EL34(6CA7) in place of a 6V6?
Posted: Wed Apr 06, 2005 8:36 pm
I've been fooling around building some basic amp circuits before I move onto some more difficult projects. I'm still a a beginner but I'm having lot5s fo fun experimenting with the circuits. My latest is a scratch built 5F1 (tweed champ) based on my '59 champ and the schematic and layout diagrams avilable on the net.
I've worked hard to get this amp running quiet and sounding good. I'm thinking since I own the real thing I could use the clone as a spring board for some experimentation.
What I'd like to do is mod it to use an EL34 in place of the 6v6 (maybe make it switchable). So far I've been able to find one diagram which deals with converting form a 6L6 to an EL34 but nothing about a 6V6.
The amp runs standard champ voltages (with 120 out of the wall)
B+ 402 vdc
Grid 325 vdc
v1.6 183 vdc
v 1.1 186 vdc
From the litlle I can find online or in print it appears I will need:
(approximately) a 250 ohm 5w+ cathode resistor and a 100 uf/100v cathode bypass cap.
pin 1 and 8 should be wired together (and connected to the cathode resistor) as opposed to on the 6v6 where 1 and 2 are wired together and go to ground (and only pin 8 goes to the cathode resistor).
a 1k5 resistor between pins 5 and 6 with pin 6 going to the 220K resistor to ground.
What have a missed/forgotten?
You can find a 5F1 schematic at http://www.ampwares.com/ffg/champ_narrow.html if you are not familiar with it.
Any pointers that someone can offer would be appreciated. Remember, this is scratch built and not a real 5F1 so changing parts isn't a big deal.
Thanks
Pelnerd
I've worked hard to get this amp running quiet and sounding good. I'm thinking since I own the real thing I could use the clone as a spring board for some experimentation.
What I'd like to do is mod it to use an EL34 in place of the 6v6 (maybe make it switchable). So far I've been able to find one diagram which deals with converting form a 6L6 to an EL34 but nothing about a 6V6.
The amp runs standard champ voltages (with 120 out of the wall)
B+ 402 vdc
Grid 325 vdc
v1.6 183 vdc
v 1.1 186 vdc
From the litlle I can find online or in print it appears I will need:
(approximately) a 250 ohm 5w+ cathode resistor and a 100 uf/100v cathode bypass cap.
pin 1 and 8 should be wired together (and connected to the cathode resistor) as opposed to on the 6v6 where 1 and 2 are wired together and go to ground (and only pin 8 goes to the cathode resistor).
a 1k5 resistor between pins 5 and 6 with pin 6 going to the 220K resistor to ground.
What have a missed/forgotten?
You can find a 5F1 schematic at http://www.ampwares.com/ffg/champ_narrow.html if you are not familiar with it.
Any pointers that someone can offer would be appreciated. Remember, this is scratch built and not a real 5F1 so changing parts isn't a big deal.
Thanks
Pelnerd