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Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Fri Nov 24, 2017 8:19 am
by Layla
Does anyone has 78rpm speed strobe for EU (50hz) at SCALE (for example A4 scan)? I found many pictures at google and StrobeMaker software, but the drawings are not to scale, so it won't work accurate.

How to use a speed strobe? Should I print it out and glue it to a broken record? There are some factors which slowdown the motor, such as record weight, soundbox weight etc..

Should the speed strobe be used with soundbox on record?

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Fri Nov 24, 2017 8:46 am
by Teak
just buy a digital tachometer: https://www.amazon.de/gp/product/B00HFQ ... UTF8&psc=1
It is absolutely 100% worth it!

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Fri Nov 24, 2017 8:46 am
by chunnybh
Try this.
http://www.78rpm.com/rescat/strobe_info.htm


Ive used the program for cylinders too.

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Fri Nov 24, 2017 8:55 am
by epigramophone
My old friend and repairer the late Philip Knighton made this strobe on a 116mm hardboard disc, but it has been unusable since I replaced all my inefficient incandescent light bulbs with modern low energy ones.

For speed testing I prefer a low tech approach more in keeping with my ancient machines. I place a small piece of paper between the record and the turntable, then count the revolutions against my watch. It works for me.

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Fri Nov 24, 2017 11:49 am
by Layla
Thank you all for tips. I purchased a digital tachometer with laser. I also have installed 2 different apps for RPM calculation, but I don't think apps will work accurate as a smartphone it is not the same weight as a record + soundbox on a turntable.

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Fri Nov 24, 2017 12:05 pm
by alang
Layla wrote:Thank you all for tips. I purchased a digital tachometer with laser. I also have installed 2 different apps for RPM calculation, but I don't think apps will work accurate as a smartphone it is not the same weight as a record + soundbox on a turntable.
I agree, that’s why I use a digital tachometer while playing a record. Just put a small strip of the reflective material under the record so that it sticks out a bit. Then play the record and point the tachometer top down to point at that bit. Works like a charm

Andreas

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Mon Nov 27, 2017 11:30 am
by howardpgh
There is a program called Strobe Maker that you can printout any speed strobe disk for 50 or 60 Hz. You have to use a neon light with it or an old style flourescent desk lamp to freeze the dots.
I made some for the different Victor speeds and 80 rpm.
I'm sorry I don't know the link to it.

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Mon Nov 27, 2017 12:03 pm
by phonojim
A strobe disc will work with a fluorescent lamp if the fixture has a magnetic ballast, however not if it has an electronic ballast. You can easily make make a neon lamp for your strobe disc using a small neon bulb with a 100,000 ohm resistor in series for 120 volt operation or a 200,000 ohm for 240 volt. It could probably be done with an LED and a series resistor also but I have not done that. The advantage of using a strobe is that speed irregularities and "creep" areeasy to see. That said, I do love my digital tach.

Jim

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Fri Dec 01, 2017 10:04 am
by arthurmacie
There are plenty of free apps for Iphone (I am sure for other phones as well) that you can use to strobe at the frequencies you want.

Re: Help need 78rpm speed strobe for EU (50hz) at scale

Posted: Mon Feb 19, 2018 9:21 am
by MarkELynch
Member Chuck Azzalina has a strobe creation program listed on his website.

http://www.myvintagetv.com/strobe.htm