A few questions about the T.M.K

[Blenji]

Hey Guys,

Ive got a few questions about this circuit, Tim Escobedos T.M.K's.



1.   Has anyone built it?
1.a If so, does anyone have a PCB for it?

2.  What are the red LED's for?

3.  Where it says Vr, are all those points to be connected?

Thanks.

[Alex C]

Hey Guys,
Ive got a few questions about this circuit, Tim Escobedos T.M.K's.
1.   Has anyone built it?
1.a If so, does anyone have a PCB for it?

I know some people have built it, but I don't know that I've heard of a PCB for it.  A search for "TMK" with and without periods should turn up some results.

2.  What are the red LED's for?

I'm not sure about the LEDs in this circuit, I believe they're clipping.  P4 is labeled "crossover distortion," and allows one to bypass the LEDs, but I am not qualified to advise you on the nature of Xover distortion. In any case, they are not being used for emitting light, but as substitutes for "regular" signal diodes, chosen for their characteristics over signal diodes.

3.  Where it says Vr, are all those points to be connected?

Vr (or Vref) is a reference voltage used with opamps, typically 1/2 the supply voltage.  Supply here is 9v, so Vr is 4.5v.  The two 100k resistors on the top right of the schematic form a voltage divider, and since their values are identical, the output voltage (labeled Vr) will be 1/2 the supply.  The 10μF capacitor is just for filtering.

All of the points labeled "Vr" will connect together, just like all the 9v points are connected, and all ground points are connected.

You can find more information about LEDs and diodes in the DIY FAQ (click), along with many other topics.
A search for "Vr" or "Vref" here or even Google should turn up more too.

Hope that helps, and hopefully some folks who know what they're doing will chime in. 

-Alex

[Blenji]

Thank you kindly.  Your time muchly is appreciated.

[Dragonfly]

does anyone have a PCB for it?

Marcos has one for it. AFAIK, its verified, but you might want to email and ask him.

http://www.geocities.com/diygescorp/