Building a new walkman

Most of us here are likely audiophiles or closet audiophiles.

I've been tinkering with the idea of building a tape deck / Walkman that's got a tiny programmable signal processor (that can be entirely bypassed) to function as Dolby / Tape Bias Selector. (You set the level of DB NR and Bias levels. Or use the factory presets.)

In short:

• Straightforward DD-style mechanism (possibly a non auto-reverse DD9 - one motor setup.)
• 2x AA Batteries (DD9's 1.5V is not enough.)
• 32 ohm headphone output. (We all know some headphones still want more, but for most, 32 ohms is plenty.)
• Line Out for headphone amplifiers.
• Boxy WM-2 styled shell and buttons.
• Quartz locked motor.
• Play, stop, rew/ff.
• User serviceable components; azimuth adjustment, speed pot, replaceable head (If you've got a DC2 head lying spare or others.), headphone sockets, belt (possibly a more common size for longevity and serviceability) etc.
• Open Source hardware certification. Anyone can then paint, re-design the shell, etc.
• Cassette door latch.

The idea of making a "DC2" that isn't a WM-DC2 is an interesting one, which also appeals to us electronics hobbyists.

 

Wishful thinking.

 

It's not too much of a big deal, we've been spoiled by modern CAD (afaik some have physical simulation now), Autodesk Eagle and such for circuitry, parts for hobbyists: prebuilt PCBs (after designing them), SMD components that are far more efficient than their 1980s counterparts, 3D printing for prototyping and actual plastic custom molding (mihokm knows of this).

The pinch roller, capstan and heads may be the worst parts to find "factory new", but since those cheap "USB Walkman" is being made still; which means a supply of capstans and pinch rollers. Initial runs might be made from "trash" components, but shows how possible it is with modern hobbyists, compared to the 1980s.

If you build something right the first time, with planning - it'll allow for future revisions that are major improvements over the first models.

 

Well good luck with your quest, you talk as if it's an easy thing to do. I think making good heads will be a major problem and making a good reliable stable transport is going to be fun. I wish you all the best, keep us posted.

 

The DD9 mechanism is actually the simplest tape transport ever built;

• It's capstan is direct drive.
• The belt runs off of the capstan and turns the hubs.
• The DD9 in specific does both capstans in fwd and reverse; both hubs and capstans are running in the same direction.

Turning the DD9 mechanism into a one-way system is far easier than rebuilding it in full, for obvious reasons.

I'm also thinking of a way to improve the longevity of tape heads, especially wear. As far as I know that the material, Teflon might be usable as a small thin coating to the top of the head. It's drag on surface areas is really really low, so it may preserve a DC2 head even longer. It all depends on how much it reduces the readability of the tape.

Useful edit:



Notice that the capstan belt wraps around the cassette hub drives. Currently using a vector editor to sketch out the layout of things.

 

Honestly, the amount of work that would take to do hurts my brain. I mean, when you dismantle these things, you can see the tolerances they're made to - tiny pieces of precisely stamped metal and ball bearings smaller than a breadcrumb - to design/source all those parts would take way too much effort (not to mention cost). Plus there's the issue with case manufacturing - it's all fine and dandy to 3D print the casings, but 3D printing is time consuming and not always particularly accurate in terms of tolerances given the particular printer you're using's axis resolution. Plus you'd need to find a motor of the correct specs and design the circuits to drive it, and driving brushless DC motors ain't a piece of cake. It's a brave idea, but I'm not convinced its achievable. Keep me posted, I'm happy to help with circuit design

Good on you! My eyes are watering at the price!

Yup, I've got a few drum machines I've saved from old home organs, and they have the same analog sound. Freebies are the best! Then again, I don't think I've ever actually used them for recording...

 

Well, just getting the DD cases and stickers made was a real challenge. Anyone contemplating a new unit should be commended for even contemplating it. My personal advice would be to just walk away and enjoy the units that are currently available to us as enthusiasts. Im not trying to shoot anyone down, or burst their bubble, but consider this:

If Sony release a 40th anniversary walkman in limited numbers, I doubt even they would go to so much effort for a roll out. It would either be a basic model, basic transport with the majority of the thought and consideration having gone into the aesthetic and marketing than the actual mechanics. Worst case scenario, it would be made under license, and whilst a considered purchase for joe public, we here a S2G and tapeheads would probably scoff at the notion.

Designing a dedicated DD style unit for retail at this level would only ever be a loss leading exercise, especially when you consider the costs of just getting a PCB designed and made at volume. Factor in tooling costs for buttons alone, then fabrication and your in very expensive territory.

Now sourcing your motor, head and IC's becomes an issue, and thats before you even get to the mechanical side of things. Gears, cogs and springs, custom screws... the list is endless.

I think seeing a fully dismantled DD unit in all its raw components, including caps, resistors and diodes and establishing a price to develop / acquire per asset would be enough to send most sane people running for the hills

Then you need to factor in the issue of patents, and paying for a full legal search to ensure that not one single piece of the design encroaches on any direct or referenced patent held. This includes any patents that are cited in a patent wether expired or otherwise.

Seems like a such a venture could end up being a complete time and resources thief.

However, those are just my thoughts on the matter...

 

I think an interesting idea would be taking an existing walkman and improving it - for example, the amplifier sections in some models are rather lackluster, so a possible project could be bypassing the amplifier and designing a new amplifier in its place. There could be potential in the modification of existing machines. Maybe Dottore Walkman could contribute some ideas

Henry

 

A word of encouragement among so many of warning & skepticism. I particularly like your open source approach, which shows an unusual attention to the community rather than to the market. Bravo!

It takes the courage of the brave to make your project work. And availability of serious resources. But if you have the theoretical know-how, the means & the patience to go ahead, please do. Novelty usually happens when somebody walks the fine line between courage and recklessness. Just stay on track!

 

When I first read this topic and it mentioned signal processing I thought "why not start doing stuff with a home cassette deck".
Most of them are full of air so there would be plenty of room for new electronics

Knowing what Hobbyists are already doing in the field of software defined radio it probably wouldn't be too difficult to feed the heads directly into an A2D converter and then do all the noise reduction etc on something like a Raspberry Pi before producing an SPI output to feed an external DAC. When recording you could play with bias levels etc as much as you liked in Software. My Akai VCR used to calibrate itself to the tape before starting recording to get optimum performance. Has such a scheme ever been implemented on audio cassettes ?

 

This has already been done before by Pioneer

 

Look here again already in progress by mihokm

 

I just watched that video this afternoon; seems to be a small world.

Open Source Hardware (as Dave Jones is a good proponent of it, and possibly, by extension, Ben Heck) is the best idea, since someone with better expertise can come along and improve it for others.

You wouldn't even need a full on rPI setup, the Arduino boards, especially the FPGA types are incredible for doing tape bias and NR stuff.

I mean, it's possible to make a wind up one with minor tolerences. (See http://www.stereo2go.com/forums/threads/tapetalk-2.294/ ) The default Arduino library also contains a stepper motor library.

This could also be the first Walkman with Dolby S decoding, if you put your mind to it...

Here's the general idea for the activated mechanism; the less IC logic and digital components used, the better.

• Pushing Play engages the Arduino / rPI NR / Bias output.
  • At best, it should be a 2-bit memory module, play, stop, rew and ff.
  • A hold and power switch mechanism.
    • The power switch should be instead the cassette mechanism to prevent accidental turn offs.
    • The hold switch should also function as the door eject mechanism.
• Servo moves the pinch roller and head into position.
• Motor engages the capstan.
• The capstan belt drives the take-up reel. (Or a smaller disc like motor found in the WM-10?)

The initial prototype "deck" area will be probably cardboard.

tl;dr The mechanism should be straightforward without many complexities.

 

you lost me when you said Most of us here are likely audiophiles or closet audiophiles.

 

Strictly speaking, these players are not wind-up. They have a crank, but it is attached to a dynamo which in turn powers a standard shoebox-type tape mechanism via a voltage regulator giving constant voltage. The deck itself is made to the same tolerances as other low-end shoebox tape recorders of the era.

Henry

 

Just want to clarify that I wasnt trying to put a downer on any of this. Far from it. Its to be applauded. I was just stating some of the factors that would put me off personally. But you seem to have a really good handle on the open source aspects and as such, I commend you fully.

 

Same here, @Jordach. You have some very good ideas, and I hope you carry on working on this project.

Henry

 

Funtastic idea! May the force be with you!

 

This sounds brilliant, I want one!