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Hi to everyone,
I would like to explore the effectiveness of power supply voltage stabilization by using only the choke. I am focusing on the preamp or 1st, 2nd driving stage of power amp, talking about around 300V HT and 5-10 mA standing current.
Instead of using active device such as tube/transistor voltage regulation circuit, does CLC circuit could also provide the same effectiveness as active voltage regulator?
If CLC can regulate the voltage, for example 300V HT , tube 7mA standing current, does a small choke allowing 15mA with 20H but resistance being 500 ohm can regulate the voltage. As I heard that using choke for voltage regulation, the DCR for the choke better to be below 100 ohm DCR. Why is that, or does it make sense. but a bulky 4 kg choke used for preamp stage, seems overkilled
If your experience, how effective with high DCR choke like 500 ohm, 20mA 20H, would be able to fit the job as regulation purpose. I saw Audionote Ankoru use 20H small 20H choke for its 1st input stage. Is it a purpose to regulate the power supply voltage?
Thx for your input
Follow Ups:
Tre' got it right. A CLC filter will not improve voltage stabilization, it has to be an LC type instead! Rectifier MUST drive current straight into choke, not capacitor. Then you also need high enough inductance such that filter remains in continous conduction mode.
I made an online calculator you can use:
https://www.hagtech.com/theory.html
The answer to the question is - yes it can! A choke-input filter has a more level V-I "curve" but does cut down the output voltage quite a bit.
Way back, I did a DIY project using a Stereo 70 chassis/iron but changed the output tubes to 6B4's, to "hear what" directly-heated triodes would sound like. To get the B+ "down" to a safe operating region for the triodes, used a choke input filter (using the 70 choke) and then "tuned" the output B+ with a "small" capacitor. Worked just fine.
Cello electronics used choke input filtering on a lot of their power amplifiers.
Charles
Thx all you guy, right, in a class A preamp stage, regulated PS or non-regulated PS may not make difference sound wise
Ae you referring to stages that are all Class A? If that's the case, the only consideration would be changes due to line voltage. Stabilizing against that requires either a constant voltage transformer ahead of the power supply or an electronic DC regulator.
--------------------------
Buy Chinese. Bury freedom.
You're talking about a "swinging choke". In the 1980's they were available in electronics shops for stabilising the mains voltage for such things as enlargers for wet process photograph printing, since the exposure would vary with line voltage, which gave inconsistent results. There was also a tube exposure meter in some old at that time equipment. Now that most photography has become digitised all that tech has been consigned to the dumpster.I've had two swinging chokes from those days, but many years have passed and in one house move or another they were lost. They were a vertitable weight addition to any boat anchor.
I doubt it was much use to hifi as it works by core saturation. nothing good about transformers and chokes in hifi equipment which saturate.
Things are done better today.
Edits: 05/13/22
A choke in a CLC filter will reduce ripple but not regulate the voltage.A critical inductance input choke filter will yield a supply with inherently better voltage regulation vs. a capacitor input filter but still not close to what can be achieved with active regulation (series or shunt).
A large final capacitor will lower the AC impedance of the supply and have the effect of voltage regulation against periodic load current fluctuations as caused in Class A circuits.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 05/13/22
In addition, note that if the load current doesn't vary much, then the voltage is inherently regulated, and a reduction in ripple becomes much more influential.
You can use PSUD2 to assess the influence of inductance and ripple, and small step changes in load current, as a way to give yourself a better insight in to what is happening at the voltage rail.
For many preamp circuits, there is no tangible benefit from regulated versus unregulated circuits, as long as ripple is minor, and even then the circuitry typically attenuates any signal or change in power supply characteristics.
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