hi all,
just an update on the pt2395 delay I'm working on. I decided that I
didn't like the filters that the datasheet uses. I bought a couple of
LTC1063 - 5th order switched cap filters from linear technology (mostly
out of curiosity). These are $6 each, but they seem do a pretty good
job. I have my 74hc4046 clocking the delay chip, the switched cap
filters are clocked by the same clock divided by 4. This is giving about
16khz for the bandwidth when the clock is at maximum, and about 6.25khz
at the longer delay times. I can't see any clock noise on my scope,
atleast not any noise that I can say is coming from the switching. I
suspect that setting the bandwidth by the delay clock should help me get
some longer delays without so much distortion, but I've got to make some
adjustments before I can test it with long delay times.
This was my second version of the delay to build. In the first one, I
tried using the filters from the datasheet, but modified for about a
10khz cutoff frequency, That didn't work as well as I'd hoped. It sounds
quite a bit better with the LTC1063 filters. Noise doesn't seem to be
much of a problem, and I haven't added the compander yet. The first
version was all on a breadboard with only one ground (noise was
horrible, so deffinently don't do that).
now, just to add a reset trigger input and a VCA for the feedback.
..Ryan
just an update on the pt2395 delay I'm working on. I decided that I
didn't like the filters that the datasheet uses. I bought a couple of
LTC1063 - 5th order switched cap filters from linear technology (mostly
out of curiosity). These are $6 each, but they seem do a pretty good
job. I have my 74hc4046 clocking the delay chip, the switched cap
filters are clocked by the same clock divided by 4. This is giving about
16khz for the bandwidth when the clock is at maximum, and about 6.25khz
at the longer delay times. I can't see any clock noise on my scope,
atleast not any noise that I can say is coming from the switching. I
suspect that setting the bandwidth by the delay clock should help me get
some longer delays without so much distortion, but I've got to make some
adjustments before I can test it with long delay times.
This was my second version of the delay to build. In the first one, I
tried using the filters from the datasheet, but modified for about a
10khz cutoff frequency, That didn't work as well as I'd hoped. It sounds
quite a bit better with the LTC1063 filters. Noise doesn't seem to be
much of a problem, and I haven't added the compander yet. The first
version was all on a breadboard with only one ground (noise was
horrible, so deffinently don't do that).
now, just to add a reset trigger input and a VCA for the feedback.
..Ryan