AMB α24 fully-differential line amplifier

My latest DIY project. Started about five years ago, aborted after buying the OG Freya, then going through the Schiit SYS and Goldpoint SA4, I went full circle and finished the preamp with the Goldpoint balanced quad attenuator and selector switch.

The alpha24 boards serve as a balanced/SE and SE/balanced converter and line stage amplifier with a fully differential circuit. The current configuration is as a passive line stage with unity gain. I plan to populate boards for +6dB and +12dB gain to give myself options down the road if I choose to change amps or speakers.

The motivation to finish this project started with @rlow's thread on his experience with the OG Freya, Saga and SYS. That thread got me a on a progressive cycle through the SYS then a Goldpoint SA4. I found I agreed with the conclusions of that thread, with the SYS improving on the passive mode of the OG Freya. I spent almost a year, I think, using the SYS as my attenuator between my DACs and my tube amp. Eventually, I got tired of the rinky dinky knob and the lack of a third input. I then bought a Goldpoint SA4 which was a noticeable improvement over the SYS.

But, I had the problem of using two preamps. One for my balanced headphone amp, and another for my tube amp. Also, I was using the SE outs of the two DACs. And I really wanted to use the Balanced outs.

So, now I have a one box solution, which gives me a differential circuit, bal/SE conversion and four inputs.

The line stage is powered by two σ22 boards for a dual mono regulated power supply.

It is not a perfect build. There are a few things I wish I could have done better. And I screwed up the lacquer coating of the rear signal chassis panel, causing some of the typed graphics to bleed. But, I am more than happy with the sound.

I'm pretty much done messing with preamps for now.

 

Holy cow, incredible work. Great frickin job man!

How do you think the sound compares to the Goldpoint etc?

You should be very proud of this. Amazing.

 

I think it is a bit smoother than Arn’s SA4. Most likely because I’m using solid silver signal wiring, while the Goldpoint units use, I believe, silver plated copper. The other thing I noticed is that the soundstage got deeper and wider, with better clarity, in terms of being able to “see” the acoustical space of the recordings. Now, this may be attributed to using the balanced out from the DACs instead of the SE outs.

Nevertheless, I am now a huge fan of Arn’s Goldpoint preamps and The Elma based DIY attenuators and switches he provides to the builder. Also, it goes without saying, that I am also a big fan of Ti Kan of AMB.

Everyone should try a Goldpoint unit in their system if it can accommodate a passive preamp.

 

That is a great build, congratulations.

 

Very nice and it looks great.

 

Seperate power supply chassis. This is the way