Universal Audio 710 User Manual
Model 710
Twin-Finity Mic/Line/Hi-Z Preamplifier
Universal Audio Part Number 65-0029
Revision 1.0
Universal Audio, Inc.
Customer Service & Tech Support: 1-877-MY-AUDIO
Business, Sales & Marketing: 1-866-UAD-1176
www.uaudio.com
Notice
This manual provides general information, preparation for use, installation and operating instructions
for the Universal Audio 710.
The information contained in this manual is subject to change without notice. Universal Audio, Inc.
makes no warranties of any kind with regard to this manual, including, but not limited to, the implied
warranties of merchantability and fitness for a particular purpose. Universal Audio, Inc. shall not be
liable for errors contained herein or direct, indirect, special, incidental, or consequential damages in
connection with the furnishing, performance, or use of this material.
Copyright
© 2008 Universal Audio, Inc. All rights reserved.
This manual and any associated software, artwork, product designs, and design concepts are subject
to copyright protection. No part of this document may be reproduced, in any form, without prior written
permission of Universal Audio, Inc.
Trademarks
710, Twin-Finity, 4110, 8110, SOLO/110, SOLO/610, 2-610, LA-610, LA-2A, 2-LA2, LA-3A, 6176,
1176LN, 2-1176, 2192, DCS Remote Preamp, UAD and the Universal Audio, Inc. logo are trademarks of
Universal Audio, Inc. Other company and product names mentioned herein are trademarks of their
respective companies
Contents of This Box
This package should contain:
• One Model 710 Twin-Finity Mic/Line/Hi-Z Preamplifier
• Rack mounting hardware
• 710 Operating Instructions
• IEC Power Cable
• Registration card
A Letter From Bill Putnam, Jr.
___________________________________________________________
Thank you for purchasing the Model 710 Twin-Finity Mic/Line/Hi-Z Preamplifier— a radically new UA
pre-amp design which combines both the classic retro warmth of UA tube design and the transient
bite of solid-state in a 2U, half-rack, all-metal chassis. The 710 was created specifically to add the
tonal versatility and sonic inspiration missing from generic audio interface preamps. The key to its
sonic flexibility lies in its innovative circuit design, featuring a solid-state transimpedance input amp
simultaneously driving separate, phase-aligned tube and solid-state gain stages, which are then
summed to a single output. The mix between the 310 volt single-ended class-A triode tube stage and
solid-state transimpedance stage is controlled via a unique “Blend” knob. Blending is continually
variable between 100% tube and 100% solid-state offering a practically infinite range of unique
pre-amp tones and the ability to easily dial in your own signature sound.
Like all our other preamp designs, the 710 features dual gain-stage controls (Gain/Level) which can
radically vary the amount of coloration and distortion by allowing you to crank up the input gain like a
guitar amp. The VU meter features a unique “Drive” mode allowing you to see how hard you are driving
the tube/solid state stage. Other features include a discrete JFET Direct Inject input which allows you
to plug in an electric guitar or bass, or any instrument with a magnetic or acoustic transducer pickup,
with 2.2M ohm ultra Hi-Z impedance; a monolithic balanced output stage; more than 70dB of gain;
+48V phantom power and a -15dB pad for the mic input; phase invert and 75Hz low cut filter; a
universal auto-sensing internal power supply that allows for operation at any voltage between 100 and
240VAC; and a portable, rack-mountable design for studio, desktop or stage. Yet for all its versatility
and power, the 710 is remarkably easy to use: you’ll find that its controls are simple and essential,
providing only those features required for practical use without needless duplication of functionality
found elsewhere in most studios.
Most of us at Universal Audio are musicians and/or recording engineers. We love the recording process,
and we really get inspired when tracks are beautifully recorded. Our design goal for the 710 was to
build a mic preamp that we would be delighted to use ourselves—one that would induce that “a-ha”
feeling you get when hearing music recorded in its most natural, inspired form.
Developing the Model 710—as well as Universal Audio’s entire line of quality audio products designed
to meet the needs of the modern recording studio while retaining the character of classic vintage
equipment—has been a very special experience for me and for all who have been involved. While, on
the surface, the rebuilding of UA has been a business endeavor, it's really been so much more than
that: in equal parts a sentimental and technical adventure.
We thank you, and we thank my father, Bill Putnam.
Sincerely,
Bill Putnam, Jr.
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Important Safety Instructions
___________________________________________________________
Before using this unit, be sure to carefully read the applicable items of these operating instructions and the
safety suggestions. Afterwards, keep them handy for future reference. Take special care to follow the warnings
indicated on the unit, as well as in the operating instructions.
1. Water and Moisture - Do not use the unit near any source of water or in excessively moist environments.
2. Object and Liquid Entry - Care should be taken so that objects do not fall, and liquids are not spilled, into
the enclosure through openings.
3. Ventilation - When installing the unit in a rack or any other location, be sure there is adequate ventilation.
Improper ventilation will cause overheating, and can damage the unit.
4. Heat - The unit should be situated away from heat sources, or other equipment that produce heat.
5. Power Sources - The unit should be connected to a power supply only of the type described in the
operating instructions, or as marked on the unit.
6. Power Cord Protection - AC power supply cords should be routed so that they are not likely to be walked
on or pinched by items placed upon or against them. Pay particular attention to cords at plugs,
convenience receptacles, and the point where they exit from the unit. Never take hold of the plug or cord
if your hand is wet. Always grasp the plug body when connecting or disconnecting it.
7. Grounding of the Plug - This unit is equipped with a 3-wire grounding type plug, a plug having a third
(grounding) pin. This plug will only fit into a grounding-type power outlet. This is a safety feature. If you
are unable to insert the plug into the outlet, contact your electrician to replace your obsolete outlet. Do
not defeat the purpose of the grounding-type plug.
8. Cleaning - Follow these general rules when cleaning the outside of your 710:
a. Turn the power Off and unplug the unit
b. Gently wipe with a clean lint-free cloth
c. If necessary, moisten the cloth using lukewarm or distilled water, making sure not to oversaturate it
as liquid could drip inside the case and cause damage to your 710
d. Use a dry lint-free cloth to remove any remaining moisture
e. Do not use aerosol sprays, solvents, or abrasives
9. Nonuse Periods - The AC power supply cord of the unit should be unplugged from the AC outlet when left
unused for a long period of time.
10. Damage Requiring Service - The unit should be serviced by a qualified service personnel when:
a. The AC power supply cord or the plug has been damaged; or
b. Objects have fallen or liquid has been spilled into the unit; or
c. The unit has been exposed to rain; or
d. The unit does not operate normally or exhibits a marked change in performance; or
e. The unit has been dropped, or the enclosure damaged.
11. Servicing - The user should not attempt to service the unit beyond that described in the operating
instructions. All other servicing should be referred to qualified service personnel.
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Table of Contents
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A Letter From Bill Putnam, Jr. ................................................................................................................
Important Safety Instructions ................................................................................................................
Two Page, Two Minute Guide To Getting Started ....................................................................................
Front Panel .........................................................................................................................................
Rear Panel ...........................................................................................................................................
Interconnections ................................................................................................................................
Insider’s Secrets ..............................................................................................................................
The Technical Stuff ................................................................................................................................
History of the 710 .................................................................................................................
710 Overview ........................................................................................................................
710 Vacuum Tube Preamp .......................................................................................
710 Solid-State Preamp ...............................................................................................
About Class A .........................................................................................................
Phantom Power ..........................................................................................................
Phase Inversion .........................................................................................................
LOW CUT Filtering .........................................................................................................
Rack Mounting ..........................................................................................................................
Optional Desktop Handle Kit ......................................................................................................
Maintenance Information...........................................................................................................
Fuse .........................................................................................................................
Voltage Select .............................................................................................................
Block Diagram ............................................................................................................................
11
11
13
13
13
14
14
14
15
15
15
16
16
16
18
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ii
2
4
7
8
9
Glossary of Terms ..................................................................................................................................
Recall Sheet ........................................................................................................................................
Specifications ........................................................................................................................................
Additional Resources / Product Registration / Warranty / Service & Support .......... Inside back cover
19
21
22
The Two Page, Two Minute Guide To Getting Started
__________________________________________________________
No one likes to read owner’s manuals. We know that.
We also know that you know what you’re doing—why else would you have bought our product?
So we’re going to try to make this as easy on you as possible. Hence this two-page spread, which we
estimate will take you approximately two minutes to read. It will tell you everything you need to know to
get your Universal Audio 710 up and running, without bogging you down with details.
Of course, even the most expert of us has to crack a manual every once in awhile. As the saying goes,
“as a last resort, read the instructions.” You’ll find those details you’re craving—a full description of
all front and rear panel controls, interconnection diagrams, insider’s secrets, history, theory,
maintenance information, block diagrams, specifications, even a glossary of terms—in the pages that
follow.
Manual conventions:
Means that this is an especially useful tip
Means that this is an especially important bit of information
And when we need to direct you to a page or section elsewhere in the manual, we’ll use the universal signs
for rewind () or fast forward ().
Getting Started With Your 710:
Step 1: Decide where the 710 is to be physically placed and place it there. Chassis mounting
hardware is provided, allowing the 710 to be used in a standard 19" rack (taking just two spaces), and
so we recommend that the 710 be securely mounted in a rack if possible. An optional desktop handle
kit (which can be purchased via www.uaudio.com) is also available, allowing the 710 to be easily
transported and used on any flat surface.
Step 2: Mute your monitors and then, using a balanced cable with XLR connectors, connect the 710’s
rear panel line output to the appropriate input on your patch bay, mixer, or DAW.
Step 3: Set the front panel +48V (phantom power), 15dB PAD, and LOW CUT switches to their down
(OFF) position.
Step 4: Set the front panel POLARITY switch to its down (INø) position.
Step 5: Connect the desired input source to the 710’s rear panel balanced XLR mic and/or line input.
Alternatively, an electric guitar or bass can be connected to the front panel unbalanced 1/4" Hi-Z
input; however, note that the 710’s jack sensing circuitry automatically disconnects the rear-panel mic
and line inputs when a cable is inserted into the Hi-Z input.
(see #3 on page 5 for more information, and see page 8 for an interconnection diagram)
Step 6: If you are using a microphone or line-level input, set the front panel Input Select switch to
Mic or Line.
Step 7: Set the Meter switch to DRIVE (its down position).
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The Two Page, Two Minute Guide To Getting Started
__________________________________________________________
Step 8: Set the Gain control to “0” and the Level control to approximately “5”.
Step 9: Set the Blend knob to its twelve o’clock position. This ensures an equal blend of both of the
710 preamplifiers (solid-state and vacuum tube).
Step 10: Make sure the Power switch is off (left position) and then connect the supplied IEC power
cable to the rear panel AC power connector.
Step 11: Power on the 710. The front-panel meter will light up.
Because the Model 710 utilizes a tube, it needs several minutes to achieve stable
operating temperature. During warm-up, audio quality may vary slightly.
Step 12: If a microphone requiring 48 volts of phantom power is connected to the 710, turn on the
+48V switch.
Step 13: Unmute your monitors and slowly raise the Gain control. You should now be hearing signal,
with the 710 meter becoming active.
Step 14: While viewing the meter, set the Gain control until optimum input signal strength is
achieved. Change the Meter switch to OUTPUT (its up position) and set the Level control until optimum
output signal strength is achieved.
Step 15: Experiment with differing degrees of Gain to hear the various amounts of coloration the 710
can impart to your signal. (CAUTION: Very high Gain settings will result in significant amounts of
distortion). For the cleanest, most uncolored signal from the 710, set the Gain knob to its lowest
usable setting, change the Meter to OUTPUT, and then adjust the Level control as necessary. If you
hear distortion when using a connected microphone even at the lowest Gain level, employ the -15 dB
pad to reduce the input level. If you hear low frequency rumble, employ the Low Cut filter switch.
(see page 15 for more information)
Step 16: Finally, experiment with the Blend control to hear the different sonic signatures imparted by
the two discrete preamplifiers contained within the 710. At the fully counterclockwise (TRANS)
position, only signal from the solid-state preamplifier is heard. At the fully clockwise (TUBE) position,
only the signal from the tube preamplifier is heard. Most uniquely, it is the in-between settings that
allow you to access the “twin-finity” of sounds offered by the 710 and create a custom blend that best
complements your signal source.
For more information, refer to the “Front Panel” and “Rear Panel” sections on pages 4 - 7
of this manual.
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Front Panel
__________________________________________________________
(1) Gain - Adjusts the gain of the input stage. Turning this knob clockwise raises the amount of gain
applied to the input signal.
(2) Level - This is the 710’s master volume control. It determines the amount of signal sent from the
rear panel LINE OUTPUT. ( see #2 on page 7)
The numeric values for the Gain and Level knobs are relative scale markings and do not
represent specific dB values.
You can come up with many useful tonal variations by experimenting with different Gain
and Level settings.
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Front Panel
__________________________________________________________
(3) Hi-Z Input - Connect high impedance signal from an instrument such as electric guitar or bass to
this standard unbalanced 1/4" jack connector. The 710’s jack detection circuitry automatically
switches from the selected rear panel MIC or LINE input to the front panel Hi-Z input whenever a plug
is inserted into this jack.
Making a connection to the Model 710’s front panel Hi-Z input jack automatically
disconnects any signal arriving at the rear panel mic or line input.
(4) +48 V - Most modern condenser microphones require +48 volts of phantom power to operate.
When in the up position, 48 volts of phantom power are delivered to the rear panel MIC INPUT.
( See #4 on page 7 and see page 14 for more information about phantom power)
Keep phantom power off (switch down) when it is not required.
Always check the power requirements of your microphone with the manufacturer before
applying phantom power.
To avoid loud transients, always make sure phantom power is off when connecting or
disconnecting microphones.
(5) -15 dB PAD - When placed in the up position, the MIC INPUT signal will be reduced by -15dB.
(This switch has no effect on LINE INPUT or Hi-Z signal.) Use this to reduce the incoming signal in
cases where undesired distortion is present at low gain levels (for instance, where especially sensitive
microphones are used on loud instruments).
(6) Input Select - Determines whether the MIC (up position) or LINE (down position) input is active.
(7) Meter - A standard VU meter that displays either the amount of output level or preamplifier
overdrive, depending upon the setting of the Meter Function switch. ( see #9 below)
(8) Blend (“”) - This unique control sets the relative contribution from the solid-state and vacuum
tube preamplifier circuits. When in the fully counterclockwise (TRANS) position, only signal from the
solid-state preamplifier is heard. When in the fully clockwise (TUBE) position, only the signal from the
tube preamplifier is heard. At the twelve o’clock position, signal from both the solid-state and tube
preamplifiers is heard at equal amounts.
(9) Meter Function - This two-position switch determines what the 710’s VU meter displays. In the up
(OUTPUT) position, it shows final output level in dB; in the down (DRIVE) position, it shows the
THD(total harmonic distortion) level after the front panel Gain control, but before the preamplifier
circuitry, thus giving an accurate gauge of how hard the tube and solid-state preamplifiers are being
driven. In DRIVE mode, the meter is calibrated so that 0 VU is equal to 1.2% THD on a 1KHz sine wave
and -10VU is equal to 0.4% THD. ( see page 9 for more information) When OUTPUT is selected, a
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