choke size and choke vs resistor

[daz]

It no longer matters, as i decided to leave the choke for a couple reasons. One is that i felt there was something in the attack that wasn't quite right and i felt like the big dropping resistors might be the cause. I recall preferring higher voltages in the preamp but if i recall but did the opposite at one point by using 18k at the 1st tube and 10k at the other 2 because marshalls used that value. (the 10k's, not the 18k) Like i said, theres a lot of leftover designs things from when it was a el34 amp. So i looked at some 6v6 designs and i think it was a deluxe that showed 4.7k resistors. So i paralleled the needed values to get them around 5k and there it was. It's just about perfect and i no longer feel the choke is causing a stiff feel. I don't know if those design changes you (Chuck) made and i implemented are no longer theoretically valid with the higher V, but it sure feels right now.

[daz]

By the way, is 2 watt oxides fine for the dropping resistors? I have 3w there now but i wanna replace the paralleled pairs with the proper value and theres some on ebay for $3 shipped while all 3w ones are more then twice that.

[Helmholtz]

There is no too much reason for sag,or substantial one,as time the current draw after plate supply is pretty consistent. You may try a simply sense diode after the plates supply cap, between plate cap and screens cap nodes if you screens current is limited .

Average screen current increases by a factor of 3 to 6 (probably more with clipping) at full output.
Typical full power signal screen current is around 20mA per tube for an EL34 or a 6L6.

Peak screen current is even higher by maybe a factor of 2. That's why screen resistors are so effective lowering dynamic screen dissipation.
Of course the B+ sag also lowers screen voltage.

What is a sense diode?

[Chuck H]

By the way, is 2 watt oxides fine for the dropping resistors? I have 3w there now but i wanna replace the paralleled pairs with the proper value and theres some on ebay for $3 shipped while all 3w ones are more then twice that.

2W should be fine. That's still a generously high rating for preamp dropping resistors.

[catalin gramada]

Average screen current increases by a factor of 3 to 6 (probably more with clipping) at full output.
Typical full power signal screen current is around 20mA per tube for an EL34 or a 6L6.

Peak screen current is even higher by maybe a factor of 2. That's why screen resistors are so effective lowering dynamic screen dissipation.
Of course the B+ sag also lowers screen voltage.

What is a sense diode?

He should be able to make a simple string series of zenners to stabilize the voltage for such of current it need.