Here's a quicky for your Saturday. The Blue Clipper was one of the small effects units by Dan Armstrong that plugged straight into your guitar output jack. It uses one side of a JRC4558 to produce a basic distortion effect.
The perf layout is verified. I think you might need to reverse the PCB image if you are etching.
Since there are a few versions of the schematic, I checked the comments for the effect on the vero site as well as Run Off Groove's archive at home-wrecker.com. I then breadboarded the circuit. Here's what I found:
-The 20k/240k resistor combo doesn't work. 200k/240k, 22k/27k and 22k/22k work nicely as a distortion. 22k/100k sounds mis-biased and kind of fuzzy, but at least passes sound. -With the 2.4k resistor, you will have about unity volume at most. Other people changed the resistor to 150R. I went with a 240R resistor, thinking someone may have misread the value when tracing it. Either 150R or 240R gives plenty of volume. -The 33nF cap muffles the sound too much for me. I lowered it to 3.3nF as suggested by Run Off Groove. -If you want a tone control you can easily put in a SWTC by replacing the 10k resistor and 33nF cap with a 10k pot with a 6.8nF or so cap from lug 2 to ground. -I tried using a 250k pot in place of the 150k resistor, but the guitar's volume knob works well enough as a gain control.
This circuit sounds pretty good, especially for how simple it is.
how do we add gain control in this?
ReplyDeletemy guess would be to replace the 1m resistor with a B1M potentiometer
DeleteThat 1M resistor is just the pulldown resistor at the input to reduce footswitch pop. Try replacing the 150k resistor with like a 250k pot.
DeleteIt works only according to the original circuit, where the 8.2K resistor is included in the diodes.
ReplyDeleteweird that whoever made this layout didn't invert the word Blue Clipper for etching the pcb
ReplyDeleteThe perf layout is verified. I think you might need to reverse the PCB image if you are etching.
ReplyDeleteSince there are a few versions of the schematic, I checked the comments for the effect on the vero site as well as Run Off Groove's archive at home-wrecker.com. I then breadboarded the circuit. Here's what I found:
-The 20k/240k resistor combo doesn't work. 200k/240k, 22k/27k and 22k/22k work nicely as a distortion. 22k/100k sounds mis-biased and kind of fuzzy, but at least passes sound.
-With the 2.4k resistor, you will have about unity volume at most. Other people changed the resistor to 150R. I went with a 240R resistor, thinking someone may have misread the value when tracing it. Either 150R or 240R gives plenty of volume.
-The 33nF cap muffles the sound too much for me. I lowered it to 3.3nF as suggested by Run Off Groove.
-If you want a tone control you can easily put in a SWTC by replacing the 10k resistor and 33nF cap with a 10k pot with a 6.8nF or so cap from lug 2 to ground.
-I tried using a 250k pot in place of the 150k resistor, but the guitar's volume knob works well enough as a gain control.
This circuit sounds pretty good, especially for how simple it is.