I am planning my Aleph J Zen build 🙂
And I need a quad of LSJ74 for that, and they are out of stock at diyAudio store.
So looking to buy Toshiba 2SJ74 from punkydawgs on eBay.
Can you please help me with some questions to be sure:
1. Two pairs are as good as a quad for AJ Zen, do not need to match between channels, right?
2. Is GR grade (Idss ranging from 2.6-6.5) even better than BL grade (Idss 6.0-12.0)?
Thanks
And I need a quad of LSJ74 for that, and they are out of stock at diyAudio store.
So looking to buy Toshiba 2SJ74 from punkydawgs on eBay.
Can you please help me with some questions to be sure:
1. Two pairs are as good as a quad for AJ Zen, do not need to match between channels, right?
2. Is GR grade (Idss ranging from 2.6-6.5) even better than BL grade (Idss 6.0-12.0)?
Thanks
An integrated BA3 preamp with Alephj
Here some pictures of an integrated BA3 preamp with Alephj in a 5U chassis.
It is controlled by a touchscreen or remote control. I've used an older Apple TV remote, small and not too expensive.
5 input channels, each configurable for balanced or unbalanced.
LS protection and error monitoring.
Preamp can be bypassed and powered down for inputs connected with high output sources.
Volume control on the amplifier is done with a rotary encoder (or remote). Left and right channel have seperate stepped attenuators, 128dB range, 0.5dB steps, so balance control is possible.
All the amp functions are controlled with a ESP32. Input selection relays, stepped attenuators, bypass, bal/unbal are controlled via a single I2C bus.
As always SW is behind the HW, need still a lot of programming, especially the display's configuration screen. 😛
Here some pictures of an integrated BA3 preamp with Alephj in a 5U chassis.
It is controlled by a touchscreen or remote control. I've used an older Apple TV remote, small and not too expensive.
5 input channels, each configurable for balanced or unbalanced.
LS protection and error monitoring.
Preamp can be bypassed and powered down for inputs connected with high output sources.
Volume control on the amplifier is done with a rotary encoder (or remote). Left and right channel have seperate stepped attenuators, 128dB range, 0.5dB steps, so balance control is possible.
All the amp functions are controlled with a ESP32. Input selection relays, stepped attenuators, bypass, bal/unbal are controlled via a single I2C bus.
As always SW is behind the HW, need still a lot of programming, especially the display's configuration screen. 😛
Attachments
for Aleph J - BL grade, pair per channel, no need to match them between channels
for J2, BL Grade, two pairs per channel, no need to match them between channels
if you by AJ Zen think on pictures of my small pcb, few pages back, there is just one pair of JFets per channel - other 2pcs of TO-92 are BC546 cascodes
ZM, yes, I refer to your small and nice pcb with IRFP150.
What is the proper name for it? 🙂
And GR grade of Toshibas in no good, it has to be BL, right?
What is the proper name for it? 🙂
And GR grade of Toshibas in no good, it has to be BL, right?
FWIW, I took delivery of 20x of the 74's from punkydawgs (BL) last week. I ordered them in a panic thinking mine were toast.
Planning on matching them and offering as many pairs as I can up to other DIYers, keep a couple for a project or two (or four?!)
Planning on matching them and offering as many pairs as I can up to other DIYers, keep a couple for a project or two (or four?!)
Eddyvb,
That is amazing! What do you do for your day job?
Do all those electronics in there affect the sound quality at all?
That is amazing! What do you do for your day job?
Do all those electronics in there affect the sound quality at all?
Thanks all, i'm retired, I've work in a design department for communication equipment. Digital stuff is separated from the analog circuits. The few direct connections between the 2 is via opto couplers. Transfo's and digital are on the front side, seperated with a big mumetal plate. Amp is very quiet.
Eddy,
Great work. I am sure your build costs a small fortune in both time and monetary investment! I see Lundahl input transformers, Toroidy PS transformers, Mundorf caps, stepped attenuators, etc...enjoy!
Best,
Anand.
Great work. I am sure your build costs a small fortune in both time and monetary investment! I see Lundahl input transformers, Toroidy PS transformers, Mundorf caps, stepped attenuators, etc...enjoy!
Best,
Anand.
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Another ZM version AJ spotted!
Hey all..
Another Zen Mod AJ nearing completion! I was fortunate enough to be provided a set of ZM AJ boards to participate in an experiment. We'd be attempting to answer the question: Is is possible for a noob to successfully build an Aleph J without excessive confusion, headaches, teeth gnashing, or other calamities?
Yes!! The answer is a resounding YES. Even someone who knows ALMOST nothing can pull this off. Ok, truth be told, I asked a LOT of questions of pFarrell, and 6L6 who were kind enough to answer all my questions.. Boards built up beautifully, were easy to set offset and bias.. and my AJ sounds amazing.
This journey started about a year ago for me with the Whammy. I really enjoyed the build, however I started itching to buy a set of descent speakers and a build a power amp. Patrick and Jim worked tirelessly putting this plan together for me..
I still have to button some things up, the LED wires leading to the front face are really janky and need to be finalized, but I'm absolutely loving the sound. Listening to the AJ via vintage Hersey I speakers, my Whammy as a pre, Schitt Modi DAC, and Tidal for source.
Thanks very much to everyone on this forum.. Particularly pFarrell, 6L6, Zen Mod, and Papa Pass!
Hey all..
Another Zen Mod AJ nearing completion! I was fortunate enough to be provided a set of ZM AJ boards to participate in an experiment. We'd be attempting to answer the question: Is is possible for a noob to successfully build an Aleph J without excessive confusion, headaches, teeth gnashing, or other calamities?
Yes!! The answer is a resounding YES. Even someone who knows ALMOST nothing can pull this off. Ok, truth be told, I asked a LOT of questions of pFarrell, and 6L6 who were kind enough to answer all my questions.. Boards built up beautifully, were easy to set offset and bias.. and my AJ sounds amazing.
This journey started about a year ago for me with the Whammy. I really enjoyed the build, however I started itching to buy a set of descent speakers and a build a power amp. Patrick and Jim worked tirelessly putting this plan together for me..
I still have to button some things up, the LED wires leading to the front face are really janky and need to be finalized, but I'm absolutely loving the sound. Listening to the AJ via vintage Hersey I speakers, my Whammy as a pre, Schitt Modi DAC, and Tidal for source.
Thanks very much to everyone on this forum.. Particularly pFarrell, 6L6, Zen Mod, and Papa Pass!
Attachments
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Beautifully done, SkyPirate!
I love that this fabulous amplifier is now even easier to build and set up successfully.
I love that this fabulous amplifier is now even easier to build and set up successfully.
That really is a sweet looking AMP! Really fantastic! I am curious if there is no performance benefit in having the heat-generating devices on the bottom rather than near the top? Perhaps the heat dissipation properties of the heat-sink are such that this is irrelevant?
Anyhow, I really looks sweet!
What is the current drain of the Aleph J? I am looking into a regulated power supply. Thanks in advance.
damn greenhorns!
unbolt those heatsinks, and rotate them for 180deg
you can do that even without undoing wires, carefully
then you'll have your Fugly!, if you upload some pics of higher resolution ...... for us Geezers
edit: or just exchange places of top and bottom lid ..........or mount set of feet on top lid, so you can rotate it by wish
that's my newest invention - how to correct amp's phase and also using it as Peltier element
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Would be nice to measure heatsink temp first and after rotation.
Warm air rises, but what does a heat source mounted on a metal plate? Go more up than down? I’m not sure. If bottom of heatsink is colder, you get a colder airflow bottom to top for cooling? I don’t know. 😱