Korg Volca Keys Delay Circuit Noise


I have had the Korg Volca Keys for a little over a week and have gotten quite comfortable with the unit. The feature set can be learned in a matter of minutes, but the sonic range of the instrument is impressive and much more broad than I expected. The strength of the Volca Keys is in the modes: poly, unison, octave, fifth, unison ring, and poly ring. The sound I posted earlier, for example, demonstrates the poly ring modulation mode. Lately I’ve been enjoying syncing the Volca Keys with my DSI Tempest and Korg Monotribe, but more about that later.

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Of course a hardware analog synth that exhibits the diminutive size and cost that the Volca Keys does is bound to have some limitations. From my perspective the most obvious limitation is the quality of the onboard delay. According to Korg’s block diagram the delay is the final circuit in the signal flow. Therefore, high frequency noise coming from the delay can’t be rolled off with the filter. The noise is most obvious when playing a sound that is programmed with the cutoff frequency most of the way down, the delay time at the slowest setting, and the feedback at the highest setting.

To illustrate the noise introduced by the delay circuit I created a few versions of a simple test sequence. One without delay, one with the internal delay, one with Ableton’s Simple Delay, and finally one with my Electro-harmonix Memory Man Delay. The sequence sounds pretty clean on its own, but buzzy, high frequency aliasing becomes audible when the Volca’s delay is introduced. In comparison, Ableton’s Simple Delay doesn’t add any noticeable noise, while the Memory Man adds a little noise (and pleasant chorusing), but nowhere near as much as the Volca delay.

Korg Volca Keys Sequence with No Delay:

Korg Volca Keys Sequence with the Internal Delay:

Korg Volca Keys Sequence with Simple Delay:

Korg Volca Keys Sequence with Memory Man Delay:

Some might find the buzzy delay noise desirable at times. To me it sounds more-or-less like a cheap, digital delay circuit that uses some down sampling and/or bit reduction to handle the memory requirements for the repetitions. I have also noticed that the filtering on the delay trails is significant. Cranking up the cutoff and lowering the attack, decay, and sustain on the EG produces obviously muffled delay trails. All of these limitations are not that noticeable when you’re using the Volca alongside two or more other instruments, but I plan on using my Memory Man as an alternative to the on board delay when it’s convenient to do so.

18 thoughts on “Korg Volca Keys Delay Circuit Noise

  1. Hi. I have a VK and dislike the noise level of the built in delay. I’m traveling right now, but last night I opened the case looking for marked solder pads, and saw a nice one marked VCA. Hopefully, that’s a nice, clean output direct from vca that bypasses the delay circuit. Will try as soon as I get home next week.

  2. Character is subjective. Some people don’t like chocolate in their peanut butter and some people don’t like buzzy digital delay noise in their analog signal flow.

  3. Thanks for this review. I love the sound of this line through the memory man delay. It makes me want to use delays on basslines now!

  4. Cheers, Lex. I think of it as more of a demo than a review. Would love to hear your delayed bass lines though. I often use just a hair of reverb on bass lines to smooth them out and add a little bit of depth.

  5. In an interview Tony Horgan had with Korg’s Volca creator Tatsuya Takahashi, he explicitly stated that the Volca Key’s delay effect was implemented in software on the microprocessor, not a DSP. I thought I’d mention it as it is known for sure now. I’d read beforehand some people suspected it as well as the LFOs were. Tatsuya also said it really maxed-out the microprocessor, that could explain a lot.

  6. I bought a VKeys (used) recently. I had read about the delay being dirty/noisy/bit-crushed sounding and it didn’t bother me…I liked the idea. But its not what I expected and its really noisy even with the delay off. On mine, delay levels down, it will be very quiet but hitting a key makes the noise level shoot up, very unnaturally, similar to something like having a compressor with extreme settings. Is this “normal” or your experience?

  7. I’m not getting that buzz sound on my VK’s delay. Bought new two weeks ago and my delay sounds pretty good, just a little noise but nothing like the one you posted. On a side note, I have a memory boy and a DD-3 and it’s probably just the lo-fi obsession I have but I actually like the VK delay better… Totally subjective.

  8. Nice Post! Did you actually bypass the delay circuit and thus ad/da-conversion or just switch it off via knob setinngs? In your audio example there is still an audible noise floor. I am interested to know if this could be lowered if the delay chip is bypassed by wiring the output accordingly.

  9. Thanks, Salinger. I did not physically bypass the delay circuit so I can’t tell you if the noise floor could be lowered, but it sounds like an interesting experiment. Please let us know if you make any discoveries!

  10. Hi! Any idea of which delay chip is it? I’m not fond of the sound of it either (reminded me of some pedals with crappy chips I’ve had previously) and I was thinking about maybe replacing the chip (although buying a delay pedal would cost the same in some cases). Cheers!

  11. My volca bass has actually hiss in its amp outcome area. i.e., if i turned off all the oscillators, and turn the filter all the way off, meetinged a note, there’s a tiny bit of hiss. when the filter is up as well as oscillators are on, it masks the hiss completely.

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