Well, had a few hiccups but I make do with what I have. The PS that I wanted to use would no longer power up so I sent that back to Instek to repair. That was 2-weeks ago, haven't heard from them since. So I pulled out my older unit instead. Works fine although the slave tracking voltmeter is a bit off and needs adj. No bigge, the primary channel is spot on and that's the supply I'll be using anyhow.
So first off, I tested the radio I intend to use for the project. I have removed the housing before and it looks like relocating some switches and maybe the rotary encoder will allow the unit to be installed in my project and also retain a tuning "knob" for those that likes to play with knobs. That includes ME. I hate up/down buttons.
First test, current consumption:
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With 12v source, consumption was 20mA in off position, and 730mA in operation. Although this will allow battery operation, if constantly connected to power to retain memory, standard alkaline batteries will be exhausted in 21 days. Obviously, for long term storage with batteries, this unit will need to be divorced from batteries with a hard switch or else you'll just be wasting good batteries. In operation, this unit will consume 8.76 watts. D cells will last only about 11.5 hours. Luckily, this module can be powered off with it's own power button. If used in the boombox, then this module should be powered off if the unit is operated in other modes. At this rate of consumption, it is prudent to keep this module idle if it isn't actively being played. Of course when on AC mode, it looks cool to be ON all the time. Ah, such is the downside of digital gear, needs to be always in active mode. An analog tuner would be far more thrifty but shoehorning one of those is much too challenging and beyond the scope of this project. However, the upside is that I've found that these tuners are extremely good performers. Far better than most boomboxes.
OK, next module is this MP3, bluetooth device that can accept USB thumbdrives or SD cards.
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I'm measuring only 30mA during operation, so this is a very thrifty module. With amplifier hooked up and "cranking" at a good clip, I see 730mA but that is just an instantaneous photo capture. The actual usage varies with the dynamics of the music between 40mA to over 3.0A (blips the current led on the PS). This is just a tiny flash so it doesn't dwell there very long.
This module is supposed to have bluetooth but I could not get that feature to work. Not really a problem because that's not why I got it. Rather I wanted an MP3 module that included a working display so I would know what I was playing. There are many that are cheap but you have no clue what you are playing and can only navigate with a Fwd or Rv button -- I didn't want those but suspect that the sound quality of those are similar since these things are almost all based on the same basic designs.. Alas, the sound quality was not good, always sounding like the circuit was either loaded down or something. Either this unit is damaged or it needs a buffer amp to beef up the output before connection to the power amp. That would be suprising since these amps almost all have an input impedance of around 10k ohms. Well, I've got another one on order so I'll know later how to proceed and tackle this, but virtually all this stuff, whether it's connectors, modules, or what-not all come from China. Meaning, at least 2-4 weeks wait every time I need to wait for something else. I still haven't ordered everything I am considering since I'm still wishy washy and undecided about what to use and/or might work best. Again, the challenge, except for the PS, all off the shelf parts that can be duplicated by any idiot here, hehe.