I'm hoping some experienced users of the Marshall "Echohead" delay pedal might be able to help me on this one..

I've had mine for about 2 years now, but have never really worked out how to combine using the "delay time" control knob in conjunction with a tap-tempo footswitch. I can tell that obviously the switch sets the tempo, but it seems that the position of the dial seems to affect that as well, as if it somehow assigns whether the repeats are quarter notes, eighth notes etc. I just play around with it the best I can with each song that I need it for, but I can't seem to predict how it will behave.

Perhaps someone could explain the effect of different positions of the delay time knob?

Thanks in advance!
PRS SE Chris Robertson
PRS SE Angelus Custom
Yamaha SF1000 (Both of 'em)

Laney L20H Lionheart
Marshall 1936 w/ Eminence

Rather large pedalboard..