LME49830 Amp starts!

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Oh yes, a lot of sand! My good friend Tom recommended me to build this amp instead of an F5. Objective is to get baby-proof in 6 months. All HT valves will be removed unfortunately :(

300B will be built for a separate room….


Testing the MOSFET rectifier board!


LME boards just need the MOSFETs and are ready to go!



4P1L Siberian Gen1 upgrade

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Some of the DIYAudio fans have built this version of the 4P1L with great success. There are several upgrades that can be easily implemented to improve this. I haven’t tried this myself, but my recent experience with the Gen3 and the 01 preamp gen2, I think are worth trying:

  1. Replace the gyrator FET for a cascoded pair (M2 and M4 below) to improve PSR
  2. Replace voltage reference by a cascoded LND150 for better HF and PSR response
  3. Optimise the LF pole of the gyrator load by increasing R4 to 4.7 MΩ and reduce C1 to 220nF
  4. Bias 4P1L to about 30mA. This will reduce distortion

Hope this is useful


4P1L Siberian Gen1b v01 4P1L Siberian Gen1b v01 THD