DS-1 Probs

[luke691]

I've made the Boss DS 1 clone from tone pad ( http://www.tonepad.com/project.asp?id=37 ).

When i play the sound cuts out or makes a farty bass type distortion depending on the pots position, i just checked the voltages at the ic transistors,etc
I also used 2N3904 transistors.



Here are the voltages :

Voltage in: 9.14v

IC1(tlo72)pin 1: 4.63  2: 4.63  3: 4.02  4:Gnd  5:9.14  6: 8.47  7: 3.86  8: 4.63

Q1 ; E: 9.07 B : 8.54  C:  9.13

Q2 ; E:0 volts B: 3.63  C: 6.73

Q3 ; E:9.00 B:8.53 C:9.12

Electrolytics:

1 uf Cap- 8.99

47 uf cap- 4.59

100uf cap- 9.11

Cap 5- 4.53

[luke691]

I just realised that the emitter is higher than the base on two of the transistors and the collector is lower on some of them is this a problem?

[MartyMart]

Luke, I think you labelled the IC pins wrong, pin "8" which is opposite pin "1"
should be 9.14v  !
Pin "5" is opposite pin 4  so :

1*      8
2        7
3        6
4        5

*  = top left circle or a "U" shape at top of IC

[luke691]

woops!

any idea what the problem could be?

[MartyMart]

8.47 at "real" pin 7 doesn't look right and your transistors have almost 9v
on every pin ... they wont pass signal like that
Check all your soldering and placement in these areas, definate mistake.

MM

[luke691]

i doubled checked all resistors transistors and everything is in place

what could be wrong

[petemoore]

  I'd check the ground connections on the emitters [or emitter resistors], you should see a small resistance betweent the E pins and ground.
  I can't find R2 on the schematic, so I can't place...I thought there was a dual oa in the DS-1 circuit..there is..so since I can't readily read it right off the bat...
  the left side of your OA [or is the pinout incorrectly typoed?]...anyway the ground pin 4 you have as 0v, good, and the right side of the oa's pins 123 [output, -input and +input] all look about 1/2v..good, but the left side isn't near 1/2v, that's a problem like non connect, misconect, misvalued R, or trace touching where it shouldn't.
  It looks as though pin 6 may have been assigned to V+, it's reading 8.47v.. compared to pin 8 which does connect to V+ but is reading about 1/2v.

[luke691]

I used the electronics program 'tina' to check what voltages the emitters on the transistors should display and it told me that the emmiters should produce 8.537 volts with the 8.53 volts on the base and 9.12 on the collector. please help

what is wrong i have checked placement, all solder joints are fine and there is no cross-tracing. what is wrong? could it be the transistors, i am using 23904 switching type.