Comments on: Teezer Through Zero VCO

By: Ian Fritz

Ian Fritz — Sat, 15 Aug 2009 22:42:12 +0000

Richard — I worked with David some in developing his 15V mods and I think they are fine. I prefer the series-zener solution somewhat, because it provides extra PS decoupling between the different parts of the circuit. Oh, those were exciting times, back in the 70′s.

By: Richard

Richard — Sat, 15 Aug 2009 20:12:41 +0000

Ian, thanks for the comments! And the link to Dave Brown’s Teezer page, which I had not seen before, even though I frequent Dave’s site. I will have to ponder his circuit changes for 15 volt supplies, although my Teezer works fine with only your recommended zener diode modifications.

Ian, I remember reading your articles in Electronotes in the late 1970′s. I have a complete hard copy of EN.

By: Ian Fritz

Ian Fritz — Sat, 15 Aug 2009 19:23:15 +0000

Thank you for taking the time to write such a nice review.

The Tri wave is derived from the Saw, and so will always have a bit of an anomaly. To see an example of a unit with the Tri trimmed to what I consider an acceptably small glitch please see David Brown’s scope shots:
http://modularsynthesis.com/bridechamber/tzfm/tzfm.htm
and very importantly his assembly note #6. This should help if you need better symmetry.

Thanks again!

By: Cynthia Webster

Cynthia Webster — Sun, 12 Jul 2009 20:31:36 +0000

Thank You for Such a Wonderful and Fair Comparison.

Congratulations on what looks like a fine new module, and
Great Post!