I recently bought off ebay a (class D AB) "LM3886TF Amplifier Assembled Board" to toy with.
According to the datasheet, LM3886TF can reach THD<0.003%. But, I am more interested to see, from a hobbyist point of view, if it can be made stable enough to be used as an AC source for calibrating DMM (against a known good DMM).
The inputs are very stable sine waves from an LCR meter. The power supply is a Power Designs 5020 plus a less speced old Ondor (that is all I have for now). As to the output stability, no conclusion yet. Has anyone tried similar setup (using classD amp) ?
The cost of this LM3886 board was just under $10 with free shipping. Interesting enough, the 5020 was also bought from ebay after reading an eevblog post about Power Designs PSU. It costed me just under $100 with shipping included. From the reading, the 5020 was supposed stable enough to calibrate DMM's DCV and DCI against a known good DMM.