Hi!
Anyone can explain to me what is it about?
"I was talking about a resistor ACROSS the inductor! so the low DCR of the inductor will be used!!!
THAT shunting offers a real need, sets the impedance of the inductor to its value
Using a choke (inductor) as plate load and shunting it with a plate load resistor, will offer more plate voltage to the tube used. due to the plate load resistor will be the load impedance, not the DCR,
The choke will be maybe 50 ohms or so......"
Thank you 🙏
Anyone can explain to me what is it about?
"I was talking about a resistor ACROSS the inductor! so the low DCR of the inductor will be used!!!
THAT shunting offers a real need, sets the impedance of the inductor to its value
Using a choke (inductor) as plate load and shunting it with a plate load resistor, will offer more plate voltage to the tube used. due to the plate load resistor will be the load impedance, not the DCR,
The choke will be maybe 50 ohms or so......"
Thank you 🙏
Does every nonsense need an explanation? The only useful function a resistor across a choke load i can imagine is to damp resonance. All other effects of such a resistor are generally unwanted. It reduces load impedance and voltage headroom. It also reduces output impedance, but at what price!
I never heard of it in my life. That's why I want to clarify. Is that possible to have such arrangement?
I have only seen it in a use where the output impedance is being used for impedance matching of a pentode/cascode stage but the operating point planned for the valve is at a current where there would be significant losses in a load resistor. This was in a "cost no object" phono stage.
Placing a resistor across a choke, depending of the value, will make the frequency response more even, similar to the way resistive loading does with an OPT. But sacrifices high impedance at midrange frequencies.
These things are basic and shouldn't need Mumbo crystal ball explanations
These things are basic and shouldn't need Mumbo crystal ball explanations
First of all whether very low DCR plate choke would be able to allow a resistor placing across the choke?
If the circuit has a 13.7K plate load resistor in the circuit and want to place a 160H plate choke with 1160R DCR there. Would it be possible as the DCR isn't around 50 ohm or so?
Therefore, I can leave the 13.7K plate resistor there and connected the plate choke to that. But how?
Many thanks for your advice!!
Attachments
You set the tube DC bias point using the choke DC resistance which is relatively low.
The choke has a very high ac resistance. The total ac load that determines the ac gain is the parallel value of the choke ac resistance and the parallel resistor.
Since the resistor is normally very much lower ac resistance than the choke, the resistor determines the ac load and the gain.
As mentioned, basic stuff.
Jan
The choke has a very high ac resistance. The total ac load that determines the ac gain is the parallel value of the choke ac resistance and the parallel resistor.
Since the resistor is normally very much lower ac resistance than the choke, the resistor determines the ac load and the gain.
As mentioned, basic stuff.
Jan
I guess it would be a wise idea by replacing the plate load resistor with the Tango plate choke, and lower the B+ supply.
However, I have a plate choke on hand which is 50 ohm DCR, Would it be a good idea to use it with the plate load resistor?
Thanks
However, I have a plate choke on hand which is 50 ohm DCR, Would it be a good idea to use it with the plate load resistor?
Thanks
What is the point of adding the choke if you keep the resistor? The AC plate load will be determined by the resistor and the DC by the choke.
The PS supply will need re-adjusting and perhaps the CF resistor too... a bit too involved for perhaps no gain at all.
Btw, which CJ preamp is that? 6GK5 tubes? And what's the choke inductance?
The PS supply will need re-adjusting and perhaps the CF resistor too... a bit too involved for perhaps no gain at all.
Btw, which CJ preamp is that? 6GK5 tubes? And what's the choke inductance?
Hello!
It is CJ Premier Ten.
Regarding the inductance, I have no idea what should I choose. Normally,ba plate choke with high inductance like 160H should be used for 6GK5. For sure, a low DCR like 50 ohm.
However, I have no idea under this circumstances.
If I use ONLY plate change kevwothout plate load resistor, then it would be a Tango plate choke and it is what I have on hand.
Thanks 🙏
It is CJ Premier Ten.
Regarding the inductance, I have no idea what should I choose. Normally,ba plate choke with high inductance like 160H should be used for 6GK5. For sure, a low DCR like 50 ohm.
However, I have no idea under this circumstances.
If I use ONLY plate change kevwothout plate load resistor, then it would be a Tango plate choke and it is what I have on hand.
Thanks 🙏
Attachments
Cannot make head or tails about this thread's objective. The quote from #1 is just BS imho. A 50ohm choke sounds like a PS choke and is very unlikely to have enough inductance for a highish Rp tube. Adding a choke to the above mentioned preamp will require a substantial redesign, unless the choke is in series with the existing plate resistor.
Have nothing more to add here.
Have nothing more to add here.