[sdiy] BBD for delay and other things

[harry]

I've done it and also had a commercial unit using the 8 track format...

They removed the 8 track guts and put in the heads from a cassette
so they could fit in the existing openings in the shell... one erase, one
record
and one play head.

Speed control was with a rheostat feeding the fast forward winding... and a
quick first pass at tape eq vs speed.

Quality was MUCH better than the BBD units of that time... (tee hee)

Also... consider using a regular cassette without an endless loop... is 45
minutes
of continuous play enough for your application... just throw out the erase
head
(I suggest just removing it and leave it connected electrically... it is
OFTEN part
of the bias oscillator) ... move the existing head to where the erase was and
set the deck to record... then add a playback head and feed that back into
the audio input.

Then just play with the speed... its good for about a 1/2 second delay at
normal speed...

After your gig... listen to the echo only tape in your normal deck...
trippy.....

H^) harry

Tony Clark wrote:

> > Speaking of tape echo, is there a tape loop cartridge similar to the
> > echoplex cartridge that will fit over a standard home-stereo
> > audiocasette head?  I'm on a quest for analog echoes, and if I have to
> > resort to tape delay, I'd rather do it via commodity components from
> > busted tape decks instead of building an echoplex and using those
> > funny cartidges.
>
>    Heh.  Well if you are adventurous enough, you could buy an old
> 8-track player to modify, specifically one that can record.  8-tracks are
> cheap and cartridges a dime a dozen (literally!).
>    There's a lot of modification that would have to be done to get it to
> work though.  The heads have to be reversed around so that the
> record/erase head is in front of the playback head.  In fact, depending
> on how keen you are on the audio quality, the heads should be replaced
> with two-track versions for better bandwidth.
>    You'll probably also want to figure out how to adjust the speed of
> play to get different delay times out.
>    The cartridges of an 8-track have a special metal splice in the tape
> that signals the player to switch tracks.  It will have to be removed and
> the tape respliced.  Easy enough to do since I doubt anyone would need
> all the tape that's in one of those things anyway!
>    You could also probably do this with a conventional tape player, but
> it would be harder to set up a continuous loop tape with one of those.
> Besides, 8-tracks are bigger and probably easier to work on.  :)
>    It'd probably be far easier to buy an old reel-style tape recorder to
> do this on, but I like the compact space that a small 8-track unit takes
> up.  :)
>    Anyone ever seen or done anything like this?
>
>    Cheers,
>
>    Tony
>
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