rocket head room

[brodie900]

yea i used to have that switch but i got rid of it and wired it straight to 300 when i put the heyboer tranny in. im in Australia so we have 240 mains but i think the 290/260 switch is supposed to be like the comfort/speed on the new z wreck.

[overtone]

I remember trying that switched option for 260V / 300V on a Rocket with the Heyboer (230V here). I also tried the so called "half power switch", but all those extra switches kind of runs against the minimalist approach of the Rocket. As I did not care for either the 300V, or the half power, I stuck with the 260V and full power.
If you use the 300V you really do need to use a higher value cathode resistor and I don't see that taken care of in the C. layout mentioned.
There is a forum member here, I forget the name at the moment, who preferred the 300V in conjunction with cathode resistor well above 70 Ohms, I think it was 76 Ohms.

[brodie900]

ok here are my new voltages @ 260V

b+1 = 288
b+2 = 279
cathode V = 8.9

power tubes;

1. pin2 = 13mv, pin 7= 279v, pin 9=272v,

2. pin2 = 13mv, pin 7= 279v, pin 9=272v,

3. pin2 = 13mv, pin 7= 281v, pin 9=272v,

4. pin2 = 13mv, pin 7= 281v, pin 9=272v,

pin 2 is only an approximation because it seems to fluctuate between 15mv and 10mv. could just be my Multimeter.

i have more headroom now too! i think these tubes are a bit dead tho as they were flogged at that high b+ for quite a few gigs

[brodie900]

I remember trying that switched option for 260V / 300V on a Rocket with the Heyboer (230V here). I also tried the so called "half power switch", but all those extra switches kind of runs against the minimalist approach of the Rocket. As I did not care for either the 300V, or the half power, I stuck with the 260V and full power.
If you use the 300V you really do need to use a higher value cathode resistor and I don't see that taken care of in the C. layout mentioned.
There is a forum member here, I forget the name at the moment, who preferred the 300V in conjunction with cathode resistor well above 70 Ohms, I think it was 76 Ohms.

it's all starting to make sense now!
i also got rid of my half power switch cos iv never been a fan of bells and whistles

[martin manning]

Running the numbers again, then:

cathode current 0.0445
screen current 0.007
plate current 0.0375
Pa 0.0375*(288-8.9)=10.47
10.47/12=72%

It should be happy there. Good work!

[brodie900]

thanks so much for the help everyone! i can gig with my rocket again now!