Aleph Jzm

Well, I can say building the Aleph Jzm a second time does go a little quicker. I still followed every step in the build guide. What a glorious build guide it is! (Thank you @ItsAllInMyHead ) I even see I'm mentioned in there....transformer seat design and wire posts are free for anyone to print BTW (search "3D" posted by "birdbox"), and if you don't have access to a 3D printer, feel free to PM me for one on the cheap.

First confirmed good PSU voltages with no amp boards (using dim bulb and variac), then a left channel check with variac, followed by right channel check (after letting capacitors discharge for an hour of course, and confirming no voltage before connecting up).

Biasing will happen in the morning for me, and hopefully glorious music after that. So far around 10-12 hours of diligent work to go from blank amp boards to power up checks (Note: @rhthatcher 's PSU was already fully populated before I started on the amp boards). Wiring actually took the longest time as I was very focused on "do it right the first time".

Now, a little amp porn....


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Image above is of the right channel check at 120VAC from variac (no DBT at this point). [Left DMM is voltage across R29 on right amp board, right DMM is offset on the right speaker posts]


Printing some wire posts just for fun. Maybe just a little "happy factor" that I can relieve any stress on the wires & connections by using the posts properly.

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All the wiring is BNTECHGO 16Ga w/ silicone insulation. I twisted the wire inside 4:1 marine heat shrink to get the tight twist and lock it in place. I know Zen Mod will suggest direct solder of all wiring to boards and I agree with that approach. I just already had the PSU all soldered up with spades and terminals, so didn't want to desolder to do that with my time crunch to have this complete by Saturday night (I fly back to WA Sunday).
 
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Well the technique to twist wires using a drill was inspired by you @rhthatcher . I simply added using heavy duty marine grade 4:1 heat shrink to hold the twist in place.....I cool the hot heat shrink under cold water to avoid it un-twisting before releasing the torque from the drill.

I'm not sure the super tight twist is really needed from an EMI reduction standpoint...but it looks nice and makes for tidy wire management.

EDIT: By the way @rhthatcher , you're stereo dual rail boards are fantastic! I highly recommend to anyone looking for a practical and easy to implement PSU board.
 
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Well the technique to twist wires using a drill was inspired by you @rhthatcher . I simply added using heavy duty marine grade 4:1 heat shrink to hold the twist in place.....I cool the hot heat shrink under cold water to avoid it un-twisting before releasing the torque from the drill.

I'm not sure the super tight twist is really needed from an EMI reduction standpoint...but it looks nice and makes for tidy wire management.

EDIT: By the way @rhthatcher , you're stereo dual rail boards are fantastic! I highly recommend to anyone looking for a practical and easy to implement PSU board.
Wire twisting by drill is the only way. Much, much neater and tighter than my old hand twisting. There's a million YouTubers on it

It looks really cool for 3 wire (different colors) for power supplies!

Russellc
 
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@birdbox Marine heatshrink 4:1 added to shopping cart... that just looks :cool:

I love that wire, but the only disadvantage (that I've found) with the high strand count and silicon insulation is that it is pretty "springy". Your solution is fantastic for maintaining the twist. I tried the zip tie every few cm etc, but yours is a more elegant solution, IMO. Wire management / dressing is one of my "biggest opportunities for improvement". That's MN nice for "I suck at it".
 
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That's why I stick with Alex jr mil-spec wire, silver coated Teflon insulated. Reasonable, solid and stranded, all colors and gauges
I love it too, and I have oodles, and oodles, but I don't like silver solder... so... compromises.

Edited to add - I should be more clear... most solders with a higher silver content.... There are some WONDERFUL solders that work well with that wire.
 
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I’ve had a handful of PMs from people asking roughly the same question, “What does it take to do a kit like the AJzm?”. So, I thought I’d try answering. I thought I had posted something similar previously, but maybe I forgot. :)

The short answer is, a lot of work from a lot of volunteers.

The longer answer is:
  • Concept / Idea – In this case, roughly, the concept is: When someone asks what First Watt should be first, the Aleph J is almost always on the list. What can be done to make the Aleph J easier for newer builders and secondarily not need to use out of production / unobtainium JFETs. If possible, can we offer some fun stuff for adventurous or more experienced DIYers?
  • Circuit design - As we all know, Papa laid the foundation, and ZM put his flair on it. In this case the Mighty ZM had the circuit well in-hand and a number of happy greedy boyz had already built it and loved it over the past few years. However, it was was focused around the unobtainium Toshiba 2SJ74 and 2SK170, the all too important "J" in Aleph J.
  • Circuit iterations / board design / layout – Test options for various JFETs in situ vs. simulation. Update board designs. 4 different board versions (at least).
  • See if other folks have success. One prototype or two doesn’t ensure success for 100s of greedy boyz. Send out some proto boards and parts.
  • Get small run of production boards made and do second round of early sourcing / checking of supply chain for all sorts of parts that may go obsolete or are not recommended for new designs at the drop of a hat. Get primary, secondary, and sometimes tertiary sources and part numbers prepared.
  • Match tons and tons of JFETs and determine yield. Starting run was XXXX JFETs (A LOT!) to see the distribution of Idss and make sure we could realistically send at least quads and hopefully octets to everyone without culling too many.
  • Testing with production parts. Send actual production kits in intended packing to early builders. Have test builders pick it apart with the most critical eye and dissect it with a microscope. Build a production version with production boards and all production parts. Test it. Again.
  • Build guide with production parts. Write it / take pics. Some / many of the pics will come from previous build. If it’s all good, send a few kits to the ‘intended audience’ and have them review the build guide to see if it’s appropriate in level / content. Revise as needed.
  • Store photography with production parts from the incredible Thuss + Farrell
  • Source production quantities of parts / packaging
  • Set up all sales from store POV
  • Package and ship kits
  • Pray to the DIY gods that every part you found 3 sources and backups for stays in production for more than 5 minutes or that someone doesn't buy out the world's stock while you weren't looking.

Packaging kits –

  • An AJzm kit (including packaging) has 37 different line items, and everyone should get exactly 125 parts (including packaging). It takes a little while to set up a production line and pack kits.
  • Every effort is made to ensure that everyone gets all the correct parts in the correct quantities. Setting up a consistent process and QA checks takes some time. Even with all that, the best of us seem to have missed a BD140 every now and again. ;) :scratch:

I had similar questions around the Iron Pre kits. Difference there is that there is some assembly (soldering JFETs, testing JFETs in situ after soldering, cleaning boards) and the matching process takes longer b/c the parts are itty bitty.

I'm an open book. PMs are fine, but it's likely if someone has a question, others may too.

Happy building!
 
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I love it too, and I have oodles, and oodles, but I don't like silver solder... so... compromises.

Edited to add - I should be more clear... most solders with a higher silver content.... There are some WONDERFUL solders that work well with that wire.
For years I used a 6n62 silver bearing solder from radio shack. Today, fire metal from the diy store. Kester works great as well.

Russellc
 
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