trinityamps.com

Hi,
i'm getting radio noise coming through with a boost pedal i put in on a jack socket.
Would i need to add a .1 cap to ground from the socket or a resistor and does it go
from the common side.
Thanks.

Noted In the Manual:

Radio Interference

If you are picking up radio stations on your amp:

1. Try a .01 uF capacitor on very short leads between the ‘ground’ side of the input jack and chassis ground. Try a 47 pf capacitor on very short leads between the ‘hot' side of the input jack and chassis ground.
2. Make sure the chassis is fully enclosed electrically. Install a piece of thin Aluminum sheet metal or HVAC Aluminum tape sandwiched between the chassis & cabinet and make sure it makes contact with the chassis.
3. Make sure the 68K grid blocking resistors are located at/on the V1 tube socket.
4. Use shielded wire between the input jack and the 68K grid blocking resistor.
5. Place ferrite beads over the shielded input cable.
6. Try grounding the shield of the shielded input cable to the chassis instead of the preamp ground.

Other useful measures to take in extreme circumstances:

1. Use a filtered IEC connector for your mains power connection.
2. Put a 100pf across the V1 Plate and cathode pins 1&3

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

The 47pF cap would actually go from the "hot" or "tip" connection of the jack, not the ground side of the jack. The 0.01uF cap goes to the ground side.

However, I suspect the fix may need to be done inside the pedal more than the amp.

_________________
Great tones come in small glass jars!

I put in the scratchy pot fix for a vrm with no problems.
If it's the pedal which makes sense, do i fix that the same way as you suggested.
Why would the pedal cause it?
Can i reduce the noise with the boost on which is mostly hiss.
Thanks.

I'd look for loose nuts on the jacks in the pedal first. Does the RF intereference come and go when you shake the pedal? Does it hapen with no guitar plugged into the pedal?

The pedal is amplifying high frequencies apparently right up into the RF range. The 47pF cap trick may help sort the pedal out. Also what Stoo suggested.

_________________
Great tones come in small glass jars!

I edited the 47pf / .1uf fix. Does it read OK now?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yep, it looks good!

_________________
Great tones come in small glass jars!

When i had that problem it ended being bad grounding in my overdrive pedal. I fixed a bad solder joint and retightend the chassis ground lug.

_________________
Guitologist at Large
"How does that feel?"