my Tube Reamer hums!!! urggh!

[siaoguitar]

Hi, just finished the tube reamer from rungrovve, at first it picks up radio frequency when on, i added a 47pf after the input cap to eliminate it,it works but next came a hum which is very irritating.
Can anyone tell me what's wrong?
How to kill the hum?

[Connoisseur of Distortion]

is it a 60 Hz hum? if so, your solution is probably to put a large capacitor across the positive and negative power. (this has saved me MANY times...)

[siaoguitar]

Anyone else?
Hi, what do you mean across the + & - of my power?

[Fret Wire]

Is this with battery power or are you using a power supply? The first reamer I built I left unboxed for awhile to develop some mods, and I never had any hum problems. And never when boxed either.

[Connoisseur of Distortion]

across the + and - terminals. try about a 100 uF and work your way up until it quiets down. if you are using a battery, this won't be the problem.

[siaoguitar]

i'm using a battery  :cry:
i read somewhere that the 741 is a noisy chip rite?
but you guys seems to have no problem, do i need to solder the cap across + & - if i 'm using a battery?

[Fret Wire]

Double check your wiring, especially the jacks and switch.

[siaoguitar]

could it be my grounding? More grounding needed?

anyone?

[siaoguitar]

across the + and - terminals. try about a 100 uF and work your way up until it quiets down. if you are using a battery, this won't be the problem.

hi, i soldered a 220uF cap across the + & - terminals but the hum is still there.  :cry:

[MartyMart]

Make sure the circuit and input/output jacks are grounded properly, it could be as simple as that, its happened to me a few times !!

Marty.

[Connoisseur of Distortion]

the reason that we solder large caps across our power supply is to smooth out the flow from the wall, which is AC. Many power supplies don't have large enough coupling capacitors, so you end up with a DC that isn't quite DC. Putting one in our pedals helps block out bad power supplies.

also, IIRC, the Tube Reamer isn't exactly a silent pedal... though hum wasn't the problem. i will vote with the commune and recommend checking the grounding.

[David]

the reason that we solder large caps across our power supply is to smooth out the flow from the wall, which is AC. Many power supplies don't have large enough coupling capacitors, so you end up with a DC that isn't quite DC. Putting one in our pedals helps block out bad power supplies.

also, IIRC, the Tube Reamer isn't exactly a silent pedal... though hum wasn't the problem. i will vote with the commune and recommend checking the grounding.

That helps, but in my experience, it's not the whole answer.  Based on information furnished in this forum and elsewhere, what's become part of my standard "wrapper" (thanks for the concept, R.G.!) is a high-pass filter across the power rails consisting of a 100 ohm resistor on the front of the + rail and at least a 1000uF capacitor to ground.  The explanation I read is that this will filter out hum, motorboating, etc.  I have to say it seems to work quite well. YMMV.

[stm]

Double check your wiring, especially the jacks and switch.

It is very common to invert by mistake the wires that come out from the input jack. This instantly generates hum.

Does the hum increase when you touch the strings of your guitar? If this is the case, it is likely a wiring problem.

You should also check your output jack wires as well.