Hi Guys
I saw a schematic using 1/2 an at7 into an el34 which then feeds the 300b. Seeing I had a bunch of at's and el34's I thought why cant we make a preamp based on the 12at7 and el34. I built one channell but it doesnt seem to output the whole spectrum. Very Bassy but mids retsained and it looks like it rolls of real early. The at7 plate voltage is 145 V and only 1/2 the tube is used. The el34 is wired in triode mode.
Any advice or am i barking up the wrong tree?
Thanks
Nick
I saw a schematic using 1/2 an at7 into an el34 which then feeds the 300b. Seeing I had a bunch of at's and el34's I thought why cant we make a preamp based on the 12at7 and el34. I built one channell but it doesnt seem to output the whole spectrum. Very Bassy but mids retsained and it looks like it rolls of real early. The at7 plate voltage is 145 V and only 1/2 the tube is used. The el34 is wired in triode mode.
Any advice or am i barking up the wrong tree?
Thanks
Nick
Geez Nick,
Take it easy.
barking up the wrong tree.... woof woof...
Anyway, while I dont think its the right thing to do (an EL34 in a linestage) that does not mean its not possible.
I have read of 6c33 linestages and 572-10 linestages so why not.
I think you are using the wrong part for the job but that does not mean it cannot be done. I tend to be old school so do not explore a lot which means I am boring
I think an EL84 triode connected makes a decent linestage though, tried it once, thats about as exciting as I get!
Andrew
Take it easy.
I don't think anyone is laughing at you. I found Sy's response funny in relation to your last sentence.
barking up the wrong tree.... woof woof...
Anyway, while I dont think its the right thing to do (an EL34 in a linestage) that does not mean its not possible.
I have read of 6c33 linestages and 572-10 linestages so why not.
I think you are using the wrong part for the job but that does not mean it cannot be done. I tend to be old school so do not explore a lot which means I am boring
I think an EL84 triode connected makes a decent linestage though, tried it once, thats about as exciting as I get!
Andrew
Hey-Hey!!!,
Run it as a pentode. Adjust the plate load R to give you the gain you need. Build a stable, low impedance g2 supply.
I did just that with a 6AV5GA. 750R plate load. 75V g2. B+ of ~200V. Sounds absolutely brilliant. I haven't put my triode linestages back in very often...
cheers,
Douglas
Run it as a pentode. Adjust the plate load R to give you the gain you need. Build a stable, low impedance g2 supply.
I did just that with a 6AV5GA. 750R plate load. 75V g2. B+ of ~200V. Sounds absolutely brilliant. I haven't put my triode linestages back in very often...
cheers,
Douglas
A "wild" triode option is to ground the plate and the suppressor grid. Use the screen grid as the anode. G2 can easily dissipate the power line stage service requires.
The EL34 data sheet shows a mu of 11 between g1 and g2. That's pretty good for line stage service.
The EL34 data sheet shows a mu of 11 between g1 and g2. That's pretty good for line stage service.
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