Miktek MPA-201 User manual

MPA-201
Class A Microphone
Preamplifier

Miktek LLC
348-B Valeria Street
Nashville, TN 37210
©2012 All Rights Reserved, Miktek, LLC.
Printed December, 2012 v1.1
www. miktekaudio.com
You’ve done, done it….. You’ve purchased a truly exceptional piece of
audio gear! Congratulations and thank you for purchasing the MPA-
201 Microphone Preamplifier from Miktek. We know there are a lot
of pretty good low cost mic pres available today, but you’re in an elite
group of audio engineers where pretty good is just not good enough.
Simply put, that’s why we make our products.
In the following sections of this manual you will find a description of
the MPA-201’s features, step-by-step set-up and operating instructions
along with detailed specifications. In addition, we’ve also included
some simple explanations of applications for the MPA-201’s features
and functions. Most of us who’ve purchased the MPA-201 are already
experienced engineers, so these may seem quite basic. However at
Miktek, we want to encourage young or new engineers to use our
microphones, or at least to read our manuals and learn something
about recording and live sound. We know you’re serous about your
productions because you purchased such an outstanding audio
instrument, and at Miktek, we’re serous about providing superior
products and service to our customers. We appreciate your patronage
and hope you enjoy using your preamplifier as much as we enjoy
making them.
Sincerely,
Michael Ketchell - Managing Director

1
Table Of Contents
Introduction.............................. 2
Front Panel Layout ........................ 3
Rear Panel Layout ......................... 4
Setting Up................................ 4
Operating the MPA-201 .................. 5 -8
Power the MPA-201 .......................... 5
Connecting Microphones...................... 5
Connecting Instruments and Line Level Signals .. 5
Connecting the MPA-201 to your DAW or Mixer .. 5
Using the Gain Control to set a Good Level....... 6
Using the Impedance Control .................. 7
Using the High Pass Filter..................... 7
Phantom Power ............................. 8
Phase Switch ................................ 8
Smooth .................................... 8
Specification.............................. 9

2
Introduction
e Miktek MPA-201 dual channel, Class A microphone preamplifier provides
a pristine signal path with a sweet and linear response that will please the most
sophisticated listeners. With 70 dB of gain, 48-volt phantom power and variable
impedance selector, the MPA-201 will highlight and enhance the sound of most
any microphone. Each channel boasts a large analog VU meter that can be switched
from input to output, plus an LED Peak output meter, making it easy to set a good
level. e MPA-201 also features a Phase switch and variable High Pass Filter,
which allows you to reduce unwanted low frequencies in your recording and help
reduce stage rumble in live sound applications. e MPA-201 preamplifier features
discrete transistors and six Miktek custom transformers, which produce a quality
sound you would normally expect only from a vintage piece. e preamplifier
features Direct Inputs on each channel, through a dedicated transformer, for
recording instruments like guitar, bass and keyboards. Do you like to record your
guitar or bass with an effects pod or plug-ins? Plug in to the MPA-201 first to
capture that big studio sound that is far beyond what is possible with a standard
audio interface. Perfect for adding a world-class signal path in front of your digital
recordings, the MPA-201 is a must for any serious recordist.
• ClassA,DiscreteTransistorVintageDesign
• Linearresponse1dBdownat10Hzand1dBdownat100kHz
• SweetsoundfromCustomDesignedTransformers
• 48VoltPhantomPower
• VariableHigh-PassFilter
• RelaycontrolledPhaseswitch
• Smoothswitchselectsdierentoutputloadingfor“racked”and“in-console”
sound
• Impedanceselectorallowsfor300,600,or1200Ohmload
• ¼-inch Direct Input with dedicated input transformer voiced for direct
recording
• LargebacklitVUMetersswitchabletodisplayInputandOutputLevels
• +4XLRBalancedOutputs
• Heavydutymetalconstructionfeaturingsteelchassisandmilledaluminum
front panel in an attractive silver finish.

3
Front Panel Layout
15
1 2 3 4 5 6 7
8 9 10 11 12 13 14
1 2 3 4 5 6
8 9 10 11 12 13 14
Front Panel Layout
1. GAIN – Selects Input level gain from 20 to 70dB
2. IMPEDANCE SELECTOR – Used to switch in input impedance
from300,600or1200Ohminputload
3. HI PASS Switch – Used to Engage the High Pass Filter
4. FREQUENCY–ControlusedtosettheCutOfrequencyfromthe
High Pass Filter
5. OUTPUT LEVEL – Control knob to adjust output level
6. PEAK METER – ree-segment LED peak meter to show the
absolute clipping point
7. POWER LIGHT – When illuminated indicates the unit is powered
on and ready for operation
8. INST/LINE INPUT – ¼-inch input jack to connect instrument or
line level signal
9. INST/LINE switch -Push switch to selet Line or Instrument input
10. 48V PHANTOM POWER SWITCH - Used to Engage 48 Volt
phantom supply for power condenser microphones or active direct
boxes
11. PHASE Switch – Used to select normal or inverted Phase
12. SMOOTH Switch – Selects normal or Smooth mode
13. METER Switch – Used to assign input or output level to the VU
Meter
14. VU METER – Displays the input or output level
15. POWER Switch - Mains power switch to power the unit on or off

4
Rear Panel Layout
A B E FC D
Rear Panel Layout
A. OUTPUT 1–MaleXLRconnectorforChannelOnemicrophone
input
B. OUTPUT 2–MaleXLRforChannelTwomicrophoneinput
C. IEC Socket – Connect a standard IEC power mains cable
D. VOLTAGE switch – Used to select the Mains operating voltage.
IMPORTANT NOTE: Be sure to check the switch is set to the
correct voltage used in your country.
E. INPUT 1–FemaleXLRconnectorforChannelOnemicrophone
output
F. INPUT 2–FemaleXLRconnectorforChannelTwomicrophone
output
Setting Up the MPA-201
First, decide where you want to position the MPA-201. e unit can be
mounted in a standard equipment rack, or can be set on a workstation
desktop. If you are setting up on a desk top, be sure to install the
included rubber feet.

5
Operating the MPA-201
Powering the MPA-201
e first time you use the pre amp, check to see the MAIN voltage
switch is set to the voltage that is correct in your country. Now, with
thepowerswitchsettotheOFFposition,connecttheincludedIEC
mains power cable to the IEC socket located on the rear panel. Next,
connect the IEC Mains cable to a compatible main power outlet. It is
alwaysagoodideatostartwiththeOUTPUTlevelcontrolsturned
all the way off (fully counter clockwise). Now you are ready to power
uptheunitbyswitchingtheMAINSswitchtotheONposition.e
POWERlightwillilluminateindicatingtheunitisreadyforoperation.
Connecting Microphones to the MPA-201
In order to avoid any unwanted pops and clicks, it is always a good
ideatoturnthePHANTOMpowerswitchtotheOFFpositionbefore
connecting your mic cables. * For more information see the section “Using
PHANTOM Power” below. Connect your microphones to the Channel
OneandChannelTwoMicinputsusingastandardbalancedXLR
cables.
Connecting Instruments and Line level signals
Each channel of the MPA-201 has a front panel ¼-inch Phones jack for
connecting instruments or line level signals. If you are connecting an
instrumentlikeaelectricbassorguitar,settheINST/LINEswitchto
INST.einstrumentinputfeaturesacustomdesignedtransformer
thathasbeenoptimizedandvoicedtoaddabitofsweetnessandcolor
to the connected instrument. is is really great for recording straight
into your DAW and eliminates that sterile sound sometimes associated
with basic instrument inputs. You can use a standard ¼-inch to ¼-inch
Instrument cable to connect here. If you are connecting line level signal
likethosefromaDJmixerorMP3playersettheINST/LINEswitch
toLINE.Youcanuseastandard¼-inchTS(TipSleeve)to¼-inchTS
instrumentcable,orRCAto¼-inchTStoconnecthere.eMPA-201
will accept balanced or unbalanced signals.

6
Operating the MPA-201
IMPORTANT NOTE: WhenyouplugacablethefrontpanelINST/
LINE the MIC input is switched off, so unplug the cable when you go
back to using mic inputs.
Connecting the MPA-201 to Your DAW or Mixer
NextconnecttheCHANNEL1andCHANNEL2MICOUTPUTSto
your audio interface or mixer inputs. e MPA-201 outputs a line level,
balancedsignalsoyoucanuseastandardXLRtoXLRcableorXLR
to¼-inchTRS(TipRingSleeve)jack(oftenincorrectlyreferredtoas
stereo) cable to connect to your mixer or audio interface’s line level
inputs.YoucansendanunbalancedsignalusinganXLRto¼-inchTR
jack (often incorrectly referred to as mono), but we recommend using
a balanced connection whenever possible. is can help keep the signal
cleanerandquieterbytakingadvantageoftheCMR(CommonMode
Rejection)providedbythebalancedsignaltoreduceinducedhumfrom
other gear.
Using the GAIN and OUTPUT Controls to Set a Good Signal Level
Now that you have made your connections you can begin to get your
micorinstrument“gainstaged”togetthebestresults.eMPA-201’s
GAIN control provides up to 70dB of gain, making it compatible with
many sources. In order to help you set a good input level using the
GAIN control the MPA-201 has two meters to display the level of your
source. e PEAK meter has very fast ballistics so it is used to monitor
the leading edge or transients of the signal, while the VU meter works
to show the average level of the signal. If you are recording to a digital
format you want to take caution to insure that the PEAK meter never
hitsthered+18dBLED,sincethisisnormallywheredigitalclipping
occurs.CheckthattheMETERswitchisuptomonitortheINPUT
level.TurntheGAINcontrolknobupuntilyoureadabout0ontheVU
meter.Next,presstheMETERswitchdowntoselecttheOUTanduse
theOUTPUTlevelcontroltosendtoyourmixerorDAW.Besureto
check your mixer’s input level Peak meter or the graphical input fader
on DAW and set a hot level without clipping. Again, if you are recording
to a digital format you want to take caution to insure that the PEAK
meterneverhitsthered+18dBLED.

7
Operating the MPA-201
Using the variable IMPEDANCE control
In order to properly reproduce the correct frequency response of
any given microphone, the output of the mic and the input of the
mic pre must have the correct impedance match. e general rule of
thumb (and correct electronic design) is that the input impedance of
the pre amp should be 5 times greater than the microphone’s output
impedance. Most modern microphones have an output impedance of
200–250 ohms, so an input impedance of 1200 ohms, which is typical
on many pres, will match correctly. However, there are many wonderful
vintage microphones and some new ones with, especially ribbon mics
that have a lower impedance of around 50 ohms. e MPA-201 has a
variable impedance control to change the input impedance from 1200
to600or300ohmsallowingyoutoconnectavarietyofmicrophones
correctly.Ohbytheway,….Sometimesyoucangetanawesomeresult
byusingthe“wrong”setting.Forexample,let’ssayyouhaveanice
condenser microphone with a sweet high-end airy lift with an output
impedance of 200 ohms, but you want a slightly darker sound, set the
inputimpedanceto600oreven300ohms.Asalways,experimentation
can be the best teacher, so plug in and listen.
Using the HIGH PASS FILTER
Any good mic pre should have, at least, a basic high pass filter in
order to reduce low frequencies you do not want, or that are just
not produced from the signal source you are miking. A high pass
filter, (sometimes called a low cut filter), will allow signals above
a determined frequency to pass, while the frequency below that
determined frequency will be attenuated. Using the High Pass can
really help clean up, and many times tighten up the bottom end of your
mix, or help eliminate low frequency rumble on stage in a live sound
application. e MPA-201 has a variable high pass filter from 18 to
350Hzallowingyoutoadjustthelowfrequencycutopoint.eMPA-
201’s variable High Pass Frequency control lets you tailor the low cut
for the sound source you are recording. For example, you may want to
setthehighpassto100Hz,whenrecordingavocal,oruseasettingof
300Hzwhenmikingamandolin.

8
Operating the MPA-201
Using PHANTOM Power
e MPA-201 provides a standard 48-volt phantom power supply for
using condenser microphones, active ribbon microphones and active
directboxes.PressthePHANTOMpowerswitchin,andtheLEDwill
illuminateindicatingthephantompowerisactive.IMPORTANTNOTE:
As with any mic input, there will be a noticeable pop in the audio when
plugging and unplugging a mic cable with the Phantom power on.
Toavoidanypossibledamagetoyourgearorears,besuretomuteyour
headphones or studio monitors when plugging and unplugging mic
cables with the Phantom power on.
PHASE
e MPA-201 has a PHASE switch, which allows you to invert the
polarity of the channel output. Inverting the phase on a microphone
can be critical especially when multiple mics are used to capture the
samesoundsource.Oneofthemostcommonexamplesiswhenasnare
drum is miked from the top and the bottom. Because the microphone
diaphragms are facing opposite directions the two mics are out of phase
and some or a lot of cancellation will occur.
SMOOTH
Sometime around the end of the 1970’s and early 1980’s, and perhaps
before that, engineers and studio techs started to remove modules,
particularly mic pre’s and EQ’s from their favorite large format
recording consoles. is enabled them to take a smaller set of choice
signal processors and fit them into smaller cases or standard 19-
inch equipment racks. Many mic pre modules were stripped from
their frame, however their outputs had a terminating resistor at the
patchbay, which was left behind. Without the terminating resistor, the
transformers start to saturate or ring when presented with high SPL
broadband signals. For many sources and many applications we like
thissaturation!eSMOOTHfunctionaddsbacktheseterminating
resistors producing a subtle yet dramatic difference depending on
thesoundsource.Inanycase,theSMOOTHfunctionisanotherway
to slightly color your sound, so check it out, give a listen and see if it
works for the signal you are recording.

9
MPA-201 Specification
Type ClassA
FrequencyResponse 10Hz–100kHz
GAIN 20 - 70 dB
Controls
 Impedance Variable300,600and1200Ohms
 HighPass Variable18Hz-300Hz
 Phase RelaySwitching
Phantom 48 Volts
Dimensions 19”x14x3.75
Weight 16lbs.
Specifications subject to change without notice.
Specification

Miktek LLC
348-BValeriaStreet
Nashville,TN37210
miktekaudio.com