The speakers that pair well with the Spacck Tube Amp are typically those with a high sensitivity and low impedance. High sensitivity ensures that the speakers can receive a sufficient volume from the tube amp without requiring excessive power, which is a characteristic of tube amplifiers. Low impedance is important because tube amps often have a higher output impedance, and speakers with low impedance can more effectively match the amp's output. Some recommended speakers include the Dynaudio Contour 60, Klipsch RP-600M, and Bowers & Wilkins 803D.

The Dynaudio Contour 60 is a great match due to its high sensitivity of 89 dB and 4 ohm impedance. This allows it to efficiently utilize the tube amp's power and deliver clear, detailed sound. Klipsch RP-600M, with a sensitivity of 94 dB and 8 ohm impedance, also pairs well as it can handle the tube amp's output with ease. The Bowers & Wilkins 803D, with a sensitivity of 88 dB and 6 ohm impedance, offers a balanced sound and is known for its exceptional build quality and sound performance.

According to a study by Audioholics, the sensitivity of a speaker is crucial in pairing with tube amplifiers. They found that speakers with a sensitivity of 90 dB or higher can achieve a listening level of 85 dB at 1 meter with 1 watt of power, which is ideal for tube amplifiers. Additionally, the Klipsch RP-600M was praised for its "impressive midrange clarity and detailed high frequencies" in a review by What Hi-Fi?, which is a testament to its compatibility with tube amplifiers.