Update
I installed some nice heavy pin sockets and have listened/measured loads of different source resistance configurations. In the end, I've landed at values pretty consistent with a stock AJ (who would've thought
) Attached are the updated schematic with the final values I liked, as well as measurements of a few other combos that sounded great and/or measured nicely.
I did end up removing the protection circuit from the output, if for on other reason than it was necessary for this kind of experimenting.
I installed some nice heavy pin sockets and have listened/measured loads of different source resistance configurations. In the end, I've landed at values pretty consistent with a stock AJ (who would've thought
) Attached are the updated schematic with the final values I liked, as well as measurements of a few other combos that sounded great and/or measured nicely.I did end up removing the protection circuit from the output, if for on other reason than it was necessary for this kind of experimenting.
Attachments
Last edited:
Progess report
Just wanted to provide an update on my noodlings with the Aleph J/SS.
Adjustments to R24 our quite impactful, which makes sense as its kinda like the 'Aleph knob.' In fact, it would be fun to throw 2 or 3 R values (along with an open circuit) into a switch for this position. Assuming you picked your values wisely, it could give you a few nice distortion signatures to choose from on the fly.
Running the SS without any degeneration works great, but it always gave me a positive phase 2nd harmonic instead of my preferred negative. I like the idea of maintaining absolute phase, but I still flip the speaker wires and run this configuration once in a while.
I ended up reducing degeneration on top and bottom, and adding a bit more resistance to R24 to maintain a nice balance with the Aleph CS. Final values are .15R up top, and .22R on bottom. I go back and forth between 1K3 and 1K4 for R24. Screenshot attached of that final distortion measurement. I've also attached a zipped folder of around 40 measurements of different degen and R24 combos. All are 1W into 8 ohms.
This project has been a tremendous learning experience. It gives me even more respect for people like Nelson, as it would be really easy to take this circuit down into .00X% territory and just go for the lowest distortion. Knowing when to stop seems to be the real trick.
Thank Nelson!
Just wanted to provide an update on my noodlings with the Aleph J/SS.
Adjustments to R24 our quite impactful, which makes sense as its kinda like the 'Aleph knob.' In fact, it would be fun to throw 2 or 3 R values (along with an open circuit) into a switch for this position. Assuming you picked your values wisely, it could give you a few nice distortion signatures to choose from on the fly.
Running the SS without any degeneration works great, but it always gave me a positive phase 2nd harmonic instead of my preferred negative. I like the idea of maintaining absolute phase, but I still flip the speaker wires and run this configuration once in a while.
I ended up reducing degeneration on top and bottom, and adding a bit more resistance to R24 to maintain a nice balance with the Aleph CS. Final values are .15R up top, and .22R on bottom. I go back and forth between 1K3 and 1K4 for R24. Screenshot attached of that final distortion measurement. I've also attached a zipped folder of around 40 measurements of different degen and R24 combos. All are 1W into 8 ohms.
This project has been a tremendous learning experience. It gives me even more respect for people like Nelson, as it would be really easy to take this circuit down into .00X% territory and just go for the lowest distortion. Knowing when to stop seems to be the real trick.
Thank Nelson!
Attachments
I believe this is what I will build with my soon-to-be received SS gift from Mr. Pass, courtesy of Cody.
Starting to plan the build. Since this uses only 1 output, can I get away with 3U 400mm deep enclosure? I just finished a Stasis 50WPC in the 4U by 400mm and it's getting a bit heavy for me to move...
Starting to plan the build. Since this uses only 1 output, can I get away with 3U 400mm deep enclosure? I just finished a Stasis 50WPC in the 4U by 400mm and it's getting a bit heavy for me to move...
Excellent, thanks. According to my calculations, the 3U 400MM has almost identical heat dissipation as the 300mm 4U and I like the low profile look so 3U by 400 it is. Plus I think I have one already...
I found my start of the Aleph J - already have the matched JFETs and 240s. But I suppose I should save the matched 240s for another project as I'll only be using one per channel.
I found my start of the Aleph J - already have the matched JFETs and 240s. But I suppose I should save the matched 240s for another project as I'll only be using one per channel.
I spent this weekend adapting my first ever layout in KiCad of Aleph J to Alep J with 2 output transistors. I called this ver. Aleph Jazz. But that is not final.
I am still experimenting with symbols and so on.
Components have old numeration. Will fix that later.
But that is not final.I am still experimenting with symbols and so on.
Components have old numeration. Will fix that later.
