V/oct CV input 290 cents low from any sequencer/voltage source

Hopefully someone can help here. Just received a used ER-301 in the mail and it’s fantastic of course, but it seems like the note scaling is off from any source. I’ve tried a Keystep, Nerdseq, and the MIDI/CV converter on my Niftycase and in order to get a “C” from a flat 3v or 5v I have adjust the tune knob up by 290 cents. Is there some setting I can’t find that would address this?

This is CV input on both IN and Ax jacks, both on a variable speed sample player and just a naked oscillator with no VCA or filter.


The default tuning of oscillators is an A note, requiring you to tune up by 300 cents… The missing 10 cents, that I don’t know about :-/

Ha, well in the context of “it’s tuned in A,” my overly-technical complaint seems a little absurd.

Not sure about the 10 cents problem either… The tuning on an unaltered source is always a sharp A.

So to sample something in for melodic playback, is A the ideal note to record for simplicity?

I usually tune everything in the 301 to C. The frequency control on oscillators steps by note value, to it’s just a few ticks up to C at 32.7.


That’s a great tip, thanks!

If your sequencers are in a different case than the ER-301 then you might have reference voltage issues. The “ground” or “common” connection at each jack isn’t so “common” when you are running multiple isolated power supplies. If this is your issue, you will notice that its severity lessens as you patch more cables between each case (lower resistance).

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INx inputs are not calibrated for pitch CV. The ABCDx inputs are calibrated for pitch CV.

also you can have hums (i suppose they are ground loops) when using multiple power supplies.
i usually patch my two halves of the suitcase (using two different psu) starting by patching a clock from first half to a multiple on second half. this seems to estabilsh a common ground and the hum disappears.

Of course it’s right there in the wiki. Thanks!

So two of the sequencers I’ve used are powered by the same power supply but the Keystep is being powered by a USB hub. Some googling around has shown other reported issues with CV note scaling on the Keystep (and I just checked and notice that the 10cent variation is limited to the Keystep).