New turntable LED light, noiseless and very handy!
Author: Ale Moglia
"A mistake is always forgivable, rarely excusable and always unacceptable. " (Robert Fripp)
Buenos Aires, 1936
Calle Corrientes – Horacio Coppola 1936
LME49830 Amp starts!
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….
Sketches from Saturday night
Crossover finished
It does make a difference to optimise the crossover frequency and use high quality components. The treble is outstanding now, very pleased with the sound. Need to listen to this setup for a while before tweaking the crossover:
Listening
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:
- Replace the gyrator FET for a cascoded pair (M2 and M4 below) to improve PSR
- Replace voltage reference by a cascoded LND150 for better HF and PSR response
- Optimise the LF pole of the gyrator load by increasing R4 to 4.7 MΩ and reduce C1 to 220nF
- Bias 4P1L to about 30mA. This will reduce distortion
Hope this is useful
Ale
Crossover (part I)
01a Preamp (Gen2)
A full write up of this preamp design and build can be found here
Reflection
