Q: My turntable has a built-in phono preamp. How do I connect it to the T4 PRO?
A: If the turntable signal has already passed through a built-in phono preamp, connect it to the T4 PRO AUX input, not the PHONO input. Connecting a preamplified signal to PHONO may overload the input and cause distortion or possible damage.
Q: How do I switch between MM Phono and AUX?
A: The 3.5mm AUX input takes priority whenever an AUX cable is plugged in. To use the MM Phono input, simply unplug the AUX cable.
Q: Can the RCA and headphone outputs work at the same time?
A: Yes. The stereo RCA and 3.5mm headphone outputs can work simultaneously, and the main volume knob adjusts both outputs at the same time.
Q: What power supply should I use with the T4 PRO?
A: We recommend using the included power adapter. Power requirement: DC 12V / ≥1.5A. Insufficient current may cause unstable operation or degraded audio performance, while voltage above 12V may damage the T4 PRO.
Q: What replacement vacuum tubes can I use with the T4 PRO?
A: The included tube brand and model may vary by production batch; please refer to the tubes supplied with your unit. Compatible replacement tubes include 5654, 6AK5, EF95, 403B, 5725, 6BA6, 6K4, 6J1, 6J2, 6J3, 6J4, 6J5, 6Ж1Н, 6Ж4Н, and 6Ж5Н.
Q: At very low volume, the left and right channels sound slightly unbalanced. Is this a malfunction?
A: This is normal. The T4 PRO uses a mechanical carbon-film potentiometer, a traditional volume control method with minimal sound quality loss. When driving high-sensitivity speakers, slight channel imbalance may occur at very low volume levels due to inherent component tolerance. To avoid this, lower the volume on the source device and raise the volume on the T4 PRO slightly to move away from the minimum volume range.
