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 I reckon the designers have undersold this section of the unit somewhat in their literature – it’s a great‑sounding analogue delay in its own right!

Teaching Machines have been far keener to highlight how effective their modulation features can be in ‘calming down’ some of those unpleasant ringing effects that, as I discussed above, are often heard in spring reverbs. They have a good point, too. The Wellspring offers two broadly different flavours of modulation, with the option of switching between sine or sawtooth waveforms, but if you want something more complex, you can always patch an external control source into the rear‑panel socket. There’s also the option of inverting the left and right channels to allow the modulation to be in or out of phase.

My experience of using the Wellspring suggests that the most important control in this section is the modulation speed, and this has a range of settings from super‑slow to very fast. To aid your ears, a small yellow LED flashes in time with the modulation speeds. This can be very helpful, although when I positioned the Wellspring in front of my mix position, as I often do when evaluating devices for review, I found it a touch unpleasant on the eyes. That should be less of an issue if set off to one side, or in a rack, of course. The simplified block diagram included with the unit is essential reading if you’re going to get your head around how things work, and this shows that the modulation is applied simultaneously to both the delay and filter sections of the circuit.

The Wellspring’s EQ and filter options are powerful tools for shaping your signal before it hits the springs. As well the expected low‑ and high‑pass filter options, you can choose a band‑pass filter to only allow frequencies in a certain range to pass through, or a notch filter to remove a narrow range of frequencies. However, you can’t use more than one of these filter types at once. A further, minor niggle is that you can’t easily bypass the filter section, other than by selecting the high‑pass option and turning the frequency control all the way left. This can seem a bit clunky when trying to fine‑tune a reverb in a mix, and a dedicated bypass switch would have made it easier to assess things. Nonetheless, this section can have a dramatic impact on the effect in the context of a mix.

There are two ‘wet/dry’ controls, one at the end of the filter section and another just beyond. The first is for the filter and delay section, while the second blends between the output of that first wet/dry control and the direct output from the springs.

The last ‘section’ at the end of the control panel is the mysterious Magic, which has a single control labelled Intensity. What this does is send some of the reverb signal back into the delay, but with the left and right channels swapped. Not surprisingly, this can introduce some pretty crazy feedback‑style effects. It can become unwieldy, but it’s aptly named nonetheless: if used subtly you can achieve an effect that’s very difficult to convey using words other than ‘magic’!

The Wellspring supports stereo and mono‑stereo operation, as well as accepting external control signals for modulation of the delay and filter sections.

A Reviewer’s Tail

I wanted to start my adventure with the Wellspring by getting a sense of what the reverb sounded like, without bringing any of the additional bells and whistles into play. In what became a common theme during my early experiments with the unit, I had to refer to the block diagram to figure out how to hear just the sound of the springs. But once I felt sure that setting the wet/dry control fully dry would achieve this, I was suitably impressed. The twin reverb tanks provide a deep, rich‑sounding spring reverb, with a long tail that decays in a smooth, natural and very satisfying way indeed. Subjectively, I’d say it sounds more ‘full range’ and ‘hi‑fi’ than my own AKG BX5.

This was an encouraging start, then, but as with most of my reviews, I was also keen to throw the Wellspring into use on a real session. In the first instance, I thought I’d try patching it in for use as a fairly conservative, general reverb option for an EP I was mixing for a lo‑fi indie band. This worked, in that the depth provided by the Wellsping was an absolute delight when applied to vocals and a few select instruments. But the naturally long reverb tail was too much, and needed shaping to make it sit nicely in the mix. I know from experience how effective EQ and filtering can be in this scenario, but I first wanted to get a feel for how the modulation section might help. Happily, it did. I struggle a little to articulate exactly how or why, but Teaching Machines explain that it can have the effect of ‘scattering’ more dominant parts of the reverb tail, and I certainly had a sense of this being the case. Higher modulation speeds in particular seemed to calm down the bouncy ‘doink’ effect that resulted from more percussive elements going into the reverb.

After getting a sense of how the modulation could help, I turned to the filter section and it was here that I found what I needed for this particular project. All four filter options are highly usable, and my only real frustration was that I could only use one of them at a time. For settings where the reverb is more prominent, the low‑ and high‑pass filters work superbly for gently shaping the effect away from the top or bottom of your mix. I especially like filtering out much of the top end so that the reverb acts as a kind of low‑level ‘thickener’ on a mix. The band‑pass filter works for using the effect in a more targeted way, and the ‘notch’ option worked especially well for settings where you want to just reduce a certain element of the ‘springiness’ — say on a snare drum or sibilant vocal. On the whole, the combination of the modulation and filter sections can work very nicely.

More Than A Reverb

I carried on using the Wellspring as a fairly conventional reverb on a few projects, and as I got more attuned to the ways in which the different sections interact, I found it to be more and more flexible and more and more fun. It was when I had some suitable downtime, however, that I was able to fully explore this device, and appreciate that it’s much more than ‘just a spring reverb’. Check out the audio examples I created.

My initial suspicions were that the delay section might be intended as a sort of pre‑delay to introduce before your reverb. You can use it like this if you wish, but it’s also a simple but great‑sounding stereo analogue delay in its own right. In fact, I often found myself using the Wellspring first and foremost as a delay when working with guitars or vocals, and then blending in the springs to taste. Having separate controls for the left and right channels is great for adding subtle (or even more extreme) interest to the delay effect, and the feedback control offers you a nice range of options for how prominent the delay should sound.

So if you like to sit, experiment and lose yourself with a piece of equipment, playing with the delay and modulation settings on the Wellspring should be well up your street. I invited more than one guitarist to work in this way, plugging straight in via the front input and getting creative, and they all enjoyed it — it’s one of those bits of kit that encourages you to play and experiment not only with the effect itself but also with your instrument and playing technique.

The springs themselves sound wonderful and there’s a fantastic range of features that can help you shape the reverb to suit any source or mix.

Summing Up

There’s definitely a learning curve if you’re to get the best from the Wellspring, but the effort is richly rewarded, and hopefully this review will make that journey a little easier. This really is a great‑sounding analogue effects unit. The springs themselves sound wonderful, and whilst you might not have a means of adjusting the length of the reverb tail directly, there’s a fantastic range of features that can help you shape the reverb to suit any source or mix. These are much more than add‑ons; rather, they’re fundamental to the designer’s intention of how you should use the Wellspring, and they allow you to create dark, characterful delays and modulation‑style effects to your heart’s content.

Hardware effects such as this will be seen as a luxury to many, but the price is pretty good for what’s on offer — especially if you compare it with vintage spring reverbs. If you’re on the look‑out for a special effects unit in the price range of a vintage tape echo or, say, an AKG BX5, I’d strongly encourage you to put the Wellspring on your shortlist.