Greetings everyone.

I was a bit confused with the way AIWA made their Heads. many time I saw HX Head, Amorphous Head, Ferrite Head. very confusing so I have decided to solve this tech riddle. I have decided to share the results with anyone who is interested.  

The World of Personal Stereo Hi-End Heads

Tape heads are the main sound element in every tape deck or portable stereo. The head has to have the capability of reproducing a wide range of frequency response in the sound spectrum. Then it is up to the amplifier to translate and reproduce the quality of the sound. A high quality head needs to be durable enough to last a long life span of use.

Good ferrite heads used to last a very long time, provided that you use high quality tapes. Low quality ferric oxide tapes are one of the most likely types to do damage. Ferrite is high permeability a ceramic material, not like an alloy, not unlike most other head materials. AKAI had their own special version of Ferrite heads which they called glass and crystal Ferrite. The housing of these heads was made out of glass, but they had ferrite cores laminated into them.

Permalloy heads were extremely soft, and would develop groves pretty quickly. Most low-end decks almost always featured the plain Permalloy heads. Permalloy is an alloy that consists of roughly 79% nickel, and 21% iron. Some decks like Nakamichi's "Crystal Permalloy" heads were surprisingly hard, and lasted extremely well. While most manufacturers used either Permalloy heads or some proprietary variation on Permalloy heads. These heads wear fairly quickly, but can be easily resurfaced.

Sendust heads had great magnetic performance and were harder than most Permalloy heads, and generally lasted much longer than average. Sendust is an high permeability metallic Alloy made out of some ratio of Iron, Silicon and Aluminum.

Amorphous Heads were the latest technology back in the 80's they are supposed to wear slower and last longer then any other types of heads. Also they have clearer highs and greater dynamic range then other head types. Many of the head manufacturers switched to amorphous heads.

Amorphous heads usually last longer than Sendust heads, and that means much longer than any Permalloy. Amorphous materials are supposed to be harder than are similarly composed crystalline materials too.  Laser amorphous heads were cut with a laser precision, for better surface contact with the tapes. without laser it is extremely difficult to cut an amorphous material in a precise accuracy.

Exception to that is the famous AKAI GX heads that were made from X'tal & Glass combination. According to AKAI they should last just about forever, and they don't groove like straight ferrite and Permalloy heads. Therefore AKAI gave a 15 years warranty just for the head itself.

The golden years of AIWA

As the leader in Personal Headphone Stereo, AIWA introduced In March 1989 their first Amorphous Head followed Sony's DC6 and later on WM-DC2.

There are 3 versions to Aiwa's Hi-End Heads and they only found on IC Logic Control units.

1. Amorphous Head.

2. Narrow Gap Head.

3. HX Head. - Hyper Xtended Bass Head.

Amorphous Head

The HS-PX303A features an amorphous head, often found only in audiophile cassette decks, for a remarkable improvement in playback fidelity. Amorphous alloy displays exceptionally high maximum magnetic flux density, outstanding signal linearity, and minimal noise generation. Add to this a remarkable hardness for extra durability and you have one of the finest heads available. (From aiwa catalog 1989)

HX Head

The HX head featured in the HS-PL303A uses a slightly peaked contact surface to achieve greater signal linearity, particularly in low bass frequencies, for clearer, more accurate signal reproduction. (From aiwa catalog 1989)

The Legendary PX303 was the first AIWA portable stereo to have the triple features combination head – Amorphous-HX-Narrow Gap Head.

Later Amorphous Heads were plain Amorphous or Combination of Amorphous & HX Head. The last one AIWA developed and upgraded to a better version V1.0 which was a Narrow Gap Heads.

At Later years AIWA manufactured a combination of different heads in selected models like:

• Amorphous Head found only on JX707, RX70 and PX1000.
• Narrow Gap Head found on the PX20, JX505, JL505 PX303, PL303, PL55 (V1.0), TP38.
• Combo: Amorphous - HX Heads Found on JX3000, JX2000, PX303, PX505, PL50, RL50, and RX50.
• HX Head found only on PL303, WR707, PL777, PL707, P705 P505MkII.

AIWA was the first to introduce Bi-Azimuth Head Alignment System.

Bi-azimuth Head Alignment

This new feature automatically com­pensates for head alignment inaccuracies which are common to auto-reverse tape drive systems with fixed heads. When the tape reverses direction, its position shifts slightly, causing a shift in azimuth, the relative angle of the tape to the head.

In either tape direction, absolutely precise azimuth alignment is essential for optimum response, particularly in the high frequencies. To assure this, the Bi- azimuth Head Alignment automatically adjusts the head to the proper position relative to the tape in each direction. Bi-azimuth Head Alignment is found on selected higher-priced models. (From aiwa catalog 1989)

Bi-Azimuth found only JL303, TX303, RL30, PL303, PX303, and TP38. also found on early versions of JX505, JX50, EX500, EX50 and JX2000.

Later on Sanyo followed and designed a better and accurate Bi-Azimuth approach with double point pins like in their JJ series.

(P4, P5, F5, W6 etc.)

Sony tried to get a different approach and invented the worlds first portable stereo with a double heads design the EX909 leaving everyone else far behind with their plastic mounted heads and a poor degrading sound.

Even though Sony was the "inventor" of the Walkman they fall behind AIWA in many categories. Sony tried to compensate that by acquiring AIWA in 1992 which led AIWA - the best personal stereo leader to their sad end. But no doubt Sony Walkmans were built to last longer, this is still Sony's greatest advantage even now days.

Be Good :-)

TheLion

Nice explanation TheLion. I have never seen the Sony dual head design before.

Thanks toocool4

Unfortunately, I have never heard how effective it is.

In theory the heads in both directions should be perfectly aligned, and if they are good heads they should sound amazing?

You right, I agree with you.

Terrific information, TheLion!  Thank you so much for sharing it with us.

I had no idea Aiwa's high-end personal cassettes had automatic head adjustment.  Is this similar to Nakamichi's Automatic Azmiuth Correction?

Absolutely have to agree with Sony machines lasting the longest. And should they encounter any problem I find them the easiest to repair. Easy to disassemble, common belt sizes, little to desoldering required in some cases.(EX1 based mechanisms are excellent).

With the exception of the crappy WM-550C/2095 mechanism, and the disc motor that came in Sonys from that era. These pieces of crap are literally held together with hot glue and corrode/crack to the point of being useless. Thankfully the later Sony Disc motors did not suffer from this.

The reliability rate of 80s/early 90s Aiwas are anything but great. CAPACITORS. LEAKING. And they are often the most difficult to disassemble, requiring desoldering most of the time to change the belt. I actually have several Aiwas with the acclaimed HX Amorphous head (JX 2000, 505, 707, and other models with the 505 mechanism) but I've only managed to get the 2000 going. Sometimes Re-capping does not help, leaving me absolutely stumped. It could be that the boards are corroded beyond reasonable repair (humidity is very high here).

@stereo2go,

Thanks

In the early years - "the golden years" They were really in to it.

but unfortunately as the years gone by (especially when Sony stepped in 1990) they stop making them. you will notice the difference before the new AIWA logo and after the new aiwa logo. For example the JX505 old logo version had Bi-Azimuth. on the new logo the Bi-Azimuth just gone..(see my attached photo's)

Nakamichi's Automatic Azimuth Correction is a motorized feature. Personal stereo don't have that kind of space or power but for sure the PX303 Aiwa's flagship they had something similar.

I take it you mean the JX505 as the photos show various JX505s. Luckily I have a boxed 1st edition JX505 with the bi-azimuth .

I have quite a few JX707s all are old AIWA logo but none are bi-azimuth

It would be good to see a bi-azimuth JX707 if you have one.

This is not the case in my experience. I have acquired a few Japan only Aiwas and they are all pretty much shot. Leaking bad caps and fried logic ICs BUT surprisingly no melted or stretched out belts though. The model numbers are  HS-PX30, HS-P50, HS-PL50. Certainly makes me think twice about getting anymore Aiwas from Japan again.

You right Plop,

I was talking about the JX505 but thinking about the JX707.

I myself Haven't seen any JX707 Bi-Azimuth and I remember we've discussed this on another post but according to Aiwa catalog from 1991 it specifically says it have Bi-Azimuth head. and on the 1994 catalog (new logo) non a word but if you look carefully you'll notice a pink icon says Bi-Azimuth Head. but next to him the JX3000 says Bi-Azimuth. (see photos)

@TheLion

Nice scans.

It is really interesting to see the really bad use of a new "aiwa" logo cut out and placed over the JX707 or should I say JX70 as it has a black border around the LCD display that JX70 models do. The text is spaced differently on a newer "aiwa" logo too, I guess they didn't have a new logo one handy for the cameras that day.

I am wondering if maybe the text was swapped around as the graphics below seem to correspond better that way (I see a Bi-Azimuth logo below the JX707A text) Maybe it wasn't even a JX707A but more likely the JX707D which does come spec'd with the TV tuner.

I can't help to wonder if Aiwa made a mistake in suggesting that bi-azimuth was even available in the JX707. I would like to be proved wrong and have the chance to see one with the bi-azimuth mech.

@Plop

Thanks,

I believe it is just a typo or maybe very early versions cause I have just noticed on the specs sheet that PX1000 has a Bi-Azimuth!!??

strange! there are many wired stuff with this catalog I have, the cut out logo is not the only one, they did it with some other models too.  

well, I guess time will tell.

Found a picture of a HS-JX707 with a low serial number and it seems to have the fixed head design.

Given that it has a seven digit serial number I do wonder just how many of these did Aiwa make in the end?

On Japanese made models, all of my mentioned Aiwas are made in Japan. Actually here in Singapore we get a mish-mash of US/Japan market Aiwas.

I do have a mid 90s Aiwa (HS-PX347) that is made in Singapore, and it has surprisingly required no service when I found it. Although I am willing to bet that it will require capacitor replacement in the future (Volume levels are not great). Compared to a japanese made model with the same mechanism, I find the build quality to be similar.

Just checked my JX-707. It has the same head as the one plop just posted. Actually the only thing holding me back from fixing the 707 is a lack of caps that can fit in the small area, and it did not come with the battery holder.

I believe I should straighten things up.

Back in February I have already posted a reply on another post by our dear friend Hugo "Preparing a tape for adjusting azimuth precisely"

for the benefit of all I have copied the reply here:

All Heads has Azimuth adjust-ability, most are manual, some are kind of automatic like Aiwa PX/JX303 and some of JX50. some are set heads with plastic housing. exception to that is the JX707 which has 2 adjustable points but it is still in a plastic housing and can be removed by an expert for best sound results. all this is more theoretical then practical. But it is still possible in extreme cases. when Sony started to buy shares of AIWA the whole manufacturing became very much cheaper and less quality. AIWA was always bragging of it's head design and of it's high quality class. they were one of the first to introduce special features head developing and extending sound features to them. note the changes that took place when Sony stepped in and the new plastic housing style. the JX707 was the last AIWA attempt to maintain that quality, there for you will notice JX707 with old logo and new logo. AIWA style was never about titanium body style like the flashy Sony WM701S & EX. even the head in the PX1000 is a Sony head (blue/green reading PX head).

As I said earlier the only one to support a Bi-Azimuth is the PX303, PL35, RL30 and some of JX3000/2000/50...  Later models didn't have that Bi-Azimuth, Just a small piece of metal reminder to move the head forward, but certainly not an bi-azimuth. most of the JX505 have this special Bi-Azimuth plate and holes for the screws but that was about it just a reminder for a budget cut on the Sony part. yes, sad enough.... cause eventually look what happened to AIWA today after all their glory days....

There are two kinds of Azimuth.

Manual Azimuth & Bi-Azimuth or Automatic Azimuth:

They are both working on the same principal, a spring and a screw which shifts the head slightly up and down. with manual Azimuth forward and reverse works on the same alignment and the sound is compromised, while the Bi-Azimuth is more precise on each direction resulting in a clearer sound. 

The Bi-Azimuth Concept

AIWA's Bi-Azimuth were used only between 1988/1989 the golden years of the 303 line. they ID them as "mechanism type a-2". The motor was a Direct Drive and the whole gear was based on that. The 505 line also had that same mechanism but not all of them actually use the Bi-Azimuth, the mechanism was there but the head itself lack the small adjustable pin underneath it. If you are an enthusiast collector and have technical skills you can easily replace the JX/PX505 or JX2000/EX50 head and enjoy the benefits of the Bi-Azimuth to be just like JX/PX505 JX2000 first editions.

Now, for the JX707/3000/PX1000 it is a different story, they are a different type of mechanism called "OZM-4" This type is based on a belt gear. therefor the gear for Bi-Azimuth is not there anymore. Even though Aiwa advertised it in every catalog they have issued all over the world, on the service manual (JX707 page 25) it specifically states "4. This model is no azimuth adjustment".

I hope now it's sounds better 

Thanks for mentioning all three walkmans - PX303, PX505 and PL30 that I don't have anymore for DrMR has three new walkmans in his collection. I don't think we'll ever see his amazing collection though.

It's sad that you've lost some great Aiwa walkmans to someone's dishonesty and greed.

From what I've read they hold sentimental attachment too for you, but take heart that although these are very rare walkmans they do turn up for sale from time to time, and in time you will have these models again to enjoy.

From your mouth to God's ears my friend! I hope so.

Hi Tuna

Sorry about that  I wasn't aware of the story.

Please do not worry, the guy will bring them back one day.

If not I will help you find replacements...

Thank you TheLion! You didn't know about that so it's okay. I have given up on DrMR even though I still him an email from time to time but I'd be surprised if I got a reply since it's been more than year and a half since I sent him my walkmans. The PX303 was really special to me since I got it along with my first cassette deck from  a friend that made me love analog again. The PX505 and PL30 were great but didn't mean that much to me even though I am sure people would like them for their style and sound. PX303 was the ultimate combination of style and sound quality in my opinion and it took me a while to realize that he damaged me more than I was aware of. Though it wouldn't be the same, I would love to have a PX303 again so by all means, I accept any help and advice, thank you.

I lost some of my most cherished items in that transaction and I hope the guy is happy. I'm not going to start all over again since this is not the place but one has to wonder why. He told me he was a doctor... I thought that doctors had to take an oath, a moral code to ive by and never to do harm but I guess he is an exception.

Back onto topic... Who thinks which is better and why - a regular shaped amorphous head or a hyperbolic shaped non-amorphous narrow gap hx head?

@plop

Well, interesting question.

It depends on what aspect you are asking, sound wise or technical, 

If it's about the sound, I believe the difference lay in the design of the unit which it is built in. The EQ of each unit is very different especially with Hi-Fi units like PX101 & PX303, PL303, PL35, PX505 etc. which they needs a wider frequency Response and higher S/N Ratio. they are unique in that aspect and they were made for that, that is why they have this unique narrow gap design. oppose to JX707 which is a generic head.

Technical wise, I Know it sounds weird but after a very extensive research. I believe that some of the declared Amorphous Heads by AIWA are not true Amorphous heads!

therefor they have a poor quality sound and low durability (as you showed on your new post) the low frequency of those heads (JX707, PX1000 etc.) is 63Hz with 43+- S/N while PX101, PX30 is 40Hz with 48+- S/N. which is a big difference in terms of sound quality.

I believe that AIWA gave some misleading information (or not enough info) on some of their units like with the JX707,JX505, PX1000 Bi-Azimuth so It could be the same story here. 

Well, If I may add my thoughts about this. It seems to me that it's not really question if the head is amorphous or not, but how many layers or laminations there are and the thickness of individual layer. For instance, Teac's cobalt-amorphous heads had 14 layers, Nakamichi's crystalloy heads had 3 layers. Presumably, a head with less layers will have a shorter life than the one with more layers. Also, you never know if the specific walkman was taken care of well or not. Tapes usually used in portable cassette players or in a car collect a lot of dust - carbon and calcium mostly and this can also damage the head, even if it is an amorphous design. No matter if the deck or a cassette player has an amorphous head or not, damage to heads isn't really an issue if you store your tapes properly and use them in your home.

About head wear: what really stuns me is that most of the Walkmans I find have very few hours put into them before they somehow get trashed/sold and end up at the fleamarket. Few have actual head wear (only my TPS-L2 and one of my Aiwas do). On the other hand, a couple have heads that were never/rarely cleaned and this causes irreparable damage to the head after many years.

On the labeling on Aiwas, some of my Aiwas have hyperbolic HX like heads without ever mentioning what head it is. And while I'm at it, I'd like to know what the EX HEAD on the Sony WM-190/EX49/GX51/2095/2097 based models really mean.

Also, the different numbers in frequency response don't have to be necessarily induced by the head itself but rather the combination of the head/preamp/electronics. 

It would be interesting to measure the head's inductance to see if in fact some heads are different or the same.

@Tuna

I believe you are referring to the inner core laminations.

The head itself is only the housing which is made from any materials like amorphous Sendust or Alloy etc.

Please check attached photo

Also, the different numbers in frequency response don't have to be necessarily induced by the head itself but rather the combination of the head/preamp/electronics. It would be interesting to measure the head's inductance to see if in fact some heads are different or the same.

I Agree, but those FR are by AIWA Service manuals. There is clearly a difference between the Hi-END HX narrow gap heads to the Plain Amorphous heads in terms of sound and capabilities.

The plain Amorphous apply to this rule you mentioned because their main goal is not pure sound but all in one therefor durability are not the main issue and their sound could be achieved by the combination of the head/preamp/electronics.

It is interesting though that the general perception of amorphous heads is durability and that there is a greater top end response. Not withstanding any potential tape wear due to various abrasive contaminants, the frequency response therefore should be reasonably decent if it is not appreciably affected by much wear.

However as can be seen from the JX707 example, once the tape head starts to show signs of tape wear the frequency response drops remarkably. Could it be a design/durability issue with the first generation "black" amorphous heads used in the JX707, and therefore they were later switched to the "blue" amorphous heads as used in the PX1000 and the later JX707 variants?

Now having swapped in a known good HX head into a JX707, it was clear that there was an issue with the swapped out head, and no amount of electronics or preamp would have compensated the frequency response of the worn amorphous head. On that basis a worn head is a head that would have reduced frequency response irrespective of it's original materials of construction. I am somewhat sceptical that the standard "black" amorphous heads showed any real benefits over the HX heads and this all may have been another example of AIWA trying to cost save by using cheaper standard so called "amorphous heads" instead of the amorphous HX heads as seen in their previous top end models. A case in point is this, the amorphous HX head is somewhat worn in my PX505. But the player is still very bright with no perceivable loss in HF. Is that a result of the better head design (ie inner core lamination) on this model?

@Plop

The blue heads are Sony's heads. except the Panasonic RQ-S80 (which is a custom made Sony) I haven't seen Sony advertise them as Amorphous heads.

The Sony EX amorphous head are black only you can clearly see it in WM-550C and WM-172 etc. I haven't seen a blue Amorphous head before the JX707 or PX1000. I even read on a Japanese forum that all the AIWA 92 line is very bad in quality and sound and they are all engineered for better frequency response. that is why they add the BBE feature which is all about to make them more affordable on hardware and still sound better. (ie heads)

I have recently discovered that there is a difference between the inner metal core to the housing. In original amorphous design they both are amorphous material but in a budget heads only the core itself is amorphous. that is the reason why they wear and causing degradation in sound quality. 

Not sure I understand your rationale regarding the addition of BBE. BBE first started appearing in top end units as early as 1990 such as the PX50, PL50 etc... The two I have just mention even have Amorphous Hyper eXtended Bass Heads, which were touted as some of AIWA's best ever heads. So why would they put something like BBE into these models if BBE as a feature was intended to improve sound on units with crappy frequency response? No, BBE has always appeared on AIWA's better or TOTL units in their model lineup. Just like how you never found Super Bass on a TOTL model and instead it was always DSL. On models with BBE, even with it turned off, I find they sound very good (even BBE can't rescue worn heads). Hardly a case for putting it on hardware that was lacking in frequency response.

You may be right in suggesting the "blue" amorphous heads are Sony, as these started appearing in later models such as the PX1000 and the JX929. By that time AIWA would have certainly been under Sony's control. The JX929 definitely does state that it has "Amorphous Heads" when you look inside it. Not sure if it is 100% amorphous core and housing.

http://REPLACEMENT ERROR/fileS...ge/true/IMAG0212.jpg

This is probably quite controversial, but lets face it, pretty much after 1992 much of what AIWA was producing was on a heading downwards a spiral towards cheap and nasty crap. With the exception of maybe one or two recycled pre 1992 designs, and even then the bean counters would have made sure that those units were cheapened down somewhere somehow.

What I said was in regards to sound quality not about the degradation or wear I agree 100% that even BBE can't rescue worn heads.

The BBE is an excellent feature, a Sonic Maximizer that emphasize the audio signal. AIWA was one of the first company's to use it for portable stereos it was a cool and awesome feature that were found only in Hi-End stereo systems. The BBE came out mid 1985 and AIWA used it for the first time for their 10th anniversary models - the 505 lines and then JX3000, JX707, JX810, RX910, JX719 & PX1000 they were all semi amorphous heads. this is the same story that we have discussed in another post about the missing Bi-Azimuth.

Because of that reason, the BBE was an excellent choice for AIWA to compensate for the lack of wide range FR instead of using expensive hardware such as HX Amorphous head and still have great frequency response and great dynamic range.

Thinking in the digital age of today. average mp3 of today are the worst form of sound quality for music (compare to wav or flac etc.) now, if you add a sonic maximizer for mp3 like DFX or SRS they will sound very rich and full.  the BBE system is like today's DFX, SRS & the great "iZotope - ozone" softwares. If BBE was excellent for Hi-End units it can do the same for mid-range portable stereos.

this is a great thread. the topic of heads and their different materials and the benifits and drawbacks of each of those materials is very interesting.

i've never had an aiwa walkman, and i don't know much about them. but this dual azimuth business seems to be found on a few sonys too. i have a wm-106, 501 and 503 that all have adjustable azimuth for both sides, and they are from '87.

maybe i'm misunderstanding how the aiwa system works.

but attached is a pic of the head of one of my wm-501. you can see the pin on the head assembly and the two screws for the adjustment, well, the bottoms of the screws anyway.

Hi,

This bi-azimuth feature seems to be quite interesting. You call it an automatic azimuth correction. Could you please explain, how it works in detail? Does it check the signal coming from the tape and correct the head so, that the signal has the best quality? Or does it only change the angle of the head, when the player changes from forward direction to reverse direction?

@Mark

That's a very nice picture of the WM501 Head Azimuth.

It is very interesting concept by Sony I haven't seen one like that before.

@Kerni99

The Signal Bi-Azimuth you are referring to are usually found only on Hi-End expensive cassette decks like the Nakamichi 700 Tri-Tracer. (see pictures)

The Bi-Azimuth found in walkmans are quiet a mechanical setting.

I call it automatic (like the AutoReverese feature) because there are two kinds, one is the manual Azimuth and there is the Automatic Bi-Azimuth, which have a special gear that align the head every time the tape direction reverse. with the manual azimuth you have to do it yourself every time the direction change sides which is a very annoying process.

Cheers

TheLion

I can answer that question.

The differences aren't easy to see from the photos at first hand, but from the base of the mounting bracket for the head there is a metal stub on the right hand side. On a mechanism that has the bi-azimuth feature, there is a very small pin which sticks out from the centre of this stub. This pin is fixed to the body of the head and pivots up and down from the opposite side of the mounting bracket. This movement is what controls the alignment. Calibration is determined by two screws and pressure plates on the tape transport. The corresponding screws align with a hole on the PCB during playback in the appropriate direction to allow adjustment.

On a later non bi-azimuth design the metal stub is still there, but the centre pin and the pivoting mechanism have now both been omitted. The pivoting bracket has been replaced with a black plastic assembly which fixes the azimuth in one position. Additionally extra tape guides have been added as well for better tape path stability. The pressure plates on the tape transport are still present, but there are no screws anymore since there is no azimuth to adjust.

Nope. It is most definitely "screw the head down and hope for the best". For all the fixed azimuth units that I have, they are pretty much spot on accurately calibrated. I think I have one that is marginally out, but I don't think it is going to bother me too much, as it is one of my lesser listened to AIWA. Even then that one is only out on the REV side.

JX303 and J303 also feature the HX head , JX303 features the bi-azimuth system.

I just wanted to add that the tape transport used largely in the 30/303/50/505 series and a few 70x/707 (such as the PL70/707 and RX705 models) are all known collectively as the α or Alpha transport (abbreviated to ALP sometimes by AIWA). 

my aiwa hs-jx505 has went from a great sounding player to a 100% dead one. i can do an occasional repair but have 0 knowledge of the electronics. can i assume the caps gradually went bad until the player is without function ? it's only good for a doorstop with it,s bright orange bbe oval.

Yes.

There is still hope. Get it serviced and it will be all good again.

who services these ? it was about in my top 5 as far as sound quality went. it even had a very functional remote. if i remember right,, it died a gradual death.

IRC you're in USA, so send member retrodos a PM/dialog. He's offering to service walkman in USA.

hi plop,,sorry i didn't get back to you sooner. we had to get some new windows in the house so that caused alot of confusion. hope you are doing well. we have had some nice weather this winter for a change. with xmas and everything i have been short on cash plus i have some broken players i need to try and get right. have you ever had the caps done on one of these run of aiws. any idea of the costs as i am clueless the amount of work it takes. i had 2 toshiba kt-as10's. neat little players but when the belt stretches they are done except the radio. excellent audio but i could get to the moon quicker than replace that belt. take care....george.....

Just a few

http://REPLACEMENT ERROR/tags/tag/224215475244401376

btw. No offence intended, but I think we are straying greatly off topic in the context of this thread and really should start a new topic rather than hi-jack TheLion's thread if you wish to continue discussing your Aiwas' issues.

All this recent talk of Sony WM-D6Cs has got me wondering ...

During Sony's very long production run of the WM-D6C, the specifications have changed. From what I can discover, the original production models were parabolic grind amorphous heads and later ones were permalloy standard heads. This presumably wasn't an overnight change, so was it a case of parabolic amorphous > standard amorphous > standard permalloy? If it is, roughly when (serial numberwise) did these changes begin to occur?

The ones before US serial number 267,201 (Canada 270,001; AEP 269,301; UK 269,601; E [Europe] 270,001) use a different PCB design and older in age and has different known issues. after those serial, they when over to a glass epoxy circuit board and using SMD components. Both sound the same and the older one uses a better head.

The different between the D6C's the earily revision uses the better amorphous head. The newer revision I notice they replace it with a simpler, cheaper permalloy type. The later head is noticeably more wear prone and doesn't last as long. Secondly, the printed circuit  glass epoxy circuit board instead of the old phenolic one. This greatly improves durability and reliability and was re-design to use surface mounted components. These were much smaller than the types used originally, but more costly to service as most techs don't do SMD rework, but haven't seen to many of these fail etheir. The early revision has known issue with servo control IC  IC601 (CX20084) off a seperate a 6V rail The servo circuit in the newer revision, uses mostly SMD components. The servocontroller is now a smaller 8 pin IC and is protected which is switched by several other transistors and a MOSFET, to prevent damage. But damage to the servo IC on the older model is cause by people plugging in the wrong adaptor and using a 9v instead of a 6v, due to it runs of the 6V rail directly, nothing protecting the IC .

Pretty much work on 100's of these, when parts were still available and was still in service, now reporters are using SD recorders.

Please feel free to add any info for this model, if their other changes, or other revisions, I forgot to add in.

I have a 27xxxx model and it has the SMD PCB. It also has the amorphous head label on the front, but no parabolic head. Is this a permalloy or amorphous head?

If it is a permalloy head, then Sony would have mis-represented the metal type used on the head with the incorrect labelling.

If not then at what point after 27xxxx did the amorphous label disappear?

More likely the permalloy type, if it has the SMD PCB, the amorphous heads, were on the older models.

So in other words the type of "amorphous head" as seen on a *cough cough* AIWA(Sony) HS-JX707.