Sony WM-D6C

[Tony L]

My next restoration project is a bit of ‘80s cassette nostalgia...

I had one of these back in the ‘90s after my previous Marantz CP230 portable’s pitch went mad. Obviously no one ‘needs’ a cassette deck in 2020, but they are nice bits of retro engineering and there is quite a niche retro-cult emerging around them at present. Some great YouTube channels etc, plus the TapeHeads forum. As such when this Walkman Pro appeared in the classifieds a couple of days ago in mostly working condition for a reasonable price I snagged it. It plays fine with nice solid pitch stability (a known area of failure), but nothing other than a bit of motor noise when winding (i.e. the reel mech doesn’t twitch even without a tape in). Interesting as the take-up reel works fine in playback. Anyway I have a set of belts and idlers on order, so will hopefully get that aspect working ok.

Thanks to the Tapehead forum I have figured out there are at least four different versions of the WM-D6C. The very first one had phenolic through-hole boards and a rather pointed 35711 Amorphous head, the second the same boards and rounder 35711 Amorphous head, the third green glass fibre boards, SMD components and 35711 head, and finally the fourth version with a cheaper 35712 or even unmarked permalloy head that was apparently less hard-wearing and the ‘Amorphous head’ branding on the front removed. The consensus is earlier is better, many even preferring the very old original WM-D6 (i.e. no Dolby C), but earlier is also older, so more chance of wear, failing components etc.

The one I have here looks to be a Mk IV, so green SMD boards and the 35712 head (which thankfully looks to be in great condition), though it does retain the ‘Amorphous Head’ brand on the front, so who knows? The 517103 serial number suggests this is a very late one indeed, maybe towards the end of production (the D6C was made up until 2002). I only had a very quick look in the bottom just to establish what I have here. I’ll not dismantle it further until I have the belt & idler kit, and even then I plan to do as little as possible. The tape counter works, so I’ll leave that be as it is a total PITA to get to! I won’t know what visual state the SMD caps are in until I get in there, the one I could see from the side looked clean, but there are a lot in there. The only through-hole cap I could see was a Rubycon and it looked fine. SMD recapping is beyond my skillset, so if there is leakage I’ll end up paying for a full service. I’ll only worry about that if there is any obvious leakage as it does certainly play fine, so I’m hoping I can fix it with a belt & idler change.

The headphone amp seems very good, it has no issue with the inefficient HD-414s.

I’m hoping this takes a lot less restoration than a TD-124!

PS Edited as I had some version info wrong!

 

[david ellwood]

Adjusting the capstan motor azimuth as it interfaces with the capstan flywheel is key to the performance of the deck.

The only common fault I encountered was the capstan motor control chip, which used to burn itself out especially if the capstan was dragging due to poor alignment or lack of lubrication

 

[foxwelljsly]

Always fancied one of these, but the format became obsolete before I could give one a go. Did use them on my degree course, where they were the alternative to some old small Uher R2Rs. Jewel like engineering on a par with the old Olympus OM pro SLRs.

 

[Tony L]

The only common fault I encountered was the capstan motor control chip, which used to burn itself out especially if the capstan was dragging due to poor alignment or lack of lubrication

Yes, I’ve heard of that. I’ve seen a lot of comments regarding the servo clock failing. At this point I can see no issue there as the pitch is stable, the pitch control works ok, and seems well centred, i.e. with the adjustment wheel centred bypassing it seems to be the same pitch. I’ll not be able to assess the condition of the lubrication until I’m further in after the belt kit arrives.

I’m just a bit confused by the fast-forward and rewind buttons not having any impact on the reels at all even without a tape in the bay when the take-up reel works absolutely fine in play-mode. I’m not in far enough to understand the mech yet though, I’d just have expected the take-up reel to be weak or non-functioning in both fast-forward and play. It must use a different belt/idler or something in each mode.

 

[david ellwood]

I used to be quite adept with them , but doubt my eyesight is up to the task these days.
The screws are almost too wee!

 

[Tony L]

Yes, loads of truly tiny things in there!

After more googling/reading I think I now have a fair idea as to why the ff/rew isn’t working. It looks to be dependent on the smaller idler wheel and the plastic mech it engages against. Apparently any grease here and it just slips killing that function. I do have an idler tyre coming for that part so hopefully I’ll be able to address it. It means navigating one type of tiny little round clip fastener (like a circlip, but far easier to break!) I was rather hoping not to have to deal with or risk losing, but hopefully it should be doable. As such I now plan to replace the capstan tyre, the drive belt and the idler tyre, I’ll leave the tape-counter belt alone if I can as that still seems to work ok. If it looks cracked I’ll do it, but I’d prefer not to as it looks bloody fiddly!

 

[deebster]

That's pretty much where I'm at with mine. And the same with the tape counter - mine works so I'm leaving well alone.

 

[lordsummit]

They’re fabulous things. I had one as a student and it was incredibly useful for listening to myself play, but it got stolen in 1993. I’d love to be able to justify owning one again.

 

[Dowser]

Yes, loads of truly tiny things in there!

After more googling/reading I think I now have a fair idea as to why the ff/rew isn’t working. It looks to be dependent on the smaller idler wheel and the plastic mech it engages against. Apparently any grease here and it just slips killing that function. I do have an idler tyre coming for that part so hopefully I’ll be able to address it. It means navigating one type of tiny little round clip fastener (like a circlip, but far easier to break!) I was rather hoping not to have to deal with or risk losing, but hopefully it should be doable. As such I now plan to replace the capstan tyre, the drive belt and the idler tyre, I’ll leave the tape-counter belt alone if I can as that still seems to work ok. If it looks cracked I’ll do it, but I’d prefer not to as it looks bloody fiddly!

Black plastic type round thing With a split in it? Jewellers flat blade under edge by split, but with Other finger covering the Whole damned thing (so you need to use feel rather than sight), to stop the damn thing disappearing over the room with a mild ping when it comes free.

Take photos before you start, I have loads of spares from repairing these and VHS-C mechanisms in a previous life...yuck!

 

[Tony L]

Black plastic type round thing With a split in it?

Kind of, but without the split! Here’s a Stereo2Go forum thread with some pictures. It is the little idler wheel I’ll need to remove.

I’ve read up a lot on Tapeheads where there are some real D6C experts. Apparently they gently nudge off ok as you describe with a flat blade, though have a real tendency to fly away. I haven’t quite decided quite how to approach it yet, I’ll figure it out when I’m in there, but I’ll likely either edge it off against some BluTac or packing tape, or maybe try to do that whole process in a clear plastic bag (I have some suitable ones). Whatever I want to be absolutely sure it, and a little circlip I need to remove earlier don’t just vanish!

 

[James]

I always fancied one of these. They have a reputation of sounding as good as a Nak. The only Walkman I ever had back in the 80s was a WM-20 (I think). It's party trick was being about the same size as a cassette case when not playing a tape. It's amazing what the Japanese can cram into tiny spaces. But, I thought the WM-20 sounded average. Maybe the main deck I had wasn't that good at recording.

I'd certainly like to add a WM-D6C to my collection of cassette decks, none of which are needed, but they are all wanted. Long live the humble Compact Cassette.

 

[Tony L]

I'd certainly like to add a WM-D6C to my collection of cassette decks, none of which are needed, but they are all wanted. Long live the humble Compact Cassette.

What cassette decks have you got and how many work?! I have a mountain of the bloody things, about half work, the rest half work. The one I want to save, other than the WM-D6C, is this lovely mid-70s Sony TC-204SD:

I actually sent it off to pfm member df_genius earlier today for the full works. I really want to get it doing its thing as its such a nice example and I have the matching amp and tuner. I think it was Sony’s first front-loader. It just looks how a cassette deck should IMO; silver, piano keys, yellow VU meters, red peak LED, just the one Dolby, the ability to record a ferrichrome cassette (despite my never having seen one in my life!). A proper thing.

 

[Stunsworth]

I had one as my main, well my only, cassette deck way back when. I was very impressed with it at the time. These days I have an AIWA full size three head deck that I’ve not used in a very long time.

 

[Tom Bonjour]

I had one of these too and it was extremely good. I still have it somewhere. I may tackle my TD 124 after reading about your journey with yours. It is much less likely that I will restore my Sony, but I will be very interested to read about your journey with your WM-D6C .

 

[James]

What cassette decks have you got and how many work?! I have a mountain of the bloody things, about half work, the rest half work. The one I want to save, other than the WM-D6C, is this lovely mid-70s Sony TC-204SD:

I actually sent it off to pfm member df_genius earlier today for the full works. I really want to get it doing its thing as its such a nice example and I have the matching amp and tuner. I think it was Sony’s first front-loader. It just looks how a cassette deck should IMO; silver, piano keys, yellow VU meters, red peak LED, just the one Dolby, the ability to record a ferrichrome cassette (despite my never having seen one in my life!). A proper thing.

I have only three for now: a Nakamichi Cassette Deck 1.5, a Denon DR-M24HX, and a Hitachi D-90S. All three are 'proper' three-head decks with twin capstan transports. Only the Hitachi needs new belts and a proper fettle. Both Nak and Denon are in fine form. I had a pair of Tascam 122mk2 earlier, but couldn't find anyone in my area to service them properly, so I sold them off.

Aside from the WM-D6C, I'd like to collect a classic Pioneer (CT-F1000 or CT-F1250), Teac C-1, Yamaha TC-800 and a couple of Naks (600 or 1000).

 

[Tony L]

It is astonishing how collectable cassette is at present, good decks (Dragons, ZX9s, Revox etc) are going for crazy cash, and I don’t really understand why. There is just no logical reason given something like a £120 Focusrite USB interface and a copy of Audacity will get you full high-res studio-quality recording.

My interest is 100% nostalgia/retro-kitsch. This is why out of the decks I have available I have picked the oldest Sony to have properly restored. I just like the idea of it playing a vintage TDK D with all the warm ‘70s saturation that implies - I want it to sound like a cassette! Maybe some Chic, Donna Summer, Stevie Wonder, that sort of thing!

The WM-D6C was just an opportunistic purchase as they are cool, but is actually of more legitimate use as there is physical space for it in my system (it sits nicely atop the Akai 4000DB open reel) and it would be nice to be able to play old band masters etc without having to dig out a big deck, but mainly an ornament. It also means I can sell off a few other decks that are just bagged and stacked up at present if I get it working ok.

I never collected music cassettes, recorded very little from the radio, so my collection is almost exclusively demo cassettes etc, though annoyingly I was burgled in the late-80s and the prick stole a load of irreplaceable ‘only copy in existence’ stuff despite leaving some properly valuable stuff in the room. I’ve still got some though.

PS If anyone reading this has a recommendation for a known-good decent quality PSU for the WM-D6C please let me know. The spec is 6V DC centre-negative and 300mA. I know a lot of people kill their WM-D6s in an expensive way by using the wrong PSU, but I suspect that’s either by getting the polarity wrong, or worse interpreting the original Sony part number, AC-9, as being a 9V AC supply!

 

[wylton]

I have two Nakamichi decks; a 670ZX downstairs and a 600 in the office system. I didn't pay much for either of them. The 670ZX I bought for £40 and had a full service by B&W. I think I paid around £50 for the 600; it's not so easy to get a service on these, due to a lack of spares, but mine's alright. I actually, do have a lot of cassettes, though I didn't buy many at the time, because the pre-recorded ones were far too variable. I recorded quite a lot of Peel stuff and I picked up some pre-recorded cassettes along the way and of course now, they have become strangely fashionable again. I had a WM-D6C many years ago, when they were the rage, but mine had an issue (can't remember what it was), that despite returning it a couple of times, didn't get sorted.

 

[Stunsworth]

I just like the idea of it playing a vintage TDK D with all the warm ‘70s saturation that implies - I want it to sound like a cassette! Maybe some Chic, Donna Summer, Stevie Wonder, that sort of thing!

I never liked TDK D, and would only use them in the car. For ‘proper’ recordings I used TDK SA or sometimes AD.

 

[jackbarron]

I used a Sony Walkman Pro to do interviews in the Eighties and Nineties. It was a huge improvement over cheaper cassette recorders.

The headphones you've got in the picture above are contemporary with the WM-D6C, I think.

Jack

 

[Tony L]

I never liked TDK D, and would only use them in the car. For ‘proper’ recordings I used TDK SA or sometimes AD.

I used SA most of the time, though I have some metal tapes too (including one of the now crazy expensive metal case TDKs).

The Cassette Comeback YouTube channel is good fun and interesting in an appropriately retro-kitsch way. He’s got some very serious decks, e.g. a Nak Dragon and a Revox, and it is amazing how good a decent old brown ferric like a D can sound if properly recorded. The thing I’ve learned from that channel is biasing really is everything. If the deck isn’t setup for the specific tape, as is the case with the majority of budget to mid-range decks, you are never going to get good performance. I never really grasped this at the time and just bought the nicest looking decent chrome or metal tape to mix-down to without having the slightest idea what the decks I had (originally a Marantz CP230, later a WM-D6C) had been set up for. As such I likely never got anything like the performance I could have.

I’ve asked df_genius to set the old Sony up for old-school D and SA. I’ve no idea what the WM-D6D is factory set for, I assume Sony’s own ferric, type II and metal.

Another thing I learned from CC is that TDK SA is not a ‘chrome tape’, it is a ‘cobalt-doped ferric’, which is an entirely different thing and has totally different biasing requirements. As such if you have anything less than a Dragon, ZX9 or other high-end deck that allows for proper on-the-fly calibration there is no way in hell you will get good results from both an SA type tape and say a BASF chrome, which actually is a chrome - if the SA sounds right the BASF will be dull as ditchwater. Basically you need to use whatever the cheaper two-head decks are set for.