planning to build audio gear--HELP

[MrDEB]

planning on building a lm3886 chip amp, a BA3812L graphic equalizer and a VU bar graph meter(lm3914/15/16??)
which goes first the equalizer then the apm then tap into the outputs for the vu meter??
which bar graph driver chip=3914,15,16?
buying the lme889 chip amp kit. just need toriod transformer.
designing pcb for all but amp and power supply as the kit has these.
need advice etc.

 

[audioguru]

The LM3914 is a linear voltmeter. Low level audio is down only 20dB and the steps are huge. The steps at the loud end are crammed together.

The LM3915 has a logarithmic response the same as your hearing. Its lowest LED lights when the output is down 30dB (1/1000th the power) and each step is +3dB and is double the power. I have one with two LM3915 ICs cascaded for a 60dB range.

The LM3016 is an odd-ball. The low volume steps are far apart and the loud steps are close together, something like an LM3914.

The datasheet for the LM3915 shows two Peak Detector circuits. Without a peak detector then the level is jumping all over the place in real time which results in the LED display being a dim blur. The peak detector has a fast attack then a slight delay before dropping so your eyes can see the peaks.