Fernando wrote:
I don't really have a good method of measuring exactly how short the
delay can be. Currently I plan on having a switch that selects either
the 64k or 256k ram which will be labeled short and long modes. If you
clock the chip too fast, it gets all messed up and starts spitting out
garbage (I have no idea if this could damage the chip, but it hasn't
yet). I will probably setup some kind of trimmer so that I'll be able to
adjust the CV input of the 4046 to allow a maximum clock frequency
slightly less that the PT2395 will accept.
For the moment, I'm using the resistor values on the 4046 that Ken had
labeled on the development board. the capacitor for the 4046 is a 33pF.
This doesn't allow the shortest or longests delays that I want with a CV
range of 0-5V. My guess is that it currently gives around 50ms-80ms in
64k/short mode. when sending it a sound from an envelope that has very
short attack and decay you can hear the echo still. I know this can be
improved quite a bit because in my first version, I couldn't hear the
echo. This part of the circuit is what I'll be working on just as soon
as final exams are over in school...
another note about the LTC1063 filters. They add several parts to the
circuit. Running of +-7.5V (which is the maximum allowed). I use two
adjustable regulators LM337L and LM317L. several additional bypass
capacitors are needed to keep the noise down on the LTC1063s. A opamp
buffer is also needed between the delay output and the output filter's
input. Thats the only way, I could figure out how to get rid of the DC
offset from the delay IC. A capacitor alone wasn't working...
> Great and exciting news, thank you! 16kHz it's very good I think.hi Fernando,
>
> What's the minimum delay time (approx.) that you can get at max clock freq?
>
> Fernando
I don't really have a good method of measuring exactly how short the
delay can be. Currently I plan on having a switch that selects either
the 64k or 256k ram which will be labeled short and long modes. If you
clock the chip too fast, it gets all messed up and starts spitting out
garbage (I have no idea if this could damage the chip, but it hasn't
yet). I will probably setup some kind of trimmer so that I'll be able to
adjust the CV input of the 4046 to allow a maximum clock frequency
slightly less that the PT2395 will accept.
For the moment, I'm using the resistor values on the 4046 that Ken had
labeled on the development board. the capacitor for the 4046 is a 33pF.
This doesn't allow the shortest or longests delays that I want with a CV
range of 0-5V. My guess is that it currently gives around 50ms-80ms in
64k/short mode. when sending it a sound from an envelope that has very
short attack and decay you can hear the echo still. I know this can be
improved quite a bit because in my first version, I couldn't hear the
echo. This part of the circuit is what I'll be working on just as soon
as final exams are over in school...
another note about the LTC1063 filters. They add several parts to the
circuit. Running of +-7.5V (which is the maximum allowed). I use two
adjustable regulators LM337L and LM317L. several additional bypass
capacitors are needed to keep the noise down on the LTC1063s. A opamp
buffer is also needed between the delay output and the output filter's
input. Thats the only way, I could figure out how to get rid of the DC
offset from the delay IC. A capacitor alone wasn't working...