Hi guys,
I got this cute miniature 6ag5 tub from a friend i traded with.
googling for an application i came across a radio citcuit using it in a 12 volt application.
Just out of curioity i powered up mu 12 V dektop supply and plugged some resistors 'n caps in my breadboard.
Within a short time i was hearing audio, after a bit tinkereing i am hearing GOOD audio.
Looks all cool on the scope. Don't know how to measure distortion, but it sounds teriffic.
Now i am suspecting there is some drawback, else we would all hook tubes to low voltage supplies.
Could anybody enlighten me why this isn't done more?
I am thinking: 12 lead acid battery and make a hummless phono!
I got this cute miniature 6ag5 tub from a friend i traded with.
googling for an application i came across a radio citcuit using it in a 12 volt application.
Just out of curioity i powered up mu 12 V dektop supply and plugged some resistors 'n caps in my breadboard.
Within a short time i was hearing audio, after a bit tinkereing i am hearing GOOD audio.
Looks all cool on the scope. Don't know how to measure distortion, but it sounds teriffic.
Now i am suspecting there is some drawback, else we would all hook tubes to low voltage supplies.
Could anybody enlighten me why this isn't done more?
I am thinking: 12 lead acid battery and make a hummless phono!
This IS being done and is already a very famous approach in the headphone amplifier scene. The most notable implementation mates it with a buffer output and is called the Millet Hybrid Amplifier.
12 Volt is maybe to overdo it.
😀
But there are a few tubes that do reasonably well at lower voltages.
Say between 50-100 Volt.
But some values of performance will not be optimal.
What will suffer I do not know, as I am no tube expert.
One tube that can run a bit lower (than 200 Volt) is 6DJ8/E88CC/6922.
Here is a thread about same topic:
Running tubes at lower voltages
🙂
😀
But there are a few tubes that do reasonably well at lower voltages.
Say between 50-100 Volt.
But some values of performance will not be optimal.
What will suffer I do not know, as I am no tube expert.
One tube that can run a bit lower (than 200 Volt) is 6DJ8/E88CC/6922.
Here is a thread about same topic:
Running tubes at lower voltages
🙂
Nope, these are tubes designed for 12V operation - typically for car radios!
Thought about finding some, but in the end I have too many other things to do!
Owen
Thought about finding some, but in the end I have too many other things to do!
Owen
For 12v single triodes we have the 12AE6A, 12FK6, and 12FM6.
These are all designed for car operation and can thus run well off a 12v SLA.
These are all designed for car operation and can thus run well off a 12v SLA.
Hi ,
I don't know about the space charge valves mentioned earlier but the ECC86 looks like a safe bet . Otherwise if you can stretch to 50v or so , miniatures such as 3S4 are a possibility and there are many subminiature types that run at low voltages . Steve Bench has a battery phono stage on his site , maybe a good reference ?
cheers
316a
I don't know about the space charge valves mentioned earlier but the ECC86 looks like a safe bet . Otherwise if you can stretch to 50v or so , miniatures such as 3S4 are a possibility and there are many subminiature types that run at low voltages . Steve Bench has a battery phono stage on his site , maybe a good reference ?
cheers
316a
I have a bunch of NIB 12CN5 and was thinking of a battery amp myself. These are IF pentode but ought to work at lower frequencies I'd think. You can actuallly get 4.5 mA plate current happening with 12 volts B+. Here's data on this baby. http://www.nj7p.org/Tube1.php?tube=12cn5
Eli Duttman said:
6GM8 is tube design especially for 12 volt supply ( in car battery operation ).
At plate 12 Volt will run like 2.5 mA
At plate 6 Volt will run like 0.8-1.0 mA
I guess that when plate 6 Volt, the supply is 12 Volt
and anode resistor is like 5 kOhm
and cathode resistor 1 kOhm
Heater is 6.3 Volt / 330mA
hi... this is my first post here....
i have a box of 3A4 they are power pentode (DHT!) for radio operation....
i have a box of 3A4 they are power pentode (DHT!) for radio operation....
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