Diy Strobe for measuring turntable speed accuracy.

bauzace50

Does anyone know where to get a 50/60 Hz *Battery-Powered* strobe light for using with LP strobe discs?
This is preferred over neon/fluorescent lights that work on household current, since household current frequency can be inaccurate.
The KAB Acoustics model comes with its own disc, but the price is rather steep. Same thing with the *300 Hz* strobe from Clearaudio.
Isn't there a 50/60 Hz battery-powered strobe light in the market which at the same time does not deplete budgets?

Steerpike_jhb · Posted: Tue Feb 14, 2006 12:40 pm Post subject:

Depends how adept you are with a soldering iron. Such a thing could be put together very inexpensively from a few IC gates, a divider IC, a quartz crystal and an LED. I would guess under US$10 for all parts.

bauzace50 · Posted: Tue Feb 14, 2006 12:54 pm Post subject:

Hello Steerpike,
Yes, I have lots of practice with kit building (mostly Dynaco). If you have a design, I would be very happy to build one unit! Please let me know. Thankyou!

padego · senior member Joined: 11 Dec 2004 Posts: 499

I second that, Ive been searching for one without much success and without costing an arm and a leg!

Blue Angel · Posted: Tue Feb 14, 2006 7:09 pm Post subject: Strobelight bulb

Hi Carlos, Steerpike & pads

Such a thing mounted on a plinth close to your platter is most useful.

If you look at my 301 in the Gallery, you'll notice the strobe gadget on a stalk, folded down so the 7 element led illuminates the platter's strobemarkings.

It's called Litlite, from Litlite Inc and obviously US-made. There is no website mentioned on the packaging I still have but the firm is situated in Hamburg, MI 48139-0430 USA.

I have a custombuilt clean powersupply fitted underneath the Garrard's plinth and when I built it, I made provision for various dc outputs as well. My Litlite strobelight is fitted with a seven-element LED and runs off 12V dc.

I did this job 12 or 13 years ago and maybe Litlite USA now has a website.

Firms reselling this equipment are usually suppliers to sound studios or audiovisual distributors.

Hope this info is useful

Blue Angel

Gatto Murr · Posted: Tue Feb 14, 2006 7:31 pm Post subject:

Gatto Murr · Posted: Tue Feb 14, 2006 7:39 pm Post subject:

By the way, a simple thing with a 555 as astable and a led could suffice...

Modifying a timer kit (Google gives a million of them) would be easy.

regards, Piero

Steerpike_jhb · Posted: Tue Feb 14, 2006 9:02 pm Post subject:

hagtech · Posted: Tue Feb 14, 2006 10:04 pm Post subject:

Here's one way to do it DIY:

www.hagtech.com/ufo.html

jh
_________________
Jim Hagerman

Gatto Murr · Posted: Tue Feb 14, 2006 10:30 pm Post subject:

[quote="Steerpike_jhb

I'll put up a plan in a day or so... will draw it up and scan it.

[/quote]

Fine! maybe I can find an use for that xtal oven I should have somewhere in my junk box.

I'd like trying the simple 555, but no time (I'm late! I'm late!)....

regards, Piero

p.s. before starting with xtals, how is the minimal speed change which can be noticed by an average listener? And what about the speed of such a change ?

bauzace50 · Posted: Tue Feb 14, 2006 11:53 pm Post subject:

Hello all,
The Hagtech looks VERY desirable. I will be looking into it. However, other designs are offered by you fellows, which would promise to be interesting also.
We'll keep in touch, and thankyou for the valued responses.
bauzace50.

padego · senior member Joined: 11 Dec 2004 Posts: 499

Very interesting, I'll look forward to the different designs although the Hagtech does look nice and compact...

Steerpike_jhb · Posted: Wed Feb 15, 2006 10:16 pm Post subject:

Here is my tentative design. I went out & got the parts for it today, but they didn't have the crystal where I usually buy components.
All the parts including a plasic case (similar to a TV remore control's box) cost me less than us$3.00. The crystals I know from past purchases are around us$1.30. When I've assembled it & tested it I'll post more, but here's the circuit for those who'd like to compare in the meantime. NOTE: as shown, it is straight out of my head and NOT yet tested. Some component values may need to change.
http://www.vinylengine.com/php.....ic_id=3065

That Hagtech works at 75Hz, which means it will only work with their strobe disc (and won't work on strobed platters like the 301/401), something I think Bauzace specifically wanted to avoid.

Incidentally, it is not possible to make a 45rpm strobe disc that is accurate under 50Hz lighting. The closest you can get is 45.112rpm, so anyone in Europe who trims their TT by a strobe to play 7-singles is actually playing them 0.25% fast (quite a big error considering the accuracy claimed by the "Quartz PLL" brigade)!
And it's not possible to make a 78rpm strobe disc that is accurate under 50Hz OR 60Hz lighting, (or even 75Hz lighting for that matter - Hagtech buyers should note).

Gatto Murr · Posted: Wed Feb 15, 2006 11:39 pm Post subject:

Hi Steerpike, what's the xtal frequency? 1.6384 MHz?

Maybe 3.2768 would be easier to find (see it here at oselectronics.com) - and you could both sections of the 4013.

By the way, that Hagtech has an ON pulse of 3.3 milliseconds or I'm wrong?

regards, Piero

bauzace50 · Posted: Thu Feb 16, 2006 2:15 am Post subject:

Steerpike,
Thankyou, so much, for your design. I will wait for your prototype testing. My ability to read schematics is limited, and am better at reading pictorials, of course.
Yes, you got the request correct, as my type of strobe disc uses 60 Hz reference light.
Pity about the 45 rpm problem, though. This means that all my readings for 45 rpm have been wrong when using 60 Hz current, right?
Thanks for the magnificent suggestions! Work continues in progress.