The Aleph-X

[jleaman]

Any one compleet the aleph - x yet and have any pics..

j'

[hifiZen]

After some simulations, I've settled on a CRC filter... 68mF, 0.25ohm, 75mF or so for one channel of the Aleph-X. This filter gave almost as much ripple reduction as a CLC configuration with 2.2mH air core inductor (14ga. wire), and in fact, less voltage loss, since the inductor's series resistance was higher.

The CRC configuration gave 19mV vs. 3.5mV of ripple for the CLC. I figure 19mV should be low enough to avoid any hum. The 8.5Hz lowpass cutoff point should also be low enough to reject almost all offensive mains voltage fluctuations, and the simulations show none of the resonance that could be observed in the CLC configuration. A resistor isn't going to generate all those lovely magnetic fields either. The final nail in the coffin is the cost of an air core inductor vs. a 10W power resistor... no contest! Case closed.

Thanks to rtirion for your input. Love to see your pics when it's done!

Cheers,

[yldouright]

hifiZen

I've settled on a CRC filter... 68mF, 0.25ohm, 75mF

You mean 68uF and 75uF don't you? What was the power rating on the resistor and how did you connect it? I would love to avoid coils if I can. Did you put it on a heatsink? Did you make up a schematic or did you just wire it in?

[rtirion]

68mF as is 68 milli Farad equals 68000 uF.
75mF as is 75 milli Farad equals 75000 uF.

HifiZen,
Thanks for your comments. Your CRC gave me something to think
about. I recently bought 300 or so 0.5 Ohm /10watt resistors.
The ones in metal jacket, easely mounted on a sink.
I will get the PSUD and do some tests.
Than built a test supply and have a tryout.

Regards

[yldouright]

rtirion

68mF as is 68 milli Farad equals 68000 uF.

Wow! Is that in addition to the normal power bank? That would put you around 0.25F of capacitance. How would you fit them in a case? How high do these filter caps have to be rated?

[skaara]

At least 20%more than rail voltage, but more is preffered..

[mpeg7]

Hi,

I am struggling to follow the discussions (I am new to this but eager to try to build one )

Can anyone capable here to summarize what so far have been achieved ? (I mean consensus on the fine tuning to the original design)

The followings are appreciated:

1) latest schematics;
2) latest PCB, if available;
3) one schematics to show how to add more output devices (I have problem to figure out what resistors to add with and where to join them);

You don't have to do all of them at one go, I guess, to benefit the rest of us. (Remember what the For Dummies books said? "A Reference for the Rest of Us" )

[hifiZen]

yldouright:

those are just simulation values... I haven't built anything yet. The simulation values should be very realistic, however. I was careful to ensure the simulated component parameters were accurate. The total capacitance in the power supply for each channel is almost 0.3F, which sounds like a lot, until one considers that the amp is operating at half the rail voltage and double the current of the typical solid state amp. I will be using 25V caps, which is plenty for 15V rails.

rtirion:

300! wow, you must have found a really good deal on those! how on earth do you plan to use all of them? If you need some help...

mpeg7:

I'm not really sure the design is far enough along to be ready for novice builders. A few experienced builders have assembled versions of the prototype, but there seem to be just a bunch of different variations so far - no clear consensus on what The Official Aleph-X schematic is. Maybe Grey will post his latest version soon? I don't think anyone has successfully implemented multiple parallel output devices yet either.

A first-time amp builder who doesn't have a thorough understanding of the circuit's operation, as well as how to test and debug the circuit, tweak it to ensure stability etc. should probably not attempt this design until it is a bit more mature. That said, I don't think it will be too long until someone has posted a well tested schematic and/or PCB that you can be sure will produce a stable and reliable amp. Keep your eye on this thread, and your patience will be rewarded...

[rtirion]

>300! wow, you must have found a really good deal on those!
>how on earth do you plan to use all of them? If you need some
>help...

HifiZen,
Could use some help...
Mail me, and I'll send you a handfull

[yldouright]

hifiZen

Will your CRC filter work with caps of the same value or is the disparity in the caps what makes the filter? In other words, can I build this filter with two 72mF caps instead of the ones you used? Also, can I put two 36mF in parallel to make up the 72mF?