DS-1 breadboard project troubleshooting help

[ElectricDruid]

The voltage readings off the chip are :

1     4.43
2     4.43
3     4.37
4     0.01
5     4.44
6     4.44
7     4.47
8     8.95

I don't know enough to know if it's good or bad

Those seem all pretty reasonable.

Pins 1 & 2 should be the same, and they are. Pin 5 is connected to that pin 1 output, so that should be the same, and it is (to within a few millivolts). Pin 6 should be the same as pin 5, and it is. Pins 4 and 8 should show a 9V supply, and they do.

Nothing much wrong there, I'd say, unless someone else can spot something I've missed?

I'd start audio-probing this circuit. There should be plenty of gain after that second op-amp stage to drive those diodes hard and get plenty of clipping and a good signal level for the tone controls. My first move would be to break the circuit after C9 and listen at that point. If I haven't got variable gain at that point, there's something wrong in the preceding circuit. If what I've got is a variable gain stage, then that part is ok, and the problem must be in the second part.

HTH,
Tom

[griff10672]

Holy crap ............... It works !!!     

I had been looking at a wrong data sheet image for the transistor all weekend .... WTF .... LMAO ...or a little too much of the old Critical OG whilst breadboarding .....

Thanks so much to robthequiet to have me check the voltage there ..... I googled another data sheet and sure enough ... I had stuff all messed up ... soon as I fixed it POW .... It sounds great into my Boogie already for a DS1 ... and I didnt even tweak anything yet really ...

there's one hell of a high pitched squeal coming off of it .... but I have it sitting on my desk under a monitor computer ... fan that's on .... ?? grounding issue ?? 

[thermionix]

Congratulations!

Duck_Arse knew the whole time, he just wanted you to have the satisfaction of figuring it out yourself.  And he knew you would, or else he would have just told you the answer.

The high pitched squeal is maybe the computer monitor.  There's no shielding when it's just on the breadboard, and high gain circuits are more likely to pick up junk from the air.  Definitely try it away from other electronics before worrying about it.

[griff10672]

I took it off the voodoo labs power supply that ironically is plugged into a Furman Powerconditioner ... which also has a few things hooked up to it including the Boogie ... and just a put a 9 volt in ...... DEAD friggin quiet ............

[duck_arse]

try putting a resistor - 1k? 470R? 220R? 100R? - value not terribly critical - in the supply line between the D1 and the C25, down the bottom left corner. that will then help filter the DC being fed into the circuit, might kill your supply noize.

[griff10672]

I will try that .... thanks for taking a peep at my breadboard ... much appreciated !!!!