Preamp help, please.

**SamanthaCay** · #1 09-20-2010, 05:08 PM

Hi, so I decided to try to through together a preamp circuit. This morning I got a schematic and went to town. I decided to try and just do a strait boost circuit with no controls to start. That way I can play around with some of the component and hopefully get a decent sound out of this thing. Well so far all I’ve gotten is a radio signal with my amps gain cranked. I am using a few different component then the original schematic calls for so I’m wondering if it might be that. I’ve included the original schematic and my slightly altered version. On the new schematic R1 and R2 are highlighted in red, as those where the two resisters I had to change do to the fact that I didn’t have what the original called for. Also I’m using a different transistor as I couldn’t find a NPN 2N5133 I am using a NPN 2N4401 So with all this info do any of you know what I’m doing wrong here?

Thank you.
Samantha.

**SamanthaCay** · #2 09-21-2010, 06:00 AM

HEY! Where my EE's at.

bigchiefbc · #3 09-21-2010, 06:09 AM

I bet you that you have the 2N4401 in backwards. Its pinout is backwards from the 2N5133 pinout. For the 4401, ff you have the rounded side facing left, the emitter is on top, and the collector is on the bottom. So just flip it backwards and you should be all set.

**SamanthaCay** · #4 09-21-2010, 06:30 AM

Quote:

Originally Posted by bigchiefbc

I bet you that you have the 2N4401 in backwards. Its pinout is backwards from the 2N5133 pinout. For the 4401, ff you have the rounded side facing left, the emitter is on top, and the collector is on the bottom. So just flip it backwards and you should be all set.

Holly crap! You where right!

The funny thing is I followed the instructions listed on the transistors packaging and it was wrong.

Wow I guess it just go’s to show you can’t believe everything you read.

Thank you so much.
Samantha.

bigchiefbc · #5 09-21-2010, 08:02 AM

Quote:

Originally Posted by buchananbass

Holly crap! You where right!

The funny thing is I followed the instructions listed on the transistors packaging and it was wrong.

Wow I guess it just go’s to show you can’t believe everything you read.

Thank you so much.
Samantha.

Glad to hear that worked. It was the first thing I thought of because I've spent many a frustrating hour debugging my breadboarded circuits just to find I had a flipped tranny