Moon Modular — 530 Voltage Controlled Stereo Digital Delay
by John L Rice
In regular production there are many pro audio rackmount and desktop echo units, even more software delay plugins, almost 100 Eurorack audio delay modules, and nearly 300 guitar delay pedals, so, where are all the 5U DELAYS? 5U Delays? 5u delays? While there are a little over ten 5U audio delay modules listed on Modular Grid, if you eliminate all the discontinued, custom one-off, and limited run modules, there are only about five currently in production to choose from. Since feature sets, performance, and yes, even looks, can be the deciding factors as to if a module makes it into one’s setup or not, the announcement of the Moon Modular 530 Delay is being welcomed with much interest and excitement! More choices for the win!
The 530 is a true stereo delay with a single set of controls and CV inputs that affect both inputs equally, so when set to normal [non-ping-pong] mode, the mix of the left input’s dry signal and any resulting delayed repeats/echoes will only come out of the left output and in similar fashion the mix of the right input’s dry and delayed signals will only come out of the right output. I mention this to call attention to the fact that the 530 is not a mono input delay with a stereo output, nor is it a dual delay with separate controls for each input/output, which could be a critical or noncritical distinction depending on what one might be interested in doing. Of course when the 530 is set to ping-pong mode, any resulting delays alternate between the left and right-side outputs on each repeat, and the left input is normalled to the right input so it’s easy to use with a mono source signal, although the left and right outputs are not mixed together when only using the left output, as is the case with some stereo guitar pedal delays. An external mixer would be needed if a mono mix of the left and right sides is desired.
As its name indicates, the 530 is a “digital” delay, and if you happened to look at the back of one you would observe a large ARM microcontroller at its heart surrounded by many other chips, all floating in a dense sea of surface mount components. The delayed output of the 530 is beautiful, clean, and pristine sounding. I can hear you readers shouting, “What about the switch that says ‘Tape’ on it?!” People familiar with tape-based delays, the kind that use electric motors to move magnetic tape over two or more record/playback heads, know that two of the most noticeable sound characteristics they produce are:
Each subsequent repeat will have greater high frequency roll-off and/or harmonic distortion than the previous repeat
Changes in tape speed [delay time] are not instantaneous which produces an up/down pitch warping/ramping effect
To my ears, the Tape mode on the 530 doesn’t really produce the former but does the latter, meaning that the repeats seem to retain their clarity and frequency response, but delay time modulation produces a very nice ‘analog’ sounding sliding pitch effect. The frequency roll-off in Tape mode is does not seem obvious, if it is there at all. Think of Tape mode as your go-to for obvious modulation effects including chorusing, flanging, and Karplus-Strong.
Even though the range of delay times in the 530 is a wide 3 milliseconds to 3 seconds, I realized a little trick to double the delay times, up to 6 seconds, though it only works for a mono signal. Just put the 530 in ping-pong mode and then only use the right input and right output. This works because in ping-pong mode the first repeat for the right input takes place on the left output channel, so if you are not monitoring the left output you will not hear it. The second—and all subsequent even numbered repeats—appear at the right channel after what is effectively double the delay time that is set.
Going beyond basic delay functionality, the Moon 530 Delay has four important and interesting extended features that are not found on all delay modules. Each of these features have a momentary LED pushbutton for manual activation and a gate input jack for synchronizing/controlling them from other modules. Looking at the panel from right to left, the first is ’Tap’ for setting delay time, and it responds with just two button taps or clock pulses as long as they are within the available minimum/maximum range of the delay, meaning that two taps longer than 3 seconds apart will be ignored. I have not eaten enough candy or drank enough coffee yet to determine if two taps closer together than 3 milliseconds will be ignored or not! In my opinion, all digital delays should have this feature for syncing to external sequencers and clocks/dividers, as well as for setting the delay time by ear to some source that cannot be clocked, like performances with live musicians or prerecorded acoustic tracks for instance.
‘Reverse’ reverses the playback direction of the repeats and works best when the source audio and delay times are carefully considered and adjusted. The last two button/jack pairs ‘Hold’ and ‘Add’ work together for the looping functionality. Up to 40 seconds of audio can be recorded for the initial loop by holding the Hold button and then additional parts can be overdubbed by holding the Add button. It is interesting to note that the loop created in memory is played back through the delay, so delay time and other parameter changes affect the loop while it is being played back but not the live audio input. Because of this it is easy to quickly lay down a backing loop/track and then continue to play over the top of it without the delay effect.
There are features on the Moon 530 that work in unexpected ways, or possibly even actual build errors/bugs, and here are a few that come to mind:
No bypass switch or gate input jack to toggle bypass
No feedback-loop send/return jacks
No indication of internal clock rate or Hold loop start point
Hold loop lost if disabled or power cycled
No mono output mix of left and right sides
Still, I found the Moon 530 VC Stereo Digital Delay to be a great sounding, creatively inspiring, and FUN module to use. See it in action at:
2 MU +15V 170mA -15v 66mA
Price: $485