@Jacruzer787 - I see your soldering iron is set to 665 degrees. You're almost there. I find setting mine to 666 is perfect for my solder AND promotes ultimate fidelity when playing heavy metal music through the amp.
Wooooo Hooooo!
Looking forward to seeing your build.
And the other docs... They really do help, IMO. 😁
Looking forward to seeing your build.
Those big resistors have bigger diameter leads. So to cover them, I had to give a little bit of extra solder.
I will let the experts chime in, but If I recall is for allowing SMD experimentation. I stand to be corrected!
I was in Classic rock mode! Gonna step my game up!
I didn’t want to polute your PSU Raffle thread, but Thank you for that. This community is just incredible. The generosity, kindness, and willingness to create products for noobz like me does not go unnoticed!
Now, no more mushiness before ZM starts calling me a Sissy!
Via Stitching provides significant benefits, such as improving ground return paths, managing ground loops, enhancing heat dissipation, and reducing noise. These advantages can significantly enhance your PCB designs' integrity and performance.Mar 27, 2024
Source - https://www.autodesk.com/products/f...nefits,PCB designs' integrity and performance.
Only the Mighty One knows for sure. 😁
Hi everyone, I haven't been on this forum for a fair while but my interest was sparked to see this Zen Mod AlephJ in full swing.
I built two of the old Aleph J amps which are both in constant service, one with me every day in my guitar workshop and one in my son's recording studio.
They are perfect for our usage. I read a lot about them before I decided they were the ones for me to build. I see lots of discussion about the building difficulty comparisons here.
But so far I haven't found any discussion of the attributes or comparisons of sound between this new version and the old one.
So I'm just asking if anyone could direct me to any such discussions if they have taken place, and indeed , if they haven't, can anyone tell me if there would be any reason for me to make this new version considering how happy I am with the old one?
Thanks.
I built two of the old Aleph J amps which are both in constant service, one with me every day in my guitar workshop and one in my son's recording studio.
They are perfect for our usage. I read a lot about them before I decided they were the ones for me to build. I see lots of discussion about the building difficulty comparisons here.
But so far I haven't found any discussion of the attributes or comparisons of sound between this new version and the old one.
So I'm just asking if anyone could direct me to any such discussions if they have taken place, and indeed , if they haven't, can anyone tell me if there would be any reason for me to make this new version considering how happy I am with the old one?
Thanks.
The choice of components, layout, hook-up wiring, grounding, the choice of metal enclosure... even the feet... make a huge difference.
It is very hard to compare the long & skinny Aleph J, with the Jzm... if you consider the above. Maybe if someone builds a "universal" test-bed amplifier, and then just swaps the two Aleph J PCB types....
... still, the final conclusion would depend solely on the rest of the system and personal preferences.
Which brings us to the real deciding factor, one that truly matters the most: which one looks prettier..??
It is very hard to compare the long & skinny Aleph J, with the Jzm... if you consider the above. Maybe if someone builds a "universal" test-bed amplifier, and then just swaps the two Aleph J PCB types....
... still, the final conclusion would depend solely on the rest of the system and personal preferences.
Which brings us to the real deciding factor, one that truly matters the most: which one looks prettier..??
Basic specs below...
Build: Super Fun
Guide: Awesome
Price: It's a steal of a deal
Learning: Top Notch Experience
Support: Phenomenal
Sound: "Just Wow!"
Overall: Everyone should have an Aleph Jzm
Oh, my bad....I just re-read and realize those are not the specs your were specifically asking about 😉
Build: Super Fun
Guide: Awesome
Price: It's a steal of a deal
Learning: Top Notch Experience
Support: Phenomenal
Sound: "Just Wow!"
Overall: Everyone should have an Aleph Jzm
Oh, my bad....I just re-read and realize those are not the specs your were specifically asking about 😉
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If you look at the link on post #61 of this thread, you will see a frequency response and phase curve of the Aleph Jzm board I had built. This a Bode plot analysis from my Keysight oscilloscope (similar models to those used by Mark Johnson and Tom Christiansen) - it’s usually the 1st test I do after building my boards. At the time, I didn’t have an audio analyzer that I have now, a Quantasylum QA403 along with Jan Didden’s AutoRanger. With these I measure harmonic distortion spectra, damping factor, etc….but only with my current builds.
Since I do not have Aleph Jzm or Aleph J modules at the moment I can’t furnish you with that data. But I can say that they will look similar to each other and definitely 2nd harmonic dominant. My guess would be that the 2nd harmonic dominance of the Aleph Jzm would be less than the Aleph J itself. And that would coincide with the subjective remarks I made in that link. A good person to ask is @ItsAllInMyHead who has probably measured the Aleph Jzm since he was involved in writing the build guide.
Power output is dictated by your voltage rails and it is all class A since these are single ended Class A designs (there is no Class AB switching, KLunking, etc…); so approximately 25 watts/8 ohms and about 13-15 watts/4 ohms with +/-25V rails. For sensitive speakers in reasonable sized rooms, I have found this to be more than enough. My room is 26 feet (~8m) deep, 16 feet (4.9m) wide and 10 feet (3m) tall. Speakers are 96dB sensitive @ 2.83V (1w/8 ohm) for a distance of 1 meter. I sit approximately 3 meters away. So in essence at 1W I am getting about low to mid 80’s Spl at my listening position.
At the end of the day, as @Extreme_Boky states, it’s all in the details, i.e. the devil is in the details.
Best,
Anand.
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My view is without a ‘compararama’ there is no use in posting subjective commentary. It’s the differences that we look for in addition to the overall aural experience. The most important for me being timbre. If the timbre is wrong, you walk out of the room and turn off the system. Timbre dominates over imaging precision, staging, microdynamics/macrodynamics and PRAT. I am not one to write or exclaim that ‘this is the best amp ever’ because that comment only serves only one person - me. It’s self fulfilling which is fine but the proud papa moments for me are long gone as I have become a veteran builder. Many do sound excellent. It’s the differences in excellency that I hope to illustrate.
Best,
Anand.
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Thanks. It's the power that interests me most as I need about 20w and I suspected that a single output device would only be capable of about 10w at reasonable temperature.
I can connect my midrange drivers in series for 16r load and use my +-33v psu. So 25w needs about 1.3amps and 20v rms (56v p-p)
I can connect my midrange drivers in series for 16r load and use my +-33v psu. So 25w needs about 1.3amps and 20v rms (56v p-p)
Not to mention some amps sound great with say acoustic music but not so good on rock. A great example would be the original Jadis JA80s, glorious on acoustic music, not so much for electric!
As you said in the end comparisons are all we got, my comment was just something that I have pondered. I will say that selling the stuff does often afford me the opportunity to compare multiple samples of the same product. Pretty much consistent results from sample to sample. That is with professionally made gear which tend to have less unit-to-unit variation than DIY.
With 33V rails, I'll have to let the Mighty One comment re: if that's a concern for the JFETs or any other components - Typical builds are ~24V rails.
If you're planning on running 1A3 Iq; I've never tried it that 'low'. The lowest I ran it was ~3A during prototyping, and we set the starting point for the build guide at 3A4. THD is inversely proportional to bias current with this amplifier. THD is also inversely proportional to load impedance. THD is directly proportional to output power. (That's true within the ranges I have tried). So, I'd say it could be worth a try, but I don't have any measurements to offer with that type of configuration. You may have to adjust the trimmers and/or a resistor or two to get the Iq into that range. If you do try it, I'd love to hear how it works out.
At 33V rails and 1A3 bias, the dissipation per device should not be a concern.
Attached is a representative set of measurements at various bias currents and a FR plot. The figures weren't tidied up for publication. They were more for my testing files; apologies. The mV figures are measured across R29. 402mV => 3A 460mV => 3A4 517mV => 3A8
I don't have any data for output impedance, but ZM may have a simulation and/or a ballpark to offer.
It should be mentioned again, that I'm still working on my measurement techniques, and I've made every attempt to keep things as proper as possible. The results should be representative of what to expect from a 'kit build' using the components offered. Happy to share any further information. The DUT was an amplifier made with exactly the components in the kit, but using prototype PCBs. The PCBs should not affect any measurements, and they used the exact same configuration, but it's only proper to mention.
Hope that helps.
Edited to add - For this purpose, 1/2 the Iq numbers above are probably more useful for your comparison. So, 3A => 1A5 etc.
Attachments
I slipped up. My drivers are 16r in parallel so in series the amp would need to drive into 32r.
My psu can give from +-33 to +-39v and according to my calcs and ignoring volatge drops, about 20w is the most I can expect. On the otherhand there is no passive crossover as the amp is just driving the midrange drivers.
However I dont kow if the amp will work with 39v rails.
My psu can give from +-33 to +-39v and according to my calcs and ignoring volatge drops, about 20w is the most I can expect. On the otherhand there is no passive crossover as the amp is just driving the midrange drivers.
However I dont kow if the amp will work with 39v rails.
meaning - you wrote Iq for 2 channels, which is somewhat uncommon
this amp with 33Vdc rails and for 16R load, doable
Rout - it's an Aleph, who cares what's Rout?!
if you care for Rout, build different amp