Introduction
The Teaching Machines Wellspring is a “boutique analogue stereo spring reverb machine” — as Teaching Machines refer to it — that offers analogue stereo spring reverb, two characterful delay lines, analogue filtering, LFO modulation and complex feedback routing in a single device. It comes in a sturdy 3RU build and is shipped with optional rack ears (for 19” racking) and attachable rubber feet (for desktop use).
The Wellspring is a fully analogue device that draws inspiration from old 70s and 80s stereo rackmount spring reverb and delay units, but brings these inspirations into the 21st century with a compact and flexible package fit for modern studio environments. With its unique take on analog spatial processing it has already attracted a number of high-profile users such as Andrew Scheps, Sam Slater and Hildur Guðnadóttir.
Basic features and layout
The basic layout of the Wellspring consists of an analogue dual delay line with feedback and LFO modulation that goes through an analogue multimode filter (that can also be LFO-modulated) and then feeds into a stereo spring reverb. The spring reverb section is comparatively straightforward, with just a simple dry/wet control. Since the delay section also has its own dry/wet control, the unit can be run as a pure delay, a pure reverb or some combination of both. When the delay section is active, the unit’s signature “Magic” control creates a feedback loop between the delay and reverb sections, which allows for a variety of sounds and makes the reverb section much more versatile than it might look like at a first glance.
I/O and routing
With its L/R inputs and L/R outputs, the Wellspring can be run as a purely mono, mono-to-stereo or true stereo device. When run in mono, both outputs can be used simultaneously to create two independent (identical) mono output signals. There is also an additional dedicated guitar input on the front panel. The Wellspring can be used both as an insert with the internal wet/dry knobs and as a fully wet effect return from a mixer or DAW.
Tone and noise
The first thing to note about the sound of the Wellspring is that the unit has a noticeable vintage "box tone". Even when passing signals through without any reverb or delay, there is a high frequency roll-off and a bit of thickening in the low end and subtle saturation. Keep in mind that this is only really noticeable when the device is used as an insert with the internal dry/wet controls. The analog input preamp, while definitely on the cleaner side, can be clipped to create some subtle additional harmonics.
In terms of noise, while the Wellspring is not nearly as noisy as comparable vintage units would be, with this kind of device a certain amount of noise is simply unavoidable, given the large and complex analog reverb and delay circuitry. When run with correct gain staging as a wet aux from a mixer or DAW, in most cases, the unit’s noise floor should be unnoticable in the context of a mix. However those very concerned with their studio's noise floor should definitely take into account that the unit is not noise free.
The spring reverb section
Like with some of the higher-end spring reverbs from the 70s and 80s, the basic character of the reverb is surprisingly "neutral" for a spring reverb. While there is some spring “boing” to the sound if you feed the device transient heavy signals, it is far from a 60s surf spring reverb. You can hear the basic character of the reverb (mono) in these two clips below, one with a percussion sound and another with a chord stab. As you can hear, the character of the reverb itself is highly dependent on the input signal and can sound quite different, depending on what you feed it — much more so than with most digital reverbs.
(all sound clips in this review start fully dry and then switch to wet)
When used in stereo, the Wellspring’s reverb can sound almost “plate-like” with a character closer to an EMT plate reverb than a traditional spring reverb. You can hear the character of the stereo spring reverb in the clip below. The amount of reverb has been turned up for demonstration purposes, however the Wellspring's stereo reverb can also act as a very subtle "space enhancer" when used in small, barely perceptible amounts.
The delay section
The Wellspring's delay section is unashamedly characterful and definitely not your standard clean digital delay! The delay circuit makes use of the PT2399 IC and there can be audible aliasing noise with longer delay times. In many other devices, this is dealt with by having an always-on lowpass filter in the delay circuit. Since the Wellspring's delay goes through a user-controllable analogue filter circuit, the user can filter out the aliasing noise to their own taste. You can hear the basic character of the delay (mono) in this clip. With some lowpass filtering, it can sound very lush and warm, like a vintage guitar pedal delay.
Since the Wellspring has two separate and offsetable delay lines, it can create a variety of stereo delays — including a ping-pong option, which is rather unusual for analogue delays. Both the delay time and delay filter LFO modulations can be stereo inverted, which can create wide, stereo-sweeping delay sounds. Below is an example that makes use of stereo ping-pong delays, inverted delay and filter modulation and just a touch of reverb feeding into the delay from the "Magic" knob.
The Wellspring's internal LFO has two waveform option (sine and saw) and can go up to audio rates with the "10x" switch, allowing for audio rate modulation of both the delay and filter circuits. This makes possible a variety of wild ring modulation sounds, especially when used in conjunction with delay feedback and the "Magic" knob. There is also a dedicated modulation CV input for even more experimental possibilities. Below is an example in which the input sound has been completely transformed through audio rate modulation.
In practical studio use
While the Wellspring has been marketed primarily as a spring reverb device, in practice it can also be thought of as an analogue stereo delay with additional reverb options. It is easy to add just a touch of space and reverb to a delay patch with the “Magic” control, without even having to turn up the dry/wet control on the reverb itself. Below is an example of a patch that is primarily a lush stereo delay sound, with just a bit of reverb enhancement.
Conversely, the Wellspring can also sound like a reverb with just a touch of additional delay, like in this example below.
As you can hear, the Wellspring's analog spaces really shine on acoustic instruments like the guitar. On synths, it tends to sound best on warm, darker sounds without too much high frequency information. Below is an example of a lush synth pad sound that is "stereoized" with the Wellspring.
On vocals, the Wellspring is useful for both subtle space-enhancement and more obvious reverb/delay effects. Below is an example of a strong effect sound that lends the vocal a "psychedelic" character.
No-input soundscapes
Finally, since the Wellspring is capable of both audio rate modulation and complex self-oscillation feedback, it can be used as a "no-input" device — but be careful with the “Magic” control, it can easily create loud, almost speaker-blowing feedback once past the halfway mark! Below is an example of the Wellspring as an experimental feedback and noise playground.
Conclusion
With a retail price of 1700 Euro incl. VAT (EU), the Wellspring solidly sits in the higher-end segment of the market and is likely not the best option for those looking for an affordable bread-and-butter device. However, for those with the budget and a taste for novel and unique sounding processors, the Wellspring could be a very attractive prospect — especially when considering that to get anything even remotely comparable, one would have to add up the price of both an analogue stereo delay and a studio-grade stereo spring reverb unit, neither of which come cheap. And even then, with its flexible routing, modulation and complex feedback options, the Wellspring is capable of unique analogue delay-reverb "hybrid" sounds that can't be found in any other device currently on the market.
You can find more information about the Wellspring over at the Teaching Machines website and you can shop it over at SchneidersLaden.