Fellas I am having RF issues. When I play sometimes there is a voice that developes in my amp. It sounds like sports radio but it could be voices from beyond...should I do what they say?
The chassis is sitting on top of my cabilnet...no lower cover attached
When I wiggle the input jack it makes lots of noise but the connections seem to be good.
Any advice would be greatly appreciated.
Thanks guys...
The Undead or Aliens are speaking to me through my Rocket
Moderators: pompeiisneaks, Colossal
Re: The Undead or Aliens are speaking to me through my Rocket
Do you have your tin foil beanie on?
If not immediatley construct one and wear it around the amp.
Don't do what they tell you to do, fight the demons!
Do you have a grid stopper resistor on the input to the first stage?
A grid stopper and possibly a small valued cap to ground off the input should cure it.
Also a cover plate is best as well.
If not immediatley construct one and wear it around the amp.
Don't do what they tell you to do, fight the demons!
Do you have a grid stopper resistor on the input to the first stage?
A grid stopper and possibly a small valued cap to ground off the input should cure it.
Also a cover plate is best as well.
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: The Undead or Aliens are speaking to me through my Rocket
You'll want a bottom plate as you've got a massive window for RF to get in at the moment.
Once you've done that, if you still have problems then there are two things I'd look at doing:
1. If you have an insulated input jack (e.g. a Cliff jack) then solder a 0.01uF capacitor from the ground connection of the jack directly to the chassis, using the shortest leads you can. This will shunt RF on the guitar cable to the chassis ground as soon as it enters the chassis. Lots of sites incorrectly reference shunting the signal connection to ground via the cap, which will merrily roll off your highs, which isn't what you want.
2. If you have a Switchcraft jack (or you still have RFI remaining after step 1) then use the smallest grid stopper you can on V1, soldered directly to the tube socket.
A 33K resistor will give you a -3dB point of around 32kHz, 47K around 22kHz, and the old Marshall favourite of 68K around 15.5kHz.
You want to eliminate RFI without altering the tone, so 33K is a good starting point.
The grid stopper really needs to be on the tube socket rather than on the board to ensure that the coupling effect between it and the tube's Miller capacitance happens right at the tube. Otherwise you have a length of wire between the resistor and the tube that's still sensitive.
Once you've done that, if you still have problems then there are two things I'd look at doing:
1. If you have an insulated input jack (e.g. a Cliff jack) then solder a 0.01uF capacitor from the ground connection of the jack directly to the chassis, using the shortest leads you can. This will shunt RF on the guitar cable to the chassis ground as soon as it enters the chassis. Lots of sites incorrectly reference shunting the signal connection to ground via the cap, which will merrily roll off your highs, which isn't what you want.
2. If you have a Switchcraft jack (or you still have RFI remaining after step 1) then use the smallest grid stopper you can on V1, soldered directly to the tube socket.
A 33K resistor will give you a -3dB point of around 32kHz, 47K around 22kHz, and the old Marshall favourite of 68K around 15.5kHz.
You want to eliminate RFI without altering the tone, so 33K is a good starting point.
The grid stopper really needs to be on the tube socket rather than on the board to ensure that the coupling effect between it and the tube's Miller capacitance happens right at the tube. Otherwise you have a length of wire between the resistor and the tube that's still sensitive.
Re: The Undead or Aliens are speaking to me through my Rocket
Greg,
If I remember right you used regular 1/4 input jack on your Rocket so this is unusal to have RF in a Rocket layout to me. You could use a shielded wire on the input even though that is one heck of a short run to the board. Use a bottom plate and tube shields on the preamp tubes.
Mark
If I remember right you used regular 1/4 input jack on your Rocket so this is unusal to have RF in a Rocket layout to me. You could use a shielded wire on the input even though that is one heck of a short run to the board. Use a bottom plate and tube shields on the preamp tubes.
Mark
RF issues
I placed the bottom plate in position and have been playing several hours today without hearing the voices of the underworld...Thanks guys.
I love this amp.
I did notice that I need to adjust tones controls ever so slightly for each guitar I play through it. I mean the PRS in single coil position sounds amazing but a Les Paul (RIP) scared me it sounded so bad. I tweaked the controls and it is awesome as well...have not found the sweet spot for a Tele yet but it sure is fun searching.
I love this amp.
I did notice that I need to adjust tones controls ever so slightly for each guitar I play through it. I mean the PRS in single coil position sounds amazing but a Les Paul (RIP) scared me it sounded so bad. I tweaked the controls and it is awesome as well...have not found the sweet spot for a Tele yet but it sure is fun searching.
Greg
Re: The Undead or Aliens are speaking to me through my Rocket
Well sure, every guitar is different. 
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: The Undead or Aliens are speaking to me through my Rocket
just a thought... but it COULD be aliens!!!
In the interest of full disclosure, I am Animal Factory Amplification.