Just like how I feel that all filters should have a big knob for sweeping, I think the perfect envelope generator is slider-based; I really don't gel as well with knob-controlled EGs, as there's something that just feels right using a slider to control stages of an envelope.
Weston Precision Audio's SE1 is a module after my own heart. It has four stages of control, with those lovely yellow-glowing sliders adjusting the attack, decay, sustain, and release stages of the envelope. Each of these stages also has a CV input for modulation as well as a Gate output that goes high for the entire duration of that stage. On top of this, the Attack, Decay, and Release stages have three switchable slopes to choose from: Logarithmic, Linear, or Exponential. SE1 is highly configurable, and even the Sustain stage, which doesn't have a slope switch (flat, flatter, flatterist?) isn't left out as there's a Sustain Env input, which allows for the sustain stage to have its own dynamics before going to the release stage. This can allow for some really cool, really complex envelope shapes.
There's also a Gate input, a manual Trigger button, and both an Envelope and Inverted Envelope output. A Loop switch lets you use SE1 as an LFO, and there's an end of cycle output that emits a short pulse when the envelope has cycled through. There's a Level CV input for patching in an external VCA to control the output of SE1, and even a jumper on the back of the module to increase the output from 5V to 8V for those souped up envelope needs.
As I said, SE1 is really flexible. There are so many ways to shape the envelope—on any of the stages—that it goes pretty far beyond what most envelope generators do, especially analog ones. You'd have to go digital and cozy up to a screen to do what SE1 can for the most part, especially when you factor in the Sustain Level Input, as it's really here where SE1 bucks traditional ADSRs and offers up something totally different.
When I was getting the lay of the land, I found it was easy to get lost using the sustain envelope if I tried to patch everything in at once. I got much better results when I configured my basic envelope shape first, and then messed around with the sustain envelope input, trying all sorts of shapes during the sustain stage. On a slow loop I'd patched up, I was able to add a fading triangle-shaped tremolo bouncing-ball type wobble to the sustain stage, kind of like the input signal was losing its balance before fading out. Add a little pinch of pitch variance to the input of my signal, and the effect was even more pronounced. Doing something similar but with a fast array of square waves via the AJH Synth Multi Burst was super cool, like adding machine gun staccato notes to a melody. Of course, using SE1 in a more traditional manner works great also, and again, I do enjoy configuring envelopes with the sliders.
The only bummer with SE1 is that it's only one channel, though you do have the two different outputs, along with each stage's output. Since, like quite a few Weston modules, their new Stereo/Dual VCA SV1, is dual channel, and it'd be nice to be able to pair both modules up perfectly. Naturally, you could always get two SE1s…
As for the SV1 Stereo/Dual VCA, as the name suggests, it is indeed two channels, Left and Right, with two different outputs each; a "vintage" style op amp-based VCA to add a bit of color to your sound, and a cleaner 2164 chip-based VCA. I really like the tone of both styles, and it's great to be able to add a little saturation to your sound without needing to patch into something else.
Speaking of patching, I normally patch my mono outputs into the left channel of whatever module I'm using. It's been ingrained that most L channels = mono, but SV1 has a unique feature where if no cable is patched into either of the left outputs, then the right outs will have a mix of both the L and R out. It's always nice to have a little extra flavor option, and this is just one of the special touches inside of SV1.
For the most part, each channel has what you'd expect from a standard VCA; Input Level control (goes from -∞ to +6dB), Bias Control, and a CV and attenuator control for the Input Level. There are LEDs to denote clip/signal levels, and the left side VCA is normalled to the right. There are also a few flourishes that give SV1 something different than your standard VCA. Situated down the middle of the module between the two channels is a light up Link button for putting the left channel controls in charge of both channels. There are also some switches; one is for overdrive, which adds +6dB to the input of each VCA for a little more saturation, and there's another switch for Zero Cross Detection, which removes clicking on fast envelopes. Clicking is one of the many, many banes of my modular existence and it's nice to not have to incorporate unwanted clicking sounds into my patch when using SV1. I'm not sure the exact circuitry used to carry out this detection, but whatever it is, it works very well and I'm grateful for it.
As a normal, two-channel VCA, you can't ask for much more. No audible clicking, Bias control, and control (and CV control) over the input signal, and the two different flavors of outputs give a lot of flexibility and options for getting the perfect output, both in terms of sound and level. With a few different ways to add some color, with the vintage output and the added distortion, you can fatten up any signal that needs it. It's really nice to be able to choose which of the two outputs suit my needs at any given time, and even better, is using both outputs for a given channel and patching them into a mixer, panning hard L and R after running through effects or a filter.
Weston Precision Audio's SE1 and SV1 are great modules, with everything you need right in front of you. With excellent build quality, classic analog designs and functionality, and with some very unique flourishes, what more could you want?

Price: SE1 $190
Price: SV1 $220

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