Grimm Audio PW1 phono stage
Grimm Audio is a name associated with high end digital, its MU1 and MU2 streamers having established the company as one of the most technologically advanced in the sector. However, Grimm’s first product was an active DSP loudspeaker system and its most recent is a phono stage, even digital enthusiasts appreciate the qualities of vinyl it seems. In fact one of Grimm’s founders, Peter van Willenswaard, has “spent a lifetime designing and improving phono preamps” using both tubes and transistors, and like most who have experience with both glass and silicon has always wanted to combine the qualities of both. The transparency and low perceived distortion of tubes as well as the quietness and gain offered by transistors, the PW1 is the result of this quest.
The first thing that strikes you is the size, this phono preamp is 10cm (under 4 inches) square and 25cm long which is not all that radical until it becomes clear that the power supply is in the same box. No other high quality phono stage of this scale manages to combine both these elements, the vast majority placing the power supply in a separate case in order to keep noise from polluting the tiny signal from a cartridge that has to be massively amplified to bring it up to line level.
Grimm achieved this by finding a very low noise transformer that fits into the end of the case, the front end as it happens, where it sits vertically and outside of an internal copper shielded sub case that surrounds the electronics that amplify and equalise the signal. This arrangement allows both power supply and circuitry to occupy the same compact case in a way not seen with other high end phono preamps. It’s a very neat arrangement and one that will hopefully  inspire others. The circuitry is described as “elegantly minimalistic” by Grimm and the way that they have managed to incorporate input sockets for moving magnet and moving coils plus outputs on single ended and balanced connections is impressive.
The casework is very elegant too, I love the different angles where the front section joins the body of the PW1, the design apparently was done by Michiel Uylings who is also responsible for the MU1 that put Grimm on the streaming map. What you don’t see without picking up the PW1 is that there is a selection of gain and loading switches located on the underside of the box. These are protected by a sliding cover and consist of DIP switches which are rather fiddly to adjust, Grimm have had the sense to include a plastic stylus to make the job of moving them a lot easier. You can also try different settings on the fly, that is if you put the PW1 on its side and slide the cover over, the various gain and impedance settings can be adjusted whilst a record is playing.
Settings extend to three levels of capacitance for MM cartridges plus another two for MCs, there are four impedance options running from 33 Ohms to 1kOhm (plus 47kOhms for MM) and the option to add 20dB or 30dB of extra gain. There is also a gain boost option for both cartridge types, the +20 or 30dB gain is added prior to RIAA equalisation, an extra 10dB is available after this stage should that be required. Grimm’s in-depth manual suggests starting with +20dB on top of the 37dB applied to both inputs and then adding +10dB if the level is still low. The +30dB option comes with a warning that all but the lowest output MCs “may occasionally overload the phono amplifier”. The loading switches are mirrored which means you have to pay attention to the legends in order to get both channels set the same, my tip is not to do this with the PW1 on the lower shelf of the rack in the evening…
Sound quality
I connected the outputs of a Rega Naia with an Aphelion 2 cartridge to the MC inputs of the PW1 and set the load to 100 Ohms and gain to +20dB in the first instance. After a bit of listening the impedance was raised to the next setting up, 330 Ohms which added both definition and drive to the sound. Playing a Freddie Hubbard album, Backlash, I was greeted by serious amounts of energy and groove, the tone being totally authentic and the sound so live that it made me wonder how they had managed to capture so much power so long ago. Jan Akkerman and Kaz Lux’s Naked Actress (Eli, 1976) is a more subtle affair with an emphasis on the poet’s spoken vocal, the word “Perfection” reflecting my initial impressions of this phono stage, an impression that stayed for the duration of the review to be honest.
Stevie Ray Vaughn’s beautiful Lenny was absolutely exquisite, the PW1 delivering his supreme guitar playing with panache, and separating out the various elements in the track like the acoustic on vocals whilst delivering a coherent musical presentation. I contrasted the PW1 with the Rega Aura that should have a natural affinity with the Aphelion 2 and got a result that was stronger in terms of body and presence, with excellent dynamics. Going back to the Grimm revealed that it has a calmer presentation, and appears to have more time to deliver phenomenal levels of delicacy, voices in particular having a depth and subtlety that is very engaging. The Weather Station’s self titled album revealing so much detail compared to the digital I am familiar with, that I kicked myself for not buying the vinyl earlier.
The PW1’s timing reflects the recording and the record player with considerable precision, leading edge definition is spot on. With a wide variety of vinyl productions this proved to be a very appealing balance, Herbie Hancock and Norah Jones’ take on Court and Spark (from River: The Joni Letters) being just such an example, the PW1’s natural brightness bringing out the brilliance of the piano playing in no uncertain terms.
I also tried a Skyanalog Ref moving coil with the PW1, this is a more open sounding cartridge than the Aphelion with impressive speed and agility, especially via this amplifier. Again energy was very well served, Nils Frahm’s All Melodycoming through in fast, fluent and finessed style and delivering huge amounts of detail. The pairing of cartridge and phono stage producing that rare combination of ease, pace and muscular bass. I particularly enjoyed the Keith Jarrett, Gary Peacock and Jack DeJohnette’s version of God Bless the Child (Standards, Vol. 1), which sounded a lot better than it has in the past, with impressive power in the bass and a really vibrant, live sound.
The Skyanalog Ref/Grimm PW1 combination was particularly strong across the board, the sound produced being extremely clean, powerful and hugely open without any loss of solidity in the bass. I could have lived with it for much longer than was possible. A review of the Skyanalog is in the works.
Conclusion
I have to congratulate Peter van Willenswaard and Grimm Audio on the PW1, it is a very good phono stage indeed and one that is unlikely to hold back any decent cartridge. It’s interesting that a company that has been all about cutting edge digital technology has a vinyl and tube nut in its midst, it might explain why the MU1 is such an exceptional streamer (and the MU2 by all accounts). Having someone on the team who is listening to pure analogue gives Grimm a breadth of experience that not all digital engineers get to enjoy.
The PW1 has some distinctly tube/valve characteristics, notably a fluency and openness allied to a balance that is revealing but never hard edged. It brings the power of solid state to the party however and has the very low noise that such tech can provide for the modern music lover. The Grimm PW1 is a good looking, great sounding winner, if you want to hear more of what’s in those grooves do not overlook it.