[PD] audio gets "scratchy"

[David Merrill]

Hi there - has anyone had the problem with PD where the audio gets 
"scratchy" after a while? I am using tabread4~ to read samples out of 
arrays, and sequencing this with OSC. From there, I run the audio 
through some effects (vcf~, a tremolo and ring-modulator that I built, a 
pitch-shifter, etc..) It seems like after a minute or so, the audio 
starts getting really grainy and broken up. Even when I re-route the 
signal *around* all of the effects, it remains deteriorated until I 
restart PD. At first I thought that maybe I was messing things up by 
throw~ ing too many signals at the same time onto a summing bus, and it 
was clipping, but I've since fixed that problem. Any ideas about what 
might be causing this, and how I could fix?
much appreciated,
David Merrill