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Old 5th Aug 2017, 3:58 pm   #1
sp10mk11
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Default UV light to UV LED conversion?

Attached is a circuit diagram for a circuit that drives a UV light for a strobe on a turntable.
MY question is can the tube be replaced with 4 UV Led's and suitable resistors, or am I being to simplistic in my thinking as the 230v supply is DC and to my mind I could use Leds
Thanks
Gary
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Old 5th Aug 2017, 10:13 pm   #2
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Default Re: UV light to UV Led conversion?

I would start again with a circuit designed specifically to drive LEDs. It would probably be a simpler circuit anyway. I am assuming that the LED would need to be pulsed at 50Hz? A half wave rectifier and current limiter would be the way to go if this is the case. I think simple neon lamps were used a few years back for this. I would be tempted to use a transformer to supply the circuit to be on the safe side.
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Old 6th Aug 2017, 5:02 am   #3
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Default Re: UV light to UV Led conversion?

Here is one done for Dual turntables:-

http://audiokarma.org/forums/index.p...-howto.383120/

Terry
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Old 6th Aug 2017, 9:05 am   #4
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Default Re: UV light to UV Led conversion?

Thanks to both of you.
Terry
I built this some years ago and it works well as replacement for neon strobe

Biggles

I have to use UV light as the marks on the platter are Phosferrous paint
I have a quartz referenced LED unit that I made i was toying with using this if the original cannot be converted, this pulses at 100hz
Gary

Ps sorry about the spelling mistake but I cannot think at this time of morning
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Old 6th Aug 2017, 10:31 am   #5
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Default Re: UV light to UV Led conversion?

A half-wave feed to an LED will flash at 50Hz while a neon on AC with a limiting resistor will flash on both cycles, 100Hz. You'll probably see a stationary pattern just the same at the right speed, of course

A 33 rpm strobe for 50Hz will have 90 dots around the turntable, for 100Hz, double that to 180

David.
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Old 6th Aug 2017, 4:32 pm   #6
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Default Re: UV light to UV Led conversion?

The only thing I do not like about the "Dual circuit" etc is that they rely on the mains frequency for their accuracy.
The above circuit and quartz referenced one do not, and having tried the quartz referenced one I now know that some decks that were often described as suffering from speed drift etc in fact do not when using the quartz referenced strobe.
Which is why I was sort of hoping I could use the built in circuit only with UV Leds instead of a UV tube.
But if I cannot then I guess I will go for the quartz referenced one with an LM regulator to run it, and obviously I would disconnect the 230/120v supplies to the old one
Thanks chaps
Gary
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Old 6th Aug 2017, 5:20 pm   #7
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Default Re: UV light to UV Led conversion?

Quote:
The only thing I do not like about the "Dual circuit" etc is that they rely on the mains frequency for there accuracy.
My mains frequency meter is usually 50Hz +/- 0.1 Hz, more than accurate enough for a deck. And why a UV LED? Surly that is invisible to the eye.
 
Old 6th Aug 2017, 6:41 pm   #8
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Default Re: UV light to UV Led conversion?

It's for illuminating fluorescent strobe dots. Probably something to keep a marketing department happy somewhere. If they run out of real things to make progress on, they have to simulate some progress.

David
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Old 7th Aug 2017, 8:56 am   #9
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Default Re: UV light to UV Led conversion?

AWWW that's a bit Harsh david if you think that's bad then I will tell you the dots are not dots but numbers 33 and 45 so you get a neat row of them This deck dates back to 1976

In one of the Technics manuals it mentions that even a 0.1% change in mains frequency will show as a speed change on the neon mains strobe on the turntable

The quartz referenced one I made really shows how speed stable these decks are (SL-110/150)

Gary
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Old 7th Aug 2017, 9:33 am   #10
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Default Re: UV light to UV Led conversion?

offers David a few mints as a peace offering
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Old 7th Aug 2017, 12:47 pm   #11
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Default Re: UV light to UV Led conversion?

Quote:
It's for illuminating fluorescent strobe dots
Ingenious!
 
Old 7th Aug 2017, 2:34 pm   #12
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Default Re: UV light to UV Led conversion?

Thanks, Gary,

That had me laughing.... I've not seen strobes done with numbers.

The Matsushita direct-drive turntables were indeed good. Just too mainstream for the cultists to accept.

Hmm, if they'd had to do a version nowadays that wasn't language specific to keep the politically-correct crowd happy (well, less upset, they never seem happy) it''d have to be rows of little hares or tortoises.

I'm not an eater of mints, but I buy plenty. The horses know exactly which pocket I happen to have a packet in.

David
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Old 7th Aug 2017, 4:30 pm   #13
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Default Re: UV light to UV Led conversion?

Don't forget David the new PC turntable would have to be solar powered and made by Tibetan black lesbian mothers in a wheel chair in a women only made yurt. (I used to work in Totnes home of the wealthy hippy)

The strobe is some thing different I must admit, I have tried taking pictures but they are not good suppose it is the black light or lack of light

The only Technics deck that is held in very high esteem is the SP-10mk11

Gary
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Old 7th Aug 2017, 4:47 pm   #14
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Default Re: UV light to UV Led conversion?

Just to brighten your day here is a video on youtube of the strobe in action
Gary
https://www.youtube.com/watch?v=W94uLq9erkY&t=28s
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Old 7th Aug 2017, 4:52 pm   #15
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Default Re: UV light to UV Led conversion?

Totally over the top and very pretty!
 
Old 7th Aug 2017, 5:31 pm   #16
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Default Re: UV light to UV Led conversion?

it is built like a nuclear shelter under that pretty wooden cover
Gary
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Old 7th Aug 2017, 5:40 pm   #17
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Default Re: UV light to UV Led conversion?

Corr, lets have a look!
 
Old 7th Aug 2017, 6:16 pm   #18
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Default Re: UV light to UV Led conversion?

Yup, gorgeous looking, and that 3009 doesn't look out of place.

I think the transcriptors hydraulic reference got shown in the museum of modern art, and there is a B&O4000 in the Louvre collection. Yours has looks in that league.

David
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Old 7th Aug 2017, 8:20 pm   #19
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Default Re: UV light to UV Led conversion?

in the flesh, a very solid one piece aluminium casting the electronics are under the black cover plates
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Old 11th Aug 2017, 9:14 am   #20
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Default Re: UV light to UV Led conversion?

I have built another quartz referenced strobe circuit in preference to using the original Lux circuit, at some point I will try this out just for my own peace of mind that if the UV tube goes down I can replace it

The strobe circuit is from vinyl engine if anyone is interested

I will get back

Gary
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