Noisy pedals

[newfish]

Hiya -

Built a Bobtavia a week or two ago.
All was fine when I played through my test bench amp (Tiny Marshall battery jobbie).

Plugging into my Classic 30 *or* 8-track recorder (hard disk, not cassette for you 70s buffs) gives a fair amount of background noise.

Not radio stations or interstellar broadcasts, just hum.
There are no CRTs or Flourescent Tubes in my practice room, and I've used shielded leads for Input / Output, with very short leads for controls.
The board is housed inside an aluminium box, with a significant amount of insulation between the board and the box.

Could anyone suggest anything I may have missed - as I'm sure the fault is with the grounding.

Cheers,

Ian.

[foxfire]

how are you powering the pedal?

[newfish]

9v battery.

Not really looked into DC Jacks for now.

[ambulancevoice]

are you using shielded wire?
if you painted or coated the enclosure, did you coat/paint the inside?
are you sure you grounds are ok?

[GibsonGM]

Sometimes, wrapping a wire around the input lead, and another around the output lead, each with 1 end going to ground, can catch RF leaking into the enclosure.  I mean wrap, like you're making a rope.    Good shielded wire, with only 1 end terminated at ground, does the same and probably better (esp. the stuff with braided shield!). 
Does sound like a grounding issue, though....how about the 8 track? Or your cables? Or computer monitors/flourescent lights nearby....

[newfish]

Thanks for your suggestions chaps,

The case I'm using is aluminium (not painted on the inside since I figured it would already act as a good ground).

I'll have another look at the 'ground' connections and make sure there's nothing as simple as a dry joint.

8-track is fine with anything else (other pedals / 'naked' instruments) plugged into the 'input'.

Might just do me some rope-making...

[petemoore]

Built a Bobtavia a week or two ago.
All was fine when I played through my test bench amp (Tiny Marshall battery jobbie).

Plugging into my Classic 30 *or* 8-track recorder (hard disk, not cassette for you 70s buffs) gives a fair amount of background noise.

Not radio stations or interstellar broadcasts, just hum.
There are no CRTs or Flourescent Tubes in my practice room, "*"and I've used shielded leads for Input / Output, with very short leads for controls.
  One end of the shielded grounded, the other cut?
The board is housed inside an aluminium box, with a significant amount of insulation between the board and the box.
  And the aluminum tests as grounded?
  Could anyone suggest anything I may have missed - as I'm sure the fault is with the grounding.
  Beep mode all ground points [marked on schematic as ground] as ground from ground.
The case I'm using is aluminium (not painted on the inside since I figured it would already act as a good ground).
I'll have another look at the 'ground' connections and make sure there's nothing as simple as a dry joint.
8-track is fine with anything else (other pedals / 'naked' instruments) plugged into the 'input'.
Might just do me some rope-making... "*"..if the I/O signal wires are shielded, rope shielding would be supurfluous.
  Especially true for amplifier / clipper circuits: cable, or guitar [muted string] noise can become much larger in proportion to large source signal outputs [which are reduced signif by the transformer losses and clipping].
  Try turning the guitar volume all the way CCW to 0.0.

[newfish]

So - 30 mins with a soldering iron and all is much quieter.

There were a couple of dry joins on the grounding - which have now been sorted.

Thanks for all your responses folks, it's a pleasure to know the internet's not just full of phishing scams and naked 'ladies'... 

...and I learned something from this issue - which is *always* a good thing.

Cheers!

Ian.

[ambulancevoice]

So - 30 mins with a soldering iron and all is much quieter.

There were a couple of dry joins on the grounding - which have now been sorted.

Thanks for all your responses folks, it's a pleasure to know the internet's not just full of phishing scams and naked 'ladies'... 

...and I learned something from this issue - which is *always* a good thing.

Cheers!

Ian.

good to hear!
eh, the naked ladies arnt to bad
there just bad actors is all