Scramjet PIF build

[arikam]

Hi all,
Thanks to ddog I got to build this nice OD.
I probably should have not put the power socket straight in the middle.
It has a nice range of crunchy tones and a versatile yet simple tone control.
Only one problem, for some reason I get a noticeable hiss I haven't been able to fix. 



Thank you ddog, I had a lot of fun putting this creature together!

[Luke51411]

Nice build! What charge pump did you use? They can cause hiss if they are not switched frequency.

[Droogie]

That's a nice layout for the Scramjet! What LEDs did you use? I went with blue, white and red. It's a great drive.

[arikam]

I used the LT1054 charge pump and also the blue, white and red leds.

[RobA]

Cool graphic! It's appropriate because it's just the sort of ting I would have loved when I was a kid.  I like the layout in that orientation. One question, how did you fit that in there?

If the LT1054 is putting out the right voltage and otherwise working correctly, I can't see it as the source of the hiss.

Is the hiss tied to either of the gain control settings?  I can't quite make it out in the photo, but I assume that's the LED ground from the stomp switch coming across near the input connection point. Is it possible that it's close enough to cause some radiated interference? The gain stages have quite a bit of gain before it's cut back down by the clippers and the tone control section. Interference or noise on the input might get boosted up to be fairly audible and then not cut by the clipping section.

[Hogharry]

Nice build. Hope you can get rid of the hiss.