Awesome LED VU meter: Any idea?

Done this, yeah

Well...Done this coolie one today on breadboard and is absolutely stunning display with the different settings selected by jumpers.

Very first project on my PIC 2 Clone which I grabbed a month before! Just burned the provided hex. That's all. But the simple looking circuit become ultra complex on breadboard due to wires all over going to 16x2 LED's.

I would say LMxxxx vu displays are like cheap toys by comparison. In the second picture, you can see the peak hold LED..Line level inputs are used as inputs to ADC. 10K Pot is used for sensitivity adjustments.

Here are the different jumper combinations:-

JP1 Bar/Dot
JP2 log. scale/lin. scale
JP3 Peak hold on/off
JP4 Peak waterfall on/off

Waterfall model is what we see on the original video.

Next phase is to complete this one on a pcb. Now I used only 3mm clear green LED's during testing. My plan is to isolate the 16x2 LED display with 12 point header connector so that I can use different LED panels as replaceable modules. Also female berg strips can be used as LED sockets so that we can remove and insert any LED combination conveniently.

That type of VU meters was used in Sony cassette decks in the early 80's. They had 16 Led's with peak hold function. of memory.

Siemens used to make an UAA 170 IC which used to drive 16 Led's ( not sure if that had peak holding capability )