Doepfer

Latest news: Though the spec of the BBD circuits says that the max. allowed
clock freqency is 100kHz we increased the frequency up to ~ 250 kHz and
obtained a minimum delay of about 4ms. It seems that the circuit is still
working at 250kHz. Beyond ~ 250kHz the chip is definitely no longer working.
But we have to try some of the BBD chips and do some long-term tests to find
out all chips will be working under these conditions without damage.

And we will additionally look for a pin-compatible 1024 stage BBD. So far I
have no answer from the manufacturer.

Best wishes
Dieter Doepfer

> > So the HCVSO goes up to 200kHz, resulting in 100kHz BBD clock and
consequently 10.24ms delay time.
> ok, so we should do a little survey here:  To my opinion 10ms as minimum
> delay I would say, there is no real "flanging" effect possible. Flanging
> is a modulation of center delaytimes between 1ms and 8-10 ms. Everything
> with delaytimes larger than 10ms I would call "chorus". Still a nice
> effect, but it will lack those 'narrow' and 'claustrophobic' aspect of a
> good flanger or very short delays.

> > At the moment we prefer
> > the adjustment of the memory length with up/down buttons (e.g.
> > 2/4/8/16/32/64/128 ..... 1M) and a 3-digit LED display (the decimal
points
> > could indicate "kilo" and "mega"). Giving devils advocat: What about a
CV-controllable division factor?

I discussed this feature with Christian. In principle this is possible but
it will reduce the maximum sample frequency as the software has to measure
and process two AD results: the result from the audio converter (written
into the delay memory) and the result from the CV converter (defining the
memory length). This will at least divide the max. audio sample frequency by
two.

> > b.t.w. The SC filter prototype working as well. To speak the truth: it's
not
> > very exciting from my point of view. Just a chaste, clean filter having
not
> > very much character to my estimation. Maybe I use to often the A-106-1,
A-107 and A-124 ...
> Thats what the SC-Filter sounds like. It is only really interesting
> because of the steep cutoff slope (and also because it can simply
> connected to any kind of sampling rate). How steep will the slope of the
> SC-Filter-module be?

probably 60dB (30dB would be possible too by using only one of the two
cascaded SC filter circuits).

Dieter Doepfer