Doepfer

> >
> > If one is looking to improve performance on the BBD modules I'd  
> think
> > besides a steep filter, wouldn't one also want a compander  
> (compressor
> > & expander) to improve signal to noise
>
> yes, indeed that helps to improve the signal/noise ratio.
> anyway you have to filter out the clock noise before
> comressing the signal, otherwise the clock noise is
> compressed too and gets even more audible.

Just to explain it a little more clearly. I agree, a filter for clock  
noise is needed too.

Companding is used on most(?) BBD delays (later Roland Space Echos too  
and is the basis of most tape noise reduction). The idea is you  
compress your signal going in (not after filtering),  so you have less  
dynamics and a higher overall amplitude dry signal. Then you expand  
the BBD output so you will lower your noise floor amplitude (since it  
was never compressed) and restore some of the dynamics that you had  
just compressed. I think you'd probably want to filter the output  
first before you expand the wet signal. That way what's left of the  
filtered clock noise will be expanded even lower in amplitude.  
Obviously this technique only works when the sounds you don't want are  
lower in amplitude than the sounds you want to hear.