Different
J2 requires unobtainium parts to be a J2
Aleph J can use those or others, depending on what you have and want to try
I like experimenting with high transconductance Mosfets, so the Aleph J SS is just my kind of game
plus the PCBs just look cool
J2 requires unobtainium parts to be a J2
Aleph J can use those or others, depending on what you have and want to try
I like experimenting with high transconductance Mosfets, so the Aleph J SS is just my kind of game
plus the PCBs just look cool
I think Patrick is asking about J2 SemiSouth and Aleph J SemiSouth in particular.
Why use the SemiSouth parts in Aleph J and not in J2.
Although I never heard of superiority claims before, they obviously will sound different.
Why use the SemiSouth parts in Aleph J and not in J2.
Although I never heard of superiority claims before, they obviously will sound different.
Thant's a great question. I was going to do something simpler, like an F2J if I was able to find a board, or a F2J with a light bulb. Elwood625 suggested doing Aleph J. It looks similar to a J2, and they had the Aleph J board in stock at the DIY audio store, so I went with that circuit. If I understand it correctly, J2 uses a Mu follower as a current source Vs NP patented Aleph Current source. My best guess ; it's not going to be a big difference, but it will great how both measure out.
I don’t think anyone on this thread have said it was superior to the J2. For me it’s just a fun/easy project that is easily adaptable for the SS jfet. On the other side, building a real J2 is not easy, information is spread everywhere and you still en up with a J2 lookalike unless you have 4 x SS and eight matched J74. And you still have to guess the way all transistors were matched and circuit tuned by the master.
I built both the ALEPH J using SJEP120R100's and EUVL's J2 clone using 2SK3497 and SJEP120R100's. I have SLOB with CUBE FR speakers in my system, I move the cables from the ALEPH J and the J2 so that each amp powers the FR or the 15" woofer.
The difference in sound between the two is VERY subtle. On some recordings the J2 sounds better and on some other recordings, the ALEPH J is superior. Before I had moved these two amps into rotation in my system, I used the SONY VFET lottery P channel amp. Once again the sound quality between these amps is dependent on the recordings IMHO.
I recommended the ALEPH J instead of the J2 to quinnling for two reasons:
1 - The 2SK3497 MOSFETs which EUVL says are needed for the J2 clone to sound like the original are very hard to find.
2 - I thought the surface mount devices on the J2 might be to much of a challenge for a "tube guy" to tackle on his first project.
I recommended the ALEPH J DIYaudio store PCB's because:
Both of these amps are very fine, and no one would be disappointed building either.
As a side note, I'm currently finishing an F6 using the last of my SemiSouth JFET's. It will be my first and only all JFET amplifier.
The difference in sound between the two is VERY subtle. On some recordings the J2 sounds better and on some other recordings, the ALEPH J is superior. Before I had moved these two amps into rotation in my system, I used the SONY VFET lottery P channel amp. Once again the sound quality between these amps is dependent on the recordings IMHO.
I recommended the ALEPH J instead of the J2 to quinnling for two reasons:
1 - The 2SK3497 MOSFETs which EUVL says are needed for the J2 clone to sound like the original are very hard to find.
2 - I thought the surface mount devices on the J2 might be to much of a challenge for a "tube guy" to tackle on his first project.
I recommended the ALEPH J DIYaudio store PCB's because:
- Available through the store, (I like to support the organization that gives us this great forum).
- Plenty of information and support, codyt did all the hard work perfecting the sound of the amp, and provided several recipes for not only the source resistor values, also the ALEPH current source.
Both of these amps are very fine, and no one would be disappointed building either.
As a side note, I'm currently finishing an F6 using the last of my SemiSouth JFET's. It will be my first and only all JFET amplifier.
Just to clarify what I might or might not have said before.
Both circuits use a Semisouth as driver, and a modulated current source to achieve quasi-push-pull.
In the latest version of the First Watt J2, the upper power device for the current source is no longer a Semisouth.
As I said elsewhere, the 2SK3497 has characteristics close to the Semisouth.
But it is not a must. You can also use IRFP150, etc.
For those who want to understand how the 2 current sources behave differently, I have already given you a hint above in post #43.
Happy building,
Patrick
PS My first ever DIY power amp was an Aleph-X with JFET input.
https://www.diyaudio.com/community/threads/pictures-of-your-diy-pass-amplifier.166784/post-2186736
Both circuits use a Semisouth as driver, and a modulated current source to achieve quasi-push-pull.
In the latest version of the First Watt J2, the upper power device for the current source is no longer a Semisouth.
As I said elsewhere, the 2SK3497 has characteristics close to the Semisouth.
But it is not a must. You can also use IRFP150, etc.
For those who want to understand how the 2 current sources behave differently, I have already given you a hint above in post #43.
Happy building,
Patrick
PS My first ever DIY power amp was an Aleph-X with JFET input.
https://www.diyaudio.com/community/threads/pictures-of-your-diy-pass-amplifier.166784/post-2186736
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Your J2 was the first amp I built using SJEP devices I received from Nelson during the codyt giveaway. This is a VERY fine amp which I consider one of my best sounding builds. One of the best attributes of the J2, along with the ALEPH J, allows either single ended or balanced inputs.
Some time in late winter, I look forward to changing my ACN from single ended to balanced, I'm curious to see what changes balanced inputs make to the amps.
I was able to purchase all of my devices from DIY members, currently the SemiSouth JFET's can be found for $100 - 150 usd each. Considering good 300B tubes with very good transformers will cost around $3000, the overpriced SemiSouths are a bargain.
https://www.diyaudio.com/community/...or-j2-vgs-matched-at-55-c.398229/post-7324167
"In addition, we have, left from the last GB, last 3 sets of curve-tracer-matched SJEP120R100 pairs.
These on request only, as I want them to find good homes and get used in builds.
Please only ask (by PM) if seriously interested to build with them."
They will not be eBay prices.
Else someone can buy them off me and resell later at a premium.
Patrick