Topping Pre90

LINE PREAMPLIFIER

- KALMAN RUBINSON

There has not been a conventional preamplifier in my main audio system for quite a while, because no multichannel preamp is available that’s of high enough quality. Instead, I use the high-precision digital volume controls in my players and DACs and choose sources with a relay-based multichannel analog switch. Plus, I tell myself that no preamp can be more accurate and transparent than no preamp.

However, I recently installed DiracLive3, which effectively reduces the available system gain by almost 20dB! In my salad days, I would have designed and built a balanced driver with gain for each channel; today, I require an off-the-shelf solution. After weeks of research, I found one: the Topping Pre90 ($599).

I didn’t really want a preamp in the system; I just needed more muscle. My DACs, which have a specified maximum output of 3V, were being pushed to the limit. The Pre90 was enticing me with 16dB of maximum gain and potential output of up to 50V peak-to-peak.

“I see [a preamp] as a high-quality volume control plus input selector,” said Topping’s John Yang. “The main goal is to achieve [the] lowest noise and distortion possible. Digital volume controls in DACs are in the digital domain, before the D-to-A conversion, so the noise of the DAC remains the same after attenuation. So, you always lose S/N ratio this way, regardless of the precision of the digital volume control. An analog volume control conserves SNR, because it attenuates the noise as well as the signal from upstream.” However, a careful design is required, he noted, to avoid adding more noise. “The noise needs to be low at all volume settings. Low-impedance internal circuitry allows this low-noise performance.”

SPECIFICATIONS