At the grid of V1-B, is that 2.2M in parallel with the 250k pot? I am wondering how to make it a more "normal" impedance of 1M. If I swap the 2.2M for a 1M will that work? Or like I asked already. is that resistor in parallel with the 250k pot, in which case the impedance would be lower than 250K.
I guess what I am asking is....What would be a better impedance at the grid of V1-B, and how do i achieve it. I am not sure i have access to a 1M PCB potentiometer.
Thank You
Crate v18
Moderators: pompeiisneaks, Colossal
Re: Crate v18
This would be a great candidate for a decade box. You could set it for 2.2M and then go up and down until you are satisfied with the result.
My Daughter Build Stone Henge
Re: Crate v18
It's a grid leak resistor, it sets the impedance of the following stage.
You can experiment with the value.
The lower it is the more it will attenuate the signal.
You can experiment with the value.
The lower it is the more it will attenuate the signal.
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: Crate v18
It looks like one of those "just in case" resistors that protects the grid (and current) from drifting up if the wiper goes bad. It's also lowering the 250k impedance a little since it’s parallel. You would need to change the pot to 1meg to move in the direction you are thinking.
If it says "Vintage" on it, -it isn't.
Re: Crate v18
10-4jjman wrote:It looks like one of those "just in case" resistors that protects the grid (and current) from drifting up if the wiper goes bad. It's also lowering the 250k impedance a little since it’s parallel. You would need to change the pot to 1meg to move in the direction you are thinking.
That is exactly what I was thinking, but I was not sure if that 2.2M was in parallel with the pot. It is hard for me to tell. OK, so I need to locate a PCB mounted 1M that will fit.
Thank You
Re: Crate v18
10-4jjman wrote:It looks like one of those "just in case" resistors that protects the grid (and current) from drifting up if the wiper goes bad. It's also lowering the 250k impedance a little since it’s parallel. You would need to change the pot to 1meg to move in the direction you are thinking.
That is exactly what I was thinking, but I was not sure if that 2.2M was in parallel with the pot. It is hard for me to tell. OK, so I need to locate a PCB mounted 1M that will fit.
Thank You