DIY tape echo -- possible?

LBucha5714 LBucha5714 at
Tue Jan 20 18:23:02 CET 1998

Hi Scott,

In a message dated 98-01-18 04:59:08 EST, 64k at writes:
 My problem... My reel to reel only has two heads,
 erase & play/record. I've sucessfully hacked on an old
  What I want to know is, how hard would it be to build a
 circuit that'd translate audio to/from the three tape heads,
 so that I can detach all three heads from the current circuit
 and run the new output straight to a jack. I'm really looking
 for the simplest circuit that'll do this. 
Scott, you're definately on the right path except for one thing - your deck.
Yes, you can hack a basic two head deck if you do all kinda of crazy stuff
like add extra heads, playback circuitry (discussed), etc.  But that's a lot
of work and time that I might humbly suggest be spent on other aspects of your

Rene's idea of using two tape decks solves your immediate problem completely
IF you are going for LONG delay times.  With RR, this is the best way for long
delays.  And you even can vary the amount of delay easily by adjusting the
distance between decks.  Your delays will aways be long though.  Pauline
Oliveros is reported to have had tape delay loops going all the way around the
studio (anyone got a picture of that??).

But for short delays, I would definately suggest using a different tape deck.
A three head deck (separate rec/play heads AND separate rec/play circuits)
will handle the entire job for you! - no need for other circuits and hacking.
You can find them cheap since unlike cassette decks, three head RR decks
was/is more the norm.  When placed in record mode, the playback head is
usually on and the delayed signal will be played back from the ouput with no
mods  - often a "monitor" or "output" switch on the deck controls which signal
is output (better verify this before you buy).  Use a simple mixer (DIY
maybe?) to feed back some of the delayed signal into the record signal to get
the echo/regeneration effect.  You'll also need to "pick off" some of the
original record signal if you want to hear this too as the RR won't play back
both the rec and play signal at the same time.

You still only get short delays with this method based on the tape speed.
Certain Akai and Tandberg decks are cool for this since they have three speeds
instead of just two.   I've always wanted to hack a deck to add a wide range
variable speed for variable delay time plus that cool "speeding up" and
"slowing down" effect you get when you change tape speed during a delay.

Let me know if you need any more details on the hook up for echo, etc.

Good luck and have fun!



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