Little Bear T7 tube phono and line preamp with RTC 5654 NOS NIB tubes (1972 FF) – MM phono stage – 2010s

The Little Bear T7 is a compact tube based phono and line preamp designed for home audio, hi fi listening rooms and simple studio chains. It supports MM phono cartridges, provides RIAA equalization, and includes a line level input for use as a general purpose tube preamp. The T7 responds strongly to tube changes, making it popular with users who enjoy tuning their system through tube rolling. For this profiling session I replaced the stock tubes with a matched pair of RTC 5654 NOS NIB valves from 1972, FF marked and in excellent condition, which noticeably increased clarity and upper mid detail. Two captures were produced, both taken at the hottest operating setting to show the extremes of what this tiny unit can do. The first capture runs through the line input and remains relatively clean, adding gentle tube bloom and gain without falling apart. The second capture is taken through the phono preamp and absolutely drives the circuit to its limits. The waveform looked so stressed that I almost felt bad for the device. Run the NAM without risks, I took them for you. These two versions provide both a controlled and an unhinged representation of the T7’s sonic personality. Everything was captured using the Matribox II as the DI, maintaining the consistent and transparent workflow I use across all my recent NAM files.