LC regulation???

Michel · 28th September 2001, 01:42 PM

DFGBH\SF

GRollins · 29th September 2001, 05:15 AM

michel,
An LC circuit by itself isn't regulated any more than a simple bank of capacitors is. Depending on whether you choose L-C (the L filter), C-L, C-L-C (the Pi filter), etc. you're going to end up with somewhat different voltage and current ratings. In general, if you start with a capacitor coming off of the rectifier, you've going to get higher voltage, but less current capability. If you start with an inductor, you'll get less voltage, but more current.

Grey

dutch diy · 30th September 2001, 12:47 AM

Hi Michel,

Basic theory starts with a Voltage Supply which has no internal resistance: at any load the same output voltage is produced.

In RealLife things change: does the output stage needs Voltage (tubes most like do) or current (as solid-state's usually do).

In the tube-era CLC filters quite suited because the current-changes were low. (changes of 200mA were considered HUGE)

In the solid-state-era current changes are HUGE indeed (rail-current in my JLH design runs from 0 - 4000mA's and it only produces 15W).

Any regulations costs power and any output current delivered to the speakers must eventually pass through the regulating devices: that is one main reason why the larger High-End Amps only use big capacitor banks and no regulated power supply.

Jos

Petter · 30th September 2001, 09:00 PM

http://www.duncanamps.com/psud2/

Very nice (free) program for designing power supplies.

Petter

Hedlund · 30th October 2001, 05:42 AM

If you're into no-feedback circuits a LC or CLC is very effective to adjust the sound.
A normal rectifier-bridge and capacitor doesn't have a even impedance, and this is clearly heard as a closed in and undynamic bass from around 50-150Hz. A suitable smoothing trough a LC or CLC makes the overall sound better.

My suggestion is CLC for the output stage and a regulation for the gain stages, and the best regulation I have found so far is a two-stage regulation, where the first is a passively regulated BJT followed by a midsize cap (app. 2200uF) and the second a passively regulated MOSFET that is followed by a small high quality foil cap.(1-2,2uF).
Feedback in the regulator have the same effect on the sound as feedback in the amp circuit itself so please use as little as possible.

/Janne

30th September 2001, 12:47 AM	#3
dutch diy diyAudio Member Join Date: May 2001 Location: NL, The Hague	re LC regulation Hi Michel, Basic theory starts with a Voltage Supply which has no internal resistance: at any load the same output voltage is produced. In RealLife things change: does the output stage needs Voltage (tubes most like do) or current (as solid-state's usually do). In the tube-era CLC filters quite suited because the current-changes were low. (changes of 200mA were considered HUGE) In the solid-state-era current changes are HUGE indeed (rail-current in my JLH design runs from 0 - 4000mA's and it only produces 15W). Any regulations costs power and any output current delivered to the speakers must eventually pass through the regulating devices: that is one main reason why the larger High-End Amps only use big capacitor banks and no regulated power supply. Jos

30th September 2001, 09:00 PM	#4
Petter diyAudio Member Join Date: Jan 2001 Location: Scandinavia	Software to check out your LC ... http://www.duncanamps.com/psud2/ Very nice (free) program for designing power supplies. Petter

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28th September 2001, 01:42 PM	#1
Michel diyAudio Member Join Date: Nov 2004 Location: L'Assomption, QC	DFGBH\SF

29th September 2001, 05:15 AM	#2
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	michel, An LC circuit by itself isn't regulated any more than a simple bank of capacitors is. Depending on whether you choose L-C (the L filter), C-L, C-L-C (the Pi filter), etc. you're going to end up with somewhat different voltage and current ratings. In general, if you start with a capacitor coming off of the rectifier, you've going to get higher voltage, but less current capability. If you start with an inductor, you'll get less voltage, but more current. Grey

30th October 2001, 05:42 AM	#5
Hedlund diyAudio Member Join Date: Oct 2001 Location: Alvesta, Sweden	If you're into no-feedback circuits a LC or CLC is very effective to adjust the sound. A normal rectifier-bridge and capacitor doesn't have a even impedance, and this is clearly heard as a closed in and undynamic bass from around 50-150Hz. A suitable smoothing trough a LC or CLC makes the overall sound better. My suggestion is CLC for the output stage and a regulation for the gain stages, and the best regulation I have found so far is a two-stage regulation, where the first is a passively regulated BJT followed by a midsize cap (app. 2200uF) and the second a passively regulated MOSFET that is followed by a small high quality foil cap.(1-2,2uF). Feedback in the regulator have the same effect on the sound as feedback in the amp circuit itself so please use as little as possible. /Janne