Building a hand crankable Casette Tape Player... but how ?

[Shroomystic]

Hey there !

I dont know how many of you are familiar with this thing here : Landscape - HC-TT (V2)

but it sparked my thoughts about how one would go down the design lane when wanting to build a hand crankable Casette Player like this thing is. What type of circuitry would be involved and how easy it could be to pull off.

If its a "recycling old walkmans" kind of project or can be done with dedicated new parts.

It would be absolutely fascinating to handcrank beforehand recorded loops super super slow or in alternating speeds per hand...

What do you think ?

 

[PermO]

Mwoa,.. I guess recycling an old walkman should get you pretty much there.

It will have the playback head and mechanism and the preamp.

Disconnect the motor and capstan drive, so you can push "play" without the tape spinning and find a means to turn it manual. If you want to be able to reverse playback make it so you can put the crank on both ends of the casette.
As you can only pull the tape, you can't push it.

 

[RoadrunnerOZ]

What you can do is remove the two spool spindles from the Walkman which means tearing it down, take out the capstain and pinch roller and reverse mount the two spindles on the inside of the case top which will close down onto the cassette, the shafts of the spool spindles will each need a bearing which you could get a pair correctly spaced by ripping down another Walkman and using the bearing plate (or get from the existing if it’s not part of the chassis needed to hold the electronics and switches) and replace the spool spindle shafts with a longer shaft that you could graft a turntable handle to - you don’t need any of the internal mechanism but as the electronics and switches are needed you also need whatever they’re mounted to. The top cover when latched closed will engage the spindles into the spools of the cassette - a bit of careful engineering to get the bearing plate set into the lid may be required as in cutting the bearing plate to be a strip and cutting the strip profile out of the lid and finding a way of fixing it to the lid that’s not too ugly.

 

[cyrano]

Even simpler: use a hand-kranked generator to feed a cassette player...

Maybe insert a supercap to store the energy and smoothen out the produced voltage?

 

[Tubetec]

A walkman style mech with a pot for vary speed in the forward direction should be possible .
Often the sony walkmans had a preset pot built in that controls the motor speed , it should be easy to replace that with a proper pot of the same value and make it available as a top panel control ,maybe with an off switch at the 0 position .

Id say if the Landscape does exactly what you want go for it , see if they could sell it to you in kit form to save some money and learn something along the way .

 

[RoadrunnerOZ]

Once you slow the tape down to really low speed you’ll start to hear the bias from the tape as a tone along with the recorded signal - not like slowing down vinyl.

 

[Walter66]

Isn't it that casette recorders do equalize the signal with every recording and repro process?
Or do they just add the bias signal when recording?
I don't think it's that easy to amplify the signal like a typical line amp stage with low impedance output..

 

[RoadrunnerOZ]

Isn't it that casette recorders do equalize the signal with every recording and repro process?
Or do they just add the bias signal when recording?
I don't think it's that easy to amplify the signal like a typical line amp stage with low impedance output..

The bias signal is high frequency signal that the audio signal is added to to give a sum recorded to tape. This bias alternately energises the tape particles in opposite directions (as does the erase bias which is a much higher level than the record) The bias is anywhere from 40KHz to 150KHz depending on vintage of recording device. This high frequency signal is not present on replay, but if you slow the tape down the frequency of the residual applied bias drops as does the audio signal, so if the tape speed is low enough the bias will become audible. When doing tape editing on a multitrack and looking for say the start of a kick drum or snare strike as a point to cut tape you can hear the bias as a sort of swooshing sound as you sweep the tape back and forth across the head manually looking for an audio start or end point for a splice, which reduces to a grumble when the tape is moved very slowly. There is very little apparent bias actually on tape for very high frequency bias but the alternate magnetisation of the particles, modified by the audio, is there.

 

[RoadrunnerOZ]

A walkman style mech with a pot for vary speed in the forward direction should be possible .
Often the sony walkmans had a preset pot built in that controls the motor speed , it should be easy to replace that with a proper pot of the same value and make it available as a top panel control ,maybe with an off switch at the 0 position .

Id say if the Landscape does exactly what you want go for it , see if they could sell it to you in kit form to save some money and learn something along the way .

I guess you don’t want to take the motor speed too far down and cook the motor - they don’t like low speed as they get hot

 

[Tubetec]

Yeah theres a chance if the motor stalls , with power still applied , could cause an overheat .

 

[RoadrunnerOZ]

Below a certain voltage the motor will draw too much current to drive the load and cook - it doesn’t need to stall, just run slow for a while - I think they only run off about 3V anyway - not a lot of room to play with.

 

[Tubetec]

H bridge PWM circuit gives a lot better control over motors especially at low speed .

 

[RoadrunnerOZ]

H bridge PWM circuit gives a lot better control over motors especially at low speed .

Yeah keeps the current down as well

 

[cyrano]

Some cassette player's motors have a built in centrifugal speed regulator. These don't adapt well to any kind of external speed regulation. Slower than 4,75 cm/sec is possible, but might show a lack of torque.

I don't know about walkmans. Too small for my fingers, so I've never repaired one. But all "hifi" cassette decks and simple players I've taken apart had that mechanical regulator. Except some high-end decks, of course, but I would never cannibalise one of those.

 

[Whoops]

Nice idea

I would go the "Walkman" route to do this, old Walkman's cost peanuts this days, or you can get one free from a friend

 

[cyrano]

Are you sure about those prices?

I just had a short look at the local 2nd hand site. Some Sony's tend to go for 250€. The cheapest I could find still was 55€...

And even other brands are fairly expensive. The two cheap ones I could find (a Yoko and an unbranded one) still needed to bring 10€. And those aren't the kind I would like to experiment with. Even the auction houses carry walkmans these days. Price starting from 1€, but that doesn't tell us what they go for and if they still work.

 

[MisterCMRR]

Isn't it that casette recorders do equalize the signal with every recording and repro process?
Or do they just add the bias signal when recording?
I don't think it's that easy to amplify the signal like a typical line amp stage with low impedance output..

"Bias" in magnetic recording is simply a way to avoid the distortion that would otherwise be produced by the magnetic hysteresis distortion (a bit like "crossover" distortion in class AB amplifiers) due to the magnetic properties of the tape coating.

The "EQ", both recording and playback, fundamentally compensate for the inductance of the heads. Recording EQ essentially creates a constant current vs frequency in the record head - which ideally produces a constant magnetic field strength vs frequency. It's called "constant current" recording and various standardized EQ are just small adjustments to the basic +6 dB/octave record EQ. Playback EQ is essentially the reverse. Much like EQ for a magnetic phono pickup, the playback EQ compensates for the +6 dB/octave rise in output of the playback head with frequency (for a constant magnetic flux on the tape). Both phono and tape playback EQ essentially boost bass and cut treble on a 6 dB/octave slope. Therefore, you can't just apply a non-equalized audio signal to a record head nor can you just amplify the output of a playback head if any semblance of "flat" record/play frequency response is desired.

 

[Whoops]

Are you sure about those prices?

Yes, completely sure.
I've bought a Sony 5 months ago for 5€ from a classified website

There's a tremendous amount of Walkman's for sale for $10 to $15 bucks

I just had a short look at the local 2nd hand site. Some Sony's tend to go for 250€. The cheapest I could find still was 55€...

It's because or you not looking in the right places or you are not searching it properly.

You have to look in Classified Local Websites (in Portugal is OLX, in the US is Craigslist) Ebay and Facebook Marketplace
Just a few examples:

From Facebook Marketplace








From Craigslist

And even other brands are fairly expensive. The two cheap ones I could find (a Yoko and an unbranded one) still needed to bring 10€. And those aren't the kind I would like to experiment with.

10€ is peanuts when compared to the 395€ that is the price of the product the OP showed .

Besides Sony, other good brands were Aiwa, Panasonic and Grundig

Even the auction houses carry walkmans these days. Price starting from 1€, but that doesn't tell us what they go for and if they still work.

From Ebay you can easily see what is the actual value they go for,
as you can search just finished auctions and then you can see the final prices.
You go to "Advanced Search", the check the "Completed Listings" option
And then you can search just finished auctions, past sales

 

[cyrano]

Thanks, Whoops. I had a look at 2dehands.be. It used to be owned by eBay, but they sold it a while ago to a Scandinavian media corp. Prices seem to go up to a level that's high enough to crumble sales. Then the sellers panic and start selling at very low prices. So, it's probably just "that time of the year". If I needed one, I'd just have to wait for the low part of the wave, I guess.

 

[thomasdf]

I don't know how portable you want the device to be, but wouldn't it be cool if you used a clock crank with flyweights that acted both for the tape transport and power generator, dynamo style ?