Beaulieu 708 sound warbbling?

[Mark Barton]

Hello all, my Beaulieu 708 capstan projector is playing back audio with a warble effect. Im assuming a loop is not correctly shaped???? Your advice please.

[Oliver Feld]

It could have something to do with the small white plastic parts at the soundhead system.
Try what happens if You lift the upper part slightly while the playback. Normally this „warble“ sound disappears this way.

[Oliver Feld]

This effect happens to my Beaulieu with „dry“ acetate prints now and then. The use of Filmguard can help.

[Brad Miller]

Definitely check your loop sizes. A bad splice can cause the loss of a frame in the lower loop and that can cause warbling.

[Phil Murat]

Not sure to clearly understand this typical defect, but I have observed sometime , something like that for particular print(s), so here is an idea :

Assuming it was due to a print showing "rough" edges, I only slightly lubricated edges and problem went away.

As Oliver mentionned above, a too much dried print could be a problem too.

Assuming this "extra noise" is not amplified by Amp circuit, I suggest you to check Nylon Heads press pins. In sound mode, insure you for a good clearance between pins clips (4) and black cover upper side. If you do not find any clearance , this means heads press pins are worn out and has to be replaced.

If film is not properly (enough) pressed on head(s) you can observed rubbing extra noises.

At the end this defect could be a combination of print showing rough edges and head press pins worn.

[Ricky Daniels]

If I recall from back when I had a Stereo 708EL, it’s important the optical photo cell speed regulating system for the capstan drive is kept super clean, so maybe check this too.
Best,
Rick

[Mark Barton]

Thank you chaps, of interest I didnt know there is an optical speed regulator. Acting dumb where is that component on the 708?? stay safe

[Ricky Daniels]

Hi Mark,

From memory there is a sliding ‘mask’ and photo cell pick-up in the vicinity of the soundhead/capstan/final sprocket that isn’t visible until the sound head cover is removed and then I think it’s pretty missable! The sliding ‘mask’ and photo cell need to be kept very clean in order to maintain smooth mechanical operation across the sound-block and thus smooth sound reproduction. As I understand it if this isn’t working correctly the floating roller after the sound-block will likely be static?

I’ve a 120 page PDF of the 708 Stereo / Mono parts and service manual I can let you have but it’s 50MB so if you have somewhere I can upload it to you’re welcome to it...

How about wetransfer? It’s free and safe but you’d need the free disc space and I’d need your email.

I’ll then be able to point you to the relevant section(s).

Rick