit, the bassist and drummer played together on D'Angelo's superb Black Messiah (2014). Jurvanen sought them out due to their work on Black Messiah and wrote much of Earthtones with these particular collaborators in mind. The result dials up the soul and slow-boiling funk while retaining Jurvanen's laid-back demeanor, all to steady, head-bobbing effect. A prime example of this is the slinky “Any Place." The midrange magic is palpable as Alfie Jurvanen sings:

Now my master has no master plan
To see us all through
As they say, the show must go on
Can't keep my public waiting long
Can't live my life inside a song
'Cause every song ends


Jasmine Thompson singing a cover version of Tears For Fears - “Mad World”, a dramatically slower version than the original. Listening to her sing, you forget about the equipment as you get caught up in the lyrics and sucked into the emotion that Ms. Thompson is conveying. It's a sad song, but you feel compelling to follow the lyrics as you get caught up in the story.

What can I say about Lalo Schifffrin’s "Ice Pick Mike" from Bullit (Soundtrack 1968) ? OMG, here is another sonic spectacle delivered with aplomb. If the BBC designs have a fault, it would be of omission, but there are no annoying egregious artifacts. The speakers absolutely disappear and throw a soundstage well outside the cabinets. So are we talking about the amp or the speakers; pretty hard to find fault with this compelling synergy.

Yello’s - "Oh Yeah" - 2009 remaster from Touch (deluxe, 2009) leaves listeners gobsmacked as they struggle to comprehend how the $3½k Graham LS6 can deliver so much bass from a single 6” woofer. The drive is relentless, the sound effects are a blast & the Swiss duo are having a ball ! Great, great fun. We’re having a party, what are you waiting for ?
Are there more expensive amplifiers that deliver greater bass articulation - undoubtedly.
Are there more expensive amplifiers that deliver greater HF extension - of course.
Are there more expensive, more resolute amplifiers out there - indeed.
But do all of those expensive amplifiers deliver the midrange magic that makes our hobby so special? NO, not at all. Though the Moon River 404 clearly can within its power envelope and the right synergistically matched speakers.
We are shipping amps out next week across the country and hope you get a chance to check out Moon River’s first remarkable instrument. For example, replace the Graham LS5/9 with a Harbeth Monitor 30 and I don’t doubt that you will have goosebumps. Ask your local dealer about the Moonriver 404, thank you for reading.
Philip O'HanlonOn A Higher Note
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@fjn04 I owned the 404 Reference for a couple of months, but really only enjoyed it with a cheap FX Audio tube buffer connected to the tape out.  I’ve found that I prefer a little tube harmonics and dimensionality somewhere in the chain.  I guess my point posting is it sounds like you already know what you like, and don’t second guess yourself.  Or go with a solid state integrated that many people claim sounds “tube like” (which of course means different things to different people).  It was an expensive lesson to reinforce what I already knew about my own listening preferences.

Philip is a class act, and since he is now distributor for Moonriver,  likely doesn't want to chime back in here. This, due to people being hypersensitive about pushing the line. But I can understand that. The Luxman 550 didn't quite do it for me, so I'd be interested to hear the Moonriver. I still have the Harbeth 7's. I don't know if I could be happy with solid state, but haven't given up on the idea. 

@gryphongryph absolutely concur - the idea of replacing a graham ls5/9 or LS6 with a Harbeth throws all perceptual credibility to the wind. 

Extracts from John Atkinson's measurements of the Reference version:

The manual says that the preamplifier output impedance is "a few ohms." I measured 96 ohms at high and middle frequencies and a higher 1426 ohms at the bottom of the audioband. However, I had problems measuring the behavior of the 404 Reference’s preamplifier output due to the presence of high levels of ultrasonic noise (footnote 1). I believe this noise, which had a center frequency around 1.7MHz, was confusing the input of the Audio Precision SYS2722. This noise was present with both samples of the amplifier, and could be the cause of a "buzz" Jason Serinus told me he experienced with the preamplifier output.

Though the 404 Reference’s maximum power is specified as 50W into 8 ohms (17dBW), using our definition of clipping, which is when the output’s percentage of THD+noise reaches 1%, fig.4 indicates that the amplifier clipped at 39.5Wpc into 8 ohms (14dBW). The Moonriver clipped at 60W into 4 ohms (14.8dBW, fig.5). (Both graphs were taken with both channels driven. The first sample’s right channel behaved identically.)
I for one would never swap out a Graham Audio LS 5/9 for a Harbeth 30.1 or 30.2
Not sure this guy has heard the two speakers in question, probably not..
Curious to hear how the Signature version sounds.
just wonder if 50 wpc can move enough air.
The phono stage originally had 100 ohm resistors soldered into place. In the new design, the resistors are inserted into posts, no soldering or tools needed.The original MC design had 40dB of gain, the new revision has 60dB.
The amp is a lot quieter than before.
The volume control on the preamp has twice as much travel as before.  Higher quality speaker binding posts.