• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Tentative EL84 SE Design.

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G

Member
Joined 2002
Hello all,

Sitting around the shop bored so I threw this design together using data sheets. Anyone see any problems or have any suggestions for improvements? I was thinking about using a 12AT7 instead of the 12AX7. Thanks for looking.

G
 

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diyAudio Senior Member
Joined 2002
THE ALFABET.

Hi,

e)better still,use a separate supply for in- and output tubes.

f)better still,regulate the anode supplies for both tubes.

g)better still,up the anode supply for the 12AX7A to at least 300VDC

h)hey,and what about a volpot at the input?

Okay you got 18 characters left...:D

Cheers, ;)
 
No, I meant seperate 250 ohm resistor for each cathode.
I think 150 will leave you underbiased, no?

It depends where you want to operate them I guess, but a 6BQ5 in triode mode will draw somewhere around 40mA. E=(250)(.040)

=-10V bias. Seems about right.

And if you run them in triode mode, you will get just under 2W per channel. Switching to pentode will get you over 5, but will be more like a guitar amp!;)
 
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