Projet G5

No, no problems I didn't cause myself.
I finished my G5 in December, got the hum out in March, and it is the amp I use for recording, practicing, and occasional jamming. I'm quite happy with it.
I'm currently fixing my bad workmanship, and doing some tuning. I'm playing it through a Jensen C12Q in a badly made home built cabinet.

2 questions:

I saw in V2 the rating of R21 was reduced to 2 watts. The Babelfish translation of the explanation didn't make any sense. What is the reason?

Also, R20 has been reduced to 120R. Am I correct in thinking this will permit me to use either a 6L6 or EL34?

thanks

steven

Hi,

120R work good. You can replace this one with a variable bias (see the G5 v2). I had made this circuit and to change tube, just adjust the bias with the trimer

excuse for my little english

your english is better than my french, which is limited to "une cru classe, sil vous plait"

Hi sjhusting,

Let's have a look on EL34 typical charasteristic (e.g. at http://www.jj-electronic.com/pdf/E34L.pdf)

Ua = 250V
bla bla bla
Ig2 ~15mA

The power dissipated in R21 will be :
P = RI² = 2200 ohms x (15mA)² ~ 0,5W

OK, 2W is quite mojo-overrated, but who cares ?

Sheers ...

I get it. The 5-watt was just way overspec'd, which was ok, but now we have to put a huge capacitor in there, too, so space is valuable.

bit by bit I understand more

steven

You bet !