I bought this generator (20 $) with TL 072 OpAmp. Only waves up to 2 kHz were ok. When I changed OpAmp with the Texas Instruments 5532 Sinus wave is very good up to 400 - 450 kHz, triangle - up to 150 kHz, square - up to 80 kHz. "Myfriend" from China gave me back 8$ - finally it cost me 12 $. Two OpAmp Texas Instruments = 0,6 $ ( price in Poland :) )
I got the KKMoon from Amazon uk today aug 2019, it says final version on boot, and a sine at about 600kHz starts to show tiny harmonic distortion but clean below that. Square wave only sharp to about 10kHz @8usec/div...pretty good. The filter drops the voltage a bit to clean the sig depending...for £20, can't complain..pleased actually..chip = Atmel ATMEGA88PA.
I have the same FG 100 DDS generator and can get a decent sine wave up to 500kHz but the square, saw, etc, become very distorted after 100kHz. Just purchased (April 2022) so it looks like the firmware has been upgraded. Also, an EKG wave has been added.
I have the same function generator and got the same problem with bag output. Tl072 are counterfeit (working in class C=Crossover distortions) and after replaced them with ne5532, the signal it's perfect until 500 khz.
That generator doesn't get anywhere near its claimed specs. Yours isn't the only one with bad output. Check out the review section on the listing page. Others uploaded pics of their bad waveforms, too. Post your review with a link to this vid.
Peter Ridge Well I wasn't expecting much and it didn't deliver much. Limitation is the processor. Atmega doesn't have a very high clock speed. It would be fine for audio work but not good enough for much else. I did a review on a dc-dc converter that performed to spec. That one will be up soon.
That looked so good at the start, but quickly showed it's utter pointless use as a audio generator later on :-( :-(. That's a real shame, a waste of parts :-( I have an ancient icl8038 based 0-200khz generator, it copes better.
That 20hz signal is like Tetanus problem not nice, would have been better if they had used a Texas Instruments DSP processor rather that what they used.
Oh that is an oldie! They published designs around that when I was in school! (and that was in the 80s') I made the Elektor design, still have the unit and it still works! It has no trouble at all getting up to 100 Khz, 200 with a few mods. It was a fairly expensive chip back then, but even so it was well worth it. Cheers Paddy
Good test ! Thought I could use this thing as a 455 Khz IF signal source, but obviously not ! 🤥
I bought this generator (20 $) with TL 072 OpAmp. Only waves up to 2 kHz were ok. When I changed OpAmp with the Texas Instruments 5532 Sinus wave is very good up to 400 - 450 kHz, triangle - up to 150 kHz, square - up to 80 kHz. "Myfriend" from China gave me back 8$ - finally it cost me 12 $. Two OpAmp Texas Instruments = 0,6 $ ( price in Poland :) )
I have the same Generator and I do not get any distortion like yours does. Try using a 50 Ohm cable instead of open leads
I got the KKMoon from Amazon uk today aug 2019, it says final version on boot, and a sine at about 600kHz starts to show tiny harmonic distortion but clean below that. Square wave only sharp to about 10kHz @8usec/div...pretty good.
The filter drops the voltage a bit to clean the sig depending...for £20, can't complain..pleased actually..chip = Atmel ATMEGA88PA.
I have the same FG 100 DDS generator and can get a decent sine wave up to 500kHz but the square, saw, etc, become very distorted after 100kHz. Just purchased (April 2022) so it looks like the firmware has been upgraded. Also, an EKG wave has been added.
I have the same function generator and got the same problem with bag output. Tl072 are counterfeit (working in class C=Crossover distortions) and after replaced them with ne5532, the signal it's perfect until 500 khz.
Well it gets better, but max acceptable results (with square/triangle/sawtooth output) are up to ~100 kHz with ne5532. Stil not 500 kHz as stated
Really appreciate your doing this extensive test. Guess I'll stick with my Casio SK-1 for generating sine waves.
I've been using an iphone app out of the headphone jack. How would that compare do you think?
The app should produce a clean sine wave. Another way to do it is with audicity, and just create a file of the tone and play it back into your amp,.
you are better off frying a 20usd FG than a phone :) ask me how I know.
That generator doesn't get anywhere near its claimed specs. Yours isn't the only one with bad output. Check out the review section on the listing page. Others uploaded pics of their bad waveforms, too. Post your review with a link to this vid.
Peter Ridge
Well I wasn't expecting much and it didn't deliver much. Limitation is the processor. Atmega doesn't have a very high clock speed. It would be fine for audio work but not good enough for much else.
I did a review on a dc-dc converter that performed to spec. That one will be up soon.
What do you expect for the price. Useful for generating low frequency for centering speaker cones when redoing the foam.
Yup, it's good to know what not to buy.
how do we adjust the duty cycle ?
for testing homemade audio amplifiers will be just fine I think
That looked so good at the start, but quickly showed it's utter pointless use as a audio generator later on :-( :-(.
That's a real shame, a waste of parts :-(
I have an ancient icl8038 based 0-200khz generator, it copes better.
So does my old HP from 1963. It goes up to 600KHz nicely.
Yep propper test gear :-).
Would be fine to use for speaker repair as you only need 40-50 hz to center the cone for surround foam replacement.
That 20hz signal is like Tetanus problem not nice, would have been better if they had used a Texas Instruments DSP processor rather that what they used.
Try living with it 20/7
Hi
Is there a way to hack to make it auto boot into 60hz each time its powered onn?
Sure just break into the code edit and recompile it.
@@12voltvids ok so where in the code is the default frequency set please ? you know ? thanks, dave
@@dave11674 how would i know that? Did I design it and write the code? No.
I Have a suggestion for a future video.
An XR2206 based unit. eBay is full of kits
Oh that is an oldie! They published designs around that when I was in school! (and that was in the 80s') I made the Elektor design, still have the unit and it still works! It has no trouble at all getting up to 100 Khz, 200 with a few mods.
It was a fairly expensive chip back then, but even so it was well worth it.
Cheers
Paddy
Where's the freaking battery?