i keep building boosts that do the opposite...

[birt]

first i made an amz mosfet boost... didn't work
it had a bad tranny so i replaced it, biasvoltage was 4,5 so it was ok.
i turned it on again, big volume drop!
i started poking around with an audioprobe. couldn't find the problem.

then i made a lpb2 boost (generalguitargadgets). it had a volume drop, couldn't find out the problem with this one either.
i used a 2n222 tranny cos i've got hundreds of em.
voltages are
e:some mV
b:0,65V
c:6,2V

and my fuzz face curently has OC202's in it and it sounds good but the sound goes away abrubtly very short after i hit a string (it worked good before when i was using ac128's but they were not fuzzy enough for me)

shoot! :lol:

[stuartgsmith]

I had the same problem with my mosfet boost at first.
I was a bad capacitor between the transistor and the output.

[Aharon]

Are you using a PCB or perf?.
It's a simple build but it can get confusing quick for beginners.
Check for miswired input jack :tip lug soldered to ring lug etc.
Check for cold solder blobs.
Check for reversed fet.
Check for right value resistors.
Aharon

[lightningfingers]

Did you try gus's NPN boost yet?

Theres a whole forum dedicated to it.....

[petemoore]

Yupp, Mosfets have given me fits before..
 The other ones should be ok, about 99.9% of the time, when wired like schem.
 Use the DMM to check Actual resistance of every resistor, just prior to installation.
 other things to look for
 Cap polarity [when applicable]
 transistor pin connections orientation
 look at the next node to be soldered and plan all connections to be made there
 Then when put together
 Test for short at battery clip
 Check all grounds
 {DO NOT use with HIGH VOLTAGE circuits]>
 Start at the output, with amp on/connecteds, get a buzz going from the cable going to the amp input [touch the tip] connect the effect ground and output to that, get a buzz going [use a metal shank/wire that touches your body and ... ... to reach in to 'touch' the circuit at points, working your way from the output toward the input.
 Buzz at output...try the volume control output, then the VC input [turn the vol control up if buzz is lost there], then the DC blocking cap, then the transistor collector etc.] follow the signal path through the circuit from the output...you could connect a guitar or keyboard with 1 key taped down for audio source to inject...I use my body's output as a more convenient source [ONLY for debugging low voltage Circuits !!!].
  Most of the time on boosters the some signal is lost between collector and base....post the voltages read between ground, and each transistor pin {Also Read and post the battery supply voltage].
 GEO has biasing info...