Design – Millennia TD-1 Twin Topology Half Rack Recording Channel User Manual
Page 6
TD-
Twin Direct
10
seconds for the phantom power to fully “ramp down” before inserting or
removing a microphone. This is good advice for protecting your micro-
phone investments, as well.
DESIGN
The TD-1 TWIN DIRECT is a collection of core Millennia products de-
signed into a sophisticated recording channel + direct box. We believe
TD-1 is the world’s most versatile and absolutely best sounding DI (direct
injection) box. TD-1 offers numerous signal path topologies (vacuum
tube, discrete transistors, monolithics, three different audio transformers,
speaker soak, REAMPs, etc.) all sonically optimized to their respective
strengths.
TD-1 offers Twin Topology DI input stages which can be switched to
employ high voltage vacuum tube (12AT7) -or- 100% discrete transis-
tor (J-FET) amplifiers. The user may also select low, medium, or high
input impedance on both input topologies, making TWIN DIRECT the
most versatile DI available. The TD-1 also offers two bands of Millennia’s
acclaimed NSEQ-2 fully parametric equalization, used by top mastering
facilities around the globe, fully sweepable from 20 Hz to 25 kHz. The
NSEQ-2 bands are provided for high-resolution audio sculpting of instru-
ments such as guitar, bass and keyboard, or artistic and corrective work
— adding “air” and “punch,” removing “mud,” and so forth — all with the
natural, artifact-free audio qualities NSEQ is known for. Numerous func-
tions and routing paths are available, as noted by name:
1.) HV-3 discrete hybrid solid state microphone preamplifier
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.) Patented REAMP
®
dual guitar simulation outputs (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 output with level adjustment
9.) Class-A biased discrete solid-state FET output stage
10.) High performance DIT-01 output transformer, 3 Hz - 300 kHz
6. SERVICING
Lethal voltages are found inside the TD-1 chassis. The user should not
attempt to repair or service this unit. All servicing and/or repairs should be
referred to Millennia.
If, after reading all instructions, precautions, and warnings, you have re-
maining questions, please contact Millennia directly before attempting to
use your TD-1. Retain this owner’s manual as a record of your purchase to
aid positive identification in the event of loss.
Before connecting power to the TD-1, assure that the rear panel voltage
selection fuse block switch is set correctly. In the USA 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
change both fuses to the correct types. See “Rear Panel” instructions for
proper fuse requirements.
The TD-1 enclosure measures approximately 8.5” wide x 3.5” high x
13.5” deep and is designed for mounting (in pairs) into a standard 2U,
19” equipment rack. If the TD-1 is mounted in a road case or other rack
which is prone to strong vibration or shock, it is highly recommended that
the rear of the TD-1 be supported or otherwise reinforced to withstand
such conditions. TD-1 contains high voltage vacuum tube and discrete
transistors, many running in Class-A bias. As such, the TD-1 TWIN DI-
RECT 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 opera-
tion, and for your own safety and the safety of others, do not defeat 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. But this thoroughbred design is not achieved
without certain operating criteria. Back-to-back Zener diodes protect the
super-matched discrete bipolar input transistors against high transient
energy spikes common when inserting and extracting XLR connectors.
To maintain top performance and protect the TD-1’s sensitive HV-3 front-
end, it is advised that you do not insert or extract XLR connectors with
power on. Get in the habit of disabling AC power and waiting about ten