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In Reply to: RE: Full wave bridge into Choke PS posted by vetmedrobert@gmail.com on March 27, 2017 at 09:34:36
Choke input topology can be used with either a full wave CT or full wave bridge configuration. As Triode Kingdom has stated: one will yield half the voltage but twice the current (full wave CT) than the other. Once that issue has been decided, then one has to consider choke input or capacitive input (or in between, but let's leave that for a future discussion). As has been pointed out choke input yields about 0.9 times the RMS output voltage of the transformer, capacitive input about 1.4 times. The big disadvantage of choke input is less voltage. The advantage? Choke input supplies draw power though the PS transformer almost continuously; capacitive input supplies in sharp, short pulses. This generates harmonics of the line frequency that can reach to the RF region. Avoiding this "hash" rather than trying to mitigate its effects is, in my opinion, one of the main reasons to use choke input and worth the price of less voltage.
Disclaimer: I use choke input for virtually everything.
"It is better to remain silent and thought a fool, then speak and remove all doubt." A. Lincoln
Follow Ups:
Thanks for your response. Choke input also means better voltage regulation if I am not mistaken.
Choke input provides better average regulation. Peak regulation - which likely has just as much impact on the music - is much worse. For this reason, choke input supplies require more storage capacitance than would otherwise be required to merely eliminate ripple. The combination of L and C can also create resonances and other undesired behavior. It's a good idea to always use SPICE to simulate the output impedance of any supply powering an audio amplifier, particularly when it uses both chokes and filter capacitors.
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Buy Chinese. Bury freedom.
10 Henry/45 uF / 8 Henry / 45 uF... SE 45 5842 input tube... LED bias
Dead quiet through modified Khorns. Some audio guys would be quite surprised by the bass slam. I never use electrolytics in my builds.
DCR of both chokes.. the 10 @ 35 ohms, the 8 is 25 ohms
That iron is HARD to find
The Mind has No Firewall~ U.S. Army War College.
What do you use for rectification?
(that info would just make TK's sim better, if he doesn't mind running it again)
Thanks
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
275 volts before 1500 ohm resistor (45)/two 816 Mercury vapor rectifiers
Power transformer is not the 5 ohm one I wanted to use (not enough real estate) Is a.NOS 180 ma one ... Chicago I believe. All the filament transformers are separate, except for the 6 volt windings for the 5842.
Probably been running non stop for 4 months.
The Mind has No Firewall~ U.S. Army War College.
That filter sims really well. Output Z very low, doesn't do anything untoward until roughly 15 Hz. Nice!
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Buy Chinese. Bury freedom.
Hard to find and weighs a TON!
!
The Mind has No Firewall~ U.S. Army War College.
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