TB or not TB, that's the question

[Fraser, Colin J]

> -----Original Message-----
> From: Mattias Nord [mailto:puny at techno.org]
> Sent: Wednesday, April 29, 1998 8:44 AM
> To: Jim Johnson
> Cc: synth-diy at mailhost.bpa.nl
> Subject: Re: TB or not TB, that's the question
> 
> Has anyone tried to build a copy of the filter in the 303? 
> Because as much as
> i´ve heard
> about the little silverbox it´s the filter that is a big part 
> of the magic in
> it.. Sure the sequencer
> too..  If anyone has tried to build that also then say AY.. ;) ..
> 

I have built a clone of the whole analogue section of the 303.
I added an accent trigger output to my real 303 to give full control of
the clone - running in parallel and a/b-ing between the two it's almost
impossible to tell them apart.
However, as soon as I tried to recreate a 303 pattern using Cubase via a
cv convertor (with slide...) the magic is lost. It's very difficult to
get close to the feel of the 303's own sequencer. There are a few
potential reasons for this that I'll be looking into sometime soon, but
it suprises me how many commercial 303 clones there are and none with a
cloned sequencer AFAIK.

I agree the filter is a big part of the sound. Also important are the
BA662A vca, the distortion in the final output stage and of course the
action of the accent circuit.
It also helps the cloning process if you have a real 303, so you can
find which two resistor values in the filter schematic are wrong by a
factor of 10, and prevent your filter working...

Colin f