Aleph J
- Description
These are the primary PCBs to create a First Watt Aleph J. This amplifier is a direct descendant of the legendary Pass Labs Aleph 3, the amplifier that turned the audio press upon it's ear, brought single-ended amps to many people, and catapulted Pass Labs into the forefront of specialist audio engineering and construction, where it still resides today.
Circuit description
The Aleph J is a single-ended, Class-A, MOSFET power amplifier, with a Jfet driver stage. It utilizes the Nelson Pass 'Aleph Current Source' to greatly increase the overall efficiency of the output stage, with the benefits of more linearity, a higher damping factor, and greater stability into tough speaker loads, doing all this with less negative feedback than it's predecessors. The Aleph J is a regular kind of amp - a voltage source amplifier, requiring nothing out of the ordinary from the preamp or the speakers.
Output power
25WPC into 8ohm
Power supply requirements
A Bipolar power supply of (+/- 24V) is required. The PSUs for almost all First Watt amplifiers including the F4, F5, F6, M2x, Aleph J, and Aleph Jzm are all essentially identical.
These Power Supply PCBs are suitable for all First Watt amplifiers.
Chassis suggestions
We have a full line of Deluxe Chassis perfect for this project. The two most common choices are the Deluxe 4U and the larger Deluxe 5U, however we heartily encourage you to consider the PASSdiy chassis currently available for pre-order until May 31st 2024. We also have a back panel parts kit to make life easier. Don’t forget the Keratherm.
| Dimensions | Each board is 250mm x 54mm |
|---|---|
| Mounting holes | UMS Heatsink Compatible |
| Number of boards included | 2 |
| Layers | 2 |
| Board Revision | 2.0 |
Customer Reviews
I just completed my build and testing of the Aleph J amplifier. It’s occupying the 4U chassis of the F6 amplifier I built and have been enjoying for the past 18 months. I liked the F6 a bunch, but at times I wished for more authority over my speakers. The Aleph J certainly has that! It sounds great. It’s detailed, has a nice soundstage, and packs a punch. So far I’ve tested it with B&W 686 S2’s and a vintage pair of ADS 1230L’s. The Aleph boards were top notch, and the build guide was very helpful. I’m grateful to the DIY Audio forum for for the great service and products it provides! Keep up the good work:-)
Just finished my Aleph J in a 5U case (big and heavy sitting on my bench) and the sound is just beautiful with my Focal Sopra 2 speakers. Those demanding beryllium tweeters just sound sweet as honey with the Aleph J and the low impedance dip in the base region is a piece of cake for this monster.
Only added the excellent Neurochrome speaker protection to be feel more on the safe side.
Before this I made me the F6 that is also one excellent amplifier to keep.
P.S. the service from the DIY -store is world class!
My Aleph J
I recently completed my Aleph J build and I have to say this has become one of my favorite amplifiers to listen to amongst my Pass DIY Sony VFET Class A amp and my McIntosh MC240 vacuum tube amp. This amplifier has exceeded my expectations. When I listen to this amp in my system, I am impressed with the fine detail, the separation between musicians within a very large, deep soundstage, and the tone and timbre.
Love the thickness and overall quality of these boards. Great layout too. Thanks!
I first came across the dii-audio, bought the pass-alep J board and the FET, and I bought the trans and case separately.
I'm happy to hear as good a sound as I expected.
There was a problem with grounding and RCA wiring, but fortunately it's been solved and I'm listening with great satisfaction.
Now I'm going to try the preamplifier.
Thank you. Everyone.
