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Aleph J Class A Amp

104.172.39.253

Posted on January 30, 2023 at 15:31:39

amandarae
Audiophile

Posts: 2591
Location: So.Cal
Joined: November 30, 2004

Have the boards since 2022 (and all the parts) but so lazy to finish the amp. Finally, because of so much rain from previous weeks, I managed to motivate myself to build the amp and completed it last week.
Built with a soft-start circuit (left of trafo in first pic) with illuminated anti-vandal push button switch on the front center allows easy turn On/Off of the unit without reaching the back side where the fused main AC switch is located. Total cost is about $800 approx or higher if using boutique components.

Very nice Class A sounding amp with my Altec and Fostex based high efficiency speakers, with very quiet background (no hum or buzz)! Hard to find an amp that sound this good at this price IMHO. I also have the F4 and M2X Pass DIY amps as can be seen in the background of pic 2 which are exceptional also!
Looking forward to motivate myself to build the ACA amps (maybe) in the future.

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triode3

04:11:16 02/22/23

amandarae

07:43:42 02/22/23

RE: Aleph J Class A Amp

pictureguy

12:37:00 02/03/23

...

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triode3

04:11:16 02/22/23

amandarae

07:43:42 02/22/23

RE: Aleph J Class A Amp

pictureguy

12:37:00 02/03/23

RE: Aleph J Class A Amp

amandarae

13:12:14 02/03/23

Congrats! Very cool (well, not temp. wise)...

musetap

11:12:01 01/31/23

RE: Congrats! Very cool (well, not temp. wise)...

amandarae

12:46:06 01/31/23

Does anyone sell a kit for the F2 or F2J?

Ivan303

10:39:18 01/31/23

RE: Does anyone sell a kit for the F2 or F2J?

amandarae

12:51:48 01/31/23

Very nice build !

AbeCollins

23:08:48 01/30/23

RE: Very nice build !

Gary

10:19:34 01/31/23

RE: Very nice build !

amandarae

10:34:24 01/31/23

I got a chance to hear these amps back in the late 90's....

Cougar

09:24:28 01/31/23

RE: Very nice build !

amandarae

07:34:56 01/31/23

RE: Very nice build !

mkane77g1

08:08:44 01/31/23

RE: Very nice build !

amandarae

21:26:28 01/31/23

RE: DELUXE 5U ALUMINUM (nt)

Johno

01:59:55 01/31/23

RE: Aleph J Class A Amp

LtMandella

21:08:23 01/30/23

RE: Aleph J Class A Amp

amandarae

21:13:46 01/30/23

RE: Aleph J Class A Amp, posted on January 30, 2023 at 21:08:23

LtMandella

Lovely work! I have a 35 wpc Class A Musical Fidelity and it can be mesmerizing with my Ref3A DeCapo I speakers.

I also purchased a couple of Pass ACA 1.8 (the most recent) kits. But damned if I lost one kit somewhere! So I guess that is the down side to putting off construction: you could lose one!

I did build a couple of Transcendent Sound kits a few years ago (GG preamp and balanced power supply) and heathkits and dynaco many moons ago.

Next up for me will probably be the DIYAudio B1 preamp. But no more SS amps for me regardless of topology. All Class D for the duration now...

RE: Aleph J Class A Amp, posted on January 30, 2023 at 21:13:46
amandarae Audiophile Posts: 2591 Location: So.Cal Joined: November 30, 2004	Thank you! I am just using what I already have as I hoarded chassis and boards awhile back. One good thing about the diy Pass amps when using the universal PSU is that boards are switchable using the same PSU and the chassis are pre-tapped already. Hope you find the other ACA kit and enjoy the amps soon!

Very nice build !, posted on January 30, 2023 at 23:08:48

AbeCollins
Audiophile

Posts: 46303
Location: USA
Joined: June 22, 2001
Contributor
Since: February 2, 2002

Where do you get those massive heatsinks these days? They must cost a good amount of cash. Are they available cheap overseas?

But does your amp cook breakfast?

My Pass Labs Aleph 3 from many years ago:

The photo was staged but it did run pretty hot! No amps were harmed in this photo.

RE: DELUXE 5U ALUMINUM (nt), posted on January 31, 2023 at 01:59:55

Johno
Audiophile

Posts: 388
Joined: June 9, 2002

Designed for the DIY Nelson Pass amps
Cheers

https://diyaudiostore.com/collections/deluxe/products/deluxe

RE: Very nice build !, posted on January 31, 2023 at 07:34:56

amandarae
Audiophile

Posts: 2591
Location: So.Cal
Joined: November 30, 2004

Thank you!
As Johno mentioned , the heatsinks comes with the chassis (5U Deluxe aluminum) from Modushop based in Italy. Reasonably priced at $399.00 with free shipping from the diyaudiostore. Heatsinks are two separate pieces per side bolted together.

The amp does not run that hot! The heatsinks are rated at 0.28 C/W max. The amp is biased at about 450 mV making the heatsink mildly hot, but not hot enough to burn.

I remember that picture! When I first saw it, my instinct says "where's the bacon?"

RE: Very nice build !, posted on January 31, 2023 at 08:08:44
mkane77g1 Audiophile Posts: 24 Location: CA Joined: January 2, 2023	About 55�C

I got a chance to hear these amps back in the late 90's...., posted on January 31, 2023 at 09:24:28
Cougar Audiophile Posts: 4593 Location: SoCal Joined: June 25, 2001	It sound good but like you said, they did run hot! Too hot for what they put out.

RE: Very nice build !, posted on January 31, 2023 at 10:19:34

Gary
Audiophile

Posts: 1297
Location: New York, NY
Joined: April 21, 2000

The chassis looks like the Deluxe 4U. That's the one I used for my M2X build.

https://diyaudiostore.com/collections/deluxe/products/deluxe

RE: Very nice build !, posted on January 31, 2023 at 10:34:24
amandarae Audiophile Posts: 2591 Location: So.Cal Joined: November 30, 2004	Thanks Gary! It's a Deluxe 5U (you can see the split heatsinks in the first photo). I have my F4 in a Deluxe 4U and still have some spare space inside when I completed the layout. I mount my trafo vertically all the time and it saves space.

Does anyone sell a kit for the F2 or F2J?, posted on January 31, 2023 at 10:39:18
Ivan303 Audiophile Posts: 48887 Location: Cadiere d'azur FRANCE - Santa Fe, NM Joined: February 26, 2001	Or even the F1? First they came for the dumb-asses And I did not speak out Because I was not a dumb-ass

Congrats! Very cool (well, not temp. wise)..., posted on January 31, 2023 at 11:12:01
musetap Audiophile Posts: 31879 Location: San Francisco Joined: July 8, 2003 Contributor Since: January 28, 2004	Good use of winter/rain time. Hope that anti vandal button isn't needed! "Once this was all Black Plasma and Imagination"-Michael McClure

RE: Congrats! Very cool (well, not temp. wise)..., posted on January 31, 2023 at 12:46:06

amandarae
Audiophile

Posts: 2591
Location: So.Cal
Joined: November 30, 2004

"Hope that anti vandal button isn't needed!"

Ha,ha! Thank you!

RE: Does anyone sell a kit for the F2 or F2J?, posted on January 31, 2023 at 12:51:48
amandarae Audiophile Posts: 2591 Location: So.Cal Joined: November 30, 2004	I do not know of any! The diyaudio store only carries F4 onwards. Your best bet is to find the gerber files and order the PCB (through JLCPCB). If I am not mistaken, mosfets for the amps you mentioned are from Semisouth and no longer in production but can still be source.

RE: Very nice build !, posted on January 31, 2023 at 21:26:28
amandarae Audiophile Posts: 2591 Location: So.Cal Joined: November 30, 2004	Thank you! I remember your build at diyaudio. Hope you are still enjoying your amp!

RE: Aleph J Class A Amp, posted on February 3, 2023 at 12:37:00
pictureguy Audiophile Posts: 22597 Location: SoCal Joined: October 19, 2008	Nice open build. And will never have an overheat problem by that means..... You make me want to at least TEST my International Rectifier 'D' amp reference board. Not anywhere near as nice or capable as your Aleph, but would be nice to hear it in action.... Too much is never enough

RE: Aleph J Class A Amp, posted on February 3, 2023 at 13:12:14
amandarae Audiophile Posts: 2591 Location: So.Cal Joined: November 30, 2004	Yes, the voice is silent at first, then all of a sudden an ear deafening shout to build something! It's a curse. Lucky for us who have resources to feed the beast. Very fortunate and thankful! Thank you for the compliment!

RE: Lazy, posted on February 22, 2023 at 04:11:16

triode3
Manufacturer

Posts: 357
Location: Midwest
Joined: August 23, 2005

>> Have the boards since 2022 (and all the parts) but so lazy to finish the amp.

I certainly would not consider this lazy for a side project. Life gets in the way, it is hard when you (as noted) have more fine amps to play with.

I have a set of Magenquest Iron for the SETH and a set for the Bugle from Gordan R. Still in the boxes as I have not gotten to it yet. I certainly feel lazy, but remind myself that my shop has moved twice, life changes happened, etc.

That is some really nice work on that amp, and I am glad to read you comments. I have looked at that Aleph J for years and wondered how it would be (Mr. Nelsen has had the schematic on his DIY site for decades, IIRC, I was reading about the J in the late 90s). Thanks for posting it.

RE: Lazy, posted on February 22, 2023 at 07:43:42
amandarae Audiophile Posts: 2591 Location: So.Cal Joined: November 30, 2004	Welcome! The AlephJ is a pretty nice sounding amp. I can say that it is worth all the wait and investment! The F4 and M2X amp are also very nice amps as well and the latter can sound different by changing the input cards. I was exclusively a tube guy. But Nelson Pass DIY amps changed me and my perception about SS amps. Thanks for the reply!

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