Convert a reel to reel into a tape echo?

[WhinyLittleRunt]

Anyone ever try re-housing a reel to reel into some sort of echoplex clone? I would love to try this, but it would take some planning and a lot of effort.... I'm curious to hear of anyone else tried or wants to try something similar. [/i]

[The Scum]

To begin, any pro, 3-head deck can be used as an echo by itself.

Some info here:
http://www.harmonycentral.com/docs/DOC-2021

A trick they don't mention: feed the signal from the left input. Take the left output and feed it to the right input. Then take the delay from the right output...this doubles your delay time, and with some clever patching can give you a tap at 1/2 way.

As to rehousing, most pro decks contain motors that weigh ~20 pounds each...just getting them mounted in the proper orientation, with the heads in the right place takes pretty hefty mechanical construction.

You might be able to add some threaded holes in the headblock or surface of the machine that let you put some standoffs between the record and play heads, such that you could route a longer loop around them for longer delays. The extra drag might confuse the tension system on a servo-controlled deck.

I've considered building something along these lines before, and it doesn't take long before a brand-new Fulltone looks economical in comparison.

And google seems to turn up all sorts of links for "Diy tape echo" starting with the folks at Make:
http://blog.makezine.com/2008/04/30/diy ... delay-mac/
http://hackaday.com/2010/12/20/tape-del ... tte-decks/

[Drone]

I got an old reel to reel for similar purpose, but the big difference from your commercial things like the copicat etc. is they have multiple playback heads, to give you multiple taps, unless you plan to buy extra heads, and build extra head preamps, and a mixer circuit, what you can do with a reel to reel is a little more limited.



I suppose if you could design a really simple head amp system, where you could get maybe 4 amps from a single quad op-amp, and find a source for the extra heads, maybe mount them on a single piece of plate steel, like a ruler even, and add a roller at the end, you could have some fun.

Adjustable tape speed might make it better too. I'd imagine older reel to reels use AC motors, which would make that trickier.

[The Scum]

Thinking about this a little more, building from scratch, or repurposing cassette decks might not be as hard as converting a full on reel-to-reel.

A reel-to-reel machine isn't a terribly practical starting point because of the huge motors, and the sophisticated speed & tension controls it'll be using to drive them.

But if you're only running an ounce or so of tape, you don't need washing machine motors...cheap DC motors would probably suffice...again, could be gleaned from old cassette decks.

Opamp Labs catalogs used to have schematics for tape head record & playback circuits, which could be easily adapted to regular monolithic opamps. Or check out any of the downloadable schems for the classics. I'd suggest that the RE150 is a decent jumping off point - the audio path mostly uses garden variety opamps.

The tension thing becomes a bit troublesome, though...Space Echoes use a little felt pad one a piece of springy metal to drag on the tape, so it sits flush on the heads...cassettes use that spring/pad arrangement that sits in the recess of the cassette itself. There is room for improvement over either of those designs.

[themagicmanmdt]

i say dremel a path to move the playback head to and fro from like an echoplex. always thought about it... never tried it.

[WhinyLittleRunt]

I'm really interested in trying something, even though I know by the time I'm done I'll have spent in mistake money what I probably could have picked up a decent Echoplex for, but...

I think it's a cool idea. The EP-3, for example, is not a very complex unit. I wonder how hard it would really be to basically copy the design and build my own... I see no harm in trying if it's really for my own personal benefit. I wouldn't really even know where to start with the circuit, but I have access to a few EP-3's that I could study in depth.

[E-money]

I made a tape echo out of a cheap Onkyo 3 head cassette deck that I found on Ebay (I'm guessing it was probably an expensive deck back in the 80s).

I took it apart, found one of the leads going to the DC motor, snipped it, added a potentiometer, drilled a hole on the front panel under the eject button, and mounted the pot through. I now have a tape echo that allows me to slow down the deck, which gives the echo a ton of character and width. I think I got the idea from one of the moderators here.
You can buy 3 head cassette decks that have varispeed, but they fetch surprisingly high prices for some reason.