Circuit for a 50Hz Red LED Strobe

[Ammonite Audio]

I need a simple little circuit to knock up a strobe using a red LED that will operate at a precise 50Hz. It's for my Thorens TD124 - I wish to remove the neon lamp and replace it with something (probably battery powered and operated via a discreet push switch) that will better illuminate the platter strobe markings.

I can always get a Martin Bastin handheld strobe and incorporate its innards into the TD124, but I rather fancy building something myself.

Can anyone help?

[Reid Malenfant]

Pretty sure i have a few circuit diagrams kicking about that will generate a 50Hz square wave from a quartz crystal & some simple dividing ICs..

That'd be more than accurate enough, i'll have a look about Hugo

[Ammonite Audio]

Thanks Mark. That would be much appreciated!

[Reid Malenfant]

Umm, just had a very quick look & not found a great deal as of yet Give me a day or so as this could take a bit of rummaging about

[Reid Malenfant]

Alternatively this could be good, just drive an NPN transistor (via a resistor) with grounded emitter on the output & put an LED & current limiting resistor on the collector

Once it's set to 50Hz the drift should be negligible..

[zanash]

try googling ...certain I've seen similar on some of the diy electronics web pages ..

checked to see if I had any info ..but no

[Ammonite Audio]

It seems that Keystrobe make such things at modest cost, but they also do a bespoke kit for the TD124, so I have ordered one. Thanks for all your help.

[nat8808]

Just get an LED night light for about £1.50 e.g. like this

Strip it out and put it in the Thorens. They run off very crude AC -> DC conversion and so flicker at the same rate as the mains.

It will be just as accurate as the original strobe, so the only real reason for constructing anything else (other than because you enjoy it) is if you want super accuracy that the mains can't match..

[Ammonite Audio]

Just get an LED night light for about £1.50 e.g. like this

Strip it out and put it in the Thorens. They run off very crude AC -> DC conversion and so flicker at the same rate as the mains.

It will be just as accurate as the original strobe, so the only real reason for constructing anything else (other than because you enjoy it) is if you want super accuracy that the mains can't match..

Thanks for that, but I had already bought the Keystrobe kit, which at least has been engineered to fit the TD124 in place of the old neon bulb. The TD124 has a few little quirks (eg the way that the platter is fixed and adjusted) and a super-accurate strobe does actually help in setting it up.