What are you using for an inexpensive frequency counter?

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I'm looking around for an inexpensive frequency counter to use for audio experiments, and hoping for some recommendations.

There's lots of little circuits around, but they seem to be mostly for RF.

Probably can't afford the $$ (or space) for an old HP bench type (I wish).

I notice that some modern meters have a frequency function, but I have never actually used one so I don't know how appropriate they might be for measuring small signal audio.

Your experience?

Thanks,
Keith
 
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I was wondering and thinking similar to what Marcel has asked. If you just want repeatability and (what ?) 1% accuracy then I think the frequency range on a DVM would be fine. My meter has that facility and its pretty accurate.

I also have an ancient Simpson 711 counter that goes up to 80Mhz with good accuracy. I calibrated it (back in the day, can't do this now of course) using the locked chroma sub carrier oscillator in a CTV which in the UK was precisely 4.43361875Mhz when tuned to a BBC transmission.

The range on a DVM should do all you want.
 
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Hi Kieth,
I'm using an HP 5385A that I got for about $110. My 34401A has a fast frequency counter good up to 300 KHz (so free with the meter) and my expensive counter is an HP 5335A with a "C" channel. My new-ish Keysight and Agilent hand held meters have counters good up to 100 KHz. My scope has a 5 digit counter built in (Agilent 54642D) - so free with the scope. The Tek 2465B CT has a counter built into it too.

So with all that, I would point you towards the HP 5385A. It's a newer LCD display type and has HP's reverse counting technique. For the low hundreds, I can't see you doing any better. Especially at low frequencies! Keep an eye on Ebay and some of the discount sellers in used test equipment.

-Chris
 
Thanks guys!

Yea, an HP5385A would be nice...

RE DVM: The specs that I've seen (not many) on DVM's tell me the freq range they measure but don't tell me the level required to get a good reading. So it's good to hear that you find them adequate- I'll need to do more homework on that. If you have a recommendation on an inexpensive DVM that will give reasonable accurate freq counter for the audio range at a little under one volt that would be great...
 
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Hi Kieth,
Just keep your eyes open for one. Then you have something that does RF too. I use a X10 'scope probe on mine so I don't upset the circuit, it has a 1 Meg input for the low band, 50R for high frequencies. It's the perfect bench freq. counter and it has a fast update rate which makes adjustments easier to do.

I see most are ranging from $140 to $250 on Ebay right now. Probably still well worth it if you can afford it. Remember, you will own it for 30 years or more.

-Chris
 
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Hi Phil,
Ahhh, those are using a u-controller instead of a frequency reference and divider chain. I wouldn't count on the accuracy at all. Also, the low frequency count will be a lot slower than the HP counters. Or any counter for that matter.

-Chris
 
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Beware the $85 "8 digit" frequency counters like this one. They don't actually display frequencies with 8 digits except in very rare cases, near the upper limits of a frequency band. Otherwise you get five or sometimes four digits on the display.

As soon as I discovered this limitation, I abandoned the cheapie counter and bought a reconditioned HP5335A for $340 from diyAudio member John Bau (his site is linearz dot com). 200 MHz, 12 digits, now THAT'S a frequency counter.

My application? Measuring the values of small (15 nH) unknown inductances by resonating them with a known capacitance, and measuring the resonant frequency on the HP frequency counter.

diyAudio thread: Measuring the ESL inductance of electrolytic caps (at 10 MHz!)
 
I'd strongly suggest using or adding a soundcard and software approach - I know that REW software can automatically lock on to and determine frequency of signals in spectrum mode, including harmonic levels when there is a dominant signal, and also noise levels. A picture (plot) can be worth a thousand discrete measurements - so to speak, and it also easily shows up spurious signals above the noise floor that you may not have observed otherwise (as the S/N range is so much larger than a scope, or would ever be triggered by a counter). The sweep capability to give an automated frequency response is just so easy for filter assessment.
 
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