Rub-a-Dub Reverb too quiet?! (FIXED)

[patrick398]

Hey, have searched around the internet but nobody else seems to have had a similar problem. Basically i've just put the rub-a-dub reverb (http://www.coda-effects.com/p/rub-dub-reverb-circuit-analysis.html) onto breadboard and i can just about make out the guitar signal if i turn the amp way up...way way to loud normally. I've re-build this 4 times now and the same thing is happening every time and really has me stumped. The reverb does seem to be working and from what i can hear sounds nice, the blend pot seems to be working too. I have the correct 4.5v at pins 3 and 5 of the TL072 and the 78L05 regulator is putting out the correct 5v to the belton. Anybody have any ideas what was cause this massive signal loss?
Thanks a lot!
Patrick

[Kipper4]

Do you have an audio probe so you can follow the signal through the circuit and try to establish where the signal looses strength.

Post up all the voltages please and maybe a pic of the bread board.

[patrick398]

Ok thanks i'll get on that first thing in the morning

[patrick398]

Also when you say 'all the voltages' do you mean at every point or some particularly significant ones?
Thanks again!

[bluebunny]

Each of the pins of the brick and ICs, plus your power supply (before and after the regulator).  That should get us going.  Check out the sticky DEBUGGING thread for more...

[patrick398]

Just probed it and i seem to loose signal at pin 1 of the IC. I have signal and R1, R2, C1, and also pin 2 of the IC but nothing at pin 1 or anywhere afterwards. Could it be a faulty IC? I've triple checked it against the schem and there's nothing else i can think of. Took some voltages as well so hopefully they well mean something to somebody haha.

Voltage between Regulators Vin and GND is 9.30v
Voltage between Regulators Vout and GND is 5.01v

Voltage between Vin and
Belton pin 1: 4.27v
Belton pin 2: 9.29v
Belton pin 3: 4.05v
Belton pin 4: 9.29v
Belton pin 5: 8.88v
Belton pin 6: 8.88v

IC pin 1: 4.03v
IC pin 2: 3.02v
IC pin 3: 4.67v
IC pin 4: 4.15v
IC pin 5: 3.16v
IC pin 6: 4.03v
IC pin 7: 4.01
IC pin 8: 4.63

R6: 4.67
C5 (+): 3.94
C5 (-): 8.93
Pot 1: 8.93
Pot 2: 8.93
Pot 3 (GND): 9.30

Here's some photos as well, sorry it's a bit messy but hopefully you can work out whats what.

https://postimg.org/gallery/iwrcrus8/

Thanks a lot!

[bluebunny]

Whilst the consistently-high voltages everywhere might normally be a cause for alarm (e.g. frying the expensive brick...), the fact that you have 0V nowhere would suggest you have a serious grounding problem.  (I assume all your readings were taken relative to a known - and good - ground point, e.g. your power supply "0V".)  So check continuity between all points that should be 0V.

[duck_arse]

I'd also add some power supply connections to that IC  in the corner .......

[bluebunny]

Nice one, duck.  I was just wondering how it was getting juice!   

[patrick398]

Balls have i made an absolute belter of a mistake? There's no connection to pin 4 or 8 on the IC in the schematic but i was slightly confused when i looked at the pinout and they're the power pins. So just hook up 9 volts to pin 4 or 8?

[bluebunny]

9V to pin 8.  Connect pin 4 to ground.  (I might still be concerned about the readings on the brick, but that depends on where your black lead was connected...)  BTW, the power connections are shown: they're the dangling "8" and "4" in the power supply section.  (You'll often find them shown that way.  Just something to watch out for, that you'll come to recognise with experience.)

[patrick398]

Ah blimey i wondered what the 4 and 8 were, what an idiot. Definitely not good practice to just ignore something if you're not sure what it's there for haha. Okay so i've connected them but just getting a high pitched whining now which modulates slightly. I think i might need to take the pin readings again, i think i've confused my self. Am i taking the readings of everything in relation to ground? So black lead on the ground and red lead on whatever pin i want to measure? Sorry to drag you into amateur hour and thank you all so much for you're help, it's really appreciated!

[bluebunny]

No problem, Patrick.  You go and ask questions.  We all do.   

Yes, clip the black lead to ground and leave it there forevermore.  Probe your volts with the red lead.

[patrick398]

Okay hopefully these reading should be more useful.

IC 1: 4.64
IC 2: 4.64
IC 3: 4.61
IC 4: 0
IC 5: 4.61
IC 6: 4.64
IC 7: 4.64
IC 8: 9.30

Brick 1: 5.01
Brick 2: 0
Brick 3: 4.64
Brick 4: 0
Brick 5: 0
Brick 6: 0

[patrick398]

Sweet i've got full signal now and everything seems to be working but still have that pesky whining. Any ideas what could be causing that? I vaguely remember reading somewhere that someone else had a similar problem so i'll try and find that too

[bluebunny]

Does the whining change if you rotate the breadboard or move some of those long connecting wires?  What lighting do you have above your workbench?

[patrick398]

ALL SORTED! seems the 47uf cap next to the voltage divider wasn't connected properly. Sounds sweet now. Thanks so much for you're help, you've been amazing!

[bluebunny]

Cool!     Now carefully put it in a box.  And post pictures when you're done - it's the law.   

[patrick398]

Yeah just got to build the @#$%ing thing now...you certainly haven't heard the last from me haha
Thanks again!

[Kipper4]

Well done Patrick.
I just love a happy ending.