TB303 vco pt2

[jhaible]

> some time. However, once I put the FET in, differences were evident. I
> used a BF244 and then a 2N3819. Both n-type JFETs. Firstly, the flat
> part of the sawtooth output was now obvious. The time of the flat was
> frequency dependent, but then again it would because the FET follower
> could follow the input. I always thought there will always be a
> noticeable Vgs between input and output in a source follower. Surely if
> the sawtooth is at 12V, the supply, the FET output will not be able to
> follow.  What type of FET are Roland using? Is this 2SK30 not a JFET? Or
> am I completely missing the point here? 

Try different types of BF244. A BF244A can have as low as 1.5V threshold,
while a BF244C can have 6V and more. (from memory; exact range see data
sheet).

JH.