The long lost 2SK 30(O)

[Fraser, Colin J]

> -----Original Message-----
> From: Trevor Page [mailto:trevor at resonance.fsnet.co.uk]
> Sent: 16 November 2000 11:28
> To: Fraser, Colin J; *Star Project; DIY skicka Lista
> Subject: Re: The long lost 2SK 30(O)
> 
> I guess it is down to luck. I must have been fortunate to get 
> a batch of -Y variants which happened to make a good 
> substitute for the -O! I used -Y's in my TB3030's and got 
> good results, i.e. producing squarewaves of the correct 
> pulsewidth. Placing a trimmer in the differentiator circuit 
> is a good idea. I stuck a trimmer in place of R35 and then 
> managed to get several JFETs to work. Trim for a nice 50% 
> duty cycle, but remember this varies with frequency anyway.

And as Tony said, the component tolerances mean different 303s will differ
slightly too.
My clone is adjusted to sound the same as my real 303.
Whether it sounds the same as any other is another question.

It might be worthwhile having a sample of a reference 303 squarewave at a
given pitch somewhere...

Colin f