Pre90 adopts full balanced structure. The output can be balanced, sin- gle- ended, balanced + single- ended.. With the balanced + single-ended two-way input, in addition to the normal preamplifier usetage. Pre90 can be used for "balanced to sin- gle- ended" orsingle -ended to balanced" signal conversion.. With the help of maximum gain +16 dB, Pre90 could easily amplify the weak input signal to acceptable level of next amplifier.. It is worth men- tioning that since the noise is as low as 0.3 uVrms, this step does not bring in audible noise while amplifying the signal.