What is Reddit's opinion of
Frequency Sound Generator?
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This app was mentioned in 4 comments, with an average of 1.25 upvotes
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Great video! For Android users this is the best tone generator I found for the job. The large dials make it easy to tune in to the exact natural frequency of your rattle.
Oh, excellent, I know the TDA2030's alter ego, the LM1875 pretty well, having built a few amps around it in the past.
Those input and output voltage figures both seem very low. Most likely this is the problem you're having. 0.216V/0.038V = 5.68. That's quite a small gain figure. is that with the volume knob turned all the way up?
For reference, my amp I use at home is based on the lm1875, and it uses a gain of ~15. I have a preamp, which will give me about 12X gain as well. My phone, at maximum volume, using this app is about 0.5 volts AC. only 38 millivolts seems very low for a phone to output. This is likely to be part of the problem, but the gain is also pretty low for running the amp without a pre-amp.
Also worth noting is that the TDA2030 with a low voltage power supply (+/-12V is fairly low voltage for a power amp) will likely not put out a great deal of power. Given you seem to be running potentially high impedance speakers out in the open (which will make them quieter than if they were in a box), with a very low input signal, and low gain, this combination of factors is leading to a very low volume.
If you check out the datasheet for the TDA2030, it guarantees an output of 12 watts into 4 ohms, and 8 watt into 8 ohms, using a +/-12v supply. you will need 4 ohm speakers, and likely a source with higher output to get a good level of volume.
One more thing you can take a look at for me if you'd like, is the gain resistors. This diagram from the datasheet shows the ones that control gain. if you can measure the values of these two, we can be sure that it's the amp's gain that's to fault for the low output. We can also raise the gain if you're game to solder in some new resistors. For your use this is the datasheet for the part you have, and it might help to read a bit about it, even if it doesn't all make sense to you, datasheets are always your friend. There's plenty of useful info, that even a beginner can get their head around.
If you can find the gain resistor values for me, we can sort out new values to boost the gain for you, so you're able to get the most out of your low output source.