Caught out in the wild! What is this rare beast-y beauty?
For me, it's like having an old friend over for dinner that I haven't seen in ages... I have missed this amp! AJ was my second amp build ever after F5. It was audio heaven—lot's of lush editorialization perhaps?—but I soon realized the amp wasn't quiet at all—After a lot of learning and experimenting—HBRs etc—Nothing would solve the buzzing...I moved on to M2X... and that's been incredible for learning and audio awesomeness.... but it's a different amp (it's a GREAT amp—we are afterall comparing Ferrari's—thanks to 6L6 for pointing that out to me one day).....
So here's my original AJ PSU and trasnfo and chassis, and with a couple of new holes tapped—and some ZM magicalness—and YES! YES! YES!
I'm seeing AJ ZEN monoblocks in my future. Might derail my BA-3 build. (also NEED to get SISSYSIT right channel working, boo.)
THANK YOU ZEN MOD!!!!!! (And Nelson
). I am truly honored to have such creations in my life everyday spreading love and joy. It was a pleasure to confirm the sweet sweetness that is the AJ Zen.
Vfet and AJ Zen cohabitate-ing — I must be VERY fortunate — Keith Jarrett on solo piano on vinyl never sounded so good (and Coltrane, and Miles, and Wes, and The Duke). So big and bloom-y and tube-y? I don't know. There's nothing not to LOVE about this amp. Maybe I just take my music with a healthy dose of MORE.
A birdie also told me that the boards are already in v.2—we LOVE a motivated ZM!
For me, it's like having an old friend over for dinner that I haven't seen in ages... I have missed this amp! AJ was my second amp build ever after F5. It was audio heaven—lot's of lush editorialization perhaps?—but I soon realized the amp wasn't quiet at all—After a lot of learning and experimenting—HBRs etc—Nothing would solve the buzzing...I moved on to M2X... and that's been incredible for learning and audio awesomeness.... but it's a different amp (it's a GREAT amp—we are afterall comparing Ferrari's—thanks to 6L6 for pointing that out to me one day).....
So here's my original AJ PSU and trasnfo and chassis, and with a couple of new holes tapped—and some ZM magicalness—and YES! YES! YES!
I'm seeing AJ ZEN monoblocks in my future. Might derail my BA-3 build. (also NEED to get SISSYSIT right channel working, boo.)
THANK YOU ZEN MOD!!!!!! (And Nelson
). I am truly honored to have such creations in my life everyday spreading love and joy. It was a pleasure to confirm the sweet sweetness that is the AJ Zen.Vfet and AJ Zen cohabitate-ing — I must be VERY fortunate — Keith Jarrett on solo piano on vinyl never sounded so good (and Coltrane, and Miles, and Wes, and The Duke). So big and bloom-y and tube-y? I don't know. There's nothing not to LOVE about this amp. Maybe I just take my music with a healthy dose of MORE.
A birdie also told me that the boards are already in v.2—we LOVE a motivated ZM!
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Wow, @pfarrell! Where do you get these PCBs? Is this the thing that ZM was hinting to me a few posts back with "build Aleph with just one pair of IRFP150, so no matching worries"?
If yes, and if I would be out of luck solving my current problems with the left channel, and if I need to change the mosfets - I would much more be willing to go big and make what I see in @parrell's pictutes!
Can I get more info, please?
-Alvis
If yes, and if I would be out of luck solving my current problems with the left channel, and if I need to change the mosfets - I would much more be willing to go big and make what I see in @parrell's pictutes!
Can I get more info, please?
-Alvis
Zen Mod, any chance of saving my bad channel of Aleph J with something other than new set of Mosfets?
And is it Babelfish J in the pictures of @pfarrell?
Any chance of getting PCBs and BOM of Babelfish? Or at least gerber files?
If there is not an easy way to make my Aleph J work well, then perhaps I could fix it with Babelfish?
And is it Babelfish J in the pictures of @pfarrell?
Any chance of getting PCBs and BOM of Babelfish? Or at least gerber files?
If there is not an easy way to make my Aleph J work well, then perhaps I could fix it with Babelfish?
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tell me just one thing ( I know how it sounds) :
-main accent was on simplicity, straightforwardness and easiness of setting (without any loss of performance); was it like that ?
Zen Mod, any chance of saving my bad channel of Aleph J with something other than new set of Mosfets?
And is it Babelfish J in the pictures of @pfarrell?
Any chance of getting PCBs and BOM of Babelfish? Or at least gerber files?
If there is not an easy way to make my Aleph J work well, then perhaps I could fix it with Babelfish?
sorry, my Force is weakening these days, probably too much of Toblerone, not enough coffee ........ so you really must try another set of mosfets;
try to compensate complexity of acquiring new matched set simply by swapping mosfets from good channel to bad channel ( not the other way, leave one channel disconnected) and observe what you'll get
if nothing else, you'll get confirmation what is culprit of your troubles
regarding pcbs you're asking about, Boyz involved should give you more info and what and when to expect
I know nothing, see nothing, hear nothing, talk nothing
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ZM: 1000% success on both fronts—YES. Assuming PSU is good, first fire up... Set offset, 0 easily achieved. Set Iq, .45 on initial fire up, dialed down to .35, let cook with lid on for an hour. Readjust Iq, dropped a bit to say .34. Recheck offset, still 0. I let it cook another hour. Stabilized at .35 Iq, Offset still 0. Good enough for me, dead easy. Been listening most of the day. LOUD. Simply love this amp. Maybe 105F on sinks... Same on Mosfets. My original AJ always ran cool though... not that it’s relevant. All twiddles on dials very stable and predictable... no drifting. Just lovely.
Ok, thanks, Gandalf Zen I will have to brace myself for all this dismantling and desoldering of mosfets. Will take some time.
@fparrell - help! Where was the birdie twitting about the v2 of that board? Which way should I listen? I love what it looks like - looks like ACA, sounds like Aleph I really want this!
I will have to brace myself for all this dismantling and desoldering of mosfets. Will take some time. @fparrell - help! Where was the birdie twitting about the v2 of that board? Which way should I listen? I love what it looks like - looks like ACA, sounds like Aleph
I really want this!
The voltage drop of 390mV points that either a MOSFET or a resistor are damaged. Or both. However, I would replace all MOSFETs and all 0.47ohm resistors due to exposure to excessive heat.
You can get a tube (25 MOSFETS) from Mouser or DigyKey and they'll all be matched. Just state on your order that you want them transistors from the same tube (same batch).
I suggest that you match those 0.47 ohms resistors. I get discrepancy in the 3rd digit; for example: 0.478, 0.477, 0.476, 0.475mV... but I matched the 0.47ohm resistors from a bag of 50.
The mains wiring runs in parallel with speaker wire (for about a 3rd of the total length) and in parallel to DC wiring. This is not good. You have 2 options:
- keep the current placement of the transformer and the power supply PCB, but run the mains wiring straight to the transformer, through the middle of the AMP PCB and then through the middle of the transformer (away from everything else). Even better, run the wiring between the bottom plates (just put some shrink to ensure no shorts!!!). But still, make sure you run the mains wiring in the middle, away from AMP PCB's.
- re-arrange things! Have a look at the photo I attached. Mains wiring length is 10cm (including the CL60!) It is completely tucked away between two metal plates as well. The layout also ensures the shortest possible DC wiring length.
You are also using borderline capacitance required for Aleph J. I think I read 18,000uF capacitors. It will be difficult to change the caps now....so your other option to tame the buzz is to do a ground lift mod. I think this is a must in your case (18,000uF caps and single-ended inputs).
EDIT:
Ground-lift instructions:
https://www.diyaudio.com/forums/pass-labs/369555-aleph-hums-quiets-shorting-plugs-5.html#post6590124
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Ok, thanks, Gandalf Zen
@fparrell - help! Where was the birdie twitting about the v2 of that board? Which way should I listen? I love what it looks like - looks like ACA, sounds like Aleph
I don’t have the specifics.. being just a glorified guinea pig. There was a revision to the boards I was given for testing to allow more space for those sexy Wima caps, since we found them a bit tight. I made it work.
I LOVE this amp. I can’t see any reason why AJ Zen can’t be the “official” AJ board.... I don’t get a say in that however.. Just here to cause trouble and stir the pot!