Ok, what I can say is typically when I adjust these WM-D3s (and it's pretty typical to SONY ones in general) the right channel trimpot needs to be set significantly higher to obtain equal levels. Yours seems to be more or less in the same position. What tape have you used exactly from the set for this adjustment ?
I've used this one (which is a Type 2, and I set the switch accordingly on the WM-D3, Dolby NR being OFF): I've also checked the cable I'm using for measurements and it's definitely a TRS Should I also share a recording of this tape from both my WM-D3 and WM-DD 33 (line out and phones out) - if you have a doubt on the tape itself?
I think it's a good idea to make recordings of the tape itself in both units, curious of the result. Also, try to see if setting the EQ to 120us makes a difference in the balance situation. Is the seller specifically asking to set the EQ to 70us ? Cause the fact tape itself is chrome doesn't necessarily mean it was recorded with 70us EQ. Given the situation with headphones, I also advice to check the jacks: both the soldering and the outer part as on many D3s the plastic is broken and might need some glue. Cleaning the inside contacts of the jacks with IPA or contact cleaner is also recommended. You can use a cotton swab by removing part of the cotton so it can easily fit inside the jack. About the cable and measurements, when I do these adjustments I double check the loading by selecting resistance range first and then move the multimeter to AC voltage.
I have uploaded the captures. Dolby Test Tape, set to CrO2 and DOLBY NR OFF on all 3 samples. You were right! I've now tried with my daughter's headphones, which is a Beats Studio 3. It even has a 4-pole jack. And surprise - no difference between Line Out and Phones Out, and no connection issue at all... So the difference I hear between the 2 outputs is totally to blame on my cable with the Bose headphones - can't really understand how/why. The Bose cable is the black one, the Beats cable the red one. What I can imagine is that the Bose cable seems to have a pre-amp incorporated, must be the culprit... I'll re-measure the PB levels now, with and without 47k load. EDIT: measures done, here are the results (Dolby Test Tape set to CrO2 and DOLBY NR OFF): WITH the 47k load: R: 337 mv RMS L: 340 mv RMS WITHOUT the 47k load: R: 370 mv RMS L: 371 mv RMS These are approximated averages as it fluctuates a bit. I'm using an auto-range multimeter (https://www.peaktech.de/uk/PeakTech-P-3350-TrueRMS-digital-multimeter-6000-Counts-Auto-Range/P-3350), selector set to mV.
Have to say I'm puzzled by the situation. The measurements look absolutely perfect, confirmed by the recorded files. Only logical conclusion I can come to (although it may be wrong) is the unit plays different tapes differently and possibly curls the tape at the pinch roller with some tapes, but not with others. This seems to be the case as imbalance heard with music tape is very high (5dB), while the levels are absolutely spot on with differences well below the threshold of audibility. So I would start to look at tape path alignment: remove the door and observe the tape. Does it move straight ? Is there a tendency for the tape to be pulled up or down ? Is the pinch roller correctly aligned ? See my thread in regard to this problem: https://stereo2go.com/forums/threads/wm-dd-azimuth-instability.7590/ Can't draw any conclusion at this point as the test tape does seem to be good: on the DD33 there is a small imbalance but it's below 1dB.
Hello Valentin, I've installed Audacity and tried to replicate your measures (as part of my learning curve and understanding your analysis). I see the following: Known Good Cassette WM-DD 33: Left -15.7213 dB, Right -17.4881 dB, diff 1.7668 dB WM-D3 Line Out: Left -15.9141 dB, Right -18.8385 dB, diff 2.9244 dB WM-D3 Phone Out: Left -14.6506 dB, Right -18.5005 dB, diff 3.8499 dB Dolby Test Tape WM-DD 33: Left -14.8668 dB, Right -15.1734 dB, diff 0.3066 dB WM D3 Line Out: -10.5782 dB, Right -10.5795 dB, diff 0.0013 dB WM-D3 Phone Out: -11.4772 dB, Right -12.4262 dB, diff 0.949 dB I guess the way I calculate the differences is not the correct one (just substracting one number from the other) but the way I understand this is: there is always a difference between Line Out and Phone Out on the WM-D3, Phone Out seems to amplify any issue the Dolby Test Tape is spot on on all units (no noticeable difference between the 2 channels) the recorded tape however shows imbalance - as well on the WM-DD 33 ??? I must say I'm a bit confused now I'll look at your other article and revert. EDIT: I see you mention springs in this other thread, am I missing any myself?
There is a difference because of the stereo potentiometer which adds a little bit of imbalance, but as we can see it's pretty low at just below 1dB. Wouldn't really consider this an issue and it's definetely not the cause of what you are hearing in the audio. Yes the Dolby test tape does seem to be spot on, which is good news since this is the only one available at the moment. The known good tape does seem to have some imbalance itself, but that imbalance seems to be much higher on the WM-D3. What I do notice in your picture of the unit, however are 2 things: - the pinch roller defintely sits at an angle relative to the capstan, typical problem as I have already mentioned in previous post. It can be seen by 2 different oxide marks, one above middle of roller which is much more pronounced. - think I see some pittings on the head. Some more clear pictures where the middle of the head is not in a shadow would be helpful. As for springs, you're not missing any the one near the head is there.
Strange, I don't really see this: I see what you mean, but since the capstan seems indeed to be parallel to the pich roller how is this possible? Sun is shinning a lot today I hope this picture is good enough:
Indeed the roller seems mostly parallel to the capstan, there is a very slight misalignment, but it's small enough that I won't bother to adjust it. It may be due to the tape itself, some new pre-recorded tapes can do that. In regard to the head, there seems to be some wear but it's impossible to tell if that is actually causing the imbalance. It's possible, but unlikely. Only test you can do now is to observe the tape with door removed. Does the pinch roller tend to pull it up or down during playback ? Even if just very slightly ? The fact problem appears with some tapes but not others (test tape) is an indication problem is in the tape path, not in the electronics.
You are absolutely right! I've just made the test and I see that the tape is slowly & slightly pulled down when I start playing the tape. I've made a video, hope you can see: https://www.swisstransfer.com/d/605dbd77-1e5b-46ff-b91f-337d5e814437
Well that was interesting the this site page said that I should be able to view the video in the page - no. I found it in my download folder 3.6mb size and then I was able to play it. I can see, Half the video is holding it and then you play and it is working but hard to see the tape traveling but I can hear it.
Seen the video, it's exactly what I suspected. This is your problem, glad you have found it ! This is what needs to be solved and then I would re-do all the electronic adjustments as chances are they're off because of this issue. The issue is most likely caused by a misalignment of the capstan, which is turn is likely to be caused by a shim under the FG coil missing (that can happen when restoring the mechanics). So what needs to be cheked next is the alignment of the capstan in the cassette hole. Needs to be perfectly in the middle, if it's tilted (in this case to the right since it's pulling the tape down), it will tend to pull the tape.
Thanks to you! Pretty sure I didn't miss any shim when replacing the central gear though The washer was on the capstan axis, I did check as this was an issue I faced with my WM-DD 33 (lost it and replaced it with a home made one from PTFE film). I've tried to make a couple of pictures - to me it would seem in the middle, maybe slightly leaning towards upper-right corner (probably your eagle eye will see better). Difficult to take a good picture given the sort focal (lens barrel distortion). Shouldn't I try to tweak the tape path alignment screw (from your WM-D3 tutorial)?
In the case of the WM-D3, that "tape path alignment" screw is for something else, specifically for adjusting the height of the erase head. Recommend not messing around with it, especially because it seems the original lock paint is still intact. What you can do for peace of mind is observe the tape (use a transparent shell cassette like the ones above) at the erase head and see if there are any curls where the guide is. However, your issue is in the pinch roller area and that's where the focus should be. Given you say you didn't lost any shim, you will have to add some yourself. So proceed in removing the capstan, then the FG coil and add one some small pieces of paper (80g/m2) to the right edge (the one towards the center gear) of the coil assembly so you lightly tilt the capstan to the left (towards the head). Of course you might need to repeat this process and add one or two more pieces of paper until the problem goes away. You can use another material if you want, but I recommend paper since it's very thin (0.1mm). After each such process, be sure to put the unit in FF or REW and clean the capstan of residual oil before using it with a cassette. Indeed from the pictures I can't see any obvious misalignment, but thing is the cassette itself has some left-right play inside the cassette compartment, so it's pretty hard to make a diagnosis just on visual inspection. What I would do personally however is more than just add these shims: - I would replace the pinch roller with a new one while also bending the head carriage shaft a tiny bit, so I completely eliminate the slight misalignment between roller and capstan; As stated don't think that's the problem, but it's something I would do anyway just to eliminate it. The best way to check this is to manually push the roller towards the capstan. When the alignment is perfect, the middle part will touch first since the roller is barrel shaped. - I would roughen the capstan (the area in contact with pinch roller) with ferric chloride just to eliminate any potential uneven wear on the capstan (which might not be visible to the naked eye);
Thanks a lot again for your time and the detailed explanations! Since the capstan is tilting to the right (on the pictures above), I believe I should be adding the shim on the right side as well (but underneath), hence on the side opposite to the center gear (seen from the other side), no? I'll see that when I disassemble (again )... I really didn't think it would be that complex when I embarked that journey with the WM-D3 - was merely expecting to replace the center gear... I hope I can manage to bring the capstan fully perpendicular to the chassis/deck. Wow that seems really above my poor skillset I've tried what you describe as a check (manually push the roller towards the capstan) and to my eyes it seems OK as their are parallel... In terms of process, I assume I should be doing the following: add a shim capture my known good tape playback (Line Out) analyze the capture under Audacity repeat from step 1 until I don't see/hear imbalance (by ear and in Audacity) re-adjust with PB levels re-adjust record levels Does that sound OK? or should I adjust PB levels every time I add a shim (as it may impact electronic adjustments) before analyzing the playback of the known good tape (which would be cumbersome )? One question still: you highlighted earlier that "2 different oxide marks, one above middle of roller which is much more pronounced" can be seen on the pinch roller. If the tape is pulled down, how come the one above middle is the one more pronounced?
Ok, so in regard to the pinch roller, just leave it alone for now. The oxide marks as said may be either due to that small misalignment I think I see in the picture (you say there isn't any, if so ingore it) or due to the tape itself. In terms of process, you need to add shim and check visually to see if the pinch roller still pulls the tape down. No need to do any measurements until it is ok visually, those will be done only once at the end. As for the position of the shim, to tilt it to the left (from the perspective of cassette compartment) you need to add the shim on the right side underneath (towards the center gear). Correct me if I'm wrong but imagining it visually that's how I see it.
Okay thanks, will try all this and revert - I'll be travelling so may take a few days. EDIT 1: before embarking in the shims journey, I've just tried to measure how tilted the capstan is compared to the deck, and took a couple of pictures. Actually it doesn't seem to have any tilt at all... I have also filmed the test of moving the pinch roller towards the capstan: https://www.swisstransfer.com/d/c0b8da1f-c4e9-4c64-8285-87bc457c2815 It would seem the issue is indeed with the pinch roller, as you hinted before. I can see that it's not really barrel shapped as you mention, and it would seem that the bottom part is touching the capstan first (although barely discernable, at least to my eye, on the video). EDIT 2: I have ordered a couple of pinch rollers from FixMyAudio (keeping one spare for future repairs) and will go through your tutorial to change it. Fingers crossed
Hello Valentin, It's been a while but I finally received my new pinch roller and managed time to change it on the unit, following your tutorial which was very clear and easy to follow (thanks for it). Having made a first visual check on the tape path, it looked like the tape was not being pulled down anymore so I was full of hope when I made my test recording... Although the imbalance seems far less (1 dB max as per the RMS measurement in Audacity, but still present to the ear), I now have awfull wow & flutter. I'm now close to desperation and of throwing everything through the window I've captured the recording, the RMS analysis, and uploaded the visual tape path check: https://www.swisstransfer.com/d/dca59085-fe10-4168-aa62-4779a291ca5b All springs are back to their location, pinch roller was oiled, I followed everything... Any idea what I'm facing now? EDIT: I forgot to tell that I went through the whole adjustment procedure as well (PB & recording levels), and adjusted the left channel, before my recording attempt.
Have you thoroughly cleaned the pinch roller and capstan after replacing it ? How does the roller look now relative to the capstan ? Are they parallel ? Watched the video, indeed can't see any tape pull but there's a catch. What cassette have you used ? As from what I remember, it didn't have any pull with the test tape even before, but it did with pre-recorded cassettes. Personally, I'm skeptical just replacing the pinch roller solved the misalignment problem... hence why I would test visually with 5-10 different cassettes before drawing the conclusion. The RMS analysis isn't that relevant if it's only valid for that specific tape. If we look at the measurement, imbalance is below 0.5dB yet something is clearly audible (at 0.3dB it won't be). Have you re-adjusted the playback levels ? Azimuth may also need some small adjustment. Being desperate about it unfortunately won't solve anything. Given you have started this journey, I think it's worth continuing it no matter how long it will take. Generally, when you're doing a particular repair for the first time, it can take quite a bit of trial and error until you get it right and fully understand the common problems.
