Teaching Machines Wellspring

Spring reverb can be a one‑trick pony, though it’s a pretty good trick! This one incorporates additional processing to make it more versatile.

Spring reverb seems to have enjoyed something of a renaissance in recent years. While I’m generally very pleased about this — I’ve long been a paid‑up member of the spring ‘verb fan club — it means that well‑regarded vintage units now command much heftier sums than when I acquired mine! So I’m always interested when something new comes out, and particularly when it’s not just copying an old unit. The latest such device to grab my attention is the Wellspring. An all‑analogue design, it’s described by its manufacturer, the small Welsh company Teaching Machines, as “a stereo spring reverb with lots of cool complimentary [sic] features”.

At the heart of the Wellspring is a pair of 15‑inch spring reverb tanks, which are housed in a metal case that’s been given a vintage hi‑fi aesthetic. The included rack ears and rubber feet can be fitted or removed by the user, so it can be bolted into a standard 19‑inch studio rack or sat on a desktop as you prefer — a nice touch. The build quality seems very good to me, with all the controls feeling solid and reassuring to use. Equally reassuring is that Teaching Machines offer a five‑year warranty as standard.

On the rear, quarter‑inch jacks provide the unbalanced stereo inputs and outputs, as well as a ±5V inlet for control signals, and there’s a high‑impedance jack input on the front to cater for guitarists. The unit has input and output level controls at either side of the front panel, and there’s a small ‘clip’ indicator light near the switches for power and for engaging the guitar‑based input.

Effects, Filters & Magic

Spring reverbs always have a strong sonic character, and because of that people tend either to love them or find them limiting, in any given situation: it’s often either just right or plain wrong for a particular source or mix. To make them more versatile, many manufacturers back in the day built some kind of EQ or wet/dry controls into their designs, but while this did help, the user was usually still left with limited control over the reverb’s decay. Notable exceptions were the higher‑end AKG models, which employed some complicated techniques for adjusting the length of the decay time, or ‘tail’ as it’s known. The Wellspring doesn’t recreate the AKG approach, but it does attempt to tackle the same issue in a different way: it features a range of analogue effects, including a pair of delay lines, and four different filter/EQ settings and modulation sources that act on the delay and filter. Taken in combination, these allow you to shape the springs’ natural decay and character. There are also creative options for introducing feedback to parts of the circuit, and a few more clever features that I’ll explore in more detail below.

Broadly speaking, there are three different sections with which you can experiment, and I’ll take you through these as they appear on the control panel, from left to right. First up is a pair of delay controls called ‘time 1’ and ‘time 2’. These can either be used independently, to introduce different delay times on the left and right channels, or be linked so that ‘time 1’ controls the delay for both channels. The feedback control works the way you might expect, and can do anything from introducing a single repeat up to ‘infinite feedback’. There’s also the option of swapping between ‘parallel’ operation and a ping‑pong‑style effect, in which the left and right channels are inverted as they pass through the feedback loop. I’ll discuss this in a bit more depth later, but for now let’s just say that...