HV1 isn't Weston Precision Audio's first go around with VCOs. As a matter of fact, it's their third currently available oscillator (not counting their AD110 drum and B2 kick/bassline modules); not to mention their previously released VCOs, of which there are more than a few. This is to point out that out of the nine modules in their lineup, one third is dedicated to VCOs. That shows some serious love in that department, and though HV1 shares traits with other WPA VCOs past and present, it more than justifies its existence in the WPA pantheon of oscillators.
A combination analog and digital oscillator, HV1 is Weston Precision Audio's first module with a screen, something I assume took a lot of consideration. HV1 uses an analog triangle core oscillator as its base that is fed into a digital circuit. The module is split into thirds: the top third is where the screen and menu controls live, while the bottom portion of the module is split in half; the left side has to do with the analog portion of the module, and the right side deals with the digital part. HV1 spans about eight octaves and it tracks nicely and accurately. One of the menu/screen items (we'll get more into that) has a tuner that displays exactly how accurate.
The analog side of HV1 consists of an FM input with attenuation, a Sync to pair with an external VCO, a PWM control with CV in, and a 1V/Oct input. HV1 outputs four analog waves: sine, triangle, pulse, and sawtooth, all contained in an "Analog Core" labeled section. The triangle wave of this section is fed into a digital phase shifter, which takes up the right side of HV1.
The digital side of the module follows suit with the same four waveshapes as outputs, along with a 16-bit / 150kHz resolution wavetable output. Even though this is the "digital side" of the module, the four basic waveshapes here are also analog derived. A Phase Angle control that goes from approximately 0-720 degrees and a Lin PM CV input with an attenuator (labeled "PM CV") moves those waves around in relation to the analog waves, and naturally, modulating this can bring about all kinds of shifty goodness. There is also a Wavetable Morph control with CV in and attenuation, and an assignable (Bitcrush or Wavefolding) external CV input.
The screen/menu part of HV1 is kept very much tamped down and is easily manageable. There are only two screen modes: Tune and Menu. Tune is a one pager that shows the tuning, whether your analog side is in VCO or LFO mode, and the phase angle between the left and right side outputs. With a long press of the endless encoder, you can tune/detune either side, and you can lock the tuning as well for each. The Menu page is a little more in-depth, but with up/down and left/right arrows, navigation is pretty basic. Here you can see the wavetables in action and scroll through and select the wavetables available; further down is where you can enter the tuning mode. It's the Options page that's more feature packed, but again, not crazy deep, which doesn't mean it isn't powerful with rich features, it's just not feature rich. This could change, of course, with future firmware updates, and you can add to this by uploading your own wavetables via the front facing SD card. There are options for choosing FM Type (Lin Thru-Zero or Exponential), FM Coupling (AC or DC), Sync Type (Reset or Reverse), Wavefolding Algorithm (sine, phase multiplier, triangle, noise x phase multiplier, and added lo-fi bit-crushed phase). Scrolling down a little further gets you to page two, which is also the end of the menu. Page two lets you assign the Aux CV input (wavefolding or bitcrushing) for modulation of the Wavetable output, shift the right side triangle output up +1 octave, shift the Wavetable output down by one octave, and turn antialiasing on or off for the Wavetable out. Again, within these two pages there's a lot of configuration that can be had, a lot of opportunity to configure the sound.
Turning into LFO mode (all oscillators become LFOs) is pretty interesting as, since the digital oscillator is driven by the left side, this now-LFO effects the right side output, same as before, but this time if you push the right arrow for the screen/menu, you can see the movement of both oscillators and the relationship between them, which supplies a little more eye candy. With nine total waveform outputs on HV1, and with the ability to play with the phase relationship between the four left-side outputs and the five right-side outputs, that means that at any given time, you can have nine LFOs. While I probably won't use nine pitch-related VCOs too often, I can never have enough modulation available, and HV1 is a killer modulator. The eight basic waveforms are great, but the WT output, where it can be configured, phased, and manipulated in so many ways is like the special sauce on the burger, the icing on the cake, the far-out modulator on the modulation device.
While you can mess with the phasing between the two sides of HV1, as mentioned, you can also tune or detune each side separately, so that HV1 can be used as two separate but connected voices, since they're both controlled by the main oscillators CV inputs. You can get some dyads happening, harmonically or not quite so.
The screen animation is pretty informative, being able to watch the wavetable cycle through its paces when being modulated, and while small, the information provided is appreciated and well laid out and is as easy to read as a 0.5" x 1.0" OLED with tiny text can be.
Syncing the two oscillators by patching out of any output on the right side into the Sync in brought about interesting rhythmic squelches like HV1 was fighting itself a bit, struggling to stay afloat and in the realm of sonic audibility. FMing with another VCO, in this case Endorphin.es' Godspeed introduced a lot of destruction, but could be tamed a bit with the onboard attenuation. As a matter of fact, I found that I liked the sounds out of HV1 a bit more when I held back on modulating it—not an easy thing to do, this thing known as self control—and dialed in the sound and phasing on HV1 before adding modulation. It's pretty easy to get lost FMing and modulating and being tasteful was rewarded.
Obviously, as demonstrated by the discontinued PA0 Phase Animated Oscillator and now the HV1, Weston enjoys experimenting with phase, and I agree, it's fun to pit two waves against each other and phase them in and out of each other, sometimes in sync, sometimes not, to create unique rhythmic patterns.
HV1 can handle either WaveEdit or Serum wavetable files, and as of this writing there are plenty of tables to experiment with (some provided by Chris Meyer of Learning Modular) and with the easy to get SD card, I assume more will be available in the future.
I would love to have the ability to use the Aux CV to cycle through the wavetable bank options, as doing so by hand by turning the encoder was quite cool.
HV1 is a really interesting module, excellent for thick and dirty basslines as well as complicated melodic runs. Actually, I got some of the best basslines I've ever had out of HV1 by detuning the WT output from the main's pulse output and CVing the phase on both. It was fun keeping the pulse output while auditioning the various wavetables to see the mixtures that could be created. 
Price: $395

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