The L-9000 is a Direct Coupled OTL/OCL Tube Preamplifier. OTL/OCL means “Output Transformer Less” and “Output Capacitor Less”. In an OTL/OCL preamplifier, there is no coupling device between the preamplifier and the power amplifier , that is, the preamplifier’s final output tubes are directly connected to the power amplifier. Normally, an Output Capacitor or Output Transformer for separating AC music signal from the DC operating potential; if this is not done, the latter will destroy the power amplifier or loud speakers.
In common circuits, output capacitors or output transformers are required to separate the AC music signal from the DC operating potential. If this is not done, the latter will destroy the power amplifier, the loudspeakers, or both. However, these two coupling devices also introduce their own influences on the transmission of the musical signal, adding their own character (colouration), increasing distortion, and consuming small signals, all as predicted by physical efficiency theory. In addition, they also limit signal dynamics. For these reasons, the elimination of output transformers and capacitors has been considered the best solution for the design of the most accurate amplifiers. Removal of these two coupling devices from the signal path achieves the best results possible:
- No colouration of the musical signal
- Extremely detailed expression, natural harmonics and subtle musical decay
- The lowest possible distortion
- The widest musical dynamics
In the L-9000, there is no coupling device between the preamplifier and the power amplifier; that is, the final gain/output tubes are directly connected to the power amplifier. Thus, the benefits listed above are fully present in the Allnic L-9000 preamplifier.
