5E3 Pre-PI Master Volume Question

[Jazzcab]

Hey everyone, I'm finishing up an 5E3 build and needed some help and clarity from the electronics wizards of the forum.

I've read many have had success taming some of the rudeness of the 5E3 (when pushed hard) by placing a grid stopper resistor before the V2b PI. Then some will add that on a switch to have the best of both worlds. I was originally going to do this mod but then...

I was reading there's a camp that instead of that will pull the 1M resistor before V2b PI and replace with a 1M pot to tame the harshness but also adding a master volume in the process as shown here.



That sounds like an upgrade to the resistor on a switch but some folks report this pot will have a limited response with most of the effect scrunched up into 1/4 to 1/3 of the range of the pot.

Then there's this one below. People report getting a full range from the pot. My question can I omit one of the .022uf caps or are they both needed, can and the 470k grid stopper resistor go? Seems like the 1M pot would be taming the harshness on its own?



TIA

[sluckey]

Hmm, I feel like watching Déjà Vu, again.

[Jazzcab]

Hmm, I feel like watching Déjà Vu, again.

Hey Steve, thanks for your help. I'm trying to finish this up this weekend and seeing if there's any words of caution, tips, tricks etc that someone can point me in the right direction with.

You mentioned you didn't know about the need for the grid stopper resistor in the second diagram so I'm just throwing it out here.

[sluckey]

Fender sold thousands of 5E3s without a grid stopper. That's why I said, "The 470K grid stopper is not needed but you may like it."

He probably didn't suspect that one day many people would "dime" all the knobs on an amp, including the 5E3. That's the reason for needing a grid stopper. It's also the reason you may like it.

But if you play a 5E3 in the manner that Fender intended, you will not need a grid stopper. Yeah, I know. Times have changed so keep the grid stopper.

[Jazzcab]

Fender sold thousands of 5E3s without a grid stopper. That's why I said, "The 470K grid stopper is not needed but you may like it."

He probably didn't suspect that one day many people would "dime" all the knobs on an amp, including the 5E3. That's the reason for needing a grid stopper. It's also the reason you may like it.

But if you play a 5E3 in the manner that Fender intended, you will not need a grid stopper. Yeah, I know. Times have changed so keep the grid stopper.

I see what you mean.

If inserting a master volume like in that second image without a grid stopper resistor would have no effect taming that rude phase inverter distortion I’ll probably stick with my original plan and just put that grid stopper resistor on a switch.

Thanks for all your help

[Ten Over]

Then there's this one below. People report getting a full range from the pot. My question can I omit one of the .022uf caps or are they both needed, can and the 470k grid stopper resistor go? Seems like the 1M pot would be taming the harshness on its own?

You cannot omit one of the .022uF capacitors.
The 470k grid stopper reduces the harshness and does you no harm. Leave it in.