8mm Forum: Grounding your projector. Static noise on Beauer T610, and crackling slider.

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Posted by Matthieu van der Sluis (Member # 6040) on April 05, 2018, 02:32 AM:

Like the title sais, the T610 has a Static humming noise.
When sound on the film is loud, i can't hear it, but without film or films with bad softer sound it's very destracting, and I need to keep the soundlevel low.

I've send this projector to van Eck for service, and replacing the belt, and normally they do a complete replacement servicepackage on this projector, for what is defective.
Does the projector need to be grounded somehow?
Can I fix this somehow?
Or is this something that is normal on the T610?

Also I still have one cracling slider.
Can I fix this, just by spraying contact cleaner in it from outside into the sliders slot?

Posted by Mike Spice (Member # 5957) on April 06, 2018, 10:22 AM:

is it a hum or a buzz

a hum could be an earth problem, a buzz could be a capacitor leaking

Posted by Tom Photiou (Member # 130) on April 06, 2018, 03:10 PM:

The T610 i owned for a short while had crackling sliders and a lot of hum. Worse than the Eumigs. Thankfully, i stuck with Elmo.

Posted by Matthieu van der Sluis (Member # 6040) on April 07, 2018, 07:54 AM:

I have also an Elmo GS1200, still not converted, so the Bauer is brighter and the light whiter which gives more beautifull colors.
Sound on the Elmo is indeed better.
Depending on what movie and reel size, I use Bauer or Elmo.
I regrat I didn't go for the Beaulieu 708 back than, so I had the best of both worlds.
Large reels, bright picture, great sound, perfect one time focus.

Posted by Oliver F. R. Feld (Member # 1911) on April 07, 2018, 08:16 AM:

Matthieu,
thanks for this marvelous definition of the wonderful Beaulieu 708!
I have the same problem with my Bauer T 600.
It’s extra disturbing when You use extern speakers.
I also think that it is an earth problem; but how to solve it?

Posted by Matthieu van der Sluis (Member # 6040) on April 07, 2018, 12:16 PM:

I've made a sound record for this.
I've put the sound level all up
Here's a link to my Google Drive upload.
https://drive.google.com/file/d/1mqVGa77ixq3HMdr5-_8WUp85IrgOUvsy/view?usp=sharing

There is no film in the projectors while recording this.

[ April 09, 2018, 12:01 PM: Message edited by: Matthieu van der Sluis ]

Posted by Matthieu van der Sluis (Member # 6040) on April 09, 2018, 12:04 PM:

I refreshed the link and hope it works now.

I also thought of trying a earted socket hahaha, and this helps a lot, but it is not taking the humming all away. When sound levels are high, there is still some noise.

Posted by Paul Browning (Member # 2715) on April 09, 2018, 12:17 PM:

Temporarily remove the earth wire from the mains plug, and see if this cures it. If it does, you probably have a hum loop, due to too many earths connected at one point somewhere on the chassis, but its does sound like a leaky smoothing cap on the power supply.

Posted by Steve Klare (Member # 12) on April 09, 2018, 12:21 PM:

To a certain extent this can be what our ears are used to from a piece of audio equipment.

If you turn on modern audio gear, you would really have a hard time pulling up hum. I have a Sony Amp that's not even that new: if I crank the volume up to levels that would be downright ear-splitting if there was a signal passing through, I may get a little hum.

If you fire up a TV or stereo or movie projector from 40 years ago, it sounds much worse. It probably always did, but hum was just part of day to day life back then and it was OK.

I'll give you an example of how this works: I run my projectors through an amp with a hum-rejection filter in between. When I go somewhere I have to leave all the external audio equipment home. (need room for other people and their luggage!) and I run on the internal speaker.

The first night I run this way it sounds absolutely awful! There is hum and hiss. A couple of nights later it's fine.

What changed?

Nothing but my own internal tolerance for the hum and hiss.

It's easy (and logical) to blame old capacitors for the hum we hear. Early on I went this route and replaced the filter cap on one of my machines with a brand new one of even larger value.

Did it help?

-maybe, but not nearly as much as I hoped it would. I think to a certain extent we are up against what 1970s designs could offer. Even if it's as good as it ever could be, it might not be that great by modern expectations (Try driving a fifty year old car: yes it's fun, but a little bit scary!)

The solution is either to grow 1970s ears or go external sound system and clean up the signal before you amplify it.

An old friend of mine had an even better solution: he decided to like the hum.

-He said it gave the sound "character".

Posted by Matthieu van der Sluis (Member # 6040) on April 09, 2018, 12:42 PM:

Using a earthed socket helps a lot, but for that I needed a longer cable, to reach that.
The rest of the bit humming that is left, is just beautyfully exoplaned by Steve.

I think it is more striking to me when I just used my Elmo, and than switch over to the Bauer.
Light is better, sound is wors.
I keep forgetting that till it's there haha.

Posted by Steve Klare (Member # 12) on April 09, 2018, 12:48 PM:

-see what's happening here? More comparative hum!

Put the Elmos away for a couple of weeks and see if it "improves"!

It's easy to forget the most complex part (and important part) of the whole sound and viewing chain is the human nervous system.

(I have films that look really awful after a couple of glasses of wine, but that could be just a focus problem!)

Posted by Matthieu van der Sluis (Member # 6040) on April 09, 2018, 12:56 PM:

Whuhahahaha, Steve your kiling me.
Next film needs to be with a bottle of whiskey.

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