Plankton Electronics - The Jellyfish


The Jellyfish module is a lovely delay for the Eurorack with a very nice sound, infinite feedback, a synchronisation input (!) and a switchable lo-fi mode. Send and return sockets allow for inserting effects into the feedback loop. In the modulation section there's an integrated LFO for delay time modulation as well as three CV inputs for dry/wet mix, delay time and feedback amount. Well done!

The newest version with the black faceplate features a low pass filter in the signal path and longer delay times.



The Jellyfish is based on the PT2399 chip we already know from Synthrotek's Echo module which sound we like a lot.
A red LED at the input warns you of high audio levels but will glow constantly at extreme feedback settings. The levels of original and effect signal are set with individual potentiometers and the wet level can be voltage controlled. In the signal path a low pass filter is integrated for dampening the high frequencies in the delay signal.

The delay time ranges from 32ms to 1.23s (which is significantly longer than the V2 version) and is set with two controls, one for coarse and one for fine adjustments. Of course there's voltage control of delay time. ATTENTION: when powering up the two time potentiometers mustn't be at minimum position, otherwise the chip won't work
Additional modulation of delay time comes from the integrated LFO with two wave forms, triangle and square, making it easy to create living and deep chorus sounds. DEPTH controls the modulation amount. The LFO's signal is available at a socket which level is not affected by the Depth control.

The feedback ranges from one single to an infinite number of signal repetitions which means you can make the delay oscillate, generate extreme effects or use the module as a sound generator. Voltage control of feedback is possible, too.
The feedback loop can be broken using the SEND and RETURN sockets in order to process the feedback with effects ... or criss-cross the sends and returns of two Jellyfishes.

Last but not least: the Jellyfish module can be synchronised to a clock via the SYNC! input. The wavelength of the clock has to within the delay time and the gate voltage has to be within the 0-5V range.


Audio input, audio output
feedback loop: send and return
LFO output, sync input
CV inputs for delay time, feedback and wet amount


3U Eurorack module, 18HP wide. 25mm deep
current draw: 60mA @ +12V and 30mA @ -12V

0.3 kg
Article Number

This item is discontinued or sold out and no longer available, please feel free to look for comparable new stuff in the following categories.