Tape delays

[Doug Tymofichuk]

On Fri, 28 May 1999 21:34:24 EDT JWBarlow at aol.com wrote:

> Hi Doug:
> 
> I think both your ideas are very good. I have a whole bunch 
> of Walkman type tape players/recorders which I've been 
> wanting to turn into some type of long delay units. I think 
> it would be a fair amount of work, however. 
> 
> Many years ago I had a friend who would open a cassette 
> tape and move the take up reel to a second (empty) cassette 
> looping the tape out the window of the supply box and into 
> the window of the take up box and across all the tape paths 
> of course. This allowed the use of two cassette machines to 
> be used as a 7 to 8 second Terry Reily type tape delay 
> system. This actually worked quite well.
> 
> I believe one would need to have pull the tape out through 
> the open part of the cassette, and then do a hell of a lot 
> of work to make an isolated loop like on many 1" and 2" 
> tape machines. I hope someone else has an easier way, but 
> to see if you like the sound, you may want to try the 
> method I've described above -- remember to figure out which 
> deck runs faster and use that as your take up deck.

What I had in mind was to take a telephone answering 
machine outgoing message cassette, which come in various 
lengths and are already looped. The only problem with them 
is the metal sensor built onto the tape, but this could be 
easily spliced out. I would then modify the tape to accept 
a third head (possibly from the side), so that there would 
be erase, record, and play heads (in stereo). Mounting an 
extra head to a transport should not be too difficult, 
although it may mean that the tape would not be easily 
removed. The signal to the erase head could be varied to 
give a recurring secondary echo from the loop if desired.

Of course, if I used a head from a three head deck for 
record/play, then I could avoid a lot of the modifications, 
but the distance between play and record would be so small 
as to not give very long delays, plus those heads are quite 
expensive.

This whole system could be done with one cassette machine 
with an extra head and one extra stereo tape preamplifier. 
Then add a little more circuitry for feedback, signal 
processing etc.
----------------------
Doug Tymofichuk
dougt at cancerboard.ab.ca