(newbie) first filter design schematic check

[jilski]

Hey DIYers,

I am new to this forum and pretty new to analog electronics, although I do audio programming as day job. I would like to build a simple state variable filter (variable f, Q and choice of LP/BP/HP), which goes into a soft clipper using diodes and came up with the following schematic.

I took the components mostly from the ESP pages and the filter itself works on breadboard. My question is, did I do the right thing interconnecting those components? filter -> clipper using a 3 way switch and then a buffer before the final audio output? Also, did I do the bypass switching correctly?

The power supply is from the "Joe Cheep" compressor schematic so I guess it won't need commentary.

I would greatly appreciate a quick look and comments. This is just one channel of a two-channel version, but the other channel is completely separate and otherwise identical.

 

[jilski]

Two more questions I would appreciate help with:

1. if an LED is strapped across +15V and GND in the power supply (including series resistor), will it cause any offset that will negatively impact the op amp functioning? Relative to the -15v.

2. are JFET op-amps good a good choice in all of the positions? It still puzzles me to where they perform better than BJT ones. Im planning on using the types of TL072 or OPA2134

I hope it's ok to post such noobish questions among this board, but I wouldn't know of a better place to ask. Thanks and please have patience with me