Analog Gear News

The Wizard has spoken — or rather, Grimm Audio co-founder Peter van Willenswaard has stepped forth to unveil his latest design triumph, the PW1 phono preamp.

For the solid-state PW1 phono preamp — which has duly been nicknamed the “Phono Wizard” — van Willenswaard made sure the linear power supply became an integral part of the unit itself (more on that in a bit). Furthermore, the PW1’s industrial, aluminum-enclosure design — courtesy Michiel Uylings of MU1 — was intended to “match the sonics with a simple but powerful cabinet shape,” while Grimm Audio’s own design team made the copper-shielded interior (all of which can be seen below).

As mentioned above, the PW1 does not require a separate external power supply to prevent hum and other interference on its MC and MM inputs. To achieve this goal, an extremely “silent,” low magnetic field power-supply transformer was custom-made for Grimm Audio by specialist manufacturer Amplimo, and has been positioned 20cm from its inputs.

Let’s now hear from van Willenswaard directly about his PW1 design philosophy. “For starters, I decided not to use bipolar transistors in the first part of the signal chain — in my experience, [they’re] too crude for very low-level signals,” he noted. “Subsequently, I made a choice for two parallel routes — opamps and fets. And in each case, I tried to avoid over-asking [and] over-stressing the active components. And I paid a lot of attention to the power supplies. After more than 100 hours of study, measurements, prototyping, and listenings tests, we decided to drop the opamp itinerary. Despite all the effort, it didn’t hold up to the 3-fets-per-channel approach that slowly had crystallized in a parallel universe. The latter was simply more seductive, more natural, and so musically involving.”

For van Willenswaard — just as it is for many of us — it’s ultimately all about the music. “In my designs, I firstly go for conveyance of emotion, the warmth of a human voice,” he continued. “I do keep an eye on harmonic distortion, but rather [more] on its character — I avoid uneven harmonics — in that I would strive for a very low percentage. And I go for the seductive tone of a violin, the air around voices and instruments — which restores their 3D reality — and the width and depth of the stereo image. If I get all that, it makes me feel overwhelmed, and happy.” (Testify!)

And now, some PW1 specs. Nominal MM cartridge sensitivity is said to be 5mV for 350mV out. An additional 10dB gain is available for the MM input if it were to be used with high-output MCs, and then the sensitivity would be “around” 2mV. (Grimm Audio points out that MM carts can deliver almost 100mV with “very deeply modulated” LPs, resulting in 7Vrms output.) The PW1’s output is said to be able to be overdriven with a maximum level of 10Vrms (+22dBu).

A separate input provided for MC carts optionally offers 20dB or 30dB gain. If all the gain available on the PW1 is switched on, a maximum gain of 77dB can be achieved on MC, which, as Grimm points out, means MC carts with ultra-low output (i.e., 0.05mV) can also be used.

The sliding panel on the bottom of the PW1 gives users access to load and gain settings for various cartridges (MC, high-output MC, and high-output MM carts). A series of capacitors and termination resistors (for MC) are provided on both the MM and MC inputs. For MM carts, capacitors of 47, 100, or 220pF can be added to the load.

The main load setting for MC is the resistive one, and the PW1 has a range of options — 33, 100, 330, and 1,000ohm (and combinations thereof). Disabling extra load is also possible, wherein the load resistance is then 47kohm.

Additionally, the PW1 offers RCA and XLR outputs, boasts a 5-year limited warranty, measures 100 x 100 x 250mm (w/h/d), and weighs 3.3kg.

Finally, the SRP for the Grimm Audio PW1 phono preamp is €4,800.

For more about Grimm Audio, go here.
To find an authorized Grimm Audio dealer, go here.