New Monday #73
We’re having a flash sale on our Pawn Shop Comp, in celebration of its birthday on Wednesday, July 9th. 50% off for 24 hours. Consider yourself alerted.
This gives me an excuse to talk about some tech stuff. For those of you interested in music and new stuff to listen to, this isn’t gonna be your type of New Monday.
For those of you who have been asking for something more engineering technique oriented, this is for you.
For those who don’t know, the Pawn Shop Comp, or the PSC, is really a channel strip—it’s a tube preamp coupled to a FET style compressor and then chased by a weird little saturator circuit.
Preamp
The tube pre… I suppose it is closest to some sort of Langevin pre from the 60s. It has an EQ circuit on it that reminds me of a Langevin or perhaps a very early Electrodyne or a Quad Eight, except those were solid state. The real magic of the PSC’s tube preamp is in the range of saturation, overdrive and distortion one can get from it.
Saturation, overdrive, and distortion are all degrees of the same thing, which is driving a circuit into clipping and causing harmonic distortion, which adds additional overtones to the signal. You can think of low levels of saturation being a subtle, wide band equalizer. As you gain things up, the “equalization” becomes increasingly harsh and eventually buzzy and fuzzy. I wrote a blog on this here. If you don’t know this stuff it’s a good introduction.
The PSC features switchable tubes, each of which has different sonic characteristics. The harder you push the preamp, the more you’ll hear the differences between the tubes. There’s also a bias control. A simple way to think of bias is as a setting of efficiency. If bias is set correctly, the circuit runs cleanly with lower noise and harmonic distortion. Screw around with bias and the circuit works poorly, increasing distortion and other artifacts. I wrote a blog on bias, too. It’s really a fundamental concept, and if you understand it, a lot of things make more sense.
Transformers
You can also swap around the transformers on the Pawn Shop Comp.
Transformers are fascinating. Transformers do exactly that: they change aspects of an audio signal via electromagnetism. They’re used to… how to say this simply? They’re used to change a signal so it better fits into the next part of a circuit. You can think of them as an adaptor or a coupler. We have a signal flowing from a mic into a preamp, we need to make that mic signal “fit” better, so we use a transformer.
Transformers are usually stealthy and you’re not supposed to hear them working, but they do have an audible effect. Like almost all analog audio components, if you overload them, they cause harmonic distortion. However, transformers tend to affect the bottom end more than the top. That is, you’re going to hear the effect of the transformers on lower frequency, instruments, but you’re not necessarily going to hear the effect in the low frequencies, you’ll typically hear a little higher up in the frequency spectrum. A cool trick with the PSC is to overdrive the transformers (and the preamp) to add saturation such that a low frequency signal is more audible on a smaller speaker. The Pawn Shop Comp is especially nice on bass and vocals because of this.
A quick thought on this: if you’re going to be using saturation on signals, and what you’re looking to do is have some effect on the presence and articulation of lower frequencies, the presence and articulation of a bass or kick, if you’re going to do high pass filtering, you probably want to do it after adding saturation. If you do it before, you might end up cutting frequencies that you want to generate harmonic distortion from.
I wrote a whole thing on transformers here.
FET Compression
A FET compressor uses a FET transistor to control the gain of a signal. A FET is at the heart of the 1176 and many other compressors and limiters.
The Pawn Shop’s compressor doesn’t really sound like an 1176, rather, it is capable of a wide range of sounds. At low ratios, the PSC can sound like an “Opto” compressor, like an La-2a - not exactly, but it can be warm and gentle.
The PSC‘s compressor is really really adjustable. You have full control over attack and release as well as ratios from 2:1 to 100:1. It’s a Swiss Army knife as far as compressors go.
That can be a little intimidating if you don’t have a good understanding of what the controls are doing.
There are excellent presets that come with the PSC, so you can always start there. Also, the default setting that comes up when you instantiate the Pawn Shop on a channel is very, very useful, and often I’ll just leave it there or tweak it a tiny bit.
Attack
Let’s talk briefly about setting attack.
Think of the attack as a gap between a door and a door frame. Fast attack means there is very little space between the door and the frame-the door is almost completely closed. A very closed door lets very little of the transient through. As you slow down the attack control, you're opening that door to let more transient through, and the more transient you let through the punchier the sound is. This is, of course, predicated on the sound having a transient to begin with. It’s impossible to make Violin sound punchy because they just don’t have much transient.
A quick way to attack: turn it fully to the left – the door is almost completely closed. Turn it to the right and you’ll hear more of that transient get through. Stop when it sounds good to your ear.
Release
Release is a little harder to conceptualize. Release, technically, is how quickly the compressor stops compressing once the signal goes above threshold. Intuitively, you might think, well if it goes above threshold, it stops compressing immediately, right?
Release is about inertia, how quickly something stops happening. You might think of it as being how quick you get your foot off the brake in a car. Pulling your foot off quickly is a fast release, gradually lifting your foot is like a slow release.
Release smooths out the transition between the compressed portion of the signal and the uncompressed portion. If you set a quick release, the uncompressed signal comes bounding up immediately. Sometimes you want this. For instance, if you’re compressing Percussion and you set the release short, you’ll hear the quiet residence of the instrument and the echo of it in the room more. If you set the release longer, you can, in effect, hold that quiet stuff down and cut down the overall apparent sustain of that instrument.
Set the release too long and the compressor doesn’t get a chance to ever cycle out of compression, so it catches the next transient, rather than letting that transient through. You can hear this by setting a long release on a snare roll. The first hit of the snare will have a nice transient click to it and then as the roll continues it’ll actually get less clicky and in some cases quieter.
I think of setting release and attack as controlling how much a sound might poke through a mix, or how much a sound hangs on, or lingers on, in a mix. Attack controls poke, release controls hang. I wrote a blog post on this that makes this idea really clear. There are also some video examples.
Poke and hang is a really useful way of thinking about how a compressor works.
Have a great week.
Warm regards,
Luke