Aleph J for Universal Mounting Spec

Just curious questions, does BA1 share the same qualities as AlephJ since both circuit's single ended class A and could share the same qualities, sonic wise. Is it not BA1 more modern or enhanced than AlephJ since it was developed 2009? What are the differences topology wise?
 

6L6

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Ok, sorry about the lack of information from me lately... I've been working. I'm a pilot, and when I'm out, I am genuinely out.

Anyway,

The original PCB house was practically impossible to work with, their Promo pricing was predicated on using a generic software, not using Gerber as they indicated. A forum member suggested another PCB fabricator in Silicon Valley, and the process is hopefully on it way as of last night. I should have the prototype boards in my hands next week.

I am going to build one prototype, buzzforb is going to build one as well.

I am looking for one more volunteer to build the Aleph J to verify that we have a good PCB. Anybody interested would need to be able to build it quickly, and preferably from stock they have on hand. If you think you can knock one together easily and quickly, PM me. I will be able to send you the last set of PCB and maybe a small handful of parts.

If you have something like an F5 that you would want to adapt the case and PSU to the Aleph J, that would be a fine project, as it would also show that once you have one DIY firstwatt amp, it's easy to try other configurations.
 
I have a nice Amplimo 625VA transformer for this project as well as about 20 IRFP240 MOSFETs, a matched pair of 2SJ74BLs from Spencer but no heatsink, caps and resistors. I am to pull the trigger on my caps order from Mouser.

The heatsink is the killer for me at the moment.
 
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6L6

Do you by any chance know if this board can accomodate Dale RN60s? I know that RN55s will probably be OK for the AJ, but when I buy resistors from Mouser I usually get a 100 at a time since shipping is expensive to here, so usually use the purchase for stocking up for other projects as well, and RN60s is a good alrounder.

I know it was discussed earlier in the thread, by I can't confirm if the spacing is adequate. You would need at least a pin spacing of 12mm for the RN60s. 10mm is too small and I hate having to mount resistors standing up. If the spacing is 10mm I will have to go for the RN55s.
 

6L6

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Joined 2010
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I think that the spacing is adequate for RN60 in most positions. The spacing was the same as the F4, which will fit them. (and PRP, and some of the other fancy expensive audiophile resistors.) Although you mention that you don't prefer it, you can always mount them standing up.

I have a bunch of RN60 on hand and will verify when I finally receive the boards.

The BOM should be similar to the original circuit, the changes to the PCB are pads for pots and resistor where there was originally just a resistor, places for film bypasses across the electrolytics, and a few spots for additional resistors if you have oscillation problems, which 99% of people will not use and just use a jumper.

EDIT - If you are trying to get everything on one order you might want to look back at the last posted PCB drawing and schematic - it will show the places where the pots and such are. The schematic numbering is similar to the original (Nelson's 'General Amplifier') schematic. The schematic I posted towards the beginning has been the basis of this whole project, although I mis-marked the pot on R7, it should be 500ohm, not 500K.

Also, if you would like to make a BOM, for the new board, that would be warmly received. :) :) :) I am a 'work off the schematic' kind of guy, and would love for somebody to make (or at least start) a BOM. My only request would to make it from Mouser. :D
 
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