Tag: Siberian Preamp

4P1L Siberian Gen1 upgrade

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

Ale

4P1L Siberian Gen1b v01 4P1L Siberian Gen1b v01 THD

 

4P1L Siberian DHT Preamp (Gen3)

Recently I finished the filament supply for the latest incarnation of my 4P1L pre-amplifier.  Here is the next instalment of this project. The HT power supply was refined after builiding more than 7 stacked HT supplies for the 814 SE Amplifier.

The supply design is very simple. Perhaps the selection of components and the refinement of some aspects of it is what makes the difference to me: Continue reading “4P1L Siberian DHT Preamp (Gen3)”

4P1L Siberian Gen3: Loctal socket board

Here is the 4P1L Siberian DHT preamp (Gen3) socket board. I’m using a pair of custom made teflon sockets mounted on a PCB sandwich with a 4mm silicon rubber sheet. The lower board is mounted over 4 silent blocks:

drilling the socket boards
Loctal sockets fit and silentblocks
finished socket board
4P1Ls
4P1Ls ready!

This should be a great improvement to reduce any further microphonic noise in the preamp!