Dual Triode Grading System: All RAM Tube Works dual triodes are tested and graded using our proprietary tube testing computer developed by Roger A. Modjeski. The following grades are available in all dual triode types. Super Low Noise (SLN): Quite simply the industry’s quietest tube, suitable for the finest phono stages as well as any other critical application. Our SLN tubes are within 1dB of the theoretical noise limit for that tube. Low Noise (LN): A superior tube especially tested for today’s quality line stages. Our LN tubes are within 4dB of the theoretical noise limit for that tube. Standard Grade (SG): Our most economical tube, yet still a product of selection. In fact, it easily outperforms the best tubes offered by other companies.
Preamplifier Tube Data: The side panel of each tube box contains the values for the following parameters for section one and section two:
VN Noise voltage ouput in micro-volts over a bandwidth of 400 - 20K Hz.
RAM Our proprietary factor for the perceived sonic noisiness and variation.
MIC Microphonics, susceptability to airborne and chassis vibration.
GAIN AC voltage gain at 1K Hz.
PVT DC value at plate to show operation variations.