Kinoton RSSD Wow

[Julian Antos]

We have a problem on an FP20 with a reverse scan sound device exhibiting an audible wow. The problem is noticeable visually on the soundhead as a "breathing" of the loop size, and audible during scenes with slow music. It seems to come and go over the course of a reel, sometimes improving after a few minutes, sometimes getting worse. The takeup mechanism is an Ernemann sidewinder running 5" hub 2000' takeup reels, and the takeup tension is nice and low.

We have already tried, with no or minimal change:

-Replacing the O rings on the pinch roller with the newer "green" style
-Lubricating the pinch roller bearings with cardan oil (old oil cleaned out first)
-Adjusting the position of the rollers under the gate
-Adjusting the takeup tension
-Removing and reseating the flywheel
-Adjusting the tension of the takeup
-Adjusting the tension of the pinch roller on the sound drum.
-Threading with a different lower loop size
-Consulting previous film-tech threads on this subject did not provide the answer.

We have not tried:
-Lubricating and/or replacing the sound drum shaft bearings. However, the drum spins freely for over a minute after the reel has run out.
-Replacing the flywheel


Looking for a remedy! There have been several moments where I think I've licked the problem, only to find it pop up again after a couple reels.

[Steve Guttag]

First, absolutely, flush the drum bearings and lubricate (I use a synthetic intermittent oil). They are notorious for causing wow/flutter. They are open bearings and dust/dirt WILL get in there. There could be an argument for half-shield bearings in that application.

I don't care what Kinoton has ever published/said, do NOT use Cardan oil on the pinch roller. You want that to be a light-weight oil like the Esso Handy Oil or a sewing machine oil. You don't want the pinch roller to provide ANY drag. The pinch roller's job is to keep the film secure against the drum. Drag on the drum will slow it down and create wow. The tension of the pinch roller on the drum has a sweet spot. Too much and you create drag. Too little and you get slip. You need enough so that the drum spins up in time for changeover/dowser opening. If you look at the film coming off of the drum and going around the rollers of the soundhead, it should appear to almost (but not quite) float. Feeding into the drum it should have a pucker and not bob up and down.

So, key points are:

• Drum bearings cleaned/lubed.
• Pinch Roller bearings clean and lightly lubed also ensure that the end cable does not cause drag.
• Pinch Roller tension set to ensure friction but not drag.
• For mechanical machines, like the FP20, adjust the rollers below the intermittent to minimize film vibration in the soundhead area.

Again, this is for the late-model RSSD head as used on all of the "E" projectors and later "D" projectors (but can be retrofitted to prior projectors). For original Kinoton optical soundheads, they will always be touchy. Their drum is too small, which requires more pinch roller pressure for good friction. You need something like 7 flywheel plates for those and they will need maintenance on the drum bearings too.

[Marco Giustini]

What! I bought some genuine Kinoton "cardan oil" exactly because Kinoton said it was needed for the pinch roller!

[Sam Chavez]

.Love to know how old the cardan oil is. This goes back to FP5's from the '40's. I think using that oil is fine and the problem is one of the other points Steve outlined.

[Steve Guttag]

"end cable" is supposed to be end cap.

Don't use Cardan oil on that roller. I defy for anyone to show what possible benefit a viscous lubricant can provide in that application. It can only hurt.

[Mark Gulbrandsen]

I tried looking Cardan up and it seems today that it's mostly in grease form for cars and trucks. It has Moly in it, so I assume the oil does too...

[Sam Chavez]

As I recall Cardan oil was to provide just a little dampning in order to reduce flutter. (When's the last time anyone used flutter film or flutter bridge?). This was relating to DP70 and earlier roundheads of course. I was told by dedicated techs like the late Bob Koch who used to post here that it worked very well. Now as to modern sound heads, I have no opinion. Probably it was just used as boilerplate text in later Kinoton manuals.

[John Eickhof]

cardan oil was developed in the early 1900s as a lubricating oil for cardan joints (now called 'U-Joints') in automobile drive trains and other industrial drives, it was a sticky viscous fluid that would retain contact well, it was soon replaced with short fiber grease as automobile speeds and size increased. i think it would be way to thick to use on the pinch roller, i suggest washing those bearings out and use a light machine oil like sewing machine oil or simplex projector oil. if the flywheel is a stabilizer type (flywheel inside a flywheel) it could have lost the viscous fliud inside and wow will be very prevalent, i have seen this on simplex, rca and motiograph sounhdeads if it is a solid one piece flywheel, take it to a machine shop and have it checked for balance. 'cardan was the inventor of the cv or cnstant velocity joint' and Standard oil (later ESSO) used it as a tradename just like 'capella' was texaco's name for light/medium wax free oil.

[Mark Gulbrandsen]

I'm with Sam on it just being a boiler plate word, especially in Europe..

John, I remember that stuff being used in Motiogrief flywheels... But everyone of those I opened, the grease, or oil, had hardened.

[John Eickhof]

yup motio used a different compound than rca and simplex they used a dow corning silicone fluid and they were hermetically sealed except the early ones were screwed together like motio and air would get in and the fluid would drain out! on rare occasion the internal ball bearing would go bad...wolk used to sell the gasket and fluid, the best set up imho was the century R2/R6, it had a dampener using magnets to turn the floating flywheel a felt lateral roller that snapped into position, plus the fluid dancer unit just after the sound drum plus a sound sprocket and a holdback sprocket...as close to zero flutter as you could get!....ahh the good old days!..

[Julian Antos]

The sound drum bearings did the trick! They weren't dirty, but were bone dry. I used a little bit of Lavezzi intermittent oil and it's running very smoothly. Took about ten minutes.

I do have some Kinoton Cardan oil, which is much heavier weight. It seems that the lighter weight oil would come off after a while and need to be reapplied, and the heavier weight oil might attract more dust and need to be cleaned off and reapplied every so often, so either way this should be checked regularly.

Would there be any benefit to replacing the open bearings with sealed ones?

[Steve Guttag]

Sealed bearings will have a grease type lubricant and if they are really sealed (not just shielded, there will be some sort of friction from the seal. As such, no I would not use sealed bearings. As mentioned, there could be an argument for using half shielded bearings (shields on the outside to prevent dust from getting in there. Still use Lavezzi or like oil. Also, put some oil in the bearing separator and you might find that they stay lubricated better.

The light weight oil would be for the pinch roller.

As for Cardan oil providing "damping" in the soundhead area...how? It makes no sense. The drum/flywheel provide the damping, not roller rotation. The pinch roller's job is to ensure that the film to drum friction is maintained, not provide daming. That is done via the O-rings (modern pinch roller) and pressure. Kinoton/Noreleco's method of isolating the area between the intermittent and drum (on non reversing machines) is the film path itself. By the time the film reaches the pinch roller, it should already be steady. Now, after the drum, on a soundhead like the AA2, yeah, you could use a heavier oil like Cardan to force tension between the roller and holdback sprocket (thus creating a slight amount of slack between the drum and roller). That can work.

Since most versions of the RSSD used delrin rollers, no lubricant should be used on them. Just keep the shafts clean. One can use a light lubricant and wipe off to act as a oxidation preventer but not as a lubricant. Kinoton DID offer a damper option on the RSSD (standard on the "Studio" version of the soundhead) that would replace the roller right after the drum but I only found it advantageous on the soundheads with reverse running machines (studio).

[Sam Chavez]

My comments about the use of Cardan oil has to do with DP70 and earlier projectors. Not sure that was the optimum solution even back then and Norelco didn't get everything perfect on 35mm but it's in Norelco's manual so please take it up with them, not me. I believe the use of Cardan oil had more to do with flutter and not Wow which is not difficult to deal with on a first rate projector.

I'm not in the mood to argue about flutter issues until someone with a flutter bridge and test film actually does the experiment and documents the result.
Guess someone could cut out the appropriate section of "Jiffy", make a loop and play away but a flutter bridge meter is the best proof of optimum performance.

[Steve Guttag]

The DP70 uses heavy metal rollers after the drum. Having a viscous lubricant there is likely to not run out as fast but if it impede the rotation a little and causes a slight pucker as the film leave the drum, so much the better as THAT would help isolate the film from the influences of the sprocket, take up reel (or platter). That would make sense.

As for flutter, yeah, a suitable meter and test film will give you a number...but, then again, so will Dolby Digital, if a digital reader is present. Dolby digital doesn't like flutter either as it turns into jitter. Those soundheads that had trouble with Dolby Digital also had trouble with flutter. If you fix it in digital, you fix it in analog as well (or vice-versa).

As for taking it up with Norelco/Kinoton...I did (you know me) and would never use Cardan oil on their pinch rollers...never had a Dolby Digital reader issue either (I didn't have issues on other manufacturers either though on Century, I always did the Component Engineering procedure of pushing the bearing into the receiver and using the loading spring on the inner race).

[Sam Chavez]

My points were mostly rhetorical but Steve always wants to win an argument. There's of course no-one around that took part of the development of DP70/FP5 soundheads.

The flutter bridge is used to quantify and note improvements before and after dealing with bearings. rollers, etc. Dolby Digital is nowhere near as sensitive to flutter as a human ear listening to a piano chord. The flutter bridge documents the actual measurement and improvement or degradation.