Aleph-X Official PCB rev. Alpha

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Hear yee, hear yee! :sarge:

This is official notice to all forum members that manufacturing of the wessol / carpenter PCB design is going ahead as planned. All interested members who want to get in on the action, please contact carpenter ASAP! He will be directing the effort from here, and I beleive has things queued up to place the order about one week from today, so don't miss out!

Please note that although this board has been built and verified to work by wessol, it has not been exhaustively tested with different transistor types and rail voltages etc, so circuit changes aren't recommended unless you have the tools and ability to test and troubleshoot the circuit for stability. In all probability will work just fine, but if you're planning to build this board, you should be aware that it is an "alpha" revision.

Thanks to wessol and carpenter for their efforts in putting together one of the first Aleph-X board layouts, and being so generous as to offer it for public consumption!

:up:
 
Also, please note that development of a more flexible, "unified" Aleph-X PCB will be ongoing in the main Aleph-X thread. The concept right now is to come up with a PCB layout incorporating some "just-in-case" changes and some alternate circuitry on the PCB. This will be built from the ground up (or starting with one of the other member's existing designs). It will undergo a prototyping fabrication run as revision "beta", and be assembled and tested by members who elect to participate in the beta test. If found stable and reliable, the design will be released as rev1.0 and development / debugging will proceed from there. Schematic variations which use the same board will be "blessed" and added as verified configurations of the rev1.0 board as members build and test them.

The process of developing the beta and rev1.0 boards will take some time... a schedule has yet to be determined. As such, these boards will not be available in the immediate future.
 
pcbs......

Hi everyone,

I'm having the artwork converted to "gerber". It should transpire the week of 11/4/02.

Quick quote prices from ECD for pcbs with standard features are as follows:

20 pcbs = $17.45 each
30 pcbs = $13.28 each
40 pcbs = $11.20 each
50 pcbs = $ 9.95 each
80 pcbs = $ 8.08 each

Because of the many developments regarding future pcb improvements, please email me if you wish to begin working with this current style pcb. For anyone who's unaware, the email link is located at the bottom of this post. After hearing the excellent sound of Shawn Wessel's AX, I'm planning on purchasing 6 pcbs for my projects.

By the way, this pcb was designed to allow for extra components used in the larger Aleph amps (Aleph 2, 3, 5). It can be likened to a pair of Alephs on a single board, ie. extra space for power resistors, off board power and ccs transistors, etc. A while back, I posted a schematic on the "Aleph X" thread depicting similarities in layout to the larger Alephs.

Thanks,

John Inlow
 
11/06/02 count

38 pcbs have been requested.

I've been in contact with a fellow at Mega Circuits. He has offered to use my artwork as "camera ready", which means I don't have to pay someone to convert it to gerber. They have given me a written quote of $5.06 per pcb for 40 pcbs. There is a tooling fee of $175.00. When split 40 ways, the tooling fee and the pcb charge add up to $9.44 per board. Now this an even better purchase than quoted by ECD.

We nearly have 40 request. So for now the cost (minus shipping) will be $9.44 per pcb. There will be a three week lead time.

I mentioned on the "beta" thread that I didn't mind waiting for the beta pcb design as long as it didn't take too long. I also realize that it's not fair to place unnecessary pressure on these guys to hurry their progress. I also mentioned that this pcb is a "treat" for those of us who want to play now. We can always purchase the more advanced pcb when it is finished. I'm listening to Shawn Wessol's AX daily and am more and more impressed with the sound. When the wife is out of town, I really crank the system up. With the Zen the sound was nice but not necessarily effortless. The AX on the other hand has power to spare. It's much brighter sounding than the Zen. I can hear details that the Zen misses. The AX is truly a design that's worth experimenting with.
 
horns, baby, horns......

I'm fully horn loaded on the left channel and horn loaded from 350hz on up on the right. The AX is running the high frequency horns (350hz to 20,000hz) which are rated by JBL at 110db 1w1m. This also explains why I get a little bit of hum from most amplifiers.



This morning, 11-7-02 I received a request for another 4 pair of pcbs. That brings the total up to 46. Yeah.........

This post will remain up another week or so and then I will place the order. This could all change if everyone emails me and request the beta board instead. Some alpha orders have been canceled in favor of the beta. Like I implied in the "beta" thread, I plan to purchase the beta pcb as well as the alpha pcb. This way, I can play very soon and still have the advanced pcb for another exercise in perfection. After the alpha purchase, I believe that we should also purchase "in mass" the beta pcb in an effort to make it cost effective for those guys. Even though the economy is depressed, most anyone should be able to come up with a spare $30.00 for a pair. This support substantially reduces the cost per item for everyone.

John Inlow
 
John,
Grey's schematic better be right, everything is based on that.;) I thought you were going to show the layout with some mods and a new schematic.
Anyways Chad rightfully pointed out that the 3 ohm from input diodes to ground need not be 3W, to that let me add that Pass/Macmillian resistors from out to S of in.diff.pair could be as low as 1k.
 
diyAudio Retiree
Joined 2002
The Aleph X files The truth is out there....somewhere.

"Grey's schematic better be right, everything is based on that."

Hmmmmmmmm...... I think everyone should realize that this not an actual Nelson Pass design. Too bad Grey never actually finished the amp to the point of bandwidth, stability, and noise measurements. Not to mention reactive load test, clipping test, turn on and turn off transient test, and listening test/tweaks. I hope someone will actually do the work required in "designing" an amp past the point of throwing a schematic together and pretending that is all there is to it. I would go back and very carefully look at the Passlabs Aleph schematics and look at the differences between the "Aleph X" and real life Aleph amps on which it was based. I guess X might stand for the unknown. I wonder what this thing does when the outputs are shorted together or one shorted to ground?

Just thinking out loud,
Fred

PS maybe you should drop official from the thread title since I can't imagine the context in which official is implied.
 
re; thinking out loud

Regarding the AX's present state of development, I can tell you this much: Shawns Wesssol's amp doesn't have any turn on/off transients that's I can hear. I'm running his amp on my JBL 2446 compression drivers with a large 150 hz tractrix horn. The driver is rated by JBL at 110 db 1w1m. If there were turn on/off transients, I would think the horns are quite capable of announcing them. The amp is capable of delivering more wattage to the horns than my ears can handle.

The sound from this amp is the best I've ever heard in any amp. It does what I expect a premium amp to do. It's output sound is clean, crisp and has extremely detailed reproduction. There is a little hum, which I CAN'T hear from the listening position. The hum may be due any number of factors. When I have my AX under construction, I will play with noise limiting techniques.

Eventually, the boys developing the beta boards will have their design sorted out. IF there is a problem with Grey's design, they will undoubtedly discover and remove the offending error.

I'm a carpenter and what I do is fabricate things. I have faith in Grey's design. I have faith in Nelson's comments regarding Greys work. I also have respect for the hard working guys developing the beta pcb. One day, we will arrive. I intend to own 6 pcb from the alpha and 6 pcbs from the beta groups.

John Inlow
 
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