What Rod Coleman Gyrator? Are you talking about Siberian 3 with the transformer and the Salas reg PS?
What resistor value for capacitor output coupling for an amp chipamp Tripath TA2022 with a guessed input impedance of 20K (attached datasheet)?
I am using the rod coleman heaters but nothing from Salas. I will look up the bib. What diff is that supposed to make?
Shunt stabilizers -like Salas xBiB- are very good for current altering devices, due to the few -ten- mOhm -mostly smooth line- AC output impedance (up to few hundred kHz, or even MHz).
DH filament requires steady current (in hot state) so I don't see the point of using this, instead of high impedance gyrator-constant current stabilizers like RC.
DH filament requires steady current (in hot state) so I don't see the point of using this, instead of high impedance gyrator-constant current stabilizers like RC.
The question is not how much the terminating resistor should be, if the load is 20k, but how much should be the capacitor value!
Right first the coupling cap value & after the resistor to calculate the discharge time for cap.
Well I have 10uF to be sure.
I have the info to calculate the RC time constant to discharge the cap in the PC not in the Phone, when I can I will calculate.
I'm sorry my ignorance I have a doubt: if the bleeder resistor to discharge the output coupling cap it's in parallel with the input impedance of the next stage that's doesn't lower the input impedance see by the peamp, for example if I use 20K as bleeder resistor at peamp in parallel with 20K of power amp the peamp will see only 10K?
I have the info to calculate the RC time constant to discharge the cap in the PC not in the Phone, when I can I will calculate.
I'm sorry my ignorance I have a doubt: if the bleeder resistor to discharge the output coupling cap it's in parallel with the input impedance of the next stage that's doesn't lower the input impedance see by the peamp, for example if I use 20K as bleeder resistor at peamp in parallel with 20K of power amp the peamp will see only 10K?
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If you use this Tripath amplifier module as the textbook suggest (usually chinese "designers" use it), the input impedance of this only 10k.
The terminating resistor value of previous stage almost negligible next to this (usually NOT 20k!, rather 100-200k), so LF -3dB point due to the previous stage driving capability (output impedance, the possible coupling capacitor value and the load (in this case the Tripath module input impedance).
The terminating resistor value of previous stage almost negligible next to this (usually NOT 20k!, rather 100-200k), so LF -3dB point due to the previous stage driving capability (output impedance, the possible coupling capacitor value and the load (in this case the Tripath module input impedance).
@merlin el mago
Finally made some progress on the preamp! Now that I have some instrumentation, I could see a low grade oscillation developing and searching on the Bartola site found that a 0.1 uF cap on the B+ near the gyrators might be a solution and it seems to have worked! I also separated the noisy cathode bias ground returns from the input gnds. I am using the bartola cap multiplier BTW.
I was about to try the SSHV2 PS before I recalled you having some problems powering DHT tubes.
Finally made some progress on the preamp! Now that I have some instrumentation, I could see a low grade oscillation developing and searching on the Bartola site found that a 0.1 uF cap on the B+ near the gyrators might be a solution and it seems to have worked! I also separated the noisy cathode bias ground returns from the input gnds. I am using the bartola cap multiplier BTW.
I was about to try the SSHV2 PS before I recalled you having some problems powering DHT tubes.
Because I am using an umbilical, I have separated the in/out gyrator returns from the cathode bias and the 0.1uF noisy suppressor cap so they now meet at the PS. It seems to have helped.
The problem isn't SSHV2, the problem is using old DHT tubes like 01A, 26, 801A, 10Y etc. Because when used active (CCS, Gyrators) anode load in place of pasive (resistors or output/chokes transformers) problems arise because pushes these old tubes.
No problem with 4P1L so you can use SSHV2 for all kind of anode loads.
