Tape stuff questions.

[JimRayden]

Alright, Let's say I've got a cassette recorder with a read/write head. Can I assign the both read and write functions, so I could have the tape sound, without the delay?

My plan is, if I make the tape move real slow, I would get this really lo-fi sound.

Using separate read/write heads would end up in a delay. And the delay would go longer, the slower I run the tape.


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Jimbo

[Ge_Whiz]

You can't read and write with the same tape head simultaneously. It has occurred to me before that you should be able to replace an erase head with a same-size record head, and set up a delay that way - but it seems a lot of hard work for a fixed delay.

[petemoore]

I've seen cassette tape echoes, they said a second recorder is needed.
 I find it just a bit surprizing that with casette players available cheep, and also the sheer vast numbers of various types [probably many of them share similar guts], that at some point a cheesy tape echo device HAsnt' been designed and mass produced. It would require mostly just a little redesigning, not many more parts than a recorder with playback and record heads...mainly just rerouting the wiring to the heads and head placement...a few more playback heads of course would make it more echoey.
 The thing now is that digital can most likely produce a reasonable enough facsimile of any of the 'lesser' tape echoes, and without requiring mechanical parts...less expensively.
 IT has been done, but I was eyeing a couple cassettes when mulling over doing one up...attempting one was too much to much for me to think about...tape alignment from one recorder to one playbacker, limited echo variables, huge gangly mess...not that any of this should thwart your enthusiasm.

[Mark Hammer]

Took me a couple of re-reads to finally grasp what your intent is, but if I've understood you as well as I *think* I have, your desire is to be able to play in real time with "tape tone".  That is, you want to make a unit that imposes tape saturation tone as another form of coloration.

There are a couple of issues to be dealt with, as near as I can tell.  First off, the read and write functions of tape heads need to be a certain minimal distance from each other if they are to be able to operate simultaneously or else the magnetic influence the write head is attempting to impose on the tape is "misinterpreted" as the magnetic field coming from the tape by the read head.  On a higher end tape head, the reading and writing CAN occur simultaneously on separate tracks, but again, there is a sort of "buffer" zone running along the tape between tracks which is a reflection of the need to have this (small but) critical distance between two heads trying to do different things.

The simple rule about tape is that the more stuff you cram onto an identical magnetizeable area, the worse the S/N ratio will be, and the lower the bandwidth.  So, running tape slower, using thinner (.5mil vs 1.5mil) and using narrower tape, will all result in worse quality sound.  The hypothetical cassette recorder you mention is probably the worst case scenario.  The tape saturation we have all come to know and love in classic recordings is often the sound of 2" tape run at 15ips, rather than 1/4" .5mil tape run at 1-7/8ips.

Of course, that may well be the sound you are aiming for.  Apparently the guitar sound on the Stones' classic "Street Fighting Man" was recorded on a simple cassette machine with the automatic level control on, so we have at least one example of where a pleasing sound can be gotten from low-end tape tech.

The noise possibilities, though, make this a less desirable avenue to pursue.  Don't expect to achieve S/N ratios any better than maybe 50db on a good day with the wind at your back.  If that doesn't matter to you, fine, but if it does it's an automatic deal-breaker I should think.  As well, there is the issue of protecting against motor noise, and the ever-looming albatross of how you provide enough tape to let you play carefree for long periods without having to fear a need to flip tape mid-riff.  You CAN consider a loop but that is also tricky.

[JimRayden]

I'll clarify. Yes, what I want, is realtime tape sound. Not delay. Just sound. And yes, I was thinking of purposely slow down the tape, to make the effect more obvious. And yes, exactly like "Street Fighting Man". Now that you mention saturation, yes, that also might be a good idea. Overdrive the tape.

Hmm, if I can't have one head do it, another question rises: What is the minimum tape delay time? How far must the heads be?

(Talking about delay, I've been thinking of building a tape reverse delay, but have come to the conclusion that it's kinda impossible. )

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Jimbo

[petemoore]

(Talking about delay, I've been thinking of building a tape reverse delay, but have come to the conclusion that it's kinda impossible. )
 It is, since the end of the note 'info' must be 'made' before it can be placed at the beginning, although a DSP can do this, the 'attack' [beginning of the 'note'] has to wait for the sustain [end of the 'note] bfore it 'knows what the 'attack' is...making 'real time' reverse delay an impossibility...
 Even if you could reverse a 'sequence' [such as note attack and sustain] you'd have to play ahead of time or delay everything else.
 Playing 'in time, ahead of timing'...very very difficult, I've trained my mind to play in time...'programming in' a, 'X millisecond' delay into your mind...not for me...
 The other way would be delay everything else in the mix that has any time reference, such as rythm.

[Mark Hammer]

Well, glad we connected on that one.

The minimum delay would depend, again,on wheter you want it for gigging purposes or merely recording/noodling.  If it's just your own playing you have to be concerned with, then a 3msec delay shouldn't be too huge a problem.  If there are other players involved then that changes things considerably.  A 3msec delay from a 1st/2nd gen guitar synth might be fine if you were playing atmospheric pads with slow attack, but NOT if you were chicken pickin Orange Blossom Special with your buddies.

If the tape is run faster, you can afford to space the heads farther apart, or rather, you can tolerate heads that are obliged to be farther apart.  If it's good quality tape, and you have a means for producing a decent tape transport, then you can begin to think about running a loop at a decent clip (pardon the pun).  You'll still be able to get tape saturation, provided you have your meters near or in the red at all times.

Finally, I'm wondering how much of the tone you THINK lies in the tape is more a product of the preamps traditionally used or even the cheesy ALC circuits in such units.  I know the ALC in a Sony cassette deck we recorded my old band with did wonderful things to cymbals.  I also know the mic preamp in an old tube reel-to-reel I owned over 35 years ago did wonderful things to my guitar.  I would send that signal into my guitar amp.  Apparently formerMember1 Blackmore did too.  There IS something about tape saturation, and that's the very reason why a buddy of mine who has a pro studio STILL records to 2" tape before he start working in the digital domain, but you need to figure out what parts of the tone you attribute to tape are coming expressly from the saturation of the tape itself.

[nelson]

A few moons ago someone or other posted this, in an effort to get the sound you desire.









I have never breadboarded it, just one of these things I grabbed for future reference. I would give it a shot, gotta be better than taking apart your old walkman.

Who is the original designer?

o my 800th post

[JimRayden]

Congrats on your 800th.
Although the tape saturation would be a cool thing, I'm actually thinking of the dull lo-fi and pitch shifting part of tape sound.

@Mark: The purpose is gigging but I guess separate heads would be OK, since I attempt using this sound effect on smooth n' calm chord pickin, so it'd give a kinda lo-fi chorus-ish effect...

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Jimbo

[puretube]

[SOT]:
"historic tape-delays...

[Nasse]

Here´s another SOT, diy stuff from year 1963

http://personal.inet.fi/musiikki/kaikugalleria/tm-63.htm

[JimRayden]

Here´s another SOT, diy stuff from year 1963

http://personal.inet.fi/musiikki/kaikugalleria/tm-63.htm

Aight, my Finnish is a tad rusty but I guess I'll handle it. Thanks.

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Jimbo