Hey gang!
IM trying to get my diy ampeg octaver to work a little better and am comparing it to the chopped oc-2.
The ampeg doesnt have the Ge diode like the OC-2 and was wonder what its purpose is.
Does anybody know what it does?
Thanks! :)
It does change the sound, in fact the diode characteristics change the sound quite a bit.
The octave sound is smoother and stronger.
The diodes change the reference point that the inverter flips around.
Without diodes
- Draw a three cycles of a sine wave.
- Redraw the waveform with the phase of the second cycle inverted.
The waveform will have two -ve humps in the middle, followed by
two +ve humps. You can see this waveform will have an f/2 component.
With diodes:
- Draw three cycles but this time shift the sine wave up so the -ve peaks are now at zero.
- Now invert the second cycle about the DC =0 line. You should see that the level of the peaks are twice as high,
and the waveshape is more like a sinewave at f/2. There's no sharp notch which
makes the sound more buzzy.
In reality everything sits Vcc/2 higher DC wise but it's easier to see the way I've explained it.
Anyway that's the general idea. It's a neat trick.
Cool! That actually makes sense. I have a couple other octave schematics with the diode in their and wondered what it did.
Now I can do my layout.
ty. :)
Anyone else that've trouble visualizing this?
Rob (or someone else who "sees it"), could you be bothered to do an illustration?
http://moosapotamus.net/IDEAS/stompboxology/Vol13No3/Page_03.gif
Quote from: Taylor on February 07, 2011, 03:14:48 AM
http://moosapotamus.net/IDEAS/stompboxology/Vol13No3/Page_03.gif
Thanks.