Schematic for EL84's in a 5E3

[Memphis]

Anyone have a schematic or layout for running EL84's in a 5E3.


Thanks
Bruce

[teleamp]

Double check me on this: screens pin 9 (6V6 pin 4), OT leads pin7 (6V6 pin 3), heaters pins 4 & 5 (6V6 pins 2 & 7), cathode pin 3 (pin 8), input pin 2 (pin 5).

For longer tube life keep the plate voltage at 300 V.
Use 100 - 1000 ohm screen resistors.
Use a 130 - 150 ohm cathode resistor.

[drlowlow]

might want to keep an eye on the current draw as the el84s will draw more amps then the 6v6s would.

[Memphis]

EL84's in a 5E3

Thanks for the replies. I was aware of the current draw and my trannies are up to the challenge. This is just one I built to experiment with.

Bruce

[Bruce / Mission Amps]

With proper power tube bias (11-12 watts or less), 350vdc on the plates is OK.
You might find that two 12AY7s work better then the standard layout.

[tubeswell]

With proper power tube bias (11-12 watts or less), 350vdc on the plates is OK.
You might find that two 12AY7s work better then the standard layout.

Hi Bruce

Is that to do with the different transconductance of EL84s vs 6V6s? i.e.; are you meaning that the drive voltage into the output tube signal grids would be better being lowered slightly by using lower gain pre-amp tubes, in order to get a cleaner signal at the output tube plates when using EL84s and opposed to 6V6s?

Sorry for these inane questions - but I think this concept is slowly starting to sink in to my thick skull , but I just want to double-check my understanding.

[Dave H]

EL84s in 5E3

I run EL84s in one of my homemade 5E3 style amps using a couple of octal to 9pin converters made out of old octal valve bases and B9A sockets. I just changed the cathode resistor on the EL84s to 150R and removed the 25u cap from the cathode of the 12AX7 to reduce the drive. It works fine. With the 25u cap removed the gain is about the same as the stock 5E3.