I’m planning to build a super simple and compact reel tape processor. Not really a recorder but essentially just a spinning disk with a loop of tape around it and three reel tape heads under. Spinning at a high speed im hoping to place the play and record heads close enough together to output the sound from the tape with no noticeable delay from the input.
I’m still figuring out how tape heads work but to me they seem pretty straightforward. What would I need to get the three heads to function erasing, recording and playing back from tape? How can they be controlled to perform on command?
Also, how close together could the record and playback head be placed? I’m guessing the magnetic fields will start to interfere with each other.
Glad for any insight!
I’m still figuring out how tape heads work but to me they seem pretty straightforward. What would I need to get the three heads to function erasing, recording and playing back from tape? How can they be controlled to perform on command?
Also, how close together could the record and playback head be placed? I’m guessing the magnetic fields will start to interfere with each other.
Glad for any insight!
The electronics from a tape recorder. This is non-trivial and unconventional stuff. Suggest you buy/scavenge rather than build.
Put heads side by side if you wish; they do not interact much. (Some cassette heads were 2 in 1.) Leave a little room to align the heads. Knowing the gap-to-gap distance and the tape speed you know the delay. 1/2" at 30ips is 1/60 seconds or 17 milliseconds. About like 17 feet of air.
>Spinning at a high speed
Wouldnt the relatively short wear-distance just chew the "tape" part up quickly? Compared to a reel of the stuff going over tape heads, that's going to be really slappin' the pavement - as that relatively short distance passes over repeatedly.
Wouldnt the relatively short wear-distance just chew the "tape" part up quickly? Compared to a reel of the stuff going over tape heads, that's going to be really slappin' the pavement - as that relatively short distance passes over repeatedly.
Thats true, i’m counting on it being more advanced than what meets the eye. But considering the transport is non-existent (only one speed one way) the advanced part will be getting the heads to work right.
Looking at this video: Tape Recording Head Experiments - YouTube
It looks like its not hard to get sound, but to make it sound good might be a bit more tricky. Question is how to ”instruct” the heads when to perform and not.
> Wouldnt the relatively short wear-distance just chew the "tape" part up quickly? Compared to a reel of the stuff going over tape heads, that's going to be really slappin' the pavement - as that relatively short distance passes over repeatedly.
Thats true! It will wear out crazy quick. Quicker than a delay unit. But i think there could be a sound to it. And its super easy to change tape loop, just prepare a lot of them in advance.
Huhh? They don't take instruction. They are not that smart. They reproduce what you drag past them. If you don't want to hear it, disconnect the audio.
Get a working tape deck, something you can dismantle bit by bit and transfer to the disk-plan you envision. Eventually you will whittle it down to just the essentials. But modifying a working machine is a tone easier than building a recorder/reproducer from scrap.
Here is a VERY crude DIY recorder for self-study. (No, you probably do not want to do tubes or wind your own heads!)
http://tubebooks.org/Books/TapeWire.pdf 11MB PDF file
it's been a while since i've thought about tape speed, bias traps and noise but as i recall they are interrelated, and if speed is increased doesn't noise/hiss increase?
...makes one wonder why tape echoes have gone the way of the dodo.... DSP can do what complex mechanical devices used to do so why bother??
what defines "no noticeable delay"??
...makes one wonder why tape echoes have gone the way of the dodo.... DSP can do what complex mechanical devices used to do so why bother??
what defines "no noticeable delay"??
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Signal increases faster than hiss. That's why 30ips is better than 3.75ips. Usable frequency response goes about as speed, both bass and treble (higher signal output overall). Bias should be well over twice the upper signal frequency but if we are doing bassband audio this will not be difficult. (If we do video or high speed copying then bias goes far into MHz and ordinary cores get lossy.)
He's not saying what this really is. If it is "tape compression" without consuming tape, then many of these speed and EQ choices may be far more significant than we know.
Not sure why you would need such a machine if not for delay, for "sound of tape"?
But i guess the easiest way would be to take a 3-head cassette deck with its complete electronics and use an "endless" loop tape as they were used in telephone answering machines. The "three head-write-read head" is the closest possible distance you can get (2 mm i guess). And you could even try to speed up tape by changing motor speed.
But i guess the easiest way would be to take a 3-head cassette deck with its complete electronics and use an "endless" loop tape as they were used in telephone answering machines. The "three head-write-read head" is the closest possible distance you can get (2 mm i guess). And you could even try to speed up tape by changing motor speed.
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Oh but thats good news! I was really expecting some kind of voltage switch to have them perform or not. Thanks for the book, great resource!
Studies and personal experience say that up to 10 ms delay is kind of maximum before it becomes noticeable when playing. Placing the record and playback head 1 cm apart you need a rotation of 100cm/s or in reel-tape terms, 39 IPS to have only 10ms latency. This way it could be used as a sort of guitar pedal, getting the saturation, compression and EQ of tape almost instantly.
Question is how the fast speed will influence the sound, the hiss should go down but I know 30 IPS yields slightly less bass than 15 IPS, maybe that effect will be even more prominent.