Millennia TD-1 User manual

Twin Direct
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TD-1
Twin Direct
Recording Channel
Instruction Manual
Rev A3, 6/03 (2500)
© 2003, Millennia Media, Inc.
All rights reserved. Litho in U.S.A.

TD-1
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ONE YEAR WARRANTY
MillenniaMediawillrepairthisproduct,freeofcharge,intheUSA,inthe
eventofdefectofmaterialsorworkmanshipforone(1)yearfollowing
dateofpurchase. This warranty is extended only to the originalpur-
chaser. This limited warranty covers failures due only to defects in
materialsand workmanship that occurduring normal, intended useand
doesnotcover damage which occurs in shipment or failures whichare
caused by products not supplied by Millennia. This limited warranty
doesnot cover failures whicharise from accident, misuse,abuse,
neglect, mishandling, misapplication, faulty installation, improper adjust-
ment,alterationormodificationofproduct,incompatibilities,line-power
surges,actsof God, or service performed by anyone other thanMillen-
niaorits authorized agent. Vacuum tube failures are not coveredunder
warranty.
LIMITS AND EXCLUSIONS
There are no express warranties except as listed above. Millennia shall
notbeliable for special, subsequent, incidental, consequential, or
punitivedamages, including, but notlimited to: damage torecordings,
broadcasts, microphones, mixing consoles, or any associated equip-
ment, downtime costs, loss of goodwill, or claims of any party dealing
with purchaser for such damages resulting from the use of this product.
Allwarranties,expressandimplied,includingthewarrantiesof merchant-
ability and fitness for a particular purpose are limited to the applicable
warrantyperiodsetforthabove.
Somestatesdonot allow the exclusion or limitation of incidental or
consequential damages, or length of time an implied warranty remains in
effect.Assuch, the above exclusions may not apply. This warrantygives
you specific legal rights and you may also have other rights which can
vary from state to state.
REAMP® isa registered U.S. trademark. REAMP technologyis used
underlicense -- U.S.Patno. 6,005,950.

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TABLE OF CONTENTS
GOVERNMENTAL NOTICES 4
INSPECTION 7
SAFETY PRECAUTIONS 9
DESIGN CRITERIA 11
QUICK START 12
FRONT PANEL FUNCTIONS
Input Section 13
Equalizer Section 17
Routing Section 19
REAR PANEL FUNCTIONS 20
SIGNAL FLOW DIAGRAM 26
GROUND LIFTING & ISOLATION 28
JUMPER MAPS 29
ASSEMBLY INSTRUCTIONS (Rack Mount, etc..) 31
PERFORMANCE GRAPHS 33
SPECIFICATIONS 36
CONTACT INFORMATION Back Cover
http://www.mil-media.com

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FCC NOTICE
INFORMATION FOR THE USER
This equipment has been tested and found to comply with the
limits for a Class B digital device, pursuant to Part 15 of the
FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential instal-
lation. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in accordance
with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interfer-
ence will not occur in a particular installation. If this equipment
does cause harmful interference to radio or television recep-
tion, which can be determined by turning the equipment off and
on, the user is encouraged to try to correct the interference by
one or more of the following measures:
1) Reorient or relocate the receiving antenna
2) Increase the separation between the equipment and re-
ceiver
3) Connect the equipment into an outlet on a circuit different
from that to which the receiver is connected.
4) Consult the dealer of an experienced radio/TV technician
for help.
The user may find the following publication prepared by the
Federal Communications Commission helpful:
“How to Identify and Resolve Radio-TV Interference Prob-
lems” (Stock Number 004-000-00345-4)
Available exclusively from the Superintendent of Documents,
Government Printing Office, Washington, DC 20402 (telephone
202-512-1800)
FCC WARNING
Changes or modifications not expressly approved by the party
responsible for compliance to Part 15 of the FCC Rules could
void the user’s authority to operate the equipment.
This device complies with Part 15 of the FCC Rules. Operation
is subject to the following two conditions: (1) This device may

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not cause harmful interference, and (2) This device must
accept any interference received, including interference that
may cause undesired operation. This Product Certified to
meet the Standards in the categories: Audio/Video and Musi-
cal Instrument Apparatus for Household, Commercial, and
Similar General Use EMI: FCC Part 15 Class B; ICAN ICES-003
Class B; EN55022 Class B
CE NOTICE
INFORMATION FOR THE USER
This equipment has been tested and found to comply with the
limits for a Class B or Class 2 digital device, pursuant to EN
55022 Rules. These limits are designed to provide reason-
able protection against harmful interference when the equip-
ment is operated in a commercial environment. This equip-
ment generates, uses, and can radiate radio frequency energy
and, if not installed and used in accordance with the instruc-
tion manual, may cause harmful interference to radio commu-
nications. Operation of this equipment in a residential area is
likely to cause harmful interference in which case the user will
be required to correct the interference at his own expense.
The user may find the following publication prepared by the
Federal Communications Commission helpful:
“How to Identify and Resolve Radio-TV Interference Prob-
lems” (Stock Number 004-000-00345-4)
Available exclusively from the Superintendent of Documents,
Government Printing Office, Washington, DC 20402 (telephone
202-512-1800
WARNING
Changes or modifications not expressly approved by the party
responsible for compliance to EN 55022 Rules could void the
user’s authority to operate the equipment.

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ICAN Class B Digital Equipment
This Class B apparatus meets all requirements of the Cana-
dian Interference-Causing Equipment Regulations.
Cet appareil numérique de la classe B respecte toutes les
exigences due Reglement sur le materiel brouilleur du
Canada
BZT Declaration (German)
Bescheinigung de Millennia Media, Inc. hiermit wird bescheinigt,
dass die Direct Box TD-1 “TWIN DIRECT” in Übereinstimmung
mit den Bestimmungen der VFG 523/1969, DIN 57871 / VDE 0871
/ 09.84, und DIN 75875 Part 1 A2 / 10.90 (Amtsblattvertugung)
funk-entstört ist.
Der Deutshchen Bundespost wurde das Inverkehrbringen dieses
Gerats angezeight und die Berechtigung zur Überprüfung der
Serie auf Einhaltung der Bestimmungen eingeräumt.
Einhaltung mit betreffenden Bestimmungen kommt darauf an,
dass geschirmte Ausführungen gebraucht werden. Für die
Beschaffung richtiger Ausführungen ist der Betreiber
Verantwortluich.
Dieses Gerät wurde sowohl einzelnals auch in einer Anlage, die
einen normalen Anwendungsfall nachbildet, auf die Einhaltung
der Funkentstörbestimmungen gerprüft. Es ist jedoch möglich,
dass die Funkentstörbestimmungenunter Ungunstigen
Umständen bei anderen Gerätekombinationen nicht Eingehalten
werden. Der Betreiber ist für die Einhaltung der
funkeutstörungsbestimmungen seiner gesamten Anlage
verantwortlich, in der dieses Gerät betrieben wird.
Millennia Media, Inc.

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INSPECTION
Congratulations on your purchase of the Millennia TD-1TWINDIRECT
recordingchannel.TD-1istheculmination of meticulous listening tests
on innumerable circuit, topology, and packaging designs over decades
ofaudio product development experience. Your TD-1is a finely tuned
instrument intended for critical professional applications — with the
added benefits of selectable vacuum tube DI amplifier, all discrete FET
solid state DI amplifier, variable input impedances, Speaker Soak(tm),
and REAMP®, we feel it offers the world’s best soundingand most
sonicallyversatileDI + recording path. With the emergence of 24+bit
digital audio, recording engineers are faced with a new requirement for
undistorted dynamic range. Twin Direct meets this challenge exception-
ally well.
NOTE: Any changes or modifications not expressly approved by
MILLENNIAMEDIA, INC. (Millennia) couldvoid your authority tooperate
thisequipmentunder the EC, ICAN, or FCC rules.
1. Copyright: You acknowledge that no title to the intellectual property in
the TD-1 is transferred to you.
2.Inspection: Inspect packing box(es),TD-1, and cable(s) fordamage,
unusualmarks, or shortages. It is yourresponsibility to report damage,
shortage,or mis-shipments in atimelymanner. Millenniaand/or its
dealers will not be responsible for claims arising from damage in
shipping, nor will claims for shortage or mis-shipments be honored, more
than 10 days after ship date.
3.Read this manual carefully and completelybefore attempting to use
theTD-1. Improper operation could resultin damage to product. Itis the
user’sresponsibilitytounderstandthesafeuseandoperationofthis
device.
4.Theshippingboxofthe TD-1 system will include (1) Owner’s Manual,
(2) TD-1, (3) a UL approved power cord, (4) Owner’s Registration Card,
(5) Four rubber feet with mounting hardware, and (6) Steel carrying
handle with mounting hardware. Fill out the Owner’s Registration Card
andreturntoMillenniaat your earliest ability.
Thematerial contained in thismanualconsistsof information thatis
propertyofMillenniaandisintended solely for use by the purchasers of
theequipmentdescribedinthismanual. Without express written permis-

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sion,Millenniaprohibits the duplication of any portion of this manualor
theusethereoffor any purpose other than the operation and/or mainte-
nance of the equipment described in this manual. This manual may not
beduplicated in wholeorin part withoutthewrittenconsent ofMillennia.
TD-1, TWIN DIRECT, Speaker Soak,and Twin Topology are trade-
marksofMillenniaMedia,Inc. Allother trademarks are property of their
respective holders. TD-1 serial number is located on the rear left side of
each unit. We suggest that you record the serial number in the space
provided below. Refer to it whenever you call an authorized Millennia
repair facility or the manufacturer. Make sure that you return your com-
pletedwarrantycardimmediately.
Featuresandspecificationssubjectto change without notice.
©2003- Millennia Media,Inc.,All rightsreserved
Serial No.
______________________________________________________________
Purchase Date
___________________________________________________________
Where Purchased
_________________________________________________________

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SAFETY PRECAUTIONS
For your safety and the safety of others, be sure to read and understand
allsafety and operational instructions before attemptingto use the TD-1.
WARNING: The TD-1 internal circuitry carries lethal voltages.
Carefullyobserveallwarnings,precautions,and instructions on the TD-1
andasdescribedintheinstructions supplied with the unit.
1. WATER, MOISTURE, AND SPILLAGE
Do not attempt to use the TD-1 in, near, or around water or in unusually
moist environments, such as near a sink or swimming pool. Prevent liq-
uids or any other materials or objects from spilling or falling into the TD-1
unit.
2. HEAT AND VENTILATION
Besuretoallowadequateventilation to TD-1 and avoid using or installing
unitinclose proximity to heat sources, such as heaters, stoves,radiators,
poweramplifiers,spotlights, or other heat-producing appliances or equip-
ment.
3. POWER SOURCES AND POWER CORD PROTECTION
The TD-1 Power Supply should be connected to a power source only of
thetypedescribedintheoperating instructions or as marked on the Power
Supply. Route the power cord so that it is not likely to be walked on or
pinched by having objects placed on it. Pay particular attention to plugs,
receptacles,andthe point where the AC power cord exits theTD-1.
4. GROUNDING
Foryoursafety, it is extremelyimportantthatthegrounding pin of the 3-wire
power cable (included with unit) be inserted into a grounding type 3-pin
poweroutlet. If you are unable to insert the pluginto an existing outlet, con-
tact an electrician to install a properly grounded 3-pin power outlet, prefer-
ablythatwith OFI / CFI protection, ifavailable.
5. DAMAGE REQUIRING SERVICE
Thisunitshouldberepairedorservicedbyqualifiedpersonnelwhenever:
· The AC power cord has been damaged, or
· Objects have fallen or liquid has spilled into any TD-1 unit, or
·The unitdoesnotfunction properlyorexhibitsa markedchangeinperfor-
mance, or
· The unit has been abused, dropped, or damaged, or

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·The unit has beenexposed to rain ormoisture
6. SERVICING
Lethal voltages are found inside the TD-1 chassis. Theusershould
notattemptto repair or service this unit.Allservicingand/orrepairsshould
bereferredtoMillennia.
If, after reading all instructions, precautions, and warnings, you have re-
mainingquestions,please contact Millennia directly before attempting to
useyourTD-1.Retainthisowner’smanualasarecordofyourpurchaseto
aidpositive identificationintheevent ofloss.
Beforeconnectingpower to the TD-1, assure that the rear panelvoltage
selectionfuse block switch is set correctly. IntheUSA or Japan, TD-1 is
shipped with the voltage selection block set to 100-120 VAC. If you
change the voltage selection block to 200-240 VAC usage, be sure to
changebothfusesto the correct types. See “Rear Panel” instructions for
properfuserequirements.
The TD-1 enclosure measures approximately 8.5" wide x 3.5" high x
13.5"deep and is designed formounting (in pairs) into astandard 2U,
19"equipment rack. If the TD-1 is mounted in aroad case or other rack
whichis prone to strong vibrationor shock, it is highlyrecommended that
the rear of the TD-1 be supported or otherwise reinforced to withstand
suchconditions.TD-1containshighvoltage vacuum tube and discrete
transistors, many running in Class-A bias. As such, the TD-1TWIN
DIRECT runs quite warm and should be mounted for proper ventilation
with at least one rack screw space open above and below the unit.
TD-1 is designed on a common ground topology. For high quality
operation, and for your own safety and the safety of others,donotdefeat
the power cord earth grounding pin. If required, earth ground can be lifted
safely via built-in switching, described later.
TD-1 FRONT-END PROTECTION: Millennia Music & Media
Systems enjoys a reputation for what many top engineers and producers
call the world’s most musically accurate and dynamically uniform
microphone preamplifier — the HV-3: an option on the TD-1. But this
thoroughbreddesignis not achieved without certain operating criteria.
Back-to-back Zener diodes protect the super-matched discrete bipolar
inputtransistorsagainst high transient energy spikes common when
insertingandextracting XLR connectors. To maintain top performance
andprotecttheTD-1’ssensitiveHV-3 front-end, it is advised that you do

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notinsertor extract XLR connectorswithpoweron.Get in the habit of
disablingAC power and waiting about tenseconds for the phantom
powerto fully “ramp down” before insertingor removing a microphone.
This is good advice for protecting your microphone investments, as well.
DESIGN
The TD-1 TWIN DIRECT is a collection of core Millennia products
designed into a sophisticated recording channel + direct box. We
believe TD-1 is the world’smost versatile and absolutely best sounding
DI (direct injection) box — andmuch more. TD-1offersnumeroussignal
pathtopologies (vacuum tube, discrete transistors, monolithics, three
differentaudiotransformers, speaker soak, REAMPs, etc.) all sonically
optimized to their respective strengths.
TD-1 offersTwin Topology DI input stages which can be switched to
employ high voltage vacuum tube (12AT7) -or-100%discretetransistor
(J-FET) amplifiers. The user may also select low, medium, or high input
impedance on both input topologies, makingTWIN DIRECT themost
versatile DI available. The TD-1 also offers two bands of Millennia’s
acclaimedNSEQ-2fully parametric equalization, used by top mastering
facilitiesaroundtheglobe,fullysweepable from 20 Hz to 25 kHz. The
NSEQ-2 bands are provided for high-resolution audio sculpting of
instrumentssuch as guitar, bass and keyboard,or artistic and corrective
work — adding “air” and “punch,” removing “mud,” and so forth — all with
thenatural,artifact-freeaudioqualitiesNSEQ is known for. Numerous
functionsand routing paths areavailable, as noted byname:
1.) HV-3 discrete hybrid solid state microphone preamplifier (option)
2.) STT-1 ORIGIN vacuum tube DI Input with selectable impedances
3.) Class-A biased discrete J-FET DI input with selectable impedances
4.) NSEQ-2 dual band fully parametric equalizer, 20 Hz - 25 kHz
5.) PatentedREAMP®dual guitar simulationoutputs (Strat & Les Paul)
6.)Numerous Ground-Lift and Ground-Isolation switches and jumpers
7.) SPEAKER SOAK(tm) guitar amplifier Input Selection
8.)Audiophile-grade headphone outputwithlevel adjustment
9.)Class-A biased discrete solid-state FET output stage
10.)High performance DIT-01 outputtransformer,3Hz - 300kHz
TWIN DIRECT has four available audio inputs:

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1.)LineInput(XLR,frontpanel)
2.)HV–3Mic Preamp Input (XLR, rear panel, optional)
3.)DI InstrumentInput(1/4"phone, frontpanel)
4.) Amplifier / Speaker Soak Input (1/4" phone, front panel)
TWIN DIRECT hasnine different rear-panel audio outputs:
1.) REAMP®LesPaultm Guitar SimulationOutput(1/4"phone)
2.) REAMP®Stratocastertm GuitarSimulation Output (1/4" phone)
3.) Balanced Line Level Output (XLR)
4.) BalancedLine Level Output (1/4" phone)
5.) TransformerBalanced Mic Level Output (XLR)
6.) Unbalanced Line Level Output (XLR)
7.) Unbalanced Line Level Output (1/4" phone)
8.) Headphone Output (1/4" phone)
9.) Direct“pass-through”Output(1/4"phone)
QUICK START
OK, let’s get started. DisconnectTWINDIRECTpower for now. Grab a
guitar or bass or some other source with a 1/4" phone jack output. Plug
your source intoTWIN DIRECT’s front panel 1/4" jack. Connect any
TWIN DIRECT output to your destination, such as the line input of a
mixer. With the TT (TwinTopology) switch, select vacuum tube or solid
state input buffer amplifier. Turn gain knob fully CCW. Now connect
powertothe unit. Let the unit“warmup”fora few minutes.
Turn the gain knob CW until a normal operating level is reached. If there
istoo much level at thelowest gain setting, engage thePAD switch.
PresstheTTswitchafew times and listen to the sonic differences
betweenthetubeandsolidstateDIpaths.Ashortauto-muteofthesignal
pathisnormalon certain switch selections, including TT. Next, check all
threeinput impedance switch positionsfor the best soundinginput
loading.If no difference is detected,use the 2M position. Selectthe EQ
bands and make some normal EQ adjustments to see what effect they
have on your source. You’re rolling!
See the signal flow diagram later in this manual forTWINDIRECT’s
extensiveversatility.Micinput(option)isrouteddirectlytoanauthentic
HV-3 microphone preamplifier with up to 65 dB of gain. Line input is
routed to a discrete-hybrid balanced receiver with +45 dB of gain.

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Instrument(DI)input is routed via TT switchtovacuumtubebufferampli-
fierordiscretesolid state (FET) buffer amplifier, with triple input imped-
anceselection switching on bothtopologies.Anyinput may beattenu-
atedvia a -20 dB pad switch. The DI inputalso offers a selectable guitar
amplifier Speaker Soaktm inputandselectablebufferedorunbuffered
“directDIthrough”output.Allinputs are followed by two bands of NSEQ-2
fully parametric EQ stages (20 Hz – 25 kHz). Numerous routing, output,
and grounding options round out the world’s most versatile and best
sounding “direct box.”
FRONT PANEL — INPUT SECTION —
INSTRUMENT DI / SPEAKER SOAKtm INPUT ¼” Unbal Phone Jack
The heart ofTWIN DIRECT. A normalled ¼” mono Phone Jack which
accepts any unbalanced source, such as MIDI instrument (keyboard,
sampler, etc..), electric guitar, electric bass, piezoelectric acoustic guitar
pickup,etc.. This DI (Direct Inject)input will accept virtually anyknown DI
signallevel,fromvery low output passive sources, to high output (>15
Volts RMS) active sources. This input is also designed to accept direct
feed from a power amplifier, such as a guitar amp (see “Speaker Soak”
switch,below). When insertingorextractinga connector fromthisinput,it
isadvised that your destination level beturned down or muted.
Mostkeyboardsand MIDI instruments have electrically bufferedoutputs
exhibitingvery low output impedance,generallyunder150 ohms. Onthe
other hand, passive electric guitar pickups exhibit significantly higher
outputimpedance. To properly “couple”this diversity of instrumentsin
the most musically pleasing manner,TWIN DIRECT offersthree differ-
entinput impedance settings that willhelp an artist “fine tune”the musical-
ity of any instrument, pickup, or program. Each time you try a new instru-
ment or MIDI device with theTWIN DIRECT,be sure to experiment with
differenttopologies and input impedances to findthe ideal sonic perfor-
mance (see “Twin Topology” and “Impedance Select” below). There is
no inherently “right” setting — use your ears and production goals to
determine the best impedance bridge and input topology.
TWIN DIRECT’s dualDI amplifiers offer rich musical variation with
electricinstruments — vacuum tube amplifiers arewell known to “couple”
electricguitarand bass pickups differently than solid-state amplifiers.
Vacuumtubes offer a unique “sound” thatsolid-state doesn’t, and visa
versa. Each amplifier topology offers complimentary sonic performance
to the other, and both are widely used in professional recording and

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TD-1 FRONT PANEL

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stage work. Taking full advantage of this sonic duality,TWINDIRECT
offers Millennia’s TwinTopology®high voltage vacuum tube DI ampli-
fier -and- all discrete J-FETtransistoramplifier. Either topology is
selectable with theTwin Topology (TT)select switch. Moreinformation
onthisuniquetechnology is found in the “Input TT” section, below.
LINE INPUT + REAMP®INPUT Balanced Female XLR
Standard3-pinXLR input (Pin 2 hot) whichwillacceptanybalancedor
unbalancedline-level signal. A 20 dB pad(attenuator) is included for
ultra-hotsignals,butbecauseoftheTD-1’sextremelyhighnativeline
input headroom (+23 dBu) this pad should rarely be required (see “Pad”
switch,below). When insertingorextractinga connector fromthisinput,it
isadvised that your destination level beturned down or muted.
This input employs a discrete-hybrid, solid-state amplifier topology and
fixedinput impedance (6,900 ohms x 2). Onecommonuse of this input will
be playback of recorded electric guitar or electric bass program. Guitar
and bass program can be recorded and then played back at a later
date directly into a guitar amplifier usingTWIN DIRECT’spatented
REAMP feature. This allows an audio engineer to achieve the original
“coupling”characteristicsofaguitaristandliveguitaramplifierwithoutthe
guitarist’s presence, thus allowing more time for experimentation with
different guitar amps, room tones, and mic technique at any future time.
(See“REAMP”section,below.)
Of course, TWINDIRECT’s Line Input is ideal for any other line-level
source, including mixer outputs, recording device outputs, samplers,
DAWs,synths,DACs,activeinstruments,outboard gear such as com-
pressorsandstand-alone instrument preamplifiers.
DI INPUT IMPEDANCE SELECT Dual pushbutton switches
Apair of switches which allowselection of three input impedanceson the
¼”InstrumentInput (above). Acoustic instrument pickups areespecially
sensitiveto load impedance. Eachinput impedance will coupleinstru-
mentswithvaryingsonicperformance.Adjust these switches with each
newsourceto find the most musically satisfying setting. In somecases,
all three impedance settings will give very similar sonic results. In other
cases, the differences will be obvious. Remember, “musically correct” is
anartisticproductionjudgement—only your ears can tell you which input
impedanceisoptimalforyourinstrumentandartisticgoals.Settingsare
LOW (aprox 470 Kilohms), MEDIUM (aprox 2Megohms), HIGH (aprox
10Megohms). HIGH input impedanceis achieved with bothswitches

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disengaged. DI input impedance is selectable only on DI input, not on
mic or line inputs. 2M is recommended as the default setting.
+48V PHANTOM POWER Pushbutton Switch (HV-3 Preamp option)
Aswitchwhichprovides phantom power (+48 Volts DC) to the micro-
phone when HV-3 mic preamp option is installed. When this switch is
depressed (illuminated red), phantom power is applied simultaneously
throughdual6.81kohmresistors to pins 2 and 3 of the rear panel three
pinfemale XLR mic input connector. Usephantom power with condenser
andother microphones requiring traditionalphantom supply. Do notuse
phantomwith ribbons, moving coil,andothermicrophones which donot
require phantom power. Use care, as well, not to insert or extract mic
cables from the TD-1 when phantom power is active. This could damage
bothmicrophoneandthesensitive HV-3 front end.
INPUT GROUND LIFT / ISOLATE Pushbutton Switch
A switch which removes the ¼” Instrument (DI) Input ground from TWIN
DIRECT’s internal audio grounding. This switch also employs an internal
jumper which selects true ground lift, or ground “isolation” via resistive
and capacitive coupling (See Jumper Map). When jumper is installed
andthis switch is depressed, ground isisolated via series resistance.
Whenjumper is not installed (factory default),and switch is depressed,
ground is lifted. A momentary pop may occur when lifting grounds – you
may wish to remove power from theTWIN DIRECT when experimenting
withanygroundliftingtechnique.
Notethat Input Ground Lift / Isolate should only beused in cases where a
ground loop cannot be corrected by first lifting earth or output grounds.
Liftingearth ground from powergroundwillusually correct groundloops
and hum problems. Of course, for safety,never defeat the earth/chassis
powercord ground bond.Alwaysassurethat the “thirdpin”(earthground)
on the IEC power cord remains connected to theTWIN DIRECT’sIEC
input connector. If you must lift earth ground, you may do this via the rear
panel switch. (See “Earth Ground / Isolate Lift” switch and “Output Ground
Lift”switch,below.)
POLARITY REVERSE Pushbutton Switch
A switch which reverses polarity of the TD-1 signal path immediately
after the gain adjustment amplifier. See Signal Flow Diagram for detail.
Polarityon main outputsisflipped 180 degreeswithrespectto theinput
whenthisswitchisdepressedand illuminated.
SPEAKER SOAKtm INPUT Pushbutton Switch

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AswitchwhichallowstheInstrument DI / Speaker Soak Input (above) to
accept signal directly from the output of a power amplifier connected to
a speaker cabinet. Note that the power amplifiermust be plugged into
speakers designed for the full power rating of the amplifier whenever the
power amplifier is feeding theTWINDIRECT. A typical application
would be taking a parallel feed from a guitar amplifier or speaker cabinet
duringlive or studio performance.Power amplifier output shouldbe
wired in “parallel” with speakers and theTWIN DIRECT’sInstrument
Input jack.TWIN DIRECT will not effect the sound or performance of the
power amplifier or speakers.TWIN DIRECT will accept power amplifier
input when this switch is depressed and illuminated. Insert a power
amplifier into the TWIN DIRECT only when this switch is de-
pressed and illuminated. Failure to do so could result in
serious damage.
Wonderfully rich and spacious electric guitar recordings can be
achieved by using a pair of microphones on a guitar speaker cabinet,
along with a direct feed into TD-1’s Speaker Soak input — with all three
signals mixed together. Try using a pair of sonically dissimilar micro-
phones, such as a Royer 121 and Josephson 606 (two of our favorites).
Placeeach mic inadifferentposition to maximizeitsuniquestrengths.
Onetrick to maximize tonal “fullness” is tofocusyour ears on the “hum”
and “hiss” of an idle guitar amp speaker, then position mics to maximize
thedepthand presence of that hum andhiss.
GAIN CONTROL
In standard configuration, gain control is a potentiometer offering up to 45
dBof discrete gain. Withoptional HV-3 preamplifier installed,gain
control can be a 12 position rotary gain-set switch (5 dB per step), or a
potentiometer, offering up to 65 dB of discrete gain.
— FRONT PANEL: EQUALIZER SECTION —
PARAMETRIC E.Q. BAND IN/OUT Pushbutton Switch “IN”
Aswitch(2 ea) which places its associated EQ band in circuitoroutof
circuit.Thereare two bands of fully parametric equalization on theTD-1.
Frequencybands are labeled LF [20 Hz- 2.5 kHz] and HF [250Hz - 25
kHz]. An EQ band is in circuit when its associated band switch and main
EQon/off switch (below) aredepressed and LEDs areilluminated.
Becauseofthe equalizer’s unique network-shunt design, EQ bands
should have no detectable sonic signature when they are in circuit as

TD-1
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longastheboost/cutcontrolis set at zero. Band In/Out switches are
provided both for comparing a single EQ band setting versus flat-band
response, and for bypassing the EQ band entirely.
PARAMETRIC E.Q. BOOST/CUT CONTROL
Conductive plastic rotary potentiometer (2 ea) offering up to 15 dB of
boost and cut. Frequency curve shape is peak/dip type (see “Q”). The
Boost / Cut potentiometer has 21 detent positions for accurate repeat-
ability and session logging. Detents can be removed by the factory upon
customer request.
PARAMETRICE.Q. FREQUENCYCONTROL
Conductive plastic rotary potentiometer (2 ea) which sweeps all center
frequenciesfrom 20 Hz to 25 kHz. The low band(LF) sweeps 20 Hz to
250 Hz-or- 200 Hz to 2.5 kHz,dependingon the status of Frequency
Range Switch (below). The high band (HF) sweeps 250 Hz to 2.5 kHz -
or- 2.5kHzto25kHz,dependingonthestatusofFrequencyRange
Switch (below). This control is optionally available with 21-step detents
for accurate repeatability and logging.
PARAMETRIC E.Q. FREQ RANGE SELECT Pushbutton Switch “10X”
Aswitch(2ea) which selects 1X or 10X parametric frequency multiplier.
When switch is depressed and corresponding LED is illuminated,
frequencies as shown on front panel legend are multiplied by 10X. When
switch is not depressed and LED is not illuminated, frequencies are as
shown on front panel legend.
PARAMETRIC E.Q. QUALITY CONTROL “Q”
Conductive plastic rotary potentiometer (2 ea) which sweeps “Q” (Quality
factor)from0.4to4.0.“Q” is defined as the ratio of the center frequency to
thebandwidth.Forexample,afilter boost setting with “3 dB down” points
near100 Hz and 1000 Hzexhibitsa“Q”of approximately 0.4. To achieve
a reasonably equivalent response of shelving EQ, simply dial in the
broadestQ(0.4)andboostor cut near a typical frequency extreme (e.g.,
50Hz or 10 kHz). Thiscontrol is optionally available with21-step detents
for accurate repeatability and session logging.
PARAMETRIC E.Q. IN/OUT SELECT Pushbutton Switch “EQ IN”
A switch which places the single (yes,onlyone) active EQ amplifier in the
signalpath. Minimal signal pathEQ topology assures consistentlyfaithful
musical performance.

Twin Direct
19
— FRONT PANEL: ROUTING SECTION —
LED INDICATORS Power / SP / OL
ThreeLEDs (Light Emitting Diodes) which indicatethe presence of DC
power(Amber), the presence of a nominal(-25 dBu) audio signal
(Green), and the presence of an audio signal which has exceeded +26
dBu at the balanced line level output (Red). Note thatTWINDIRECT’s
balanced line level output has a maximum output level of +32 dBu. As
such,whentheredoverloadLED turns on, the TD-1 balanced line output
is not clipping,buthastwicethereserveoutputvoltageheadroom
remaining before clipping. The OL LED is set to indicate a maximum
operating level in typical audio environments.
INPUT “TT” TWIN TOPOLOGY Pushbutton Switch
Aswitchwhich selects the amplifier topology used to buffer theDI
InstrumentInput. Whenswitchis depressedandilluminated, theInstru-
ment Input is routed to an all-discrete, solid-state J-FET (field-effect
transistor)DI buffer amplifier providing musically accurate Millennia
audioperformance. When switch isnot depressed and notilluminated,
theInstrumentInput is routed to a highvoltagetwintriodevacuumtube
(12AT7)DI buffer amplifier which can providea softer, rounder tonal
coloration. Note that Twin Topology input amplifiers are available only
ontheDIinput,noton the Mic or Line inputs. Mic and Line inputs are
routeddirectly to a discrete-hybridsolid-state amplifier (see SignalFlow
Diagram).
INPUT SELECT Pushbutton Switch
AswitchwhichselectsbetweentheLine/MicandInstrumentinputs.When
switch is depressed and illuminated, the Line/Mic Input is selected.
When switch is not depressed and non-illuminated, the Instrument DI
Inputisselected.
PAD -20 dB Pushbutton Switch
Aswitch which attenuates (“pads”)all inputs (balanced orunbalanced)
by -20 dB, thus increasing the maximum input headroom. Pad is en-
gaged when switch is depressed and illuminated. In most recording or
stage applications, this pad will not be necessary and is included only
forunusuallyhotsources.

TD-1
20
REAR PANEL
MICROPHONE INPUT “HV-3 MIC IN” (OPTION)
Millennia’sHV-3 microphone preamplifier isa world standard inclassi-
cal and critical acoustic music recording. Now used to record well over
half of all major Hollywood film scores, chosen by countless recording
andtouringartists,employedby numerous microphone manufacturers
for research and development, and found in more symphony and opera
halls than any other — we believe there is no better choice when musical
reality and dynamic uniformity are sonic priorities.
HV-3 input is a conventional 3-pin female XLR input jack for use with all
standard balanced microphones, both phantom and non-phantom
powered.Provides +48 Volts DCPhantom powering via frontpanel
switch. Inputimpedance is approximately 6,200ohms with phantom
powerswitched in.Wheninserting orextractingaconnectorfromthis
input,it is advised that yourdestination level be turned downor muted.
Microphone Input shares the same internal signal path as the balanced
line level (front panel) input but is not designed as a mixing path. For
optimalperformance when line inputis in use, disconnectmicrophone,
andvisa versa. To achieve asignal path that is identicalto Millennia’s
HV-3B, HV-3C, or HV-3D units, use the active balanced line ouput (Main
Output #1, below).
Pin 2 is positive polarity. Pin 3 is negative polarity. Connector contacts
are Neutrik gold plated. It is suggested that XLR cable connectors used
with the TD-1 employ identical plating. Maximum microphoneinput level
is +23 dBu. For reference, a Neumann U87Ai directly in front of a scream-
ingvocalist(127dBSPL)will output approximately -6 dBu.
TRANSFORMER-COUPLED (GALVANIC ISOLATION) BALANCED OUTPUT
Unsatisfied with “off-the-shelf” DI transformer solutions, Millennia de-
signed a superior DI-dedicated transformer from the ground up. This
superiorlarge geometry transformer (Millennia type DIT-01) exhibits
betterthan3Hzto300kHzfrequencyresponse(-3dB),verylowdistor-
tion,andexcellentphaseuniformity.
Output employs conventional 3-pin male XLR connector providing the
transformer-coupled, fully “galvanically isolated” microphone level
signal.Pin1 is ground. Pin 2 is positive polarity. Pin 3isnegativepolar-
ity.Output impedance is approximately150 ohms, which isnominally