Yet another Aleph 5!!!!!

[DirkD]

Hi there

I would like to share my two Aleph amplifier projects with everyone.

I have just completed building two Aleph amplifiers. One is an Aleph 5 that I built for my brother to use with his Apogee Centaurus ribbon hybrid loudspeakers. The other is an Aleph 4 that I built for a friend. I have completed them in about six months and am very pleased with the results of my labour, but more on that later.

I used IRFP250 Mosfets because that is what I could easily find locally. Both amplifiers use six Mosfets per channel because the IRFP250 can handle the increased load required for the Aleph 4. The bias resistors for the Aleph 4 are 0R68 as suggested by Mark Finnis on his website. The capacitors on the amplifier boards are Nichicon Muse 220uF, Silver Mica 680pF and 10pF and Solen 0.047uF. Resistors are Dale ¼ W 1% and 3W 1%. For the power supplies I used 12 x 10 000uF 63V Rubycon Electrolytics per amplifier bypassed with 3.3uF polypropylene caps. I used Keystone CL-60 thermistors for inrush protection and CL-40 thermistors on the ground lines.

The Aleph 5 has a single 650VA 28V-0-28V toroidal transformer while the Aleph 4 has a single 650VA 38V-0-38V transformer.

I used Michael Finnis’ Aleph 4 PCB design as starting point for my PCB design. I changed the board to accommodate heat sinks on the input Fets and to allow the mounting of the Mosfets without any additional wiring. I also designed a board for the power supply and what I call the voltage input boards on which the thermistors and 250V AC capacitors are mounted.

All internal wiring is either Kimber or DH Lab and connectors are Cardas RCA’s, Neutrik XLR sockets and Vampire speaker binding posts.

The heat sinks are from Fischer and measure 40mm H x 250mm L x 400mm W. They have a C’/W rating of about 0.22 each. The chassis consist of laser cut 3mm black Anodised Aluminium top, bottom and rear panels and 6mm front panel, all bolted onto the heat sinks with Allen head bolts.

Both amplifiers worked when first switched on and I am absolutely delighted with the sound quality. I have listened to a very large number of big-ticket amplifiers, but I can honestly say that the Aleph designs have the best reproduction of vocals that I have ever experienced. The timbre of vocals and natural instruments are unmatched by any other amplifier that I have ever heard. Sound staging and transparency is beyond reproach. If I have any, very minor, criticism of the sound it would be that I have heard tighter bass on some of the more powerful high current designs available.

I would like to thank Mr Pass for sharing his exceptional designs with the audio DIY community and wish him every success in future.

D

[DirkD]

Another pic!

[SNOWCRAB]

HI

Good work, can you show us the rear side with the input.
You have a lot of space in your case, very easy for repair.

My aleph have a little less space

How is the sound?, what is your drive and préamp?

Again very good job, more pics from your ALEPH 4.

My Aleph 5 ...

Regards

Thierry BASSAL

[MikeW]

Nice amp. Very good job.

[DirkD]

Hi there SNOWCRAB

My pre-amp is a diy clone of a Conrad Johnson PV10A and my source is a cheap Pioneer DV355 DVD player that I modded. Replaced the coupling capacitors with Elna Cerafines, replaced the opamp with AD826 and fitted a Trichord Clock 2. I also damped the chassis and transport with bituminous pads.

Interconnects are Kimber PBJ and speaker cable is Kimber 4TC. I listen to my DIY bookshelf loudspeakers with Scan Speak 18W8543 woofers and D2010 tweeters.

D

[DirkD]

Thanks for the kind words MikeW!

D

[kilowattski]

Super job dirk! Well done all around. Best of luck with it.

[DirkD]

Hi there SNOWCRAB!

BTW the Aleph 4 looks exactly like the Aleph 5. It is simply run on a higher rail voltage and the bias resistors have different values than those of the Aleph 5.

D

[Netlist]

Another black beauty.
Don't forget to post it at Passdiy.com

/Hugo

[Audiohifi]

Hi DirkD

You mentioned about upgrading your DV-355. I would like to mod it. Do you have the schematic? What are the components you have upgrded
Appreciate if you can help

Goh A S