Film-Tech Forum ARCHIVE: Using a Century JJ atop a R3 Sound head

This is topic Using a Century JJ atop a R3 Sound head in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Don Furr (Member # 1469) on 02-03-2011, 03:58 PM:

I've mounted a JJ on top of my spare R3 sound head but the JJ is turning too slow. I assume there is a different projector pulley on the JJ as opposed to the Century SA. Can anyone tell me which pulley to use? Or maybe the motor shaft has a different pulley??

Thanks...
Don

Posted by Gordon McLeod (Member # 33) on 02-03-2011, 04:09 PM:

Is this an issue of both the soundhead and projector running slow
i guess is that if the projector is running slow you have the wrong pulley i bet the main drive assembly was for a direct drive and the pulley is the wrong ratio

Posted by Don Furr (Member # 1469) on 02-03-2011, 04:18 PM:

Yep I think you're right Gordy. I'll just change the bottom gears on the vertical shaft to SA gears, use the SA pulley and that should do it. Thanks for your help.

Don

Posted by Louis Bornwasser (Member # 3063) on 02-03-2011, 10:16 PM:

Is your goal to run 70 mm; I have several JJ optical soundheads/could swap. Louis

Posted by Don Furr (Member # 1469) on 02-03-2011, 10:35 PM:

Thanks Louis. I'm only running 35. I've always believed a JJ had a better 35mm picture than a SA. That's the only reason I'm doing the change. I guess I could always convert to the JJ optical head and re-install my CE red reader.

Don

Posted by Don Furr (Member # 1469) on 02-09-2011, 03:20 PM:

OK, now that I've obtained a "selection" of pulleys can someone out there measure the pulley on the drive motor and the pulley on the JJ main drive and give the the diameters. My motor is a 1725 rpm. The picture head is a JJ-1 and the optical head is a TR-50 direct drive. The diameters in inches would be very helpful. I can't go by part numbers as my pulleys don't have any number on them. I could also use the part number on the main drive belt.

Thanks

Posted by Steve Guttag (Member # 268) on 02-09-2011, 04:14 PM:

Are they Polly-V pulleys or gearbelt? If Polly-V the motor and projector pulleys will be similar in size (not exact)...if you have gearbelt pulleys, I can try and look up the tooth count for you.

-Steve

Posted by Don Furr (Member # 1469) on 02-09-2011, 05:00 PM:

Steve I've got gearbelt (timing belts) pulleys...NOT Poly V.
These have the notches in them. Thanks for your help.

Don

Posted by Don Furr (Member # 1469) on 02-10-2011, 08:05 PM:

Thanks for those who have helped. Problem solved. A JJ-1 fits perfectly atop a R3 optical head IF....you change the motor pulley from a 10 tooth to a 14 tooth. (gear drive pulley, not poly v.)
[beer]

Posted by Louis Bornwasser (Member # 3063) on 02-12-2011, 06:27 AM:

JJ-1?? Serial number??

The first one is s/n 101.

Louis

Posted by Don Furr (Member # 1469) on 02-12-2011, 11:41 AM:

Louis it's a JJ-1 as opposed to a JJ-2 or JJ-3. Serial number of this one is 1070.

Don

Posted by Gordon McLeod (Member # 33) on 02-12-2011, 04:21 PM:

The pair serial # 101 is installed at the Music Hall in Toronto

Posted by Louis Bornwasser (Member # 3063) on 02-12-2011, 06:01 PM:

I have 104 and 105 from Oakland CA. Louis