Hello,
Want to build a simple amplifier with 6p21s(DHT) at power stage and 6n2p (non DHT) at préamplificateur stage.
Filement voltage is 6,3v for both.
Want to use the same power suply (Regulated with a transformer),same circuit for these both kind of tube .
Is it possible ?
What the disadvantages?
Any review ?
Please
Regards
Want to build a simple amplifier with 6p21s(DHT) at power stage and 6n2p (non DHT) at préamplificateur stage.
Filement voltage is 6,3v for both.
Want to use the same power suply (Regulated with a transformer),same circuit for these both kind of tube .
Is it possible ?
What the disadvantages?
Any review ?
Please
Regards
If two sequential stages have a cathode-cathode connection they want to be unstable.
Since these are directly heated tubes the "cathodes" are the heaters. If fed from one power sources they will be connected to each other.
It can be done. But there IS a reason indirectly heated cathodes got VERY popular.
Since these are directly heated tubes the "cathodes" are the heaters. If fed from one power sources they will be connected to each other.
It can be done. But there IS a reason indirectly heated cathodes got VERY popular.
Is the DHT cathode biased ? If so - can the 6Н2П (6N2P) withstand the cathode voltage (Data sheet rating for Vhk) ? If not, stop, immediately!
If the Vhk is OK, you can consider running the 6Н2П from the same transformer/rectifier as the DHT.
But normally, every DHT should have a private transformer winding, and DC circuit. Remember that the anode current (signal) flows in the filament - connecting it to another circuit will mean long wires attracting noise (etc).
The filament voltage means that the effective grid-cathode voltage decreases across the length of the filament. This change in bias means that a signal voltage appears across the filament too. Don't disturb this signal!
If the Vhk is OK, you can consider running the 6Н2П from the same transformer/rectifier as the DHT.
But normally, every DHT should have a private transformer winding, and DC circuit. Remember that the anode current (signal) flows in the filament - connecting it to another circuit will mean long wires attracting noise (etc).
The filament voltage means that the effective grid-cathode voltage decreases across the length of the filament. This change in bias means that a signal voltage appears across the filament too. Don't disturb this signal!
> It was wrotten that i should wire a virtual ground with 2 100 Ohms resistors,isn't it ?
You need to do the 2-resistor "Y" (make a centre-tap) if you have some noise on the filament supply: or else the DHT will amplify the noise.
But you do not need the resistors, when you have a properly regulated supply (µV-range noise). Connect FILAMENT + to ground (or cathode resistor) for current-drive DHT regulators.
You need to do the 2-resistor "Y" (make a centre-tap) if you have some noise on the filament supply: or else the DHT will amplify the noise.
But you do not need the resistors, when you have a properly regulated supply (µV-range noise). Connect FILAMENT + to ground (or cathode resistor) for current-drive DHT regulators.
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