GGG Reverb problem

[mnordbye]

I've been troubleshooting my GGG reverb for a couple of hours now, and i can't seem to find the solution. ALL the voltages are half of what they should be, including the power supply. When measuring the adapter out of the circuit, it measures around 9V, but when connected, it's halved.

Even stranger, when lifting the voltage regulator from the circuit, the voltages all raises about 2-3 volts.

That got me thinking, is my power adapter unable to handle the pedal? The Belton brick uses between 60-100 mA, but it should be enough for the adapter, which can handle 500mA.

I also read some post about using a LM317 to make the input voltage stable.

It is not a reverb kit from GGG, and i'm only breadboarding it at the moment.

I'll check my component placement again too.

Regards,
Magnus

[Govmnt_Lacky]

Check the voltage regulator (should be a 5VDC regulator if memory serves me correct). Make sure you get 9VDC on input and 5VDC on output.

Furthermore, ensure that you installed the CORRECT regulator (not a 6V or 9V regulator), make sure it is oriented correctly (according to the datasheet, not the layout), make sure there are no solder bridges ANYWHERE ON THE BOARD, make sure all of your component values are correct.

Personally, I did not use the SMT voltage regulator that GGG suggests. I used a TO-92 type 5V regulator that could handle up to 100mA and it works great. (KA78L05)

Good Luck 

[mnordbye]

Check the voltage regulator (should be a 5VDC regulator if memory serves me correct). Make sure you get 9VDC on input and 5VDC on output.

Furthermore, ensure that you installed the CORRECT regulator (not a 6V or 9V regulator), make sure it is oriented correctly (according to the datasheet, not the layout), make sure there are no solder bridges ANYWHERE ON THE BOARD, make sure all of your component values are correct.

Personally, I did not use the SMT voltage regulator that GGG suggests. I used a TO-92 type 5V regulator that could handle up to 100mA and it works great. (KA78L05)

Good Luck 

I used the same type of regulator as you, 78L05 from Smallbear. And i don't have the circuit on a PCB, but a breadboard.

The thing is, even if the adapter measures around 9V when measured out-of-circuit, but when connected all the voltages halves, including the direct power from the adapter.

Strange!

[Govmnt_Lacky]

The thing is, even if the adapter measures around 9V when measured out-of-circuit, but when connected all the voltages halves, including the direct power from the adapter.

Strange!

Not strange at all. This just means one of two things:

1) Something on the breadboard is loading down the power input to the point where it is halved.

2) Your power supply is not operating within tolerance (500mA draw)

My bet is more towards #1.

Do yourself a favor and triple check your component values, placement, and orientation of it all and recheck. You could always try a battery too. 

Good Luck 

[mnordbye]

The thing is, even if the adapter measures around 9V when measured out-of-circuit, but when connected all the voltages halves, including the direct power from the adapter.

Strange!

Not strange at all. This just means one of two things:

1) Something on the breadboard is loading down the power input to the point where it is halved.

2) Your power supply is not operating within tolerance (500mA draw)

My bet is more towards #1.

Do yourself a favor and triple check your component values, placement, and orientation of it all and recheck. You could always try a battery too. 

Good Luck 

Thanks for the help so far.

I'll recheck component values, try a battery etc. Something IS loading it down, yes. It's annoying.

[mnordbye]

Problem solved!

Turns out i had the breadboard connected to the adapter via a module that i built, with the same kind of power filtering installed. The voltage from the adapter was double halved!

So, the reverb works and sound pretty good. But now i realize that the circuits volume is much lower than the dry signal. I'll recheck my component values tomorrow.

Thanks!

[Govmnt_Lacky]

Good to see you got it working (Kind-of  )

[mnordbye]

Forgot to report the results! 

Got it working as it should, i had a bad resistor in there, which had the wrong color code! One that should have been 470 ohms read 1M ohms!

When in doubt, always check resistor values with a multimeter.

By the way, i'm using the brick with the "long" reverb length. I must say that i like the medium length brick better, less "spongy".

Magnus