VVR. Entire amp or power section?

[Madison]

Which is your preference?
Looks like just the power section is less work and parts?
This for an SE EL34 amp.

[Boots Deville]

I built a tweed style SE EL34 amp where I scaled just the EL34 plate and screen, and am happy with the result.

I added an additional PS node for the preamp to give it some additional filtering since it was getting "cheated" out of the filtering for the place and screen due to the VVR.  If its a new build, no problem.  In an existing build it might be a hassle.

[jojokeo]

I did the same thing as Boots suggests and love it. I don't turn the VVR down as much as I thought I would before I built it but it's there if you want it and it works and really soungs great. I've got about 265v to the preamp load resistors w/ the VVR up and it raises to 300v when it's fully turned down due to less loading. I use the VVR as the Master Vol and it's all you need. I couldn't imagine needing or wanting a regular MV and the VVR for this type of amp. I hear it's good w/ a PP amp w/ more power but for only SE there really is no point IME. I just posted a pic here of it after swapping my PT. http://www.el34world.com/Forum/index.php?topic=12160.msg112890#new

[Madison]

Great info.
I'll see how it goes.
Thanks a lot!

[LooseChange]

Done many amps with just the plates and screens regulated. I like this way the best.
I agree with jojokeo, once you get over the cool bedroom levels, turning it down just a bit to get the grind you want at any volume is the way I use it too.

[Madison]

Ok,I am sold.
I will ace the existing 250K MV on this amp, replace with a resistor, and have that hole the VVR.
Anything to worry about running wires under the board for interferences?
No shielded wire necessary?

This actually helps my a lot with the cabinet.
I have a hole drilled in the rear of the chassis for the VVR pot, I guess I can cover it up with that back panel.

>>PS node for the preamp
PS?
What is it?
(I am going to kick myself when you guys tell me)

Thanks!

[Boots Deville]

sorry.  PS node is "Power Supply Node".  An extra dropping resistor and filter cap in the power supply to filter the DC to the preamp.  The preamp won't benefit from the filtering for the plate and screen, so I've had to install more filtering for the preamp in a few VVR installations.  You may not need to, but if it's a scratch build, might as well leave room for it, if you have the space.

[Madison]

This works really well!
Thanks guys.
BTW, Boots, I definitely needed the P.S.!
On an SE amp it works very well, can't wait to try it on a 50 watter.

Onward!

[harryk]

This works really well!
Thanks guys.
BTW, Boots, I definitely needed the P.S.!
On an SE amp it works very well, can't wait to try it on a 50 watter.

Onward!

Hi Madison! Did you scale the whole amp or only PA or PI+PA?

[Madison]

>>Did you scale the whole amp

Only the power tube.