Hey, I'm getting some DC crackle from my 18W on my guitar's volume pot.
I put a 100nF coupling cap from the input jack to the grid stopper to block DC, but it didn't help. Any ideas?
Getting DC Crackle from VVR?
Moderators: pompeiisneaks, Colossal
Re: Getting DC Crackle from VVR?
Do you have the 1meg resistor mounted on the jack? (common location)azrael wrote:Hey, I'm getting some DC crackle from my 18W on my guitar's volume pot.
I put a 100nF coupling cap from the input jack to the grid stopper to block DC, but it didn't help. Any ideas?
If so, you need to move it to the other side of the new cap.
Re: Getting DC Crackle from VVR?
If you scale the whole amp I think you also have to put a cap and resistor at the grid of the tube where the volume pot is connected. This is what the directions indicated for the VVR that I got from Hall amps and I don't have any DC scratch on my 15 watt Lightning clone.
Re: Getting DC Crackle from VVR?
You said "guitar's volume pot." True? Then dirty pot.azrael wrote:Hey, I'm getting some DC crackle from my 18W on my guitar's volume pot.
Re: Getting DC Crackle from VVR?
No - a VVR can leak DC back onto the guitar when turned down to very lownsettings. Dana documents this along with the solution (easy).xtian wrote:You said "guitar's volume pot." True? Then dirty pot.azrael wrote:Hey, I'm getting some DC crackle from my 18W on my guitar's volume pot.
Re: Getting DC Crackle from VVR?
The 1M resistor is after the 100nF cap, but before the grid stopper.
I have the directions from Hall, but it's rather invasive, as the Baby Will 18W project uses a PCB and also uses two triodes in parallel.
I have the directions from Hall, but it's rather invasive, as the Baby Will 18W project uses a PCB and also uses two triodes in parallel.
Re: Getting DC Crackle from VVR?
azrael wrote:The 1M resistor is after the 100nF cap, but before the grid stopper.
I have the directions from Hall, but it's rather invasive, as the Baby Will 18W project uses a PCB and also uses two triodes in parallel.
My Lightning has both triodes of V1 in parallel as well and it works fine just attach the cap and resistor to where the signal is coming into the grid.
It sounds like you aren't sure how or where to mount the caps and resistors in your amp which is the boat I was in. Check out the link below to when I posted about this recently wondering how to mount the caps and resistors especially the link that angelodp sends which shows how to use a terminal strip to mount everything, this is the way that I did it. I attached the terminal strip to one of the tube socket screws and connected everything between the strip and tube socket pins. I don't think you need both the 1 M resistor and grid stopper either, the 1 M IS the grid stopper on my amp.
I hope this helps, good luck!
http://ampgarage.com/forum/viewtopic.php?t=14866
Re: Getting DC Crackle from VVR?
When I installed it in my amp, I wired the jacks like this, It should work just fine in a lightning.
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Re: Getting DC Crackle from VVR?
The 1M resistor is after the 100nF cap, but before the grid stopper.
In the link yowza posted, there is a photo of my V1 half way down with the terminal strip idea. I think you need to move the grid stopper before the capacitor like in the photo. Input to grid stopper to cap to pin with a 1M from pin to ground.
the 1 M IS the grid stopper on my amp
Yowza that doesn't make sense the 1M should go to ground not the pin. Did you mean to write grid leak? Either way this is not what Dana's instructions state to do.
I haven't yet bothered to understand the VVR circuit as I have other more important areas of amp design still to master but I hope to one day get all this VVR stuff.
In the link yowza posted, there is a photo of my V1 half way down with the terminal strip idea. I think you need to move the grid stopper before the capacitor like in the photo. Input to grid stopper to cap to pin with a 1M from pin to ground.
the 1 M IS the grid stopper on my amp
Yowza that doesn't make sense the 1M should go to ground not the pin. Did you mean to write grid leak? Either way this is not what Dana's instructions state to do.
I haven't yet bothered to understand the VVR circuit as I have other more important areas of amp design still to master but I hope to one day get all this VVR stuff.
Re: Getting DC Crackle from VVR?
Yes surfsup is correct, I was wrong, my grid stoppers are back at the input jack not at the tube socket and the cap is after those stoppers at the tube's grid with the 1 M after the grid pin going to the grounded terminal strip I used. I hope that makes sense. Sorry for any confusion! That's what I get for typing while watching the MLB all star game.surfsup wrote:
Yowza that doesn't make sense the 1M should go to ground not the pin. Did you mean to write grid leak? Either way this is not what Dana's instructions state to do.
Re: Getting DC Crackle from VVR?
Okay, cool guys. I'll try switching it around and seeing what happens. Should have time tomorrow.
In the meantime, I fixed up my Peavey VTM and am playing through that.
In the meantime, I fixed up my Peavey VTM and am playing through that.
Re: Getting DC Crackle from VVR?
Okay guys, I put the 100nF cap after the 33k grid stopper, but before the 1M resistor.
Still crackles when i roll down my guitar volume! ideas?
when I had it open, I modded it for tighter bass and more gain, totally worth it.
Still crackles when i roll down my guitar volume! ideas?
when I had it open, I modded it for tighter bass and more gain, totally worth it.