delay questions

[Paul Sullivan <paulsull@gis.net>]

Some more questions for those more knowledgeable about the nature of loops 
and
analog/digital delay units. Can a loop be sped up or slowed down only if 
the delay
time is adjustable with a knob? Is every delay that has knobs capable of 
being
sped up/slowed down? I assume the position of the delay time knob  (at the 
time of
the loop recording) would determine the degree to which the loop could be 
sped up/
slowed down (in the middle would mean it could be raised or lowered the 
same
amount, etc.).

Most digital loops seem to destruct when you try to change the delay 
time-are
there any (except the EH 16 sec delay) that are able to do this? Has anyone
overcome these limitations by using a pitch shifter  the loop, and if so, 
which
model (s) seem to work best for the thick texture of a multi-overdubbed 
loop?

Thanks for your time,
Paul Sullivan