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Topic: Crackle noise when turning on power - Steve Klare....HELP!

Chip Gelmini
Phenomenal Film Handler

Posts: 1733
From: Brooksville, FL
Registered: Jun 2003

posted April 27, 2018 12:31 PM

Virtually all amplifiers of some sort will do this when old. It doesn't matter if it's a radio, receiver, or in our case, a sound projector.

Does someone know the variables that cause this. In particular, to the GS 1200. One of my machines just came back from a tech for this problem. It doesn't do it as much as before he got it, but it still does.

So on a GS, what are ALL the possibilities that would cause this?

Steve Klare I understand you might not have a GS 1200 but perhaps you could know about this having repaired your own ST models?

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Paul Adsett
Film God

Posts: 5003
From: USA
Registered: Jun 2003

posted April 27, 2018 03:09 PM

Hi Chip, what you are describing is very common on GS1200'S. For whatever reason they are very sensitive to all forms of electromagnetic interference, arcing of switches, lights being turned on in the house, you name it. The best solution for me is to simply disconnect the internal speakers by pulling that connector off the main PC board inside the machine. No more Rice Krispies (snap, crackle, pop!) [Smile]

--------------------
The best of all worlds- 8mm, super 8mm, 9.5mm, and HD Digital Projection,
Elmo GS1200 f1.0 2-blade
Eumig S938 Stereo f1.0 Ektar
Panasonic PT-AE4000U digital pj

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Mike Spice
Master Film Handler

Posts: 421
From: none of your business
Registered: Jun 2017

posted April 27, 2018 03:24 PM

Any chance you could record a quick bit of video, but pointing the mic of the phone at the noise, so we could hear it?
Post at youtube perhaps?

Could be many reasons, loose board connector, capacitor, volume pot in a bad mood.. dry solder joint....

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted April 27, 2018 03:43 PM

Hi Chip,

This time It's something I haven't had with my machines.

There is such a thing as a start-up transient where you need to go from everything discharged and dead to fully up to operational levels and a lot of energy can slosh around until it settles. If speakers are involved it can make some pretty rude noises!

-as long as it goes away in a couple of seconds it's OK.

Mine have a turn-OFF transient: a little chirp or buzz when you turn the volume knob all the way down until it clicks. If I don't turn the external amp off first my wife says "What was that?!"

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All I ask is a wide screen and a projector to light her by...

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Rob Young.
Phenomenal Film Handler

Posts: 1633
From: Cheshire, U.K.
Registered: Dec 2003

posted April 28, 2018 01:44 PM

Yes, Steve, the ST does indeed have that strange little "ZZZzzzz..." audible through the internal / externally connected speaker when you click the volume off!

I have found that the only way to prevent audio interference with an ST / GS / Beaulieu is to isolate them from the rest of the household's dirty mains with (in the UK) a 230v to 230v floating transformer.

Of course, I may fry myself, but it hasn't happened in 30 years and I don't have crackles on sound...pros & cons... [Roll Eyes]

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

posted April 28, 2018 01:50 PM

-and an ST turn-on transient is like a tiny gunshot!

Regret the day you DON‘T hear it!

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All I ask is a wide screen and a projector to light her by...

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Rob Young.
Phenomenal Film Handler

Posts: 1633
From: Cheshire, U.K.
Registered: Dec 2003

posted April 28, 2018 02:02 PM

Yes, it is indeed a reassuring "pop" / "bang" into life each time you switch on an ST amplifier.

Before I isolated my ST from the mains and when feeding the monitors out to a stereo amp, there would be a substantial bang every now and again. I finally realised it was when the oven was on...each time the thermostat turned the element back on...BANG!

A new oven helped to reduce this effect...

Beaulieu's don't seem anywhere near so vulnerable as Elmo's in this regard, but I'd still recommend isolating from the rest of mains and most problems will be solved.

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Chip Gelmini
Phenomenal Film Handler

Posts: 1733
From: Brooksville, FL
Registered: Jun 2003

posted April 28, 2018 02:31 PM

Do any of your projectors react with audio noises when your cell phone communicate with the local tower I know my iPhone make strange noises through the receiver it sounds like I’m being invaded by Mars

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Phil Murat
Jedi Master Film Handler

Posts: 671
From: Villeneuve St Georges, France
Registered: Dec 2015

posted April 29, 2018 01:06 AM

Hello Chip,

I amn't surprised by this report.

An effective and economical way to solve (or almost solve....) many interference problems and to reduce the effects of EMI/RFI is to shield wire and cable bundles ; close to heads , and between Preamp Stages and Power Amp . Braids are connected to earth.

Moreother, you can increase Board tracks density for ones dedicated to ground and/or (-) connection , by expanding them with tin ......

Sometimes, it could be necessary to ad a copper cover , installed above sensitive stages and connected to earth too , of course depending on the room you get inside the machine, so this is an other story.........

From my side , I often time switch off my mobile when not use....

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