PowerTube™ Preamp
True to the Music
®
Radial Engineering Ltd.
2
FEATURE SET
1. GAIN VU: 10 Segment LED bar provides visual signal
status by simulating the natural ballistics of a VU meter.
Single fl oating LED with peak hold lowers power demand
for greater effi ciency.
2. TRIM: Control lets you set the input sensitivity going to the
tube and class-A circuit. Set high to add harmonic content
and character.
3. 180º: Polarity reverse used to phase-align two
microphones or as a creative element when recording.
4. GAIN: Control lets you adjust the overall drive circuit.
When pushed hard, the PowerTube adds character and
harmonics to the signal path.
5. AIR: High frequency boost at 8kHz for clarity, presence
and shimmer.
6. FILTER: 100Hz high pass fi lter removes low frequencies
to help eliminate excessive bass that can cause rumble.
This also helps clean up the recorded track by reducing
‘mud’ and is particularly useful when layering acoustic
instruments.
7. 48V: Phantom power for condenser microphones is
equipped with power-on LED and recessed switch
to prevent accidental use that could damage ribbon
microphones.
8. MIC INPUT: XLR female connector is conveniently located
on the front panel and placed at the bottom to keep the
cable out of the way. Wired pin-2 hot following AES
standard.
9. OMNIPORT: Rear mounted ¼” connector designated as
an instrument input to allow guitar and bass to be recorded
direct. Available when used with the Workhorse.
10. GROUND LIFT: Disconnects pin-1 ground on the XLR
input to eliminate ground loops. This special feature
should only be used when interfacing the PowerPre with
electrically powered instruments like a keyboard.
11. 12AX7 TUBE: The PowerPre employs a select low-noise
12AX7 tube with a non-radiating 140V charge pump to
deliver the performance of a high voltage tube preamp.
12. POWER ASSIGN SWITCH: Lets you toggle the input
supply from the positive or negative rail. This enables
multiple PowerTubes to be used together without power
sag.
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