Moonriver Audio 505 MM/MC Hybrid Phono Preamp

We only got a brief sneak peek at Moonriver Audio’s cool new 505 MM/MC hybrid phono preamp in action at Munich High End 2023 back in May — more specifically, it was part of a top-shelf demo system comprising a Takumi TT Level 3.1 turntable, Moonriver 404 integrated amps, Aretai speakers, and Viablue cables in Halle 4 R10 (a.k.a. Hall 4, Booth 10) — but now it’s time to take a much closer look at it now that it’s officially on the market.

In case you were wondering and/or had a hunch about the company’s origin story, Moonriver is indeed named after the Henry Mancini/Johnny Mercer song of the same name, and all their products are designed, made, and hand-assembled in Sweden. (Moonriver is based in Malmö.)

Now that you know some Moonriver history, let’s get back to the 505. Designed with “audiophiles, record collectors, and vinyl freaks in mind” (their well-chosen words), the 505 phono preamp offers four inputs and supports adjustments “on the fly” with dedicated knobs and switches to match either/both MC or MM cartridge options without the need to switch the unit off, remove the cover, switch it on again, and wait for it to warm up.


According to Moonriver, the hybrid design of the 505 “combines the use of ICs and discrete solid-state circuits to form an ideal, high-performance and ultra-low noise circuit.” The company’s product design philosophy hinges on the idea that “the soul of the music is in the midrange . . . where most of the emotion, the passion, [and] the joie de vivre is contained.” Technically speaking, Moonriver feels that mid-oriented statement translates between 200 to 4,000Hz.

The 505 contains six separated power supplies, including 70,000uf total capacitance, and in dual mono operation. Each stage has its own power supply, including a linear discrete regulator circuit and a discrete noise-rejection circuit.

Using ultra-low-noise active gain stages, the Moonriver 505 is said to deliver a maximum gain of 72dB (x4k) in the MC setting. The MM and MC settings use different input stages with different op amps specifically chosen for each one. All setting functions are performed with air-sealed, extremely low-impedance relays.

A microcontroller controls all functions and “ensures an entirely silent operation.” Every setting change is stored automatically for each of the four inputs. Each time the user changes the input, the last chosen settings are recalled automatically. Moonriver further notes that you can connect four MC cartridges, four MM cartridges, two MC and two MM carts, three MM and one MC cart, et al — in effect, every combination is possible with different settings for every input.


Moonriver Audio’s 505 phono preamp has an SRP of €4,990 or $5,270 U.S., given the current exchange rate at the time of this posting.

For more about Moonriver Audio, go here.
To find an authorized Moonriver Audio distributor, go here.



(€4,990, or $5,270 U.S.)

Specs & Features
Minimum gain: 34dB
Maximum gain: 72dB
Capacitance: 100, 220, 330, 470, 680pF
MC load impedance: 10, 47, 100, 470, 1KΩ, and custom
MM load impedance: 22K, 47K, 75KΩ
Stereo/mono options
De-emphasis curve: RIAA, and Decca or Columbia (for 78s)
XLR and RCA inputs and outputs
Separate shielding for the transformer and gain stages
Auto mute
Dimensions: 430 x 135 x 390mm (w/h/d)
Weight: 12kg


brenro12's picture

Seeing quite a few phono stages being introduced with balanced input/output but not a lot of info on its pluses or minuses. Theoretically it sounds as though it would be quieter but would be nice to see it confirmed or disproved.

liguorid42's picture

Yes, though I've never owned a balanced input phono pre, common mode rejection can have distinct advantages at the very low signal level of phono cartridges. I've wrestled with hum problems in phono stages plenty of times in my half century or so audio experience. Of course, the tonearm has to be wired for it. Most do have four wires plus ground, often terminated in an DIN jack or plug. I don't know what sort of fancy audiophile cables they're making to feed things like this, but if all you have is RCA outs from your tomearm, balanced in is going to do you little good.

JACK L's picture


Very true !!

Balanced audio transfer is critical for recording studios & for indoor/indoor PA system where miles long runs of audio cables are involved. So balanced audio is crucial to reject the common-mode noises induced at the receiving end, e.g. recording mixing consoles multi-mic inputs in recording studios, & the racks of many power amps located miles away to from the control console at the performance podium, to drive the remote loudspeakers columns.

But surely for home audio, all audio cables are way way too shot to worry about the common-mode induced noises.

Such home audio with balanced inputs does more harm than good to the music signals, IMO. The main issue is: How to ensure the op-amps or even matched discrete devices forming the differential inputs are 100% fully balanced ???

More electronics in the signal path surely generate undue harmonic, intermodultion & phase distortion. This is physics.

Balanced input & output transformers are better than the above active electronics. But such transformers are not all angels. Their inductance, leakage inter-winding capacitance, resistance limit the high frequency & low frequency responses & generated undue harmonic & phase distortion besides hum noises. Last not the least is the high costs of such transformers.

I still maintain using single-ended unbalanced signal transfer as used for decades since day one of electronic audio inventions. Less electronics in the signal path, Better is musical sound!! Again, this is physics.

FYI, the 99.99+% pure silver interconnects I am using in my audio rig are all single-ended unbalanced run, including connecting my 2 TT (MC & MM).
Hum noise ? None audible given proper grounding.

So why all those amps coming with balanced inputs/outputs in recent years?
Sales gimmicks, IMO.

Listening is believing


rich d's picture

And the answer re: balanced operation is: yes, if the product is competently designed the balanced input should sound better, at least with moving coil cartridges.

JACK L's picture


To pay over 5 grands to buy a phono-preamp using ICs ! Thanks but no thanks.

For only $399, any audio Joe Blow can own a non-hybrid solid state phono-preamp of much better design:

Schiit Audio's new $399 Skoll MM/MC phono preamp features fully discrete, differential Class A zero feedback gain stages and a fully passive RIAA network. No op-amps are in the circuit. Skoll’s gain stage is a compound JFET-BJT pair running on "massive" 64V rails for enhanced linearity and freedom from overload. The result is over 100dB signal to noise ratio for 40dB of gain, and up to 70dB of gain available.

Design/built in USA.

No IC balanced input with all discrete devices is technically superb design let alone its dirt dirt cheap price !!!

Be vinyl smart !!


Anton D's picture

I am yet to hear them, so I will leave the sound comparison to you!

JACK L's picture


Of course NOT. Only PERFECT audios would sound "identical". Nothing is this world could be made perfect unless created by the Almighty.

Honestly, what should we expect from a $399 MC/MM phono-preamp ???


liguorid42's picture

Yes, that is an entirely different meaning of "hybrid". I was expecting a combination of hollow and solid state.

On the other hand, the "IC's bad!" audiophile wisdom dates from the 1970's and the "venerable" LM301, which had terrible open loop specs (distortion, SNR, frequency response, etc.) and required feedback to tame it. Today's serious op amps are much better than that, and have distinct advantages in audio design.

JACK L's picture


Me too. I thought it should be solid state + tube. So misleading !

Op-amps, being cheap & easy to install, are most commonly used in balanced audio inputs as a differential device to reject common-mode induced noise from the programme source, e.g. phono cartridges & preamps with balanced output.

Yes, op-amps nowadays are design/built much better than ICs in the old times. But still any op-amps are built with a number of PN bipolar junction devices, e.g. transistors, FETs, with tons of local & global feedback, primarily used in control circuitry instead of in audio.

Because of the built-in high gain active devices & feedback loops, op-amps are not ideal for processing music signals with high orders of HARMONICS !
Skeptical ears, like mine, can detect it. This is physics.

That's is why the $399 Schitt MC/MM phono-preamp I stated in my post above is a very rare optimum solidstate balanced input design using all discrete FET devices. It shows the designers know how they are doing right MUSICALLY in their design ! And for such incredible dirt cheap price !!! My hi-5 !!

As a die-hard tube guy, I would definitely prefer using a pair of triodes as the input differential devices instead of the cheapie op-amps & the expensive input transformers !!!!


rwwear's picture

It would be nice to be able to read the text on the faceplate.

Tom L's picture

Wider than a mile.