Ferrite Split Beads

[lldrew]

To reduce RF frequencies in a noisy pedal, I've seen alot of talk about putting a ferrite bead in series with the input and then a 47pF cap to ground before the input cap.  Would it work just as well to put the 47pF cap in and use a Ferritte split bead on my guitar cable that goes into the input of the pedal? 

[Paul Perry (Frostwave)]

With radio interference, there are so many variables, that one never really knows what might work in a particular case. No harm trying the ferrite around the cable. But I woulod expect the series approach to have more chance of working, myself.

[sta63bmx]

I have noticed some hiss noise in my 9V Electric Mistress at some clock settings.  Would that classify as RF interference from the clocking or...?  I have a ton of tiny little chokes in salvaged equipment.  Could I put one of those in series with the input?  Is the ferrite bead just a type of choke?  The clock in there isn't running faster than 20-40kHz, I don't think, and I don't think AM even starts until about 500 kHz. *scratching head*

Can I use any more question marks in these post.  Sheesh.

[Peter Snowberg]

Ferrite beads have different response depending on what material they're made from and their mass.

Hiss is a BBD based effect is usually just BBD noise.

[Eric H]

Ferrite beads have different response depending on what material they're made from and their mass.

Yes. I've seen recommendations for years to "put a ferrite bead on the input wire", but the catalogs list many different ones, with different frequencies. So do you get anal about it,  or just grab the nearest one?

-Eric

[lldrew]

do they mean an putting one on the input wire from the circuit board inside the effect?  How would you do this and which one would you purchase?

[lldrew]

also, does the 47pF cap to ground go before or after the input cap on the board?

[lldrew]

bump

[Gilles C]

Here is about ferrites beads:

http://users.catchnet.com.au/~rjandusimports/tut_9a.html

The mentioned article is very interesting:

http://www.elmac.co.uk/pdfs/ferrite.pdf

After the input cap

Gilles

[lldrew]

Fixed it!  I put a 1k resistor in series with the input wire going to a 220 pF cap to ground.  No RF noise at all and no tone loss!  For good measure I put a ferrite split bead on the incoming guitar cable as well as upgrading my cables.  This pedal is amazing.  I'll post pics later.  My fiance hand painted it with paint pens and it looks fantastic.  Thanks for everybodys help here

[Eric H]

Here is about ferrites beads:

http://users.catchnet.com.au/~rjandusimports/tut_9a.html

The mentioned article is very interesting:

http://www.elmac.co.uk/pdfs/ferrite.pdf

After the input cap

Gilles

Good links, Gilles.
Thanks,

-Eric