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Design Considerations concerning Electrolytic Capacitors in an Outdoor Tube Amp Power Supply before and behind Choke

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tiefbassuebertr

tiefbassuebertr

Member
Joined 2005
tiefbassuebertragung.de
Several years ago on the power amplifier model "Compact 100" from VTL - go to
https://www.diyaudio.com/community/threads/vtl-compact100-monoblock-blows-fuse.170592/
was made various modifications.

The modifications mainly consisted of optimizing the ground routing (GND management) for hum reducing, converting from ultralinear (penthode operation) to triode operation, as well as swapping out the mains transformer, rectifier and installing high-quality electrolytic capacitors to replace the cheap old ones.
Due the now present outdoor power supply the problem of lack of space is eliminated - thus a small outline for parts isn't longer necessary.

Shortly I try an additional step to further increase the sound quality; the introducing of an inductor.
I choose the Hammond EDB196M4, 5mH or 20mH choke - go to
https://www.hammfg.com/files/parts/pdf/196M4.pdf
for connecting between rectifier for anode voltage (~400VDC) and the already present electrolytics - at whole 1,5mF (1.500µF).

Now the question rises up, what value of capacitor I need between rectifier and choke (I use in the moment only 150uF and thus achieve a further improvement in sound quality).

The fundamental question must actually be - which rules must be observed with regard to the value of the capacitors before and behind of the choke.

Are there papers resp. app-notes concerning this question ?

Thanks for an advice.

P.S.: The whole idle (quiescent) current of each VTL mono power amp is 150mA and the current while listening at normal level therefore is the same value (CCS-character resp. class-A character) - 35mA for each EL34 and 10mA at whole for both the input and phase splitter-tube.

This threads don't provide the wanted information:
https://www.diyaudio.com/community/threads/choke-where-to-begin.232116/
https://www.diyaudio.com/community/threads/power-transformer-and-choke-effect-on-sound.376885/
https://www.diyaudio.com/community/threads/electronic-choke-for-valve-amplifiers.173280/
https://www.diyaudio.com/community/threads/tube-power-supply-and-chokes.344853/
https://www.diyaudio.com/community/...mplifiers-which-rules-for-calculating.199645/
https://www.diyaudio.com/community/...ke-for-power-amp-psu-inductive-filter.382441/
https://www.diyaudio.com/community/threads/best-placement-for-a-choke-vht-tube-amp.256167/
https://www.diyaudio.com/community/threads/choke-inputs.254978/
https://www.lundahltransformers.com...MI5KXQyb3M_wIVhgiLCh26CAWCEAMYASAAEgKySPD_BwE
 
dubadub

dubadub

Member
Joined 2020
What type of rectifier are you using? If Solid State, you have more choices of caps, but if you have a tube rectifier, you must consult the datasheet to determine the max value of your first cap (C1/reservoir cap). 5AR4 can take up to a 47uF, 5U4 can take 32Uf max, etc.
 
tiefbassuebertr

tiefbassuebertr

Member
Joined 2005
tiefbassuebertragung.de
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