Use large (5X your current draw) schottky diodes to minimize the voltage drop. You should be able to get near 12V that way. For a single 12AX7 1A diodes will work fine, but 3A might give you less forward drop.
What topology rectification are you using? Half wave? Full Wave center tapped? Full wave bridge?
What is the ampere rating of the transformer? You may have too much internal IR Drop.
What size capacitor do you have?
How much ripple (AC) riding on the DC?
What topology rectification are you using? Half wave? Full Wave center tapped? Full wave bridge?
What is the ampere rating of the transformer? You may have too much internal IR Drop.
What size capacitor do you have?
How much ripple (AC) riding on the DC?
heater center tap
There is a center tap on the heater of the 12AX7, making it two six.threes (nine). I've been rectifying the AC heater supply of my H182 organ to try to get some dc to bias a NFET gate, I cant get more than 5 VDC, so I think Hammond runs their heaters at about 5 vac. The tubes lasted 42 years so far, and they don't hardly glow. Go the the flea market, buy a 6VAC wall plug transformer, they are $1 here at the charity resale shops.
There is a center tap on the heater of the 12AX7, making it two six.threes (nine). I've been rectifying the AC heater supply of my H182 organ to try to get some dc to bias a NFET gate, I cant get more than 5 VDC, so I think Hammond runs their heaters at about 5 vac. The tubes lasted 42 years so far, and they don't hardly glow. Go the the flea market, buy a 6VAC wall plug transformer, they are $1 here at the charity resale shops.
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