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Aleph J illustrated build guide
Aleph J illustrated build guide
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Old 2nd December 2019, 02:10 AM   #4341
Extreme_Boky is offline Extreme_Boky
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Very nice, thanks for sharing.
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Old 2nd December 2019, 09:22 AM   #4342
Georg Kovalcik is offline Georg Kovalcik
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Quote:
Originally Posted by genechow View Post
Thanksgiving present to myself.

Thanks to Nelson Pass and everyone else involved.
Where did you get the nice handles from ?
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Old 2nd December 2019, 03:50 PM   #4343
genechow is offline genechow  United States
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Quote:
Originally Posted by Georg Kovalcik View Post
Where did you get the nice handles from ?
They are cabinet pulls from Amazon: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Be careful if you get them. The hole spacings were slightly different on the two that I got.
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Old 3rd December 2019, 01:48 AM   #4344
Extreme_Boky is offline Extreme_Boky
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Default C1 and its purpose - an easier to understand schematics

Had to reposition the C1 cap....and then the things got clearer

So I'm placing the schematics here as well; hopefully, it will help others with getting their head around C1 and what it does to sound and to DC.
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File Type: jpg Aleph J single ended IN.jpg (194.6 KB, 291 views)
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Old 4th December 2019, 01:49 AM   #4345
audionut is offline audionut
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Aleph J illustrated build guide
about a 100 posts ago, I reported that I built a new Aleph J using the u5 chassis the diy jfet boards and the diy power supply boards.

I used hexfred diodes on the boards.

I can compare this Aleph J to my other Aleph J's whose power supplies usedold surplus capacitors and regular rectifier diodes.

This new Aleph J replaced an older Aleph J on the tweeters in my bi-amped system.

I have to say that I hear a definite improvement. Less sibulance on passages that have sibulance...overall smoother, better to listen to.

I am going to change the power supplies in all my Aleph J's...

These Aleph J's do great justice to Doede Duama's excellent DDDAC 1794 DAC.
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Old 4th December 2019, 02:54 AM   #4346
Extreme_Boky is offline Extreme_Boky
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Thanks for the feedback. Good to know that the Hexfreds work well in power supply, providing a noticeable improvement. They are fast switching AND soft recovery -> both ingredients make for an excellent meal.
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Old 7th December 2019, 11:22 PM   #4347
Pavo is offline Pavo
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Default Loud buzz in right channel, unstable offset.

Hello everyone. I could use a bit of help, I've tested and built my AlephJ with the help of all of your contributions to this and other threads. I had a bit of buzzing in both channels after testing and setting the bias/offset but I seem to have cut most of it out with some wire twisting, re-routing and moving the transformer. I re-adjusted the bias/offset and got a rock-steady 400mv/0vm bias/offset. The amp was sounding great. After the listening session today, I am hearing a loud buzz out of the right channel (this is new).

If i ground the input it quiets but does not go away. I checked left channel and it is steady 400mv/0mv Bias/Offset. The right channel is a steady 400mv for bias but the offset seems to be unstable. The meter shows it reading anywhere from -20 to 20 mv constantly jumping around and I can't keep it stable.

I backed up and checked the power supply. 19v AC after the transformer, 17v DC after the bridges, I get a steady +25v and -25v unloaded out of the power supply. I read about +22.7v and -22.7v hooked up to my amp boards. Still have a jumpy offset on the right channel. I've included some pictures. Any help would be appreciated. I have multiple multimeters, but do not have a scope. What else can I test to figure out what's going on here?
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Last edited by Pavo; 7th December 2019 at 11:36 PM.
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Old 8th December 2019, 01:21 AM   #4348
ItsAllInMyHead is online now ItsAllInMyHead  United States
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@Pavo - A few pieces of advice that kind people gave me. They may or may or may not help, but they're fairly simple implement and cost little to nothing. I put them in my perceived order of ease.

1) You can try running your negative outputs to the gnd on your PSU vs. back to the amp boards.
2) You can try shortening up your transformer primaries and secondaries along with your purple shield wire.
3) Reroute all signal as far away from any AC as you can and use some cable ties.
4) You can try adding one more gnd wire and twist V+ GND and V- GND separately between the amp boards and PSU.
5) You can try running your AC mains wiring between the internal chassis plate and the bottom plate and running all the primary wiring closer to the front

I don't see anything too obvious, but others may have better eagle eyes and certainly more experience. I can't see your CL-60 wiring back from PSU to chassis / safety ground, but I'll assume it's all good.

Hope it's hum free soon.

Last edited by ItsAllInMyHead; 8th December 2019 at 01:27 AM. Reason: Clarity
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Old 8th December 2019, 03:50 PM   #4349
Pavo is offline Pavo
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Quote:
Originally Posted by ItsAllInMyHead View Post
@Pavo -
I don't see anything too obvious, but others may have better eagle eyes and certainly more experience. I can't see your CL-60 wiring back from PSU to chassis / safety ground, but I'll assume it's all good.
Hope it's hum free soon.
Thanks so much for the reply and for the list! Safety/earth is connected to the chassis securely with a star nut and machine bolt, the power supply ground is connected to the same bolt through the CL-60 so only one earth connection. The only other chassis connection is the shielding wire for the transformer which is short and connected right under the transformer (not part of the circuit).

Most of this list are the things I tried to do when I first had a slight amount of hum in both channels right after the build. I call this "hum 1." I know my transformer secondaries could be a bit shorter, but I HAD the hum 1 all gone. If you see any specific places I have wires too close if you would be so kind to point it out to me?

What I'm getting now is a very loud hum out of the right channel only. I'll call this one "hum 2." The amp works still, just much louder than it ever was and seemingly NOTHING was changed to make it start.

One additional piece of information I just remembered: While I was troubleshooting hum 1 at one point I plugged in the amp and had knocked one of my connections off my bridge on the DC side of the negative rail of the power supply. I powered up the amp with only the positive side connected essentially. I powered down the amp within a few seconds realizing what happened. I reconnected the loose wire and the amp fired up normally with seeming no ill effect. No appreciable hum in either channel. The amp was working for a week before hum 2 appeared. I wonder if I possibly "partially cooked" something
and the week of normal use finished it off?
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Old 8th December 2019, 04:45 PM   #4350
elwood625 is offline elwood625  United States
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I'm about to start building my Aleph J, I finished matching the MOSFETS and the store is about to ship the FET's. Since I start at the power supply, I have a question regarding filter capacitors. I was on the Mouser website purchasing the items on the BOM, when I came across Nichicon FW (Audio Grade) 15,000uF 25v capacitors.
These are smaller in diameter to the 35mm snap in capacitors I usually use, they almost seem wimpy considering their size. Are these acceptable or even better for power supply applications since they are "Audio Grade"?
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