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Old 2nd February 2007, 02:19 PM   #11
jeapel is offline jeapel  Canada
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the right expression is "rule of thumb" not "thumb law"

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Old 2nd February 2007, 04:17 PM   #12
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Why doesn't everybody use Inductors?

I am building an Aleph X, with CLCRC.

When I calculate with my 10mH inductor (100 mOhm), I will end up with a ripple of 17 mV
When I calculate with a resistor with the same resistance (100m), I would get 21 mV

That means for an extra 170 dollars, I only got an extra 4 mV improvement. Not everybody thinks that is good value for money. (I got mine second-hand, so my ratio is better...)

By the way, splitting things up with smaller values and introducing another resistor only brings an improvement of 1mV (CRCRCRC)

Greetings, Harry
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Old 2nd February 2007, 05:29 PM   #13
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally posted by harryeng
Why doesn't everybody use Inductors?

I am building an Aleph X, with CLCRC.

When I calculate with my 10mH inductor (100 mOhm), I will end up with a ripple of 17 mV
When I calculate with a resistor with the same resistance (100m), I would get 21 mV

That means for an extra 170 dollars, I only got an extra 4 mV improvement. Not everybody thinks that is good value for money. (I got mine second-hand, so my ratio is better...)

By the way, splitting things up with smaller values and introducing another resistor only brings an improvement of 1mV (CRCRCRC)

Greetings, Harry

you probably use PSUd for calculating?

so- you know for 100 (120) Hz ripple .........what is with upper freqs and with "supply modulation"............there you'll see difference between R and L
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Old 3rd February 2007, 09:29 AM   #14
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Hi Zen Mod,

You are right of course!

There are several goals one has to achieve when designing power supplies. One of the reasons I like chokes, is that it filters a lot of the HF I have on my powerline. When I installed chokes in my Aleph 5, and my DAC everything was kind of less stressing to listen to.

You should check the Bob Cordell interview on Power Supplies thread in Solid State amplifiers. There people argue that the rise time from the PSU should be slower than the lowest frequency the amp is designed for.

I try to incorporate a CL before the CRCc in a way that I always have enough capacity after the L not to have to bother with the influence of L on my power supply for the amplifier. In my Aleph 5 design I calculated the minimun capacity, and went on from there. I was very dissapointed with the result, so now I just over-design.

To be honest, for the Aleph X I am building now (70W RMS on 4 Ohm) my criteria were: more than 100 mF per rail (after choke), and a ripple smaller than 10mV. These numbers are not substantiated by hearing tests, just best guesses. Now I am building with 3 60mF capacitors, a 10mH choke (70A), 50MOhm resistors and a small 8uF capacitors to top it off. With my 700W tranny this also means I have to use a softstart, which I made with power resistors (70Ohm) and some relays.

Greetings, Harry
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Old 3rd February 2007, 09:42 AM   #15
Zen Mod is offline Zen Mod  Serbia
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Quote:
Originally posted by harryeng
Hi Zen Mod,

You are right of course!

There are several goals one has to achieve when designing power supplies. One of the reasons I like chokes, is that it filters a lot of the HF I have on my powerline. When I installed chokes in my Aleph 5, and my DAC everything was kind of less stressing to listen to.

You should check the Bob Cordell interview on Power Supplies thread in Solid State amplifiers. There people argue that the rise time from the PSU should be slower than the lowest frequency the amp is designed for.

I try to incorporate a CL before the CRCc in a way that I always have enough capacity after the L not to have to bother with the influence of L on my power supply for the amplifier. In my Aleph 5 design I calculated the minimun capacity, and went on from there. I was very dissapointed with the result, so now I just over-design.

To be honest, for the Aleph X I am building now (70W RMS on 4 Ohm) my criteria were: more than 100 mF per rail (after choke), and a ripple smaller than 10mV. These numbers are not substantiated by hearing tests, just best guesses. Now I am building with 3 60mF capacitors, a 10mH choke (70A), 50MOhm resistors and a small 8uF capacitors to top it off. With my 700W tranny this also means I have to use a softstart, which I made with power resistors (70Ohm) and some relays.

Greetings, Harry

just for teasin' ya..........what you'll change if you make X for 16 ohms lload ...........
anyway-I don't think that you need at all that R part in your filter.....
but-if you'll be happier , just go for it
btw , my babelfish CLC is 10 x 10mF - 9mH(0,2 ohms) - 10 x 10mF.....all that for stereo 4A Iq
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