MCMEAT HELP!

[blackbirdneo]

ei guys. i've finished making the mcmeat project but heres as few problems.(im using it on bass)
1. on some settings it squeals
2. it picks up radio frequency( i think this happened when we tried it on an active bass)
3. the green led is on even when bypassed if sw2 is in sw2-2( well i think this si because when its in sw2-2 its directly connected to the 9v source?)
4. low volume. it wont get louder than the bypassed volume.

any insights?

[Tuemmueh]

The low-volume is a known problem. You could fix that by adding a gain-stage after the input-stage. A single-opamp could do that.

I did "a modded meatball work-a-like" with a LOT of help by markusw ... known for his lovetone-love
The schem is NOT verified because I'm a bit lazy ... But I will finish it someday. Maybe this year

http://forum.musikding.de/yabbse/index.php?topic=8420.0

I added an wah-expression-pedal-jack which should work much better than the original. But, like it was said, it's NOT tested ... but it SHOULD work

Cheers ... Timm

[blackbirdneo]

is there anyway i can integrate the gain stage part in my clone?

[petemoore]

  ei guys. i've finished making the mcmeat project but heres as few problems.(im using it on bass)
1. on some settings it squeals
2. it picks up radio frequency( i think this happened when we tried it on an active bass)
3. the green led is on even when bypassed if sw2 is in sw2-2( well i think this si because when its in sw2-2 its directly connected to the 9v source?)
4. low volume. it wont get louder than the bypassed volume.
  This may offer some help, read the debugging thread for greater detail.
  your description leads me to believe perhaps the circuit is not functioning correctly, I would debug to known proper function before doing work arounds to any problems.
  The '*' texts are examples which can be deleted and filled in with relevant information about your circuit.
  Name and show link to circuit schematic.
  *Garfunkels accoustic pre-amp
  If you're using a layout or PCB post a link to that too.
  *GAPP layout
   Is there a connection between circuit power supply V+ and Gnd. under any of all power supply 'conditions' ie...is there shorting under and 'normal' switching conditions of input jack or DC jack or any other time? Fix power supply shorts before applying voltage to the circuit.
  *YES   /    NO  [enter comments
  Measure battery voltage.
  *X.X2VDC
  Measure battery voltage with circuit loading
  *X.21VDC
If using a power supply, what does it say on it about voltage rating?
  *Xvolt
  Also name power supply type
  *AC  or DC output
  test the voltage of the power supply.
  *9.2VDC
  Test votlage of power supply with circuit connected
  * .22vdc
  Is the circuit npn-negative ground?
  *Transistor type [npn/pnp...jfet, mosfet, Ge, etc.
  *Circuit polarity [neg gnd. or pos. ground?
  *Opamp type [Dual, single, OTA, CMOS...other
  connect DMM to ground, and test for continuity at every point in the schematic with a ground symbol, from the most 'distant' [test points should be beyond all connections and solder joints].
  Test the cables that are plugged if they can be plugged in, at the plug sleeves which connect to guitar and amp
  Is there continuity at all 'distant circuit ground points
  Stage 2
  Connect power supply, if there is a large current draw [ie voltage drops by 10% or more, disconnect power and post that result].
  Is there a >10% voltage drop in battery when circuit is connected?
  *Yes  /  No
  What voltages are measured [using ground as reference voltage =O.0V], using DMM at all active component pins?
  *Dual opamp
*1  4.5v
*2  4.5v
*3  4,5v
*4  0.0v
*5  4.5v
*6  4.5v
*7  4.5v
*8  9v
-----
  *Single opamp
*1  NC
*2  4.5v
*3  4.5v
*4  0.0v
*5  NC
*6  4.5v
*7  9v
*8  NC
-----
*Transistor type
  *NPN
  *PNP
  *Jfet/mosfet/BJT/Ge?
  *Transistor part #
  *Data sheet pinout information
  Pin Voltage
  *D 9v         
  *G 2.2V
  *S  .21V
  Or substitue 'E/B/C if using bipolar transitor
  List any pertinent comments and questions.
  Stage 3
Audio probe, and list results and comments.
  Test that all stages are 'separated' by DC blocking capacitors,
  Can you physically see that a capacitor is properly wired to the input and output of each active component stage? ie signal path must go through the cap to enter or exit the active stage.
  The circuit debugging may have limited results if the answers with * are not known or posted.
  BTW the opamp pins for most distorters [gain stages] are more than optimal, bias is 'centered' at 1/2 the power supply, except for the power supply pins [the 9v and 0.0v ones.