Digital Delay chip as base part of chorus/flanger?

[Steben]

Hey there.

I was thinking: if you use a digital chip, is it possible to use it as a chorus by tweaking the delay pot?
My yamaha green meanie DDS-20M works perfectly this way as I turn the delay knob very slowly around, yet I seem to need my hand for playing somehow. Yet I have seen plenty of delay chips (newer generation) that need either programming (sigh) or simply need reconfiguration (time) every time you wanna change the delay time?
Will it work on a PT2399?
Does anyone know a "perfect" range digital delay chip with let's say 0.5ms to 100ms delay?

And what about this:
http://www.elecdesign.com/Articles/Index.cfm?AD=1&ArticleID=8056

[amz-fx]

The trouble with most digital delay chips is that the delay time is too long for good flanging and chorusing, although there is at least one commercial pedal that manages to tweak one of the chips into doing a decent chorus.

-Jack

[bioroids]

You can get good chorus with the PT2399. Just use your favorite LFO and hack it to control the delay time with a transistor to ground in place of the delay time pot. You're gonna have to tweak the depth of the LFO to get good chorus instead of weird pitch shifting effects.

Luck

Miguel

[amz-fx]

It has to be a really fast clock...  over 2M Hz if I am remembering correctly.

regards, Jack

[bioroids]

I think the clock is pretty faster than that, maybe 20Mhz for 30ms of delay, but its all internal. I just only messed with the delay-time setting resistor, replacing it with a NPN to interface with the LFO. Had to use a 470ohm resistor in parallel with the trannie to avoid excesive depth.

I find it is a great chorus for clean work/bass guitar. Not so good on distortion, probably because the minimum delay time is 30ms.

It also draws a lot of current (well, around 40mA the whole circuit) on this short delay times (because of the faster clock I assume)

Luck!

Miguel

[Steben]

I think the clock is pretty faster than that, maybe 20Mhz for 30ms of delay, but its all internal. I just only messed with the delay-time setting resistor, replacing it with a NPN to interface with the LFO. Had to use a 470ohm resistor in parallel with the trannie to avoid excesive depth.

I find it is a great chorus for clean work/bass guitar. Not so good on distortion, probably because the minimum delay time is 30ms.

It also draws a lot of current (well, around 40mA the whole circuit) on this short delay times (because of the faster clock I assume)

Luck!

Miguel

Well it are these things that make me think twice. The PT2399 is indeed a "medium to long" delay chip.
I'm looking for short to medium ones, but they are not thrown at you for free. The PTxxxx range offers shorter delays but without the "realtime current" control of the delay (preset switches etc...).

But nice work anyway on the PT2399. Would do fine on the Rebote Delay I guess.