AMZ MINIBOOSTER BUILD REPORT !

[LMJS]

Caferacernoc

"Cafe Racer Norton Owners Club" by any chance?

[Caferacernoc]

No, but close. I started using Caferacernoc as my "handle" for forums, IM and whatnot about 6 years ago. I had a network support job and everyone in my office chose AIM names ending in NOC. I am into caferacer style bikes, I currently own a '72 Honda CB750 cafe'd out, so I became caferacernoc.

[dmc777]

Wow! I'm the first person to build the mini booster since 08!  The page was linked to me when I purchased the board. It's supposed to be the help page and I'm confused. If anyone has the newletter, at the very bottom right of page 8/20 shows the booster with a 100k gain pot and a paralleled "Rx".....Could someone please tell me how to wire this? In order to do it you have to delete some of the other components and I'm not sure which ones to change. I'd like to be able to blend in a little gain with my booster. I may add some diodes as well.

Also, Is there a way I can hook up an spst switch that will allow me to turn the buffer on or off? Any help would be much appreciated. I purchased the newsletter thinking all of the schematics on there could be used with the minibooster.

[Renegadrian]

Wow! I'm the first person to build the mini booster since 08! 

... the booster with a 100k gain pot and a paralleled "Rx".....Could someone please tell me how to wire this?...

I haven't got that newsletter, but looking at the AMZ schem HERE I guess the gain pot should be wired as it's on a Fuzz Face - take that schem for comparison, it should follow the same method. As for Rx, I can't know its value...
Hope that helps!

[dmc777]

http://www.muzique.com/amz/miniboo.gif

On this minibooster schematic I'm referring too pretty much everything has been changed. Does Aaron chime in on here? It is his schematic.

[dmc777]

I just looked and it's nothing like the Fuzz Face or any other pedals of his I saw. It says the Rx resistor is used to modify the taper of the drive control pot to yield more useful response. It should be equal in value to R2 or less for best results. Damn I wish I could just pot this schematic.

[Renegadrian]

How can you say it's nothing like the Fuzz Face!
A res and an electro on the emitter is a common way of getting gain from the tranny. Look at how the ELECTRA or better my rendition ELECTRADRIAN works - If you look better at a FF schem like THIS ONE, you'll agree that it uses the same way to manage gain. Said that, my best advice is to try to replicate that way, so have a 1k-5k pot and wire the electro accordingly.

EDIT: Obviously you ain't got emitter here, but the same method apply to FETs as well (so in miniboosters, Tillmans, ecc)

[dmc777]

Yes it is similar to the top fuzz face except the pot goes before Q1 and I don't know which path to take. The gain pot is devised and controls an input divider and the source feedback. Signal goes in, C1+ through 100k which carries straight to the Q1...but inbetween the 100k and Q1 attaches the positive lug, I assume, of the 100k drive pot....which has Rx resistor on the ground lug and middle lugs going to ground and the other goes to C2 and R2 to ground which come from the Gate of Q1. Bare in mind this schematic really looks a good bit different. That's the best way I can describe it. Below is pretty much what the schem says.

One section of the drive control resistance is forming the ground leg of the input voltage diveder and the remaining section is providing series resisistance to ground for the Q1 source through C2. The input divider network is dominating the control repsonse until the wiper is moved close to C2, at which point the paralleled resistance of the drive pot, R2 and Rx begin to increase the gain.

The Rx resisitor is used to modify the taper of the of the drive control pot to yield a more useful response. It should be equal in value to R2 or less for best results.