Celsius input buffer, bicolor led & dpdt as bypass

[Riccardo Turacchio]

Hi folks! Almost finished to build my Celsius, just waiting fo some caps and a metal can 2n2222A...so in the while I decided to check here on the forum for possible issues with this circuit and seems like a common problem is a treble drop when switched on high sensitivity mode
Many agreed that a solution would be a buffer before the input....
So my plan was to use a simple 3 X mixer before the preamp input and I was wondering if working with the right resistor values could be enough as buffer stage or would be better to use also a circuit like the simple jfet buffer or kliche buffer??

Here a schematic of the mixer

 

[Riccardo Turacchio]

I was reading somewhere that is possible to use a dpdt as bypass instead of a 3pdt
Cons....no more led for the status....in my case that wouldn't be a problem because what I'm building is more a "desktop version" than a stompbox...
On the other side I would be more interested to include a bicolor led that to goes from green to red when level is at max...
Suggestions ?

 

[Riccardo Turacchio]

Anyone?

 

[jwin615]

I swear
A color changing led when level is at "max" would be a clipping indicator circuit, I suppose. Unless you just want the LED to change colors when the level knob is fully turned clockwise.
If you search the web for "diy clipping indicator circuit", you'll find some schematics. Also, you'll need to define what "max" is, electricity. There are different designs of varying degrees of crudeness/complexity.
It's probably going to be more trouble than it's worth though.

As for darkness/buffers:
If you are referring to the 3 channels mixer project here on PPCB, that will work fine as a buffer. Though, the necessity of a buffer is likely dependent on the impedance of the incoming signal. If you don't need the mixer, you could always try it first before commiting to it. You're basically switching from an opamp input buffer to a transistor input buffer with the hi/low switch. Those are going to sound a little different and have different input Z, to an extent.

Hope this helps