O/P tran impedance

[Enzo]

Oh yay, another semantic exercise.

The current flows through the circuit - I'd hesitate to call it used up. If anything the resistor uses up voltage. Current is the same throughout a series circuit.

If you increase a series resistance, it decreases the current a load can draw.

[tubeswell]

Okay then - if I was to reiterate, I would say; I = E/R, therefore as you increase R, you are making the fraction that is 'I' smaller so for e.g.; 1(I) = 10(E)/10(R) whereas 10(E)/100(R) = 0.1(I). However to take this further, if E gets smaller at the same time as R gets bigger then I = 1(E)/100(R) = 0.01(I). Which comes back to saying there must be less 'I' if you add 'R' and decrease 'E'.

Forgive me for my laconic expression "use up current".

[Enzo]

What are friends for if not to pick on you?

[alastair_in_oz]

Oh so sweet!

I used 4 x 5v 5w zeners in series to get 60v drop. The trany was a little higher on the secondary 385 - 0 - 385, but it all worked out perfect with 419v B+ loaded. I used the 60v drop to create my bias voltage.
Wired up the amp and tested voltages. Had to adjust the supply dropping resistors from 10k to 20k because this amp has 2 x 12AX7/12AT7 type valves, not the 6 or so a DR has.
This is a 1 channel amp with ss reverb... I know, why put a ss reverb in? A short tank is all I could fit into the amp head and I was unable at the time to get a short tank with low impedance input. Also I don't have to have the 3.3meg resistor and the extra valve stage.

Trust me on this, I did try and build a tube reverb with this tank, but the sound sucked, so ss for now.
I tried the tone stack bypass mod, I just wired the 47pf across the vol pot and used the bright switch to lift the mid pot off ground. There is a large jump in vol and the tone is much more clearer, fuller, less "filtered". Its hard to give the sound a name, but it rocks! My bright switch has a spare set of poles, I was thinking of using this to bring in a series resistor before the PI, to equalize the vol a bit, have to have a play and see what value resistor and bypass cap will work. (The whole exercise may be pointless if it sucks some tone off: gain tone by removing the tone stack and loose it later in the circuit.)
Well, one can only try and see for yourself.

I was a bit worried that the tone stack bypass mod would now overload the input of the reverb when the amp is cranked. So I connected the now unused master volume pot across the input to the reverb. Set about 8 or 9, this has improved the overall sound of the reverb, not so poingy and I can turn the reverb pot up to 6 or even 12 and it sounds great! Just have to measure the pot in this position and use a couple of fixed resistors.
The next mod I may try is the PI master vol. Not so sure about that one though, I don't want to loose any tone, after all, I built this amp to get "that sound". The only way is to try it.