Summit Audio TD-100 User manual

Summit Audio Model TD-100
Instrument Preamp and Tube Direct Box
Summit Audio, Inc.
P.O. Box 223306
Carmel, CA 93922
[phone]
email: [email protected]
Operation Manual

Model TD-100 Tube Direct Box 2
Introduction
The TD-100 is a single channel direct box and instrument
preamp featuring a hybrid signal path utilizing a solid state
output device and a 12AX7A/ECC83 vacuum tube. This
unique combination of of solid state and vacuum tube tech-
nology gives the TD-100 the benefits of both worlds: the high
reliability and long life of solid state and the warm overtones
associated with vacuum tubes. Other great features such as
continuously variable input impedance, polarity switching, and
a headphone output make the TD-100 a great sounding tool
for the studio or the stage. Enjoy!
Features
• Ease of Operation
• Headphone Output
• Variable Input Impedance
• Direct Output for easy parallel connections
• Balanced Outputs
• Hand Crafted in the U.S.A.
Carefully unpack the TD-100 and it’s power cord. Save the
carton and packing material for possible future use. Before
powering up the unit, read this manual and observe the cau-
tions for HIGH VOLTAGE .
DANGER!
HIGH VOLTAGE
IMPORTANT: Check
the back panel to make
sure the TD-100 is
configured for the volt-
age used in your coun-
try. This is done at the
factory ONLY.

Model TD-100 Tube Direct Box
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Front Panel
Front Panel
Ground Lift Switch
This two-position switch removes the third prong of the
power cable from the circuit. Lifting the ground can some-
times reduce the hum caused by a ground loop in your audio
system.
Polarity Switch
This switch changes the polarity of the outgoing signal.
Direct Instrument Output
This jack mirrors the instrument input. Plug your instrument
into the input and run a line from this ouput to the input on
your amplifier. This output is not affected by the Loading
control.
Instrument Input
Input for your bass, guitar, keyboard or other instrument.
The maximum input level is +24dB.
SIGNAL DRIVE
024
1M
10K 2M
LOADING
INPUT
DIRECT OUT OUTPUT GAIN
SIGNAL
GROUND LIFT
POLARITY
+- ON OFF
INSTRUMENT PRE-AMP
TD-100
TUBE DIRECT

Front Panel
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Summit Audio, Inc.
Loading Control
This knob controls the loading or impedance for the instru-
ment input. The impedance can be set from 10K ohms to
2M ohms.
You can set this control to match the TD-100 to the imped-
ance of your instrument or as a kind of tone control. In prac-
tical use you’ll set this control to get the sound you like best.
Signal LED
This green LED lights to indicate a proper level at the input.
Drive LED
This amber LED lights to indicate clipping on the input.
Output Gain Control
This control varies the output gain. The XLR output can be
varied from -20dB to +4dB. The 1/4” TRS output can be
varied from 0dB to +24dB. (0dB input level)
Power
This switch toggles AC power on and off.
Important - Please Read!
The TD-100 contains a vacuum tube which
generates heat.
Do not block the cooling holes on the top of the
TD-100 and always allow adequate ventilation when
mounting the unit in a rack enclosure.

Model TD-100 Tube Direct Box
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Rear Panel
Rear Panel
A.C. Receptacle
The TD-100 is factory wired for either 100, 115 or 230
Volts AC. Before connecting AC power make sure the
TD-100 is wired for the voltage used in your country.
Headphone Output
Use the TD-100 as a practice amp by inserting your head-
phones here. Use the Output Gain control and the instru-
ment’s volume control to control the volume.
1/4” TRS Line Level Output
This is a balanced/unbalanced 1/4” high level output
designed to interface with your recording device, compressor
or EQ without adding a preamplifier. Simply plug in a mono
phone plug to use this output unbalanced.
XLR Mic Level Output
This is a balanced low level output used for injecting the TD-
100 into another preamplifier. This is most often used in a
live performance setting. Pin 2 is positive (+).
PHONES
CLASS A -TUBE INSTRUMENT PRE-AMP
MODEL TD-100 20 WATTS MAX
SUMMIT AUDIO INC. CARMEL, CA USA
115V 50/60 HZ MIC
PIN2+
LINE
BALANCED
OUTPUTS
FUSE

Basic Operation
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Summit Audio, Inc.
Basic Operation
Important: For proper
operation of the
TD-100 (or any vacuum
tube device for that
matter), allow the unit to
warm up with power on
for 15 minutes before
use.
Important: Do not block
the cooling holes and
allow adequate
ventilation.
Just Plug-in & Go
1.
Plug your instrument into the front panel input jack.
2.
Connect either the rear panel balanced Mic or Line output to
the input of your mixer or recorder. (An unbalanced cable can
be used with the Line Level output.)
3.
Adjust the Output Gain for an optimal signal level.
4.
Adjust the front panel Impedance control to match for the
best sound.
5.
Start playing!

Model TD-100 Tube Direct Box
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Applications
Applications
Live Sound
A direct box or “DI” (direct input) is used to take a high
impedance instrument signal and transform it into a
balanced, low impedance output. In the example below, the
Direct Output feeds the Bass Amp and the low impedance,
balanced microphone output is sent to the mixing console.
Direct Box Connection

Applications
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Summit Audio, Inc.
Using the TD-100 as an Instrument Preamp
You can use the TD-100 to go directly to your recording
device for an ultra-quiet sound. The output is already ampli-
fied so there’s no need to re-route through your mixer. The
line level output of the TD-100 is ideal for interfacing with any
other effects you wish to use.
To Recorder Input
Balanced

Model TD-100 Tube Direct Box
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Applications
Using the TD-100 and TLA-50 together
For a great bass or guitar channel, try using the Summit
Audio TD-100 instrument preamp and tube direct box in
conjunction with the TLA-50.
Plug your instrument into the front panel of the TD-100 and
run an XLR or 1/4" cable from the output of the TD-100 to
the input of the TLA-50. Use the 1/4”output of the TD-100
into the TLA-50 to go directly from the TLA-50 to your
recording device, or use the XLR output of the TD-100 into
the TLA-50 and patch the XLR output of the TLA-50 into a
microphone preamp, then into your recording device.
OUTPUTS
CLASS A -TUBE LEVELER
MODEL TLA-50
SUMMIT AUDIO INC.
CARMEL, CA USA
115V 50/60 HZ
100V 50/60 HZ
INPUT
+4 BAL. -10 UNBAL.
LINK
INSERT
SIDE
CHAIN
+4 BAL. -10 UNBAL.
20
WATTS
MAX
FUSE
PUSH
Compressor
(such as the Summit TLA-50)
To Recorder Input
Balanced
Balanced

Circuit Explanation
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Summit Audio, Inc.
Circuit Explanation
The Instrument Input to the TD-100 is directly connected to
the Direct Output. The Impedance control sets the input
impedance of the first stage input. The Impedance control
can be used to match the impedance of the instrument and
to provide subtle tonal coloration.
The TD-100 features a vacuum tube amplifier driving an elec-
tronically balanced output stage. All the signal amplification in
the audio path takes place in the tube circuit. The balanced
output drivers provide a low output impedance for driving
cables and 600
Ω loads.
12AX7A
AMPLIFIER
GAIN
IMPEDANCE
INSTRUMENT
INPUT
DIRECT
OUTPUT
DIFFERENTIAL
OUTPUT
Tip
Signal
Present
Peak
Hold

Model TD-100 Tube Direct Box
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Electrical Connections
Electrical
Connections
Input
Unbalanced 1/4” jack
Sleeve - - Ground
Tip - - - - (+) Signal
Output
Balanced 1/4” jack Balanced 3-pin XLR
Sleeve - - Ground Pin 1 - - Ground
Tip - - - - (+) Signal Pin 2 - - (+) Signal
Ring - - - -(-) Signal Pin 3 - - (-) Signal

Specifications
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Summit Audio, Inc.
Specifications
Circuit Topology
High-voltage Class A
Gain
Switched 6dB steps, maximum gain +24dBu (at 1/4”TRS
output)
Maximum Output Level (Class A)
+24 dBu. The outputs are electronically balanced or
unbalanced. XLR type (pin 2 hot), 1/4”balanced TRS
(Neutrik)
Input
Input impedance is variable from 10K
Ω to 2M
Ω .
Maximum input level is +24dBu unbalanced.
Noise 20kHz unweighted
-121 dBu minimum gain position
Distortion THD, IMD
0.07% at +10 dBu
Frequency Response
-/+0.01dB, 10Hz to 100kHz

Model TD-100 Tube Direct Box
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Specifications
Power
Internal AC Supply
20 watts
115 volts
50 or 60 Hz
Fuse size is .5 amp, slo-blo for 100/115 V
Fuse size is .25 amp, slo-blo at 230 V
Dimensions
W: 8.5”, H: 1.75”, D: 8.5” (Two units fit side by side on a
standard one-space rack shelf.)
Weight
7 pounds (3.15 kg)

Summit Audio, Inc.
P.O. Box 223306
Carmel, CA 93922
web page: www.summitaudio.com
email: [email protected]
Please fill in and mail your warranty card today. We would
like to know a little bit about you. We will provide periodic
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to include your email address if you have one. Thanks.
TD-100 Op Rev. A