The ground (
) terminal is internally connected to the chassis and safety ground on the AC linecord.
The PRIORITY terminal activates the priority function for the BALANCED IN by using an external 
(ground) terminal. When the PRIORITY function is enabled, the UNBALANCED IN is muted (no signal from the UNBALANCED IN is transmitted to the outputs).
This GND terminal is the common connection point for BALANCED IN and PRIORITY.
The BALANCED IN terminals are the main input for the amplifier and accept a balanced 
The STAND BY terminal is used to turn on the amplifier with a remote switch.
terminal with an external switch causes the amplifier to become fully operational.
The STANDBY GND terminal on the COMMANDS terminal strip is the common connection point for STAND BY.
The OVERL. 300mA terminal is active whenever the amplifier's overload protection circuit is activated. This provides 18 VDC with a maximum output capacity of 300mA for driving an auxiliary relay or indicating LED.
The OVERL. GND terminal on the COMMANDS terminal strip is the common connection point for OVERL. 300mA.
AC Protection Fuse protects the power supply and amplifier circuitry. Replace only with same type fuse.
Connect the supplied AC linecord to the IEC AC Socket. The AC line fuse is contained in the socket, behind the cover located at the bottom of the socket. Replace only with same type fuse.
The VOLTAGE SELECTOR switch is used to select the AC supply voltage for the amplifier. Move the switch so the AC line voltage used appears on the switch (DOWN for 115V, UP for 230V).
The H.P. switch activates a 
The L.P. switch activates a 
UNBALANCED IN is an RCA jack that can be used instead of the BALANCED IN, or both can be used with the PRIORITY function, which gives the BALANCED IN priority over the UNBALANCED IN.
PARALLEL OUT is an RCA jack that is in parallel with the UNBALANCED IN jack for connecting to the input of another power amplifier.
The SENSITIVITY switch adjusts the input sensitivity of the UNBALANCED IN from 0 dB (typical 
0dBUP4061, UP4121, UP4161 specifications
The Mackie UP4161, UP4121, and UP4061 are part of Mackie's extensive range of professional audio products, designed primarily for live sound reinforcement and studio applications. These high-performance units hold a reputation for their reliability, robustness, and superior sound quality, which is essential in professional audio environments.The Mackie UP4161 is a 16-channel mic preamp featuring high-headroom, low-noise performance, and an impressive dynamic range. With its onboard 96kHz/24-bit A/D converters, the UP4161 ensures that audio is captured with exceptional clarity and detail. The presence of individual channel gain control and a -20dB pad provides versatility, allowing users to manage a wide array of sound sources, from soft vocals to loud instruments. Additionally, the device integrates seamlessly with various Digital Audio Workstations (DAWs), making it an ideal choice for recording studios.
The UP4121, on the other hand, is tailored for applications requiring fewer channels without compromising quality. This 12-channel preamp shares many features with the UP4161, including the robust 96kHz/24-bit A/D conversion technology. The UP4121 is equipped with advanced metering for each channel, ensuring that audio levels are monitored accurately, preventing clipping and distortion. Its lightweight design enhances portability, making it suitable for both studio and live settings.
Finally, the UP4061 rounds out the lineup with its 6-channel configuration, perfect for smaller productions or personal use. Despite its compact size, the UP4061 does not skimp on features, offering similar performance specifications that are consistent with its larger counterparts. It utilizes high-performance analog circuitry and delivers rich tonal quality, making it suitable for both powered speakers and passive monitors.
All three models feature Ultra-low noise, which minimizes self-noise, ensuring that recordings are clean and professional. The high-quality components and durable construction mean that these preamps will withstand the rigors of regular use, making them indispensable tools for audio professionals.
In summary, the Mackie UP4161, UP4121, and UP4061 are versatile audio solutions that cater to a variety of needs, from expansive studio recordings to intimate live performances. Their built-in technologies ensure high-quality audio while maintaining excellent usability, solidifying Mackie's standing in the professional audio market.