• 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.

Dynaco Mk3 Poseidon input/driver boards

Hi, knowing that pcb's are no longer available, i will do a point to point poseidon circuit based on that design.

Planning on using LM334 for constant current source the 12AX7 input tube.

I saw that 12AU7 driver could be subt. for a 12BH7A, any mods I have to look for this driver stage?

Since Poseidon designer does not sell or follow??? theses boards or circuit, is there recent mods I have to take to before start installing and soldering parts???

Thanks
 
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[URL="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=2ahUKEwjsl-y166vnAhUYXc0KHbVNDbYQFjAAegQIAhAB&url=http%3A%2F%2Fsite.triodestore.com%2Fposeidon.pdf&usg=AOvVaw2ICAvdlCNm8iVJcuFAGMlR”]MKIII h - Triode Electronics[/URL]

Yes I know about this previous link , thanks but they don't have the pcb anymore.
I'm looking for some user feedback regarding 12BH7A driver.
It is pin-to-pins drop in tube, but operation is the same???

I've use this 12BH7A in the vg Quicksilver's V4 monobloc.

Thanks.
 
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No, the driver stage 12AU7 pins 3 and 8 where U1 LM334 is current source.
 

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Hi, knowing that pcb's are no longer available, i will do a point to point poseidon circuit based on that design.


Planning on using LM334 for constant current source the 12AX7 input tube.


I saw that 12AU7 driver could be subt. for a 12BH7A, any mods I have to look for this driver stage?


Since Poseidon designer does not sell or follow??? theses boards or circuit, is there recent mods I have to take to before start installing and soldering parts???


Thanks
This is an oxymoron. A Dynaco MkIII has no poseidon bords. An amp with poseidon bords is a 60w amp made
with some dynaco parts.

An accurate title could attract knowledgeable people, an suspect title could repulse readers.
 

baudouin0

Member
2019-03-22 5:41 pm
UK
A 12BH7 will work just fine in place of the 12AU7 the DC plate voltage is not determined by the choice of valve (as long as the grid does not go positive) but by the CCS and the 68K. Gain is not much different. Heater current is double however.
 

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