Just playing with consepts.
Intrigued by the use of active valve pre-amps to set up a character to the sound of a solid state amp. Which I know people here do.
Just a thought, googled low voltage valve behaviour. Have always like the Vlave wizard's stuff. He comes from the guitar amp angle.
Last concept on the link, just go to END.
But add a third triode, CF on input then this lot. ECC82 looks the most suitable.
Might already have the necessery power available in a solid state pre-amp , use the power and the selectors, throw out the circuit.
Sorry to say I'll never get anything done for Owsten least of all this. There are always more Owsten's.
Low voltage valves
- Paul Barker
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#1 Low voltage valves
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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- Old Hand
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#2
I know the concept and have spent some time in various experiments.
Not all tubes are adequate for starving (low anode voltage), a good example in the mu=20 class is the inconsistency of 6SN7 (12SN7) that has lead to the development of the 12SX7 as low voltage "stable" variant.
In the ECC82 family, this task is probably best performed by the 5693, and industrial version.
I don't like the sound of "starved" triodes. There is a certain point that we might consider as "minimum" voltage across the tube. For 5670 that is slightly less than 90V, after which point the sound is not good.
The ECC88/6DJ8 is the most forgiving probably among "normal" tubes, and of course there are sub-miniature tubes that were specifically designed for low voltage operation, which would probably be best suited to such conditions.
Not all tubes are adequate for starving (low anode voltage), a good example in the mu=20 class is the inconsistency of 6SN7 (12SN7) that has lead to the development of the 12SX7 as low voltage "stable" variant.
In the ECC82 family, this task is probably best performed by the 5693, and industrial version.
I don't like the sound of "starved" triodes. There is a certain point that we might consider as "minimum" voltage across the tube. For 5670 that is slightly less than 90V, after which point the sound is not good.
The ECC88/6DJ8 is the most forgiving probably among "normal" tubes, and of course there are sub-miniature tubes that were specifically designed for low voltage operation, which would probably be best suited to such conditions.
- Paul Barker
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#3
Yes a friend was playing with one designed for 12v in car radios. But the curves show that it is only any good for class B push pull.Alex Kitic wrote:there are sub-miniature tubes that were specifically designed for low voltage operation, which would probably be best suited to such conditions.
The guitar boys were making great distortion for practice amps from them.
No good for our needs, but fun.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein