in the past when I make 45. I plan to use parafeed to on 1700R plate resistance of 45 which need choke around 30H as picture.
However I don't know the value of 811A plate resistance to calculate. Anyone can guide which value of 811A plate resistance to be used in calculation of CHOKE.
Hammond 1628SE has 40.78Henry. instead of using OPT as parafeed choke I think buying 45H choke 120mA might save a lot of cost.
However I don't know the value of 811A plate resistance to calculate. Anyone can guide which value of 811A plate resistance to be used in calculation of CHOKE.
Hammond 1628SE has 40.78Henry. instead of using OPT as parafeed choke I think buying 45H choke 120mA might save a lot of cost.
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If EL84 can drive 811A, I hope 6P14 (I already have) might be applied to be modified to replace 6V6GT of Mr. Palustris in post #36.
PS mistake in post #39 I have 6P14 not 6P15
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430VDC 100mA x 2 my HV reg clone from PV12 preamp using in 45 can't handle such 200mA. Only choice I see is T-Reg HV reg that can handle 500VDC 400mA.
If use CLCRC, and control voltage by changing R to match 430V. I need to buy many R to test.
Then any simple HV reg that can handle 500VDC 300mA than T-reg recommend?
If use CLCRC, and control voltage by changing R to match 430V. I need to buy many R to test.
Then any simple HV reg that can handle 500VDC 300mA than T-reg recommend?
I've traced the 6F12P and 6J52P.
Since the image is too big, I put them into the Zip file.
Hope they could be helpful
Since the image is too big, I put them into the Zip file.
Hope they could be helpful
I found old documents of the 811A prototype I built almost 15 years ago. My version has relatively high supply voltage (750V) and therefore grid current drive of 811A is lower than examples shown here with 400...500 V supply voltage. Therefore I would recommend 6N6P or 6DJ8 as a driver tube.
Attached the schematic and test results.
Attached the schematic and test results.
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Using 811a at low/er/ anode voltage (and class A2: positive grid voltage, relatively large grid current == beefy DC coupled driver) advantage is the lower impedance OPT (lower cost).
Sample:
Sample:
Thank you all of kind many experts guys whom kindly help me
Yesterday, i went to tube shop nearby and shop owner has recommend 6SN7 EL34 811A on 3.5K Opt
Modify alike this JAPAN
https://www.wavac-audio.jp/md811_e.html
I have to study all of your guys recommendation for awhile
Really appreciated so much for kundly help
The latest schematic is my first priorty on 3.5K to get high watt from 811a
Now my SB brommo 85db will have more power to rock than 45 SE or 4p1l PP
Yesterday, i went to tube shop nearby and shop owner has recommend 6SN7 EL34 811A on 3.5K Opt
Modify alike this JAPAN
https://www.wavac-audio.jp/md811_e.html
I have to study all of your guys recommendation for awhile
Really appreciated so much for kundly help
The latest schematic is my first priorty on 3.5K to get high watt from 811a
Now my SB brommo 85db will have more power to rock than 45 SE or 4p1l PP
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I think this schematic match all my tequirement but just 2 things needed
1. Replace 6v6 to EL34 mullard Russian made cheap and ok
2 EL34 should be fixed bias to prevent unbalanced tube that I encouter with 45 SE how much negative voltage of fixed bias of EL34 if replace?
I guess if replace with EL34 fixed bias negative voltage will be around -15V
I don't have knowledge I just clone other i admit it.
Thank you so much
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