Digital Laser Tachometer

[Lah Ca]

I bought a cheap generic/white-box digital laser tachometer today, a DT-2234C+. It cost $27.00 CDN or about $20.00 US. I bought it from a guy running a business out of his garage. I could probably have gotten it cheaper online, but hey ....

2023-06-10 16.43.20 makezine.com c435b8f2cbf4.jpg (36.99 KiB) Viewed 695 times

https://makezine.com/article/workshop/t ... achometer/

I took a piece of the reflective tape that comes with it and stuck it on the label area of a 78 I am not fond of. I tested all my currently functional/hooked up disk playing devices, needles on record for machines with 78 speeds and appropriate styluses/needles:

1) My Aeolian Vocalian machine was running about 4 RPM too fast for 78s. It was a total pain to reset the speed, because there seems to be a lag between adjusting the speed and the speed stabilising. I was always overshooting and undershooting. Eventually I got it right so that the speed is at 78 RPM. I will probably have to test this again.

2) My 1940s RCA Victor portable turns at about 85 RPM. The speed control does nothing at all to alter the speed--faster to the max or slower to the min, it's all the same, a constant and unchanging 85 RPM. I checked that the control lever was actually turning the shaft down to the motor--it is. I will need to look into this later, or not. Most people wouldn't notice the difference in speed.

3) My expensive Clear Audio turntable turns about 2 RPM too slowly at 33 and ⅓. I didn't test 45 RPM. The 2 RPM too slowly does not translate into an audible pitch difference between a record and my piano, at least not to my ear.

4) My old Dual 12xx something turns a few RPM too fast at all speeds. There is an adjustment wheel. I may play with this, or not ... it's close.

5) The only machine bang-on at 78 RPM with the speed lever set to 78 RPM was my HMV 102c portable. I tested the control, adjusting the speed up and down and using the tachometer to view the changes. The control actually works well and in mostly fine increments, and the speed stabilises quickly. Nice. LOVE this machine!!!

[CarlosV]

I wish you better luck than me on that purchase, mine lasted about one month and died. I resorted to the app in the phone, it works well, provided that you balance the phone in the center of the turntable and keep an eye to prevent it from flying across the room. The app does not replace the tachometer for cylinder machines, however, due to obvious physical limitations.

[AudioFeline]

I have that exact tacho. I found the battery ran down quickly, because the buttons aren't very well protected. If the unit is placed upside down, or something put on top of it, the buttons are pressed (the grey ridge before the orange tip isn't big enough to protect the buttons). I made a plastic cover with some raised supports inside, to fit over the tacho so the buttons are protected. It fits within the zip cloth cover.

[Lah Ca]

I wish you better luck than me on that purchase

Thanks. Fingers crossed.

This is always a risk with cheap Chinese-made tools, electronics, musical instruments, etc. I have rolled the dice knowingly here, having been burned many times by the ever so alluring temptations of cheapness.

My tach did not work properly out of the box because the device seems to need a battery with a full charge. The cheap no-name, presumably Chinese-made and obviously slightly swollen, battery that came with it did not register a full 9 volts on my cheap, but long-lasting and durable (if somewhat mildly inaccurate with very small voltage, amperage, ohm, and capacitance readings), Chinese-made multi-meter. It's all good (so far) with a fresh Home Depot purchased, Defiant brand, Chinese-made battery.

You pay your money and you take your chances.

I resorted to the app in the phone, it works well, provided that you balance the phone in the center of the turntable and keep an eye to prevent it from flying across the room. The app does not replace the tachometer for cylinder machines, however, due to obvious physical limitations.

Much earlier, I downloaded the Android flavour of the tach app and installed it on my phone, but it wouldn't work because the phone is a cheap, Chinese-made, Motorola model which is too inexpensive to include whatever device or electronics are required to support the app.

[Lah Ca]

I have that exact tacho. I found the battery ran down quickly, because the buttons aren't very well protected. If the unit is placed upside down, or something put on top of it, the buttons are pressed (the grey ridge before the orange tip isn't big enough to protect the buttons). I made a plastic cover with some raised supports inside, to fit over the tacho so the buttons are protected. It fits within the zip cloth cover.

Having had to rely on battery operated tuners, metronomes, effects pedals, etc, I never leave batteries in anything, except remote controls and flashlights, and even with these two types of devices, I am sorry sometimes. I am still trying to clean the corrosion and battery puke out of the remote control for my expensive CD deck, and these batteries were premium name-brand alkaline ones. But then, I suppose you can never really be certain about anything anymore--there are a lot of knock-off products floating about.

As said above, my tachometer does not seem to work unless the battery has a full charge. The LCD panel will light up, but the laser light only comes on momentarily and the device reads nothing, if the battery is not strong.

[AudioFeline]

Interesting. I've not had any problem with my tacho. Admittedly, not much use. Have checked a few turntables over the years, plus using it to amuse the cat a few times when it's been out, and some experimentation with anything I could find that rotates when I got it.

[need4art]

Like AudioFeline, I have not had issues with mine either. I have the original, poorly, written instruction sheet and it tells you to disconnect the battery when not in use. I have had it for over 5 years and am just now on the second battery. Really like the unit and it works well.
Abe

[alang]

I had the exact same experience. Mine works fine. After the first battery drained quickly while in the case, I now remove the battery after every use. It make sense since I only use it a few times a year. No problems since.

Andreas