Surf PI: Audio tone mod?

[douglas]

I love the surf PI that I built on the longboard, but the pitch coming out of the phones drive me crazy. As a matter of fact I have altered the tone on my white's detectors sop that it is a lower frequency. How do you do this to the surf PI in the Non VCO version?

[Comp]

Hiya!!!! Bit low, aint it??!! LOL!!! The tone (AFAIK) is taken from the initial oscillator that feeds the FET...... so tweaking R1 (100K) should tune it, or C1 (22nF), I think I have tried my board with a 10nF in, and it went up to about 1300 Hz,.. (I have very limited/restricted hearing range, so was fiddling with it....)


Hope that helps, Cheers, Fred

[douglas]

I soldered 33 nf onto C1 and got the tone I'm looking for. You want it to be higher and I want it lower, I like the bumble bee sound, Thanks Fred.

[TH Jim]

Hi Guys,

You are also altering the transmit frequency by making these modifications - have you noticed any change in performance??

Regards Jim.

[homefire]

Yea, this slows down the whole timing chain, Right?

Your going to have to adjust your sweep speed too.

[douglas]

I know that it has slowed down the frequecy

But its a temporary change for now. I have to find my notes and do the tuning process over againd and check the flyback. It still detects a ring in the air at the same depth though inside the house, It is very cold here so I am limited, But I remember the adjustment on the Hammerhead project for the frequency also changes the speaker pitch.

I remember when I built the Surf PI there was a trimmer that was adjusted for a voltage reading. Thats what I want to go over really after making the frequency change. Ajusting for flyback is an easy thing to revisit and is board adjustable.

[Tibuck19]

If I understand right , if I change the value of C1 it will change the sound ? also it will change the delay ? I want lower tones rather then a high pitch squeak as it doing now.