DIY tape echo

[panasonic_youth]

alright then, what about just a straight up DIY solid state tape echo?

[Hal]

there's some stuff around - you need a 2 head recorder, kinda rare.

[panasonic_youth]

id really like to know this, i read somewhere about a guy ripping some record heads out of a few recorders he had, but once you mounted it all, how would you get it to do its magic?

[Mike Burgundy]

In its most basic form, you'll need an eraser head, a write head and a read head.
You set up the tape so you have a loop continuously passing the heads, wiper first, then write, then read. Delay speed is varied by varying tape speed.
Electronically the wiper is permanently wired to a very high-freq. oscillator to wipe the tape.
The write head has an appropriate buffer amp from input, some kind of bias provision.
The read head has the appropriate ouput amp which is combined in a mixer with the straight-through signal (for blending wet/dry) AND gets sent back to the input head amp (for delay feedback: how many repeats)
That, basically, is it, after a lot of tweaking.
Commercial units have more heads (both read and write) to achieve different effects. I have a Klemt unit (think Dynacord) that has three write and two read heads, individually adjustable in level to give weird bouncy effects. The copycat (I think) had physically adjustable read heads so you could vary the delay time of each head - weird mismatches come to mind... They also vary in how the loop is configured. The Dynacord and copycat style is one closed loop under tension (spring-loaded capstan), the famous Roland Space Echo has a "cassette" with a VERY long loop folded in, which is kind of left to its own accord. Only a very small portion of this loop is pulled out of the cassette at any time, pulled taut by a driven capstan and one that's carefully held back, and sent back into the cassette.
Because you have a LOT more tape length, this increases time before a tape change is needed.
hih

[David]

id really like to know this, i read somewhere about a guy ripping some record heads out of a few recorders he had, but once you mounted it all, how would you get it to do its magic?

DIY echo?  Search, oh seeker of knowledge!  Buried deep in our forum's great computers are references to just what you seek.  Your quest will take you to our own Ansil, the unconventional applied electronics wizard.  There will your thirst for recording be satisfied.

[panasonic_youth]

cryptic david, very cryptic.

[panasonic_youth]

found it, thanks. but what about blending the wet and dry signals to get an actuall delay effect? how could i do that?

[panasonic_youth]

could i do it w/ one of those fisher price ones? just take a stereo jack, wire one lug to the microphone, space the record and play head differantly, and wire the other lug directly to the speaker (or what would become the output)?

EDIT

got a link from exp anon to this site about cassette looping, pretty straightforward, easy enough to understand, not what i was looking for, but it told me basically that it can easily be done w/ a recorder and an endless loop cassette.  would the fisher price recorder have an erase head? or do all recorders have an erase head?

[petemoore]

Sounds simple enough, but I don't understand it.
 You need the wiper as the last thing that happens to the tape loop, or the first thing it goes past on way to...record head, then however much length between the Rhead and the play head determines much of the echo speed. Other play heads spaced after the 1rst...more echoe repeats.
 I think youd need to tear into 2 recorders, fit a head where a head don't wanna fit, I doubt you'll wanna buy new stuff to tear up, so you'll be using old head, have to deal with limited echo length, risk high voltage, I'm not trying to steer you off it not....lol.
 It was the Sony tube tape Rec. that did the limited echo, all by itself.
 The TEAC we had a loop of about 1 min. playing repeatedly, sound effects for our haunted house.

[panasonic_youth]

high voltages? what do you speak of? heres my basic design idea:
E=erase head R=Record head p=play head I=input O= output  (=)= parallel wires   [=connect to the point above or below


             [-----------------------------------------------[
                                                                                                                                                                                                                                                                           [                                                           O
I<=====--------E------------R-------------P----------[


beneath the play heads is a looping cassette. it seems workable enough to me, i dont think youd have to rip open two and frankenstine it.  youd just have to keep play and record down and wire a pot for variable speed.  the volume on the unit would controll the mix between wet and dry,  no EQ, but you could put one in there if you so desired. would this work guys? id actually love to use a fisher price/playschool model, as thats what thurston moore used as his noise preamp on stage sometimes.  i love sonic youth, btw, thats what leads to this whole obsession with lofi sounding things like this. but do you think it will work?

[panasonic_youth]

i'll make this double post count, sorry, i mis-spoke about thurston, he used a my first sony, but for me, any recorder will do, a childrens one would just look so cool, plus you could call it 'held back'!

[mojotron]

I got a Danelectro Reel Delay - it's close to an echoplex... I use it all the time... I just hate the idea of using tape on a really tempermental device....

[panasonic_youth]

thanks mojo, but ive kind of got THIS in mind, but does it seem probable guys?

[zac102]

I think its more than probable.  I've actually been thinking about undertaking a similar project.  here's a diagragm I found that just out lines how a tape delay works.



If you could find a tape player with three heads, the modifications you'd have to make wouldn't be that large, since you aren't modifying the actual function of the player.  it's still erasing, recording, and playing an audio signal, though you might have to isolate the play and record circuits from each other so that it could do all three at one time.  then it's just a matter of mixing the signals to achieve the desired sound.

my only concern would be that it might not be very easy to change the length of the delay.  as I understand it, the time of the delay depends on the distance between the play and record heads. since a cassette deck is considerably more compact than your typical reel to reel or tape delay unit, its physical limitations might be too small to generate an appreciable delay sound. simply slowing down the tape speed might be a solution, but I fear that may adversly effect sound quality.   though this might not be the case as its playing and recording at the same speed.  

in my searches on the forum, I saw that moosapotamus built a tape delay like this a little while ago, unfortunatly, his site is still down so I have no idea how his project turned out or what it entailed.  I would think however, that if you could find a suitable tape deck and a walkman to use for parts, you could build a pretty nifty and relativly compact delay, probably not much larger than a memoryman, for not a whole lot of coin.

[petemoore]

Persistance pays off...sometimes. If you get one going it would be cool.
 Echoplex has a movable head on a 'slide rule'...logical choice would be the record head I'd guess.
 The heads/tape probably need a contact area of a certain dimension for best results.

[zac102]

I think this one is going on the shelf until I get a 3 head tape deck for free or very little money.  maybe I'll hit up the junk stores this weekend.

[petemoore]

trikki...lukki
 hard to do.
 Call Behringer and see if they can get a line on a batch of these.
 tape loop draw slide bar between playback and R

[David]

cryptic david, very cryptic.

Sorry.  It wasn't meant to be cryptic.  What I was hoping you'd pick up on is that you'd make progress faster if you did some searching here on your own.  This helps you hone in on what you really need to ask.  Demonstrating that you've done your research prior to asking about something shows that you're serious about seeking the answers, and will get you the nuggets of wisdom you really need.

This is not any criticism of you.  It's wisdom that I got the hard way.

[lightningfingers]

okay, say I have 3 walkmans of the same brand.....I could feasibly cannibalize them for the replay/record and erase heads, and build something workable right ?

[panasonic_youth]

walkmans? do they have a record function? i dont know what the whole thing around here w/ frankenstining it is, you DONT NEED TO! unless you want multiple echo sounds, then  you'll have to hack it, other than that, you dont need to hack anything up.