AMZ Minibooster schemo questions

[petey twofinger]

 i wanted to try a clean boost for solo's i think the amz mini booster may be perfect and fit in the enclosure i have (small one) . i saw this layout and i have vero here but i have a few questions .

http://img100.imageshack.us/img100/8347/xb7ny.jpg



1. on the right it shows "A and B" what is connected to this , the pot ? a switch ?

2. for c2 it is in a blue box , on the legend there is a blue box that states "physical cap size" ??

3. c2 is labeled 1uf BP , what does the BP mean , bipolar ? is bp the same as np ? is this an odd part ? what type of easily obtainable cap could be recommended , would a polarised "work" ?

4. would i be correct in assuming that r6-3 goes to the 3rd pot lug of a 100kA , then lug one would go to ground and the middle lug would go to the output ?



5. in this layout c2 is listed as a 3.3uf np (non polarised?) cap i am guessing this is a hard to find part . if this is correct what would the effect be if using a 1uf bp cap as listed in the first vero layout that i posted have on the circuit ? (putting it together and trying is not an option , as i do not have a 3.3 np , nor do i think i have a 1uf bp)

6. i noticed in a blog a user claimed that this vero here is incorrect , any comments ? he claimed the trannys where flipped . i do not care to socket as this is goingi n a TINY chassis .

7.  could i simply run this at 12 volts without modification ? would that be beneficial ?

thank you very much !

[blackcorvo]

- Have you checked the original schematic at http://www.muzique.com/amz/mini.htm ?

If not, here it is:



It says in the link that points A and B are for mods and future expansion... probably something to do with the boards they sell for this project.


- I took a quick look at the vero board, and it looks right. Only thing that seems misplaced is C4, wich is supposed to go AFTER R4, and not before as it was placed there.

BUT, there's a simple fix for it, and only requires changing C4's position on the board, 1 strip cut and a jumper wire:



Other than that, seem OK to me.
I also have no idea what the "cap size" thing is all about...


- You're right about the Volume potentiometer, as you can see more clearly on the schematic.


- BP means Bipolar, wich is the same as non-polarized. It's not an odd part, you can easly find it.


- There's no problem on running it at higher voltages, as long as you keep it under the transistor's max voltage (wich for the ones listed on the schematic, is usually about 30v... so 24v is the max I'd go with these guys). But if you increase the voltage, remember to use higher voltage caps! 25v is fine if you run it at 9 or 12v, but if you decide to go for 24v, use 50v caps, or just use 50v caps at once. They're not really much bigger than 25v caps...


- You might wanna try a socket for C2, and try both values, or even other values/types of caps. 1uF is from the original AMZ schematic as seen on the top of my post, while 3.3uF is the value used in the Fulltone Fat Boost. For this cap (and also C6, in case you wanna mess with that as well), higher values = more bass and gain, and lower values = more treble and less gain.


I hope this helps you get this little project done!

[PRR]

> i am guessing this is a hard to find part

You got that idea from the text on the diagram. Did you read the rest of it? It tells how to use a polar cap. Which is probably the better plan. The value of the cap is not critical. 1uFd will support bass far below a guitar's lowest note.

[petey twofinger]

excellent info all around .

the socketing concept , i never would have thought to do that because the chassis is so tiny . i have read that many times , i bought a bunch , i just haven't done it yet so i feel like a goof once again . i am sure i could make it fit somehow .

i actually do only have two fingertips to fret (lawnmower), so ideally my circuits should function well for both since i play both . once again socket the caps , and the actives . 

i just didnt have much faith in the last diagram , i did read it , but the pinouts were bad (at least someone claimed that , then i googled the active and it looked wrong too) . i may go with a larger box , and try a fat boostered .



thank you very much !!

[MikeH]

I've always thought the "A B" points were to sub a potentiometer for the 1 k resistor to experiment with different values.

Btw- the Mini booster is not exactly "clean".  I prefer the AMZ MOSFET boost for that task.

[WGTP]

47n - 68n seems popular for rolling off some bass.