User Tools

Site Tools



This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
x0x:vcamods [2007/09/19 07:49]
x0x:vcamods [2016/01/28 18:05] (current)
Line 18: Line 18:
 This also might make a passive filter due to C38.  ​ This also might make a passive filter due to C38.  ​
-  From C38 ----+---- To VR8  +{{x0x:​mufflersmaller.png|}}
-               | +
-              /|\ +
-             O O O +
-                +
-             O O O +
-               | +-----+ +
-               ​| ​   +--+--+ +
-               ​| ​   |     ​| ​  +
-               ​V ​   V     ​- ​ Diodes +
-               ​- ​   -     ^ +
-               ​| ​   |     | +
-              ---  ---   --- +
-              GND  GND   GND +
 === Choosing Diodes === === Choosing Diodes ===
Line 43: Line 29:
 +==== ADSR for VCA ====
 +Posted by [[Guest]] on the forums: ​
 +"while working on adjusting the attack time
 +for the vca envelope
 +i figured i might as well make a full adsr
 +the values could probably use some tweaking
 +and there are some oddities
 +but this seems to work"
-==== Another Overdrive Distortion ==== 
-I think a good overdrive is probably the single best mod for the 303. For a fully adjustable overdrive section I did a circuit based on the same principles as the many stomp box overdrives out there. I just tailored it for the 303. Below is the basic idea of the circuit. The values in the circuit should work well. I took a look at the output level from the VCA on an oscilloscope and found that it's generally about 50mVrms compared to 100mV for the main output of the unit. This is right in there with the levels from guitars etc... so I found the circuit clipped well using values similar to what you find in stompbox overdrive pedals. You could also put the circuit in there post-volume pot and have some control over the drive level (using the 303's volume control). If you were going to do it this way you could obviously just then do it externally like a guitar pedal since it's really just workig on the final output. I spent many hours testing different circuits and different component values and stuff and this was the best case for my tastes. You could bypass the input and output discrete buffer stages (the emmiter followers based around Q1 and Q2). I have them in there becuase I found that for whatever reason I found the sound preferable to what I get when I bypassed them - I like it best with both the input and output buffers. 
/home/ladyada/public_html/wiki/data/attic/x0x/vcamods.1190188188.txt.gz · Last modified: 2016/01/28 18:05 (external edit)