Problem with GGG 5 Band EQ

[merlin]

Hello,

i build the Graphic EQ Wiring Diagram, 5 Band with Gain control knob and i found a error into the parts list.
There are 4 10k resistors listed in the parts list.
But in the layout are 6 10k resistors.

Is it possible to get a Voltage chart so i can search the failure, because i missed the 2 10k resistors at the power
path before the 2 10uF elkos.
Is it possible that this damaged the TL074 IC´s ?

The bypass works but after i switcht the effect on, nothing comes out.

I used 1 9v battery  should i connect the ground from the battery and the ground from the DC jack?

Best regards merlin

[rhys]

When I built mine I had signal in bypass; when engaged the LED came on but no sound came through.  My problem was with power consumption; the 9v I was using wasn't enough to power those chips.  I tried it with a wall adaptor and it worked fine. 

(Incidentally, that's still the only way I can power it--it has to be connected to the wall.  Even if I daisy chain it with other pedals from a wall adaptor the EQ won't work when engaged). 

[CGDARK]

Is it possible to get a Voltage chart so i can search the failure, because i missed the 2 10k resistors at the power
path before the 2 10uF elkos.

Those resistors form the voltage divider to obtain the Vref needed to power the ICs, because you are using just one battery. You have to put those resistors, without them the circuit will never work unless you use two batteries (bipolar supply) like in the GGG 6-band graphic. BTW, both EQs share the same PCB as I can see in the layouts, only wired differently.

CG

[Dean Hazelwanter]

Hi,

BTW, both EQs share the same PCB as I can see in the layouts, only wired differently.

It is exactly the same layout. I sent it to JD as a 6 band, noting that the 1st band was only marginally useful, except maybe for 7 string players. He released it as a 5 band, realizing the majority of people wouldn't want or need that 1st band.

You have to put in those resistors

CGDARK is correct.

[merlin]

Hi,

thanks all for the help.

Rhys has help me out. I used awall adaptor and it worked fine.
With the battery the pedal did not work.


greetings merlin