Dixie II Tracking Puzzle

TL;DR abstract: Even though voltage from two sources is identical, my Dixie II tracks way differently.

Okay, this is a strange issue, and I want to see if anyone’s had a similar experience. Here are the weird facts:

(1) I just bought a Dixie II. When I plug my Little Phatty Pitch CV out directly into the Dixie II’s V/oct input, the oscillator tracks perfectly throughout the Little Phatty’s range. (Note: My Little Phatty’s CV out is perfectly calibrated. It’s dead nuts across its range).

This leads me to believe that the Dixie II is calibrated properly.

(2) When I plug the Little Phatty into my Pittsburgh Distro’s buffered mult in, and then into the Dixie II from the Distro, the oscillator goes flat quickly. One octave up from in-tune to E, it’s about a quarter-tone flat. By three octaves up, the tuner reads D#. But before you blame the Distro…

(3) When I do the same experiment with my Sputnik Dual Oscillator, both oscillators track perfectly when using the Distro AND when using the Little Phatty directly.

When I measure voltage from the Distro with a meter, it looks perfect throughout the range, regardless of how many of the buffered mult outputs are in use. (Note: I have tried both of the Distro’s buffered multiples, with identical results).

If the voltage is the same, then perhaps there’s something other than voltage that I should be measuring.

I feel your pain. It sounds like there is still an impedance problem with your specific Buff-Mult setup. It may take shopping for the right Buff-Mult. I have an Intellijel 1U Buff-Mult, a Beast’s Chalkboard (it has a buff-mult built-in), and the M-32 has a buff-mult. Any one of these may produce different results. Are you measuring voltage at the Dixie II end with a stacked cable while it’s hooked up? If I had to guess the voltage isn’t really tracking well when hooked to the Dixie II. I hope you get this straightened out.

When I hit snags in tracking I go to the following:


EDIT: Measuring at the Dixie end will probably still give correct voltages. It’s inside the unit where the voltage will drop. My statement above, "Are you measuring voltage at the Dixie II end with a stacked cable while it’s hooked up?"is probably bad advice.

Thank you for your reply. I haven’t tried measuring the voltage with a stacked cable, but I’ll do that as soon as I’m able to tear down my current patch.

I asked this question on another forum as well, and impedance mismatch appears to be a consensus. Perhaps I’ll try a Links at some point instead of the Distro.

The Learning Modular article is a good read; unfortunately, manufacturers hardly ever list output impedance specifications, so its value is almost entirely theoretical. For example, I’d love to know comparative output impedance of Distro vs. Links. Otherwise, as you say, it’s about shopping around for the right buffered mult.

If you have some kind of attenuator, you could try putting this between the mult and the dixie (or between the phatty and the mult, for that matter). I run my mother-32 voltage out through a Quadratt or a Math’s channel at unity gain, and impedance issues go away.

That’s an interesting idea. I tried it with my WMD/SSF SPO, and the behavior was the same as it is with the Distro.

However, when I run the pitch CV through my µScale II, it tracks fine.

Clearly, the answer is to always stick with Intellijel stuff! They need to make a 4HP response to Links and Distro.