by Robin Vincent | 5,0 / 5,0 | Approximate reading time: 2 Minutes
Morphor AP-1

Morphor AP-1  ·  Source: Morphor


Morphor AP-1 is a fully analogue string synthesis Eurorack module based on the Karplus-Strong principle. It’s vibrating on Kickstarter now.


Morphor AP-1

The Morphor AP-1 came out of the love of electric bass sounds. Consequently, engineer Thijs wanted to bring this into a Eurorack module. Using a form of the Karplus-Strong principle it’s possible to generate realistic sounding plucked string type sounds using a filtered delay line. Thijs calls it the “Analogue Plectrum”.

The module can put out a wide range of sounds from the plucked starting point. You can then tune the pitch and modulate for additional vibrato effects. The timbre can be controlled with the Colour knob that sweeps a filter across the signal causing everything from dampened to noisy, resonant sounds. One really interesting feature is the ability to bypass the internal filter and loop in your own. That would nicely increase the tonal potential. Finally, the Feedback knob takes care of the decay which can be pushed to the point of self-oscillation. It looks like a really solid module.

Morphor, supported by R&D firm ENT Studios, are hoping to raise enough cash to get the Morphor AP-1 into production. They are halfway through the campaign and almost halfway to a very modest goal of £5,540. All the Early Bird pledges have gone but you can still pick one up for a very reasonable price of £117. ENT Studios anticipates delivery of the AP-1 in September.

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I think Eurorack is a difficult thing to sell on Kickstarter. It’s such a niché market and to be successful you have to have something pretty stunning backed up with an enthusiastic and groovy marketing campaign. Thijs and ENT Studios seem like a nice bunch of people with a reasonably cool product but the demo videos are a little bit underwhelming. They all seem to have the same thump thump thump going on whereas Karplus-Strong can produce moments of stunning beauty and dynamic emotion. It could benefit from some more interesting videos.

However, they only need to take another 20 or so module pledges to reach the goal which doesn’t seem impossible. It’s also good to see that they are already responding to feedback, improving the front panel, and adding a dedicated 1V/Oct input separate from the FM input. Hopefully, this article will help bring them some more punters.

  • Morphor AP-1 Kickstarter page.



Morphor AP-1

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One response to “Morphor AP-1: Karplus-Strong analogue string synthesis module”

    Morphor_Thijs says:


    I am Thijs, the engineer of AP-1, and just found this article. Thanks for the shoutout, nice words and feedback. We will try to record some more ‘advanced’ videos and put them on the Kickstarter page soon.
    Thanks again!

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