Andrew Lipinski on Preamp design...
“In order to decide what technology to use to build a timeless microphone preamp, I took the time to evaluate all components from the ground up: preamps built with transformers, transformerless designs, old classics and contemporary designs, preamps built on tubes, on discrete transistors, on integrated circuits and on a combination of all of these. Again, this was some of the most extensive research I accomplished throughout my life. Finally my research and development concluded with the following design:”
Two Separate Transformers
- The L-408 has a 200 kHz bandwidth and an acceptable input level of up to +16 dBu.
- The L-409 has an 80 kHz bandwidth and an acceptable input level of up to +29 dBu.
- Both units have front panel switchable, two position turn ratio. They have different cores, therefore they sound different. In case of the second, saturating it with high input signal recalls the effect of the old, pricey classics with some contemporary “edge”.
- Each transformer has two amplifying stages, two separate 10 step gain controls, and two meters representing each stage:
The first stage is built on discrete transistors and has class A circuitry with minimal negative feedback, and with a separate unbalanced output.
The second stage uses the fastest available current feedback integrated amplifiers, and has a balanced output. Selecting transformer ratio, setting a particular gain at the first and a separate gain at the second stage gives a talented engineer/producer an enormous creative palette of sounds.
Copper anodized enclosure for the best RFI protection
Separate Power Supply (L-410) with oversized toroidal transformer