Author Topic: Strange Problem With NPN Boost  (Read 6967 times)

Muaar

Strange Problem With NPN Boost
« on: October 30, 2006, 08:32:15 PM »
OK hopefully someone can help me! I've done the NPN boost with OUT the switch, because I just wanted to see if I could get it working first without one. I wasn't sure where to solder the black (negative) wire of the battery snap, and had seen someone put it on the input and on the ground point also.

I figured I'd plug my guitar in and hold it to see which one works, if any. With the black cord not touching anything and even with the battery OUT it still has the signal from the guitar into the amp but it's not very loud. If i touch the black negative wire from the battery snap to the ground point or to the input, the signal stops all together, after buzzing loudly.  If I hold it to the input on the circuit board, though, it raises the volume of the signal, by about 2x or so. I can't hear any distortion or overdrive, but I have it down pretty low. If I hold the wire here and turn the pot, the signal goes down just like a volume knob.

Honestly this is the first time I've done ANY circuit work, and I just don't know where to go from here.  Any suggestions?

captntasty

Re: Strange Problem With NPN Boost
« Reply #1 on: October 30, 2006, 10:03:17 PM »
When you say you omitted the switch, I assume you mean the bypass switch.  If you are using a stereo jack for the input then you technically could have a power switch.  In this case, the black bat lead would go to the ring lug, another ground wire would go from the sleeve lug to board ground - when you insert a regular instrument cable which is mono, a connection is made along the sleeve of the plug between the ring and sleeve of the jack, which completes a ground path for current to flow, thus turning the effect on.  The tip lug would have a lead going into the input pad of the effect board.  If you're using a mono jack with only two lugs for the input, there is no ring lug, only tip and sleeve.  Tip would go to board input, sleeve to board ground - the neg battery lead would also go to a seperate board ground.  This would mean that the effect is drawing current as long as there is a battery hooked up.  If you ARE using a bypass switch, that's a little different - the tip lead would be routed to the bypass switch.  Here's a bunch of switching options that will make things a bit more clear - wherever you see leads going to a switch, you can leave out and go directly to and from the board.  Hope this helps...
http://www.generalguitargadgets.com/index.php?option=content&task=view&id=172&Itemid=200
It is no measure of health to be well adjusted to a profoundly sick society. - Jiddu Krishnamurti

Muaar

Re: Strange Problem With NPN Boost
« Reply #2 on: October 30, 2006, 10:49:51 PM »
I'm using a stereo input jack and a mono output jack. I'll put the black battery lead back on the ring of the lug and wire it to the ground of the circuit. Could someone post/tell me a little diagram of the parts of the jack? I have a hard time figuring out what's what.

aron

Re: Strange Problem With NPN Boost
« Reply #3 on: October 31, 2006, 02:33:19 AM »
Check out the FAQ, it has a picture of the stereo input jack explained.

Use your meter and measure the voltages on the transistor. You do have a meter right?

http://www.diystompboxes.com/wiki/index.php?title=DIY_FAQ

Muaar

Re: Strange Problem With NPN Boost
« Reply #4 on: October 31, 2006, 05:24:50 PM »
I'm going to go solder it right now as explained above, and I'll measure it also. Hopefully it will work!

Also, I know that a NPN boost will have SOME effect on the signal other than volume, but how noticeable will it be? Will it be just louder or louder/overdriven some? (I have the exact parts from the guide bought at Radio Shack.)

aron

Re: Strange Problem With NPN Boost
« Reply #5 on: October 31, 2006, 06:09:24 PM »
It will make your guitar louder and a little brighter at first, then as the volume goes up, it will darken and have more overdrive.

Good Luck!

Aron

Muaar

Re: Strange Problem With NPN Boost
« Reply #6 on: October 31, 2006, 09:03:10 PM »
OK I soldered it right, the black battery cable to the ring on the input lug, but now when i connect it there is no signal from the guitar at all. If i remove the black battery cable from the ring on the input lug (jack) it lets some sound through, and then if i touch the black battery cable to the input on the board it increases in volume by about 2x. The pot works and increases/decreases the volume as long as the black battery (neg) cable isnt hooked to the ground.

This being my first build, and having read all I can think of, I'd love some advise on how to trouble shoot this and I think by giving you guys this info you can help me determine where the problem is. Is it a wiring problem with a specific part of the circuit? It seems to work if the negative cable of the battery is on the input on the board, and works faintly when the black negative battery cable isn't connected at all, but when I connect it to the ground (be it on the board or on the input jack) the signal stops all togeather.  The pot seems to work fine, so I don't think its a wireing problem on that end....


Thanks in advance,

aron

Re: Strange Problem With NPN Boost
« Reply #7 on: October 31, 2006, 09:29:37 PM »
It's some sort of wiring problem - somehow you have a short or something happening. Can you post a picture?

You need to proceed slowly and take a good look at what you soldered vs. the pictures. Did you use perfboard? Did you substitute any components?
« Last Edit: October 31, 2006, 09:31:39 PM by aron »

Muaar

Re: Strange Problem With NPN Boost
« Reply #8 on: November 01, 2006, 12:25:41 PM »
I'll post some pics soon. You'll have to excuse my horrible wiring skills, its my first project. The only thing I can think of is it's a short that is somehow going around the ground part of the circuit making it silent when i power the ground. Hopefully with pics you guys will be able to help me figure out what's the problem.

Muaar

Re: Strange Problem With NPN Boost
« Reply #9 on: November 01, 2006, 01:46:40 PM »
Haha, I just realized I made a typical overlooked mistake. I forgot to plug the transistor into the transistor socket we made!  :icon_redface: I did that and connected the negative bat cord to the ground on the input jack and BINGO! Works like a charm, and sounds great with my Boss SD-1 into my old Ampeg VT-22.

Any recomendations on a next project for a beginner? I was thinking about doing the Green Ringer Octave pedal, because I need one anyways, and it looks simple. I want to eventually work my way up to a professional Fuzz and hopefully a tube overdrive (Hotbox rings a bell - if I can't buy an origional.)

I'll post some pics of my ugly-but-functioning board later tonight, and hopefully I can get some tips on wiring better, so I'll be able to fit it into a box next time. I'm thinking of rewiring this one to fit it into a box now that I've got it working.

Pics to come when I'm off work.

aron

Re: Strange Problem With NPN Boost
« Reply #10 on: November 01, 2006, 02:46:07 PM »
Quote
Haha, I just realized I made a typical overlooked mistake. I forgot to plug the transistor into the transistor socket we made!   I did that and connected the negative bat cord to the ground on the input jack and BINGO! Works like a charm, and sounds great with my Boss SD-1 into my old Ampeg VT-22.

Any recomendations on a next project for a beginner? I was thinking about doing the Green Ringer Octave pedal, because I need one anyways, and it looks simple. I want to eventually work my way up to a professional Fuzz and hopefully a tube overdrive (Hotbox rings a bell - if I can't buy an origional.)

WELL congratulations!!!!!

I have never tried to build a Green Ringer. Apparently you did a great job on the first project. I believe you should do well with the ringer!

Aron

Muaar

Re: Strange Problem With NPN Boost
« Reply #11 on: November 01, 2006, 04:16:01 PM »
Thanks, I'll post pics of the NPN boost as well as the Green Ringer when I'm done!

Muaar

Re: Strange Problem With NPN Boost
« Reply #12 on: November 01, 2006, 06:01:36 PM »
Here's some pics of the NPN boost.

(large pics, 56k beware!)

Click for zoom
http://i11.tinypic.com/3y2iowj.jpg

http://i12.tinypic.com/403z1nd.jpg

http://i12.tinypic.com/4ccp369.jpg

http://i11.tinypic.com/40c9aib.jpg

http://i12.tinypic.com/2efpz6o.jpg


any advice on wiring, ect? I know I could have put the wires going down and soldered them through the perfboard, but didn't think of it at the time. I'm going to take my Boss pedal apart and look for some tips on wiring.
« Last Edit: November 01, 2006, 06:04:59 PM by Muaar »

aron

Re: Strange Problem With NPN Boost
« Reply #13 on: November 01, 2006, 08:13:16 PM »
That's too neat. I run from the top of the board through the bottom and solder on the bottom. GREAT JOB!

PNG123

Re: Strange Problem With NPN Boost
« Reply #14 on: November 03, 2006, 02:40:50 AM »
Haha, I just realized I made a typical overlooked mistake. I forgot to plug the transistor into the transistor socket we made!  :icon_redface: I did that and connected the negative bat cord to the ground on the input jack and BINGO! Works like a charm, and sounds great with my Boss SD-1 into my old Ampeg VT-22.

Any recomendations on a next project for a beginner? I was thinking about doing the Green Ringer Octave pedal, because I need one anyways, and it looks simple. I want to eventually work my way up to a professional Fuzz and hopefully a tube overdrive (Hotbox rings a bell - if I can't buy an origional.)

I'll post some pics of my ugly-but-functioning board later tonight, and hopefully I can get some tips on wiring better, so I'll be able to fit it into a box next time. I'm thinking of rewiring this one to fit it into a box now that I've got it working.

Pics to come when I'm off work.

Well you could try ;
- The Cream Pie (distortion)
- Dallas Rangemaster
- Green Ringer
- Electra Distortion

These are some of the simplest i think

Muaar

Re: Strange Problem With NPN Boost
« Reply #15 on: November 03, 2006, 07:42:03 PM »
I need an octave pedal anyways, so I'll go with the green ringer. Hopefully the parts are semi-cheap!

Minion

Re: Strange Problem With NPN Boost
« Reply #16 on: November 14, 2006, 08:21:58 PM »
I just did my first effect pedal project (I have built amps and Preamps and Mics and Power supplies before) Well I actually put it inside my DIY Guitar amp for a overdrive circuit....

It was called the "4 Trans Boost" which is loosely baced on the Electra Distorion accept that it has 4 Cascedeing NPN gain stages with 4 distortion stages...

I have to say that this simple circuit is probably one of the best Distortion sounds I have ever heard and it was extremely easy to build...I did make a few changes as I didn"t have the correct parts but ti still sounds great...

I don"t know if I got the schematic from here or someone else but if anyone wants to try it I will post it....


Cheers
Go to bed with itchy Bum , wake up with stinky finger !!