I will give it a try and let you know. Thanks.
ryan williams wrote:
ryan williams wrote:
> the two non-output 2n2222s would be the differential pair. Those two
> transistors set the cutoff frequency. what happens if you connect a volt
> meter across the colloectors of these two transistors, then adjust the
> frequency pot. The voltage difference between the collectors (also
> across the diode string) should increase as the pot is increased.
>
> also, check the voltage at the center of the diode string. This should
> be around +6V and will only change a small amount as the cutoff
> frequency changes.
>
> check that the emitters of the 2n2222s (differential pair) are about
> -0.65V. make sure that the voltage at base of the 2n2222 on the left
> side increases a small amount as the frequency pot is increased.
>
> you can do all these tests with no audio input. These just check the
> biasing of the diode string. so, what results do you get?
>
> -ryan
>
>