For this particular application I think most (if not all) test tapes are ok since you won't obtain less than 0.15% WRMS even in the absolute best case scenario. And most tapes are recorded on decks that have W&F significantly better than that. So for the most part unless you intend to measure units that have very low W&F (like SONY DDs), no need to be super concerned about tape used. I would go for the FixYourAudio one, recorded on a SONY TC-K555ESJ which has a W&F spec of 0.022% WRMS.
Hi, Valentin thanks for your guide on this forum, very helpful. I need little help, I carefully removed two flywheels and when I flip the device, two washers fell out, I can't figure out where they should be? I removed only two flywheels and nothing else. Does anyone know where they should be? The big black washer seems like it should be in the big flywheel now it has a smaller one but where should be the small grover washer? upd_1: I checked the big flywheel, it has two washers, the lower one is white, the upper one is black, and they are the same diameter, smaller than the black one that fell out. upd_2: I think I found where they were They were on the back side of the PCB. I added a photo with them, one on the PCB and the other on the pins. Maybe it will help someone in the future. P.S. I have an early model with the sign on the door "Stereo" instead of "Sony"
The small one goes underneath a screw that holds the PCB (where the PCB is grounded). Big one can't remember exactly where it goes, but you can see it's inner diameter is much larger than the capstan and it's obvious it doesn't belong on any of the mechanism's shafts. Also it's visible the capstan has its washer inside the flywheel. Small pulley shouldn't have a washer.