i've tried to build a simple delay effect (via [delwrite~] and [vd~], but when i try modulating the fader for the delay time, there occur terrible scratches. can someone tell me how to fix that? smoothing the slider-output with vline~ or something only leads to pitch-fx.....

Pitch changes are expected. Think of it as taking the playhead and moving it across the playing tape. This is going to result in the tape moving across the playhead faster or slower (depending on direction), which will also result in raising or lowering the pitch, respectively. Take any commercial delay effect and change the delay time during playback, and you'll hear it there, too (or if it's badly designed, you'll hear those scratches) . If you want to avoid this but have echoes at various unrelated intervals, then you might want to consider tapping the delay line at different points using multiple [vd~]s or [delread~]s. Or is there a particular effect you're trying to acheive?

yeah, you could probably set up a whole bunch of [delread~] objects for the same cpu cost as the single [vd~], and then crossfade between them as your slider moves. but the result would probably have a fair bit of phasing weirdness and might not be pretty.

as far as i know, there is no simple way to do what you request.

now, ok - thanks for your help! i also use reaktor and i thought, i didn't have this problem there, but i was wrong... i tried it out, and i got a scratchy sound too, while tweaking the time knob .... although not as terrible like in my pd delay. but doesn't matter - thank you for your help!