Nelson Pass Aleph X clone build log

This is the biggest amp build so far and I doubt I will ever build anything bigger. Again, I went with a clone from the father-figure of DIY amps, Nelson Pass. Again, I got lots of help from the community. And also got a ton of help from this particular website.

I won’t bore you with the details. If you’re interested in the nitty gritty, read through the diyaudio thread. Instead, here are a few photos from the build.

That is a lot of heat sinks and a lot of power transformer. Being class A comes at a cost.

These are the power supply boards half populated with big capacitors. Almost 300,000uF of capacitance could hurt you. A lot.
Aleph X

These are the boards for one channel. The main board and the daughter boards that parallel the MOSFETs to handle the extra power.
Aleph x

Here’s the basic layout on the heat sinks:
Bottom view showing the 1/4″ aluminum tie pieces:

I mounted the PSU board on one of the heat sinks:
Aleph X

Here they are completed and in testing position:
Aleph x

Like I said, they’re big. I think 20″ deep, 14″ wide, and probably about 50 lbs each. I’ll put them on a scale to find out for sure, but they’re really heavy.

Still breaking in, but so far, they sound really good. And act as space heaters as well.

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10 Responses to Nelson Pass Aleph X clone build log

  1. Peter Hedlund says:


    From where did you get the Aleph X board?

    Best Regards!

  2. jason says:

    I got them on eBay. (And paid my penance to the community as they are not licensed boards.)

  3. Peter Hedlund says:

    I had not seen Aleph X boards with more than 8 output devices per channel before.

  4. book says:

    Hey there, I think your website might be having browser compatibility issues.
    When I look at your blog site in Opera, it looks fine but when opening
    in Internet Explorer, it has some overlapping. I just wanted to give you a
    quick heads up! Other then that, very good blog!

  5. jason says:

    Thanks for the input, I’ll look into it. It’s a standard wordpress theme and I don’t keep close track of it nowadays but appreciate the heads up.

  6. Jo says:

    i have just got hands on a PCB set for a Aleph-X and a power supply.
    Now i’m searching for a wiring sheme for this PSU.
    The PCBs are signed with Power Supply Board rev.2
    I suppose they are to find somewhere in the deep of the diyaudio forum.
    But it looks that i am way to stupid to find this informations.
    Why i am treating you with this?
    Have a look at your PSU PCBs above 😉
    Did you have any further informations about this PCBs?
    Thanks a lot

  7. jason says:

    I’m not sure which boards you have but I would say to contact the seller and see if they can help. Usually, PSU board wiring is pretty simple. And BOM is pretty simple to as you just need to make sure the caps and resistors are sized to fit the board. And of course, balance the values for what you need. Feel free to post your build on a new thread too. Then you can show pictures and get help from the real experts.

  8. Jo says:


    i have the same boards as you 😉
    Meanwhile i found a BOM but without the resistor values.
    Time to simulate
    Thanks a lot for your support

  9. moreno says:

    hello, with these pcb, did you have problems with DC output on the speakers? thank you

  10. jason says:

    I didn’t. But you could also use DC protection circuit if you wanted peace of mind.

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