NPN Booster completed ...& pics!!!

[siaoguitar]

Finished the booster for the 2nd time!! yea yea...

here it's:




the rest: http://community.webshots.com/photo/193638340/545562686nfHPbv

[aron]

It looks GREAT!

[siaoguitar]

Thank You Aron!
                       Still thinking of putting the circuits in different enclosures like mint tins....etc...It's so fun man!!
Aron, i got a strange problem with this npn, when i max the vol, and turn the gain 3/4 way up, i get a continuous who....wee... sound.

And sometimes with both vol & gain maxed, i get TREMOLO effect, whatz up with that?

Need some advice..Aron

[aron]

>Aron, i got a strange problem with this npn, when i max the vol, and turn the gain 3/4 way up, i get a continuous who....wee... sound.

I have never heard of this happening, but I would guess it's oscillation. Try and keep the signal wires very short and if necessary, shield the input and ouput (ground only one side of the shield).

[siaoguitar]

Hi Aron,
          you mean ground either input or output jack is it ?

[aron]

I'm sorry. What I meant was use shielded cable for the input and output wires from the circuit board to the switch and from the switch to the jacks. Only ground one side of the shield (board side for wire going to switch, jack side for wire going from jack to switch) and see if it helps.

[windwaker]

Hate to be such a noob, but eh, what schematic did you use?  The only NPN boost schematic I've found has only one pot. 

[siaoguitar]

Hate to be such a noob, but eh, what schematic did you use?  The only NPN boost schematic I've found has only one pot. 

The usual one man, did you see the 100k pot for volume? that's the one!!!

[windwaker]

http://www.elixant.com/~stompbox/smfforum/index.php?topic=763.0

This one has only one pot for volume, and yours has added gain.  Did you just swap out a resistor for a pot?

[siaoguitar]

I guessed so......variable - adjustable.....

[windwaker]

Your pedal has two potentionmeters, one for volume and one for gain.

This one only has one potentionmeter.  Where did you use an extra one?

[siaoguitar]

Your pedal has two potentionmeters, one for volume and one for gain.

This one only has one potentionmeter.  Where did you use an extra one?

That's the 100k pot for volume.

[woulfer]

I have to agree with windwaker here, if I click the link you listed,

http://community.webshots.com/photo/193638340/545562686nfHPbv

I see two knobs, one titled "Vol", and one titled "Gain". In the schematics, I only see one variable resistor in the schematic.

[aron]

He must have wired the 100K as a volume pot.  10uF to outside lug, wiper to output jack, other outside lug to ground. Reverse outside lugs if backwards.

[woulfer]

Thanks for the explaination, Aron. That makes sense.

Nice job, by the way, siaoguitar.

[siaoguitar]

yo guys,completed now:

http://community.webshots.com/photo/193638340/545562686nfHPbv

[alvintang]

sorry for being a noob..but i still dont get it.
can anyone who has added the volume pot post some pics on how u do it?
thks heaps!

[KORGULL]

sorry for being a noob..but i still dont get it.
can anyone who has added the volume pot post some pics on how u do it?
thks heaps!

I'll elaborate on Aron's description to hopefully make it clearer:

aron wrote:

He must have wired the 100K as a volume pot.  10uF to outside lug, wiper to output jack, other outside lug to ground. Reverse outside lugs if backwards.

You see the 100K resistor that is between the 10uF cap and the output? Replace it with a 100K potentiometer (preferably audio taper, but linear is okay too).

Break the connection between the 10uF cap and the output jack.
Connect one of the pot's outside lugs to the 10uF cap.
Connect the other outside lug to ground.
Connect the middle lug (also called 'wiper') to the output jack's tip lug.

If the volume works backwards - so the level gets lower when you turn it up - that means the two outside lugs need to have their connections swapped.
Here is more info on wiring pots that may help you get the connections right the first time: http://www.diystompboxes.com/cnews/FAQ.html
Lug 1 is the one that usually connects to ground.
 Hope that helps.

[alvintang]

thks for the help mate, really appreciate it