Aikido

[simon]

Okay, if I understand this correctly, considering the first circuit on the third of Steve Bench's pages here: http://members.aol.com/sbench/reg3.html if I use a 750V ct tx, a GZ37 and choke input I reckon I should be able to achieve maybe 300V on the pass tube anode. Output voltage could be a little more than this, but if I assume 350V and the JJ EL509 has Vhk=150V I should elevate the heater supply to just over 200V, say 210V.

Using the pentode section of the ECL82 as the error amplifier with Vhk=100V, the cathode is at 105V thanks to the VR tube, so the difference between cathode and heater is 105V which is more than 100V and perhaps a little too high.

So elevating the heaters to:
105V + Vhk(ECL82 - 100V) - a bit, say 195V
would give me a maximum B+ dictated by the heater/cathode insulation of:
195V + Vhk(EL509 - 150V) - a bit, say 335V.

Presumably I can set the 195V with a divider from B+? If I were to use a lower B+ then although the elevated voltage would drop, the difference between heater and cathode should be okay. If the output voltage were to go as low as 170V the heaters would be elevated to approx 100V, 70V diffference for the JJ509 and 5V difference for the ECL82.

Or have I just made a load of numbers fit flawed logic???

[Nick]

Sounds ok, 6080 might be a better bet though, as that can handle Vhc at 300v.

We can witter about it tonight of you like.

[simon]

Look forward to it!

[shaun]

thanks for the iluminating posts nick they have helped me to see whats happening to the signal current.i had not given it that much thought and as you say seen things as a one way street.

i have not had time to try the 1ohm resistor yet but i will and let you know how it goes. i think i can see where your comming from on that so it should be interesting.

by the way i'm using two fillament supplies on my regs. one AC for the pass and a regulated supply on the control valves. (i know not strictly needed but i had a spare one )

take care

shaun

[shaun]

Hi Nick

How’s it going?

I had some time off today so I tried your idea of putting 1Ω resistors on the OP if my Regs.

First impressions are cleaner, clearer, and tighter and to my ears better (more of the sound of the OP caps less of the Reg). at first it seemed to be a bit counter intuitive to increase the OP resistance of the Reg but once I started to think about what happens to the signal current it made more sense.

It has made a noticeable difference in my set up so I guess that’s two of us that are hearing things.

Thanks for sharing your thoughts on that

Take care


Shaun

[Nick]

Ok, thats good to know that both of us are finding the same thing.