API 3124mb+ User manual

3124+
3124mb+
3124+ / 3124mb+ Mixer
Features
Uses API 2520 Op Amp
Classic Console Circuit
Four XLR Mic Inputs
Four1/4”Un-BalancedInputs
Front Panel Polarity Switch
Front Panel 20dB PadSwitch
Front Panel Mic / Line Switch
Front Panel 48V Power Switch
Output Clips at +30 dBm
Boththe3124+andthe3124mb+aredesignedwith
theprofessional engineerin mind,giving thehigh-
est possible quality 4 channel Mic Preamp and
with the 3124mb+, an audio mixer, while keeping
the size and price at a reasonable level. Several
3124mb+mixerscanbelinked toincreasethenum-
ber of bussed channels. Both models are equally
athome in the controlroom, the studio,a news or
recordingtruck,atthehouseconsole,onthestage,
direct-to-DAT, or at the artist’s disposal for the
sourceof hismusic.
Themodel3124+utilizesthesame microphonepreampcircuit
thatisused in all API consoles. ItusestheRE-115K mic input
transformerandthesame output transformer thatisusedinall
APIequalizers. Allfourmicinputs ofthe3124+andthe3124mb+
arepowered byaninternal48 voltphantompowersupply, front
panel switchable for each channel. Also provided is a front
panel20dBpad switch that effectsboththeMicand Line in.
Themodel3124+ can provide up to65dBof gain to anoutput
clip level of +30 dBm. The Hi-Z front panel input goes directly
to the op amp, allowing a low level input such as a guitar or
bass to be amplified without a matching transformer or direct
box. ThisHi-Zinputcantakeinputlevelsashighas +22, mak-
ing it perfect for keyboards and other high level devices. The
rear output is an XLR connector.
TheModel3124mb+ is a 3124+withtheadditionof a complete
stereomixer. Inconjunctionwiththegain control of the 3124+,
the 3124mb+ adds a stereo panner with a level control, and a
post“fader”auxsend. Thestereopanners and the aux sends
arebussed tomasteroutputcontrols andthentothe rearpanel
jacks. Astereo aux return isprovided to return effectsorcas-
cadeadditionalmixers formoreinputs. Theuniqueaux return
pot acts like a panner to balance the left/right signal, yet stay-
ing stereo. It can also be used as a mono return. A standard
3124+ can be further expanded to an “mb” at the factory. Sev-
eral options for the “mb” include a discrete unbalanced stereo
outputoradiscrete balanced stereo output.
8301 Patuxent Range Rd. Jessup, MD 20794 Phone [phone] Fax [phone] [email protected]

3124+ and the 3124mb+ Features
Represented by:
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3124+/3124mb+Specifications
Input Impedance: 1500 Ohms Mic, 470K Ohms
Un-Balanced, HI-Z in
Output Impedance: Less than 75 Ohms
Channel Outputs
Nominal Levels: XLR Channel Output +4dBu
Stereo Output Level: Unbalanced: nominal -2,
Balanced: +4
Clipping Level: XLR Channel Output better than
+28dBm
Frequency Response: +0, -5, 10Hz to 20kHz
(-.5 at 10Hz)
Noise EIN: -129 Mic, -125 Un-Bal. Actual
Measured Noise: Better than -91dBm / below
Nominal +4.
Distortion: All Outputs at +4 out, .03%, at +22,
.09% Max,
Gain Range: 150 Ohms Input 10dB Min., 65 dB
Max (inc. PAD). Un-Bal. Input
14dB Min., 50 dB Max
VU Meter: Calibrated for XLR Outputs,
OVU=+4dBu,
(-12, -6, -3, 0, +3, +6, +18)
Controls: GAIN, PAD (20dB), 48Volts, POL
(polarity), MIC (mic/un-ba;), VU, AC
Size: 19” X 1U X 8”
Shipping/Actual Weight:
3124+: 13lbs./11lbs.
3124mb+: 11lbs./9lbs.
StereoOutputs
AuxSendOutput
AuxReturn MICInput Output Insert
3124+
3124mb+
8301 Patuxent Range Rd.
Jessup, MD 20794
Phone: [phone]
Fax: [phone]
Website: www.apiaudio.com