T&L Publications

From your scope PIX the "noise" isn't noise, its 60Hz AC leaking in somewhere. True. So the goal is to clip the input peaks symmetrically? Yes. This is a necessary condition or it sounds harsh and 'unmusical'. So the clipping is hard not soft (as seen in an overdriven tube/valve amp)? Not...

My experience from work with IP based Audio/Video suggests excessive jitter in the packet stream. Depending on the video encoding method (and I don't know what digital TV uses), the pix may be tolerant of a late packet (e.g. MPEG-4 interpolative encoding, etc.), but the audio can't fill the gap. The...

Thanks for the questions. Actually, except for the AC noise, the box works quite well. high degree of control over the sound quality and degree of distortion. I get good general control over degree of fuzz by the drive pot (10K) output from input Amp A to the diode clippers. But if I want extreme fu...

Not at the project at the moment, but R1 is either 100K or 1Meg, I think, and just added to make sure the Fuzz on LED path in the 4053 switch is not floating with Fuzz off. R2 is somewhere in the range of 470 to 680, to current limit the diode. C8 is a local bypass cap for the 4053, probably 100pf.

Thanks for the replies. Some clarifications: the box labeled U2 is just the +/- voltage source for the 4053 electronic switch. I eliminated the power supply part of the schematic from the diagram for clarity, as it is just a vanilla 7805 / 7905 dual supply. I do have high freq filter caps on both ra...

I'm working on a 'Fuzz box' for a bass guitar, ckt diagram below. With fuzz on and gains up, I'm getting a strange (to me) AC artifact -- Oscope images below (AC waveform from isolation xfmr at 10V/div, signal out at 2V/div). With fuzz on, and the input shorted to ground, the artifact is timed to th...

Well, certainly wouldn't pay $500 for a kit, but it might be a fun project to build from scratch. Even more fun to do it without a uC.

Also seems a lot like some 'cute' homework assignments I've had in a college class (way back when).

Thanks for the pointers. I'm just getting back into hobby building after many years away. Built a 317 based variable bench suppy many years ago and thought it would be a useful 'return' project to do something similar, but with based on modern approaches. Thanks again for the links, I'm sure I'll ha...

Can anyone point me to a circuit for the above? I want to get switching mode efficiency, but also variable output voltage. Thanks.

Just used a 4053 for the same purpose -- switching audio signals. $0.37 each at Jameco. You can also use a 4016/4066 which are SPST, but the 4053 gives you essentially 3 DPDT switches. So, you can switch the input to audio processor A or B then back to a common output using another of the 3 switches...

Thanks for all the input. Problem solved. Simple dumb @#$ wiring error.

7905 pin out is not the same as 7805. Surprised more stuff didn't smoke.

The circuit diagram is exactly as Steve G posted. I.e. simple, simple, simple. (I'll have to figure out how to post these kind of diagrams later). I've replaced all the caps and both the regulators, thinking there was a bad component, but with no change in the symptoms. Maybe something to do with di...

I'm having trouble with the power supply portion of an opamp circuit I'm working on. The supply is +/- 5 Volt using 7805/7905's. Half wave rectifiers provide the unregulated input with 1000uF input caps and 100uF output caps. AC is supplied by a 13VAC 'wall wart' with no center ground tap. Any load ...