AC-2 nabo acoustic simulator

[geoffro]

Hi All i have been lurking here for a little while, and have only recently become a member of this great forum.
I recently built a distortion plus pedal, which didn't work first up but after a little bit of fault finding got it to work, but it was noisy
too noisy.it was like it had an earth problem when i turned the gain knob the noisy got worse, anyway i have always thought of my self as being a little adventures so i took on the acoustic simulator as this was something i could really do with especially if it worked well.
ok so i made the pcb, i bought the parts, i sat down and built it today, and just a few minutes ago at 9pm in australia, i sparked it up, well it was just a tad disappointing, i know you shouldn't take on things when you aren't very compident at doing this, but i was motivated and i took my time soldering, the problem i have is when i depress the footswitch the volume goes way down and the tone knobs are doing something but it doesn't seem like it is much, and there is a hiss not too bad but it is there. if anyone has a sugestion as to where i should start looking i would greatly appreciate it.
thanks in advance.
cheers
Geoff

[petemoore]

  Welcome to the forum !
  Really the best way to find the problem is:
  Get coffee, then sleep..lol
  Get familiar with putting the DMM probes to the circuit points to test..every way possible.
  Power supply, connectivity, and bias issues can often quickly be found with the voltage measurements.
  Signal flow and coonective problems can always be tested with the audio probe, though I use signal injector because it's very fast and reliable [thumb>Probe, but safe only with small voltages].
  Last night I tested with a 6.4v battery, the DIST+'s neg input [LM741] had only a little more than 2volts on it, below 1/2 v of supply^, but D+'s can do that and sound good. Battery technically too low a voltage for measuring and testing, so I pulled the DMM's 9v and sound tested the circuit.
  It's actually more of a DOD250 now..
  No shorting, I did have a problem with *polarity...ughhh, I *tested + to Gnd. and changed it [*before applying power]. Sorting out the power supply correctness with the DMM before power up is good! 
  See "Debugging: what to do when it doesn't work" thread.
  Test every ground marking is connected to ground.
 
 

[geoffro]

Hi petemore,
thanks for the advice, i should have taken it.
but being a very noobie to electronics and to pedal making, i have forgot to put in the 2 ic's before i tested it lol 
now like i said before, i got sound through at a much lower volume, since putting in the ic's i dont get any guitar sound through, but when i turn up the bass tone pot all the way i get this god aweful sound come out of it.
i will be doing some volt tests and sound tests this arvo when i get home.
hopefully i will find the problem pretty easy.
thanks for your advice again petemore.
cheers
geoff

[geoffro]

well after pulling the guts of this pedal out of the box it works now.
sounds great layed out on the bench with a single coil guitar conected, but i want it to have the same acoustic tinny twang with my epiphone sheraton with seymour duncan jb humbuckers.
i have already tried swaping out transistors but they only created distortion, if anyone has any ideas as to how i can go about this it would be great.
in the mean time i will try to contact christian the designer.
cheers
geoff