Summit Audio 2BA-221 Mic and Line Preamplifier - Manual (Page 5)

Model 2BA-221 Microphone Preamplifier 5
Front Panel
Tube Output Gain Control
This control varies the tube output gain, including the XLR
and balanced TRS outputs. Turn this dial up for more vacuum
tube sound and to get more gain. Both the Line/Hi Z input
and the Mic Preamp gain controls feed this control. For the
most vacuum tube sound, turn this dial up to 2 or 3 o’clock
and adjust the solid state input gain (Line/Hi Z or Mic) for
the proper signal level. This control has no affect on the
stacking output.
Mic Preamp Gain Control
This control adjusts the gain of the solid state microphone
input. Use more of this control for a cleaner, less vacuum
tube sound. Adjust this control along with the Tube Output
gain to get the proper output level and to get the desired
sound.
Mic Preamp Loading Control
This knob controls the loading or impedance for the micro-
phone input. The input can be set from 100 ohms to 10K
ohms. You can set this control to match the 2BA-221 to the
impedance of your microphone or as a "tone" control. Try
sweeping the impedance control to hear the different sounds
available from a single microphone.
Check the manual for your microphone to find the output
impedance or check the charts on page 18 which shows the
output impedances for many commonly used microphones.
The loading impedance should be about four times the micro-
phones output impedance. Check the users manual of your
microphone for more information.
If you are in doubt on how to set the Mic Loading control, set
it fully clockwise to the 10K
Ω position.