Vox AC30 CC2 PPIMV. What are these R´s for?

[Mostro]

Hi.

I´m trying a PPIMV, and I see in the Vox AC30 CC2 schem, that has a PPIMV also, that it has 10K R´s inline between the PI caps and the power valves grid resistors, before the master volume pot. What do these do? What are they for? To avoid having zero resistance between the two lines? To solve a pot feel issue? I´m clueless.

Cheers.

[Stevem]

They are called grid stoppers and they are used to stop oscillations from taking place in the output stage.

[Mostro]

Stevem, the amp also has the typical 1K5 grid stoppers of the AC30, these are in addition to the 1K5 R´s. Do they also work as grid stoppers, so each power tube gets 11K5 of resistance?

EDIT: What calls my attention is that they are before the master vol pot. Why not put them after if they are grid stoppers?

[talbany]

Stevem, the amp also has the typical 1K5 grid stoppers of the AC30, these are in addition to the 1K5 R´s. Do they also work as grid stoppers, so each power tube gets 11K5 of resistance?

EDIT: What calls my attention is that they are before the master vol pot. Why not put them after if they are grid stoppers?

Do you have a schematic I can look at..

Tony

[Mostro]

Yep, here:

http://www.bymcomunicacion.com/pvecino/ ... 2_CC2X.pdf

[mauiboy81]

They make the cut control and MV work better together

[Mostro]

Mauiboy, could you explain a bit more? How do they work? Do they isolate the master from the cut so they don´t interact?

[surfsup]

Voltage divider sending less signal to the output? I dont have a schemo...

[mauiboy81]

Hey mostro I was in a hurry earlier. Yes, the 10k's isolate the two controls so the loading of the MV doesn't mess with the cut response. Without them the cut control is pretty much useless as the master is turned down.

[Mostro]

Thanks Mauiboy for the explanation. Makes sense now.