The Aleph-X - Page 52

yldouright · 5th September 2002, 02:15 PM

rtirion
I got more MPSA18's than I can use too so I'm up for trading

Nelson Pass · 5th September 2002, 05:10 PM

Maybe you should parallel all you've got into 2 channels
of MC preamp. I've got M1 schematic...

Aaaarrrrrr

irate:

(pirate icon doesn't work!)

yldouright · 5th September 2002, 05:29 PM

Nelson Pass

Ha! I can barely get my head around the power supply for this Aleph -X. I haven't even started to think preamp yet. I think I may have to build HarryHaller's Ratshack attenuator until you publish your patented current preamp and phono stage. Since I have your attention, I would like to ask what defines a choke regulated power supply and does one reduce the need for a power capacitance bank?

Nelson Pass · 5th September 2002, 05:34 PM

It's just a "pi" filter, where you follow the usual capacitor
bank with a coil and a second capacitor bank for filtering.
It works great, particularly if you have lots of caps.

yldouright · 5th September 2002, 05:46 PM

Nelson Pass

hifiZen used a CRC filter where two large capacitors are presumably put in series with a power resistor. Does this alos fall into the category of a choke regulated supply even though no coil is used?

rtirion · 5th September 2002, 07:31 PM

yldouright,

Mail me an address, and I'll snailmail you some.
Use your mpsa's for the MC or something else.

eLarson · 5th September 2002, 07:59 PM

Somewhere way back in this thread I posted some "rules of thumb" courtesy of an old copy of the Radio Amateurs Handbook. The choke input power supply was a way for them to get a higher average current from a tube rectifier without exceeding a peak value.

If the current draw dropped below a certain minimum value for the voltage output and choke size the filter would tend to act like a capacitor input supply, giving a higher output, but evidentally -- they didn't show an example-- a peakier looking waveform.

I used one in my modified BoZ lineamp. Big sucker. 1.5 H, if memory serves me right. For a class A power amp drawing 1000s of mA of current, the size of the choke could be far, far smaller.

Erik

yldouright · 5th September 2002, 10:39 PM

eLarson

You posted that on page 31 but the choke does not answer my question about whether the CRC filter used by hifiZen qualifies as a "choke regulator" even though it doesn't use a coil.

Nelson Pass · 5th September 2002, 11:33 PM

I suppose it would have to have a choke (inductor) to
qualify.

CRC filters are a little more lossy, but they work great, in
fact I've plugged them into a couple of upcoming projects.
I like to use Thermistors instead of resistors, as they have
a more gentle turn-on rush and can take more abuse.

yldouright · 6th September 2002, 12:04 AM

Nelson Pass

Thanks for making the distinction between a pi filter and a choke regulator. In an earlier post, hifiZen voiced his concern about the magnetic effects of the coil in a pi filter. What should we do to minimize these effects? Another member eLarson brought to light some hifi publication that stated that there can be a smaller inductance when the current is higher. Is this just because the volt potential is lower or is some other dynamic at work here?

5th September 2002, 07:59 PM	#517
eLarson diyAudio Member Join Date: Aug 2002 Location: Gaithersburg, MD	Choke regulated power supply Somewhere way back in this thread I posted some "rules of thumb" courtesy of an old copy of the Radio Amateurs Handbook. The choke input power supply was a way for them to get a higher average current from a tube rectifier without exceeding a peak value. If the current draw dropped below a certain minimum value for the voltage output and choke size the filter would tend to act like a capacitor input supply, giving a higher output, but evidentally -- they didn't show an example-- a peakier looking waveform. I used one in my modified BoZ lineamp. Big sucker. 1.5 H, if memory serves me right. For a class A power amp drawing 1000s of mA of current, the size of the choke could be far, far smaller. Erik

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5th September 2002, 02:15 PM	#511
yldouright diyAudio Member Join Date: Aug 2002 Location: New York, NY	rtirion I got more MPSA18's than I can use too so I'm up for trading

5th September 2002, 05:10 PM	#512
Nelson Pass The one and only Join Date: Mar 2001	Maybe you should parallel all you've got into 2 channels of MC preamp. I've got M1 schematic... Aaaarrrrrr irate: (pirate icon doesn't work!)

5th September 2002, 05:29 PM	#513
yldouright diyAudio Member Join Date: Aug 2002 Location: New York, NY	Nelson Pass Ha! I can barely get my head around the power supply for this Aleph -X. I haven't even started to think preamp yet. I think I may have to build HarryHaller's Ratshack attenuator until you publish your patented current preamp and phono stage. Since I have your attention, I would like to ask what defines a choke regulated power supply and does one reduce the need for a power capacitance bank?

5th September 2002, 05:34 PM	#514
Nelson Pass The one and only Join Date: Mar 2001	It's just a "pi" filter, where you follow the usual capacitor bank with a coil and a second capacitor bank for filtering. It works great, particularly if you have lots of caps.

5th September 2002, 05:46 PM	#515
yldouright diyAudio Member Join Date: Aug 2002 Location: New York, NY	Nelson Pass hifiZen used a CRC filter where two large capacitors are presumably put in series with a power resistor. Does this alos fall into the category of a choke regulated supply even though no coil is used?

5th September 2002, 07:31 PM	#516
rtirion diyAudio Member Join Date: Nov 2000	yldouright, Mail me an address, and I'll snailmail you some. Use your mpsa's for the MC or something else.

5th September 2002, 10:39 PM	#518
yldouright diyAudio Member Join Date: Aug 2002 Location: New York, NY	eLarson You posted that on page 31 but the choke does not answer my question about whether the CRC filter used by hifiZen qualifies as a "choke regulator" even though it doesn't use a coil.

5th September 2002, 11:33 PM	#519
Nelson Pass The one and only Join Date: Mar 2001	I suppose it would have to have a choke (inductor) to qualify. CRC filters are a little more lossy, but they work great, in fact I've plugged them into a couple of upcoming projects. I like to use Thermistors instead of resistors, as they have a more gentle turn-on rush and can take more abuse.

6th September 2002, 12:04 AM	#520
yldouright diyAudio Member Join Date: Aug 2002 Location: New York, NY	Nelson Pass Thanks for making the distinction between a pi filter and a choke regulator. In an earlier post, hifiZen voiced his concern about the magnetic effects of the coil in a pi filter. What should we do to minimize these effects? Another member eLarson brought to light some hifi publication that stated that there can be a smaller inductance when the current is higher. Is this just because the volt potential is lower or is some other dynamic at work here?

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