Previous PageNext Page



A few years ago destroyer X (with Hugh Dean's permission) published the conceptual schematic of one of Hugh Dean's commercial AKSA 55 kitset products. Being a conceptual schematic, it is not identical to the commercial AKSA 55, there are a few components that are not shown on the schematic and the values of some of the components are different.

Here is the DIYAudio thread for reference:

I was learning EAGLE at the time so I drew the schematic and designed a PCB as an exercise. At the time the AKSA 55 was still a commercial product, so I didn't think it was appropriate to publish the PCB. But now, the AKSA 55 is no longer for sale, so I sent the PCB files off to a PCB manufacturer and have now built a few of these amplifiers.

Note: My schematic is a little different from the one that was shown in the reference thread in a couple of ways. I changed a couple of values that were obviously wrong, I used BD139 / BD140 as drivers and I used a BD139 for the VAS. When testing the PCBs I used the recommended transistors mentioned in the quote below.

Here is a quote from destroyer X's original thread:

  • Differential transistors (Q1, Q2) are matched 2N5401
  • Voltage bias multiplier (Q4) can use BD139
  • Voltage amplifier (Q3) can not inform, a lot of them works there (I used a KSC3503)
  • Drivers (Q5, Q6) are 2SC4793 and 2SA1837
  • Output (Q7, Q8) are 2SC5200 and 2SA1943

See the DIYAudio thread Based on Hugh Dean's AKSA 55 for more information and discussions.

More information:

Previous PageTop Of PageNext Page