[sdiy] MS 20 FILTER

[harrybissell]

Hi Diogo (inline)

synth DIY wrote:

> hi! i have this MS 20 filter project to do and i've been have some
> problems:
>
> in this schematic i don't really understand the meaning of the symbol
> in the output of U1a and U1b.

This symbol means the output at this point is a current source, not a
voltage
source like most outputs...

> "Vr" voltage is the ground voltage?

Vr = Vreference. Tie all Vr points together... the junction of the 100K
resistor,
LEDs and the 10uF cap (+) is the source

>
>
> between pin 7 and 8 ( and 10 and 9 ) it's a buffer circuit. should i
> use any specific kind of buffer?

The buffer is inside the chip between the pins listed...

>
>
> Lm 136000 datasheet is not available, but i found a
> http://www.datasheetcatalog.com/datasheets_pdf/L/M/1/3/LM13600.shtml.
> is it the same?

LM136000 ??? (typo?)
LM13600 is the right number.  Also NJM13600  (different manufacturer,
same chip)

H^) harry

>
>
>
> thanks
> Diogo
>