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Old 15th December 2002, 12:54 AM   #11
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Aleph X operates on the same principle as regular Aleph. The only difference is that you are running 2 separate output stages side by side sharing the same input differencial. That's about it.
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Old 15th December 2002, 01:26 AM   #12
fcel is offline fcel  United States
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Peter,

When you said "2 separate output stages side by side", you meant it'll need 2 sense resistors for the 2 banks of 3 mosfets? In another word, instead of 1 bank of current stage and 1 bank of gain stage for the Aleph 2, the Aleph-X will have 2 banks of cuurent stage and 2 banks of gain stage?

What about the other components (e.g. resistor or capacitor values) if more output mosfets are being utilized? I know that Aleph 2 and 5 has slightly different values in some of the resistors/capacitors on the input stage.
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Old 15th December 2002, 02:26 AM   #13
BrianGT is offline BrianGT  United States
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Quote:
Originally posted by fcel
1. I have to break the trace on the output boards (the output boards that I got from "harvadian" has space for 6 mosfets) to give 3 mosfets per bank and I'll have 2 banks per output board?
For the Aleph X, you will need 4 output boards per channel of 3 devices each. I don't know if you will be able to seperate the boards in half. I haven't looked at them closely.

Quote:
Originally posted by fcel
2. And that it would need 1 sense resistors for every 3 mosfets?
You will need 1 sense resistor per output device bank. Think of the Aleph-X as two Aleph 5 amplifiers put together. each side of the amplifier is essentially the second stage of an Aleph amplifer, so each side has two banks.

Quote:
Originally posted by fcel
For Aleph 2, for each channel, it has current source (6 transistors) and gain source (another 6 transistors). Is Aleph-X operating in the same principle?
No, it is different. Look at the Aleph 5. It has 3 current source output devices, and 3 gain source devices. Think of the Aleph-X as two of these in parallel. It is very similar to bridging two Aleph amplifers, except that the X front end has some feedback with it, giving differential error correction. If you want to understand exactly how it works, read the patent for the X amplifier. I have read it a couple of times, and don't fully understand it, but have an idea how it works.

That should answer your questions. Take a closer look at the Aleph-X schematic. If you look closely, you will see that each side almost exactly the same as the second stage of the Aleph amplifier.

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Old 15th December 2002, 02:39 AM   #14
fcel is offline fcel  United States
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I've got it. Thanks a lot Brian. Now back to transformer discussion.
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Old 15th December 2002, 03:41 AM   #15
grataku is offline grataku  United States
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I know that there are different schools of thought about this BUT I am ordering my transformers 14 VAC from VM. My rule of thumb is to end up with as much DC as my starting rms AC or slightly above. 15VDC out of 12 VAC is too much IMHO.

There is a lot of current going around and you need to shave off a few volts to really get good ripple suppression especially if going for a single CRC, the X helps out by nulling out most of the bad stuff but still my speakers are 91 dB... Remember to use good caps especially for the first bank after the rectifier, multiple parallel caps, low ESR, hi ripple long life 105C are highly recommended here.

Brian
I got my free diodes from fairchild, I plan to snub them as shown in the article in the snubbers thread.
0.01u for the parallel Cx and 0.068+110 ohm for the RsCs. I should really re-calculate the values for a more specific set of condition but I feel lazy right now. All the messed up equations in the pdf don't help my mood either.
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Old 16th December 2002, 07:36 PM   #16
Eric is offline Eric  United States
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Default losing track of design variations...

Brian, there are several designs for the Aleph-X floating around here, so I'm getting a bit mixed up and hoping you could post a quick reply: Will a single 600VA with dual 12v secondaries power a mono or a stereo Aleph-X? Working through the numbers, I'm thinking that I need 1 per mono... Thanks!
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Old 17th December 2002, 02:06 AM   #17
grataku is offline grataku  United States
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600 VA will drive a stereo NO PROBLEM. People around here like to go for 3,4,5 times the actual used power.
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Old 17th December 2002, 02:37 AM   #18
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What is the power rating of the resistors and the voltage of the caps in the snubber used on the rectifier bridge.?

Thanks
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Old 17th December 2002, 02:47 AM   #19
grataku is offline grataku  United States
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A couple of watts and anything above 100 volts.
The nominal values should really be recalculated. I'll do it when I am at that point in the construction.
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Old 17th December 2002, 02:49 AM   #20
halojoy is offline halojoy  Sweden
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I do not like to exagregate
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