I would like information on how I could amplify the low level signal from a tape playback head. I realize that I could take an existing player apart however the amount of mechanical parts used to operate the player would probably over complicate things for my purpose. Is a preamp necessary or could one go directly to an amplifier? I do not need audiophile quality. What are the various leads off the back of the head for. Some have two and others have four.
Thanks in advance for any input.
Jason
Thanks in advance for any input.
Jason
OK... tape heads. Most cassette decks use a combined record and play head. Two wires for mono, four for a stereo head. Top end machines use separate record play heads siamesed onto the same block so could have eight wires. Erase heads normally have just two wires (unless its a specialised head that allows individual tracks to be erased)
(Post a good close up picture of the head face if your not sure and we should be able to identify it)
An opamp is all you need to amplify the head output (you do need a preamp). It should also have the correct response (a bit like RIAA for phono preamps).
Stereo Tape Head Playback
If all you want is to get some kind of audio then you could try using a MC phono stage if you have one. Have a look at some old cassette deck manuals such as a Sony TCK5. That just uses a two or three transistor (from memory) simple single rail preamp.
(Post a good close up picture of the head face if your not sure and we should be able to identify it)
An opamp is all you need to amplify the head output (you do need a preamp). It should also have the correct response (a bit like RIAA for phono preamps).
Stereo Tape Head Playback
If all you want is to get some kind of audio then you could try using a MC phono stage if you have one. Have a look at some old cassette deck manuals such as a Sony TCK5. That just uses a two or three transistor (from memory) simple single rail preamp.
Thanks, that is helpful. Can a record only head be used for playback? I see heads on ebay that are not indicated as play or record. They are mono and only have one contact
area and only two leads off the back. I think I will use the phono stage from a marantz tuner to test my idea and then refine from there. Thanks again, Jason
area and only two leads off the back. I think I will use the phono stage from a marantz tuner to test my idea and then refine from there. Thanks again, Jason
One of the main difference between a record and a playback head is the size of the actual head gap (between the pole pieces). Playback heads have a small gap for good hf response, the record head tends to have a larger gap. Single heads are a compromise.
If you have an ebay item number or link we can take a look.
If you have an ebay item number or link we can take a look.
Sorry, those are stereo, here are the mono set:
10 Pcs Audio Head for Tape Recorder Cassete Mono | eBay
10 Pcs Audio Head for Tape Recorder Cassete Mono | eBay
They are standard mono record/play heads as you would find in any cassette player of from the 70's and 80's.
Here is a simple transistor preamp, single rail. It would probably work OK from 15 to 20 volts or so with no changes. The switches are all in the playback position so the head connects from ground to C117 with a 390pf across the head (value to suit head ideally... experiment).
Here is a simple transistor preamp, single rail. It would probably work OK from 15 to 20 volts or so with no changes. The switches are all in the playback position so the head connects from ground to C117 with a 390pf across the head (value to suit head ideally... experiment).
Attachments
Let's hold on here a minute. Playback heads are "higher Impedance", anywhere from below 100 millihenrys (mH) for transistors to over 600mH to better match the "older" tube circuits. They "look like" a moving magnet cartridge and need in the neighborhood of 50dB voltage gain to get their output up to an "acceptable level" to feed a line stage. Record heads typically have MUCH lower impedances (maybe 10mh) and can't be used for playback (OK-never say never - but now you need 60dB or greater and here comes a hum proboem). There is also the fact that, like phono, there was an "accepted" pre-emphasis/de-emphasis curve used (NAB/IEC) so you do have to "tailor" the response of a preamplifier to accommodate this.
From your statements, I don't know if you are referring to a reel-to-reel or cassette deck. Cheap units used a combined head - (a stereo head had four posts, two for each channel) - better units used separate heads. Since you seem to indicate that sound quality is not a problem, if you have a preamp with a phono input you could feed the output of the head into it and see what it sounds like. It won't have the correct equalization (RIAA versus NAB/IEC) but you could at least see of you have enough gain for the rest of your system.
Charles
From your statements, I don't know if you are referring to a reel-to-reel or cassette deck. Cheap units used a combined head - (a stereo head had four posts, two for each channel) - better units used separate heads. Since you seem to indicate that sound quality is not a problem, if you have a preamp with a phono input you could feed the output of the head into it and see what it sounds like. It won't have the correct equalization (RIAA versus NAB/IEC) but you could at least see of you have enough gain for the rest of your system.
Charles
Ok let's make this super simple as I am a simple fella. Could I take one of the tape heads in the ebay link above, mono not stereo, and run it through the phono stage of my tuner so that when passed over a length of magnetic tape of appropriate width, it will reproduce the recorded sound to a acceptable level of fidelity? I don't mean to be unappreciative of the other aspects of your feedback, I simply don't know if it will matter for my purposes. Charles, hum is certainly something I want to avoid however.
Thanks,
Jason
Thanks,
Jason
Hi,
Those mono heads are simple cassette one gap record / play heads.
Impedance is about 500 ohms. What are your purposes ?
rgds, sreten.
Those mono heads are simple cassette one gap record / play heads.
Impedance is about 500 ohms. What are your purposes ?
rgds, sreten.
I want to be able to pass these over a surface that has magnetic tape applied to it and
hear the recorded content. The heads will be wired to allow for a range of motion. If you haven't guessed yet, this is an artsy thing.
hear the recorded content. The heads will be wired to allow for a range of motion. If you haven't guessed yet, this is an artsy thing.
Hi,
I don't understand the "range of motion". You'd have to precisely follow
the line of the tape, maintain the head vertically and horizontally precise,
ideally have the tape mounted on a slightly forgiving surface, and then
also maintain a consistent downward pressure on the tape head.
And of course move at a fixed speed of 1 7/8 " / second.
(All these things are done by a Walkman, and a pad in the cassette)
You'll also need special tapes, you can't use normal cassette tapes.
(1/8" wide with 4 tracks, 1 and 2 is one direction, 3 and 4 the
other direction. The mono head will read 2 and 3 together if
misaligned, they will be different and one of them backwards.)
FWIW I had guessed this was mainly misguided wishfull thinking.
It hasn't a hope in hell of flying in any practical sense AFAICT.
What is the concept of the art piece ?
rgds, sreten.
I don't understand the "range of motion". You'd have to precisely follow
the line of the tape, maintain the head vertically and horizontally precise,
ideally have the tape mounted on a slightly forgiving surface, and then
also maintain a consistent downward pressure on the tape head.
And of course move at a fixed speed of 1 7/8 " / second.
(All these things are done by a Walkman, and a pad in the cassette)
You'll also need special tapes, you can't use normal cassette tapes.
(1/8" wide with 4 tracks, 1 and 2 is one direction, 3 and 4 the
other direction. The mono head will read 2 and 3 together if
misaligned, they will be different and one of them backwards.)
FWIW I had guessed this was mainly misguided wishfull thinking.
It hasn't a hope in hell of flying in any practical sense AFAICT.
What is the concept of the art piece ?
rgds, sreten.
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Yes, as long as you have sufficient gain (moving coil input if you have it, if not try what you have ?). Remember that the output from the head will vary in amplitude depending on how fast you move it over the tape. You will probably have to snap the metal tape guides off the head too.
Laurie Anderson made a violin that used tape rather than horse hair for the box and tape heads where the bridge would be located. I have thought often on the potential of this.
The alignment certainly is an issue as well as grounding as mentioned above. Would 1/2" studio tape be easier to align?
The alignment certainly is an issue as well as grounding as mentioned above. Would 1/2" studio tape be easier to align?
I would think so. Wider tape so track widths are wider and so "more signal" to pick up... or at least more room for error if the head moves about off track.
(Sounds an intriguing project 🙂)
Sreten, will pm if you want more info on the idea. I have been beaten to the punch on every other idea that I've hatched. T-shirts with brail messages on them to mention one.
Shocking how many people are making those 🙂 So please indulge a bit of paranoia on my part in not posting the complete concept here. Regards, Jason
Shocking how many people are making those 🙂 So please indulge a bit of paranoia on my part in not posting the complete concept here. Regards, Jason
If there were partial contact with a 1/2" tape using say, a conventional 1/8 head what degree of loss would there be taking into account the decreased surface are in contact with the head?
Thanks, Mooly. We'll see if it ever comes to fruition. This and my open baffle speakers are about all I think about other than my mortgage and how I can raise my 4yo daughter as I soon turn 50!