Listening to it now
. I am no hifi guy (lacking the ins and outs). Note that this is not a hifi amplifier, nobody labelled like this.
I tried, as hifi guys asked for it, to see the answer of a rectangular signal at 10kHz. I could do it only to 7kHz, see the attachments for input signal and output signal. The hifi guys asked me to decrease the 33uH inductance to about 15 or even 10uH. I did not do it, as it sounds OK for my hearing (found out lately that fairly low volume - shall I say like whispering - signals above 15-16kHz are not anymore heard by me). I intend to use it as a 5-10W ambient music. Actually I drive some satellites at 6ohm. I am looking for some shelf speakers to match this "raging moster".
I even input sine from 50 to 20kHz, mine it shown like attached. About -3dB attenuation at 20kHz. See the out_1.JPG below. Like I said in my original message, I should test the frequency response with a better generator, but I do not have one available for the moment. Some other guys on the Internet had it linear in 20 to 20kHz. See here: http://www.360customs.de/en/2014/08/max9708max9709-25w50w-class-d-messungen/
I built for it a Baxandall preamp (the 10dB version of ESP) powered by single supply. Works great too. Even built a clipping indicator, but not tested yet so I will not publish it yet.
I bought Hammond box (model 1455T2201) to house it as final product sometimes soon. I will connect it to a 20V laptop supply.NOTE: The diode in the ground pin of the 78L05 was intended to provide additional 0.6V to the output of 7805. It is wrongly shown on schematic. I finally put a 78L06 and jumped the diode. Beware!
For the records, my audio experience is limited to:
1. A TDA2030 amplifier built in the beginning of the 90s.
2. The Universal Tiger amplifier built in mid 90s.
3. The TDA7294 amplifier built in late 90s.
4. The MAX9709 and TDA2050 amplifiers built last year.
Well, this tells you about my experience with amplifiers.