Passlabs Amplifier Projects

Initial efforts were "Dick Smith - Build a 3W Amplifier" type affairs, which quickly were surpassed by more complex designs.

The main amp from my teens was a Marshall Leach "Low TIM3 Amp". This was 100W class AB and was in use up until several years ago when I built the A40. With 25+ years service from an amp you begin to feel it doesn't owe you a lot.

While my father and I were building amps for ourselves back in the 70's, we were persuaded to build a 20W Class A amp for a friend. This had just been published in Audio magazine and was designed by this fellow who used to work for Threshold Corp.

Suffice to say this was the best amplifier we had ever heard, period! The clarity of sound, transparency and accuracy were stunning. The impression made was everlasting.

Many years past before I returned to HiFi. I then found myself at a stage where money was less tight and a hobby outside of work was highly desirable. I turned to the web and found the Passlabs site and I've been keeping moderately busy since.

The A40 seemed the logical choice for a living room amp and this was my first project. I took a lot of care in building this and I was very pleased with the result. An excellent amplifier, though I was always left with the feeling it didn't quite measure-up to my recollections of the 20W Class A.

As an exercise in extremes I then built a version of the Son of Zen and complimentary Line Stage. This really appealed to my sense of simplicity, but unfortunately it is not a living room candidate (not for me anyway!). Sonically it is a delight and if you (or more specifically, your wife) can handle the hardware it is highly recommendable.

Having had several of these projects posted on the PassLabs Gallery I received many e-mails regarding parts, design, sound etc. One of these posts drew my attention to the fact that the service manuals for the Aleph series amps had been posted to the website. This drew immediate focus in my attention and led to the production of my Aleph4.

This turned-out to be a very rewarding adventure and this is an amplifier which I can happily live with for a long time. This particular Aleph4 was built at the very outset of the "Attack of The Clones" and as stated was done "on-the-cheap" as it was really a proof of concept project.

So, I decided to build another Aleph, choosing the '5' as I do not need 100W, 60W is just fine and the extra heat of the '4' is a considerable burden. As opposed to the '4', this was designed around commercially available parts and is quite reproducible, for anyone who should want to consider such a project.

On balance, if you are going to build one Pass amp, build either the Aleph 5, 4, or 1.2, depending upon your finances and power requirements.

And ..... I still need new speakers !!!!

Regards

Mark