CHAPTER 51
UA 610-B Tube Preamp
Historical to Modern Tube Amplification from Universal Audio
The Universal Audio 610 Modular Amplifier was designed by audio renaissance man and UA founder M.T. “Bill” Putnam, and was a major milestone in
console design. An all tube and transformer class-A design with feedback
style EQ, the 610 was the first preamp design to include echo sends and modularity that allowed channels to be swapped mid-recording session.
The Universal Audio 610 mic preamplifier has an illustrious history associated
with numerous landmark recordings of the past, and is widely used today in
its modern hardware incarnations (Universal Audio 2-610, 6176, LA610mkII, SOLO/610, and M-610). The UA 610 is one of the best selling
preamps in the boutique preamp market.
The sheer number of classic recordings made by the 610 – new or old – is
staggering. From Coldplay to Cold War Kids, and Duke Ellington to The
Doors, the 610 has been part of the fabric of modern recording since 1958.
With over a year in research and design, the UA 610-B Tube Preamp plugin represents the next major milestone in the evolution of Universal Audio's
610, and for preamplification as a whole. For the first time, the 610-B Tube
Preamp offers the digital audio workstation environment the complete sound,
behavior, and features of a dedicated tube preamp.
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UA 610-B Screenshot
Figure 159. The UA 610-B Tube Preamp plug-in window
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UA 610-B Overview
The complete signal path is modeled in the UA 610-B plug-in, including tube
amplifiers and transformer components, along with all the phase shift, slew
rate, and distortion characteristics that are inherent in the hardware.
Modern 610-B
The 610-B is the modern Universal Audio preamp design used in our popular
hardware products such as the 2-610, LA-610mkII, and 6176.
The UA 610-B plug-in faithfully models this newer design, including all the expanded features optimized for modern use.
In Use
A primary use for the 610-B is for individual vocal or instrument tracks where
colorful tube character and broad EQ strokes are desired. The 610-B is
widely used as a vocal channel and bass channel, but it sounds great on any
source signals.
Tonal Range
From clean to clipped, with a broad sweet spot between, extreme tonal flexibility is possible with the UA 610-B. The input and output circuits each have
their own tube-driven gain stage, and because each stage imparts its own
color, many variations can be obtained by tuning the I/O gain structures.
The 610-B equalizers can also add lots of flavor. Because the EQ has a feedback-style design, it effects the distortion characteristics of the output stage.
Presets
The UA 610-B includes presets in the internal factory bank which are accessed via the host application’s preset menu. The presets are also copied to
disk by the UAD installer so they can be used within Apollo’s Console application. The presets can be loaded using the Settings menu in the UAD Toolbar
(see “Using UAD Powered Plug-Ins” in Chapter 7 of the UAD System Manual).
UA 610-B
Latency
The UA 610-B uses an internal upsampling technique to achieve sonic design
goals. Upsampling results in a slightly larger latency (55 samples; 85 samples
at 176.4/192 kHz) than non-upsampled UAD plug-ins. These additional samples are automatically compensated by modern host DAWs. See “Delay
Compensation” in the UAD System Manual for more information.
Unison™
Integration
The UA 610-B plug-in features Unison mic preamp technology integration
with the mic preamp hardware in Universal Audio’s Apollo audio interfaces.
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When Unison is active, related controls in the plug-in and the Apollo hardware are mirrored. Modifying a control on Apollo’s front panel will modify
the plug-in setting, and vice versa.
Note: Unison is active only when the plug-in is inserted in a PREAMP insert
slot within Apollo’s Console application. For complete Unison details, see the
Apollo Software Manual.
Input Level Controls
Input levels for the UA 610-B plug-in is controlled by the overall combination
of the input select, pad, and gain controls available within the plug-in.
These parameters control the first tube gain stage in the plug-in. Generally
speaking, higher input gains will produce more color in the signal.
Input Select
The 610 hardware has both mic and line level inputs. The Input Select control
switches between the “virtual input jacks” in the emulated models.
In most mic preamplifiers (including the 610), the difference between the mic
and line inputs is simply that the line input is attenuated before entering the
preamp circuitry; the gain circuits are typically not different for the mic and
line inputs.
Line
When set to Line, it’s as if the DAW signal is plugged into the line level input
of the emulated 610 hardware. Less tube gain is applied, and a cleaner
sound is obtained.
Mic
When set to Mic (the 500 and 2.0K settings), it’s as if the DAW signal is
plugged into the microphone input of the emulated 610 hardware and approximately 30 dB of additional (unattenuated) tube gain is applied. Since
the incoming signal in from the DAW is already at line level, this mode will
more readily result in the tube color, saturation, and/or clipping associated
with overdriving the input.
Important: Use caution when switching to Mic (500 or 2.0K settings) from
Line, as signal output levels can increase significantly (as they would with a
hardware preamp).
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Impedance
Impedance selections are available for the Mic input. The Mic inputs
can be set to 500 ohms or 2 Kilohms; the different input impedances
have subtle effects on the signal color and response.
Unison
Impedance
When the plug-in is inserted in a PREAMP slot within the Apollo Console, the
hardware input impedance of the Apollo mic preamp changes to match the
value selected in the plug-in for unprecedented realism.
Matching the microphone to the closest impedance value is generally recommended, but this parameter can be used creatively and will not harm equipment connected to the Apollo mic preamp.
Note: For complete Unison details, see the Apollo Software Manual.
Input Pad/Gain
In addition to the Input Select switch, the plug-in has Pad and Gain parameters that control the signal level at the tube input stage.
The Pad controls are used to attenuate incoming signals for less coloration,
while the Gain controls increase the signal level for more tube color.
Note: Like the original hardware, values on the control labels may not match
actual measured values.
Input Gain
The rotary Gain switch (at the top of the plug-in, beneath the
Power switch) changes the level at the tube input stage. The
control attenuates the input signal by –10 or –5 dB, or adds
+5 or +10 dB of gain. In the center “0” position, neither
gain nor attenuation is applied.
Input Pad
Additional attenuation for the Mic input is available via the two-position
Pad switch (at the middle of the three up/down switches near the center
of the plug-in). Setting the switch to the “–15” (up) position attenuates
the Mic signal at the tube input stage by –15 dB. In the down position,
no attenuation is applied.
Note: Like the hardware, Input Pad for UA 610-B effects only the Mic input.
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Output Level Controls
Level
Level (aka “the big knob”) is used to control the gain of
the tube output stage of the preamp. Higher values add
more coloration and provides amplification to the feedback-style EQ circuitry.
The amount of available gain using this control is approximately 61 dB.
Output
Output adjusts the signal level at the output of the plug-in without
effecting the sonic character of the signal. The range is from –∞
dB (off) to +12 dB.
This control, which does not exist on the original hardware, facilitates the ability to increase the Level control for output stage tube
coloration while maintaining the ability to cleanly adjust the overall output volume.
Tip: Click the “0” label text above the control to return Output to 0 dB.
EQ
The 610-B features high and low frequency boost/cut shelving filters with
stepped gain controls. The equalizers utilize a feedback-style design which effects the distortion characteristics of the output stage.
Low EQ
The low frequency (“LO”) shelf EQ has a selectable cutoff frequency which can be cut or boosted by various amounts.
Lo EQ Frequency
This switch determines the cutoff frequency (70, 100, or 200
Hz) of the low shelf EQ. This switch has no effect if the Lo EQ
Gain value is zero.
Note: Like the hardware, low frequency values are not consecutively ordered.
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Lo EQ Gain
This rotary switch determines the amount of boost or cut applied to the low frequency signal. Fixed values of plus or minus 9, 6, 4.5, 3, or 1.5 dB can be
selected. When set to 0 dB, the filter is inactive.
The high frequency (“HI”) shelf EQ has a selectable cutoff frequency which can be cut or boosted by various amounts.
High EQ
Hi EQ Frequency
This switch determines the cutoff frequency (4.5 kHz, 7 kHz,
or 10 kHz) of the high shelf EQ. This switch has no effect if the
Hi EQ Gain value is zero.
Note: Like the hardware, high frequency values are not consecutively ordered.
Hi EQ Gain
This rotary switch determines the amount of boost or cut applied to the high
frequency signal. Fixed values of plus or minus 9, 6, 4.5, 3, or 1.5 dB can be
selected. When set to 0 dB, the filter is inactive.
Polarity
This switch inverts the polarity (aka “phase”) of the signal. The signal
polarity is inverted when the switch is in the up position. Polarity is normal when the switch is in the down position. Polarity inversion can help
reduce phase cancellations when more than one microphone is used to
record a single source.
Power
Power is the plug-in bypass control. When set to OFF, emulation processing is disabled and DSP usage is reduced (if
DSP LoadLock is inactive). Power is useful for comparing the processed settings to the original signal.
610 History
Creating an original 610 desk meant buying the individual modules and
building the console from scratch, as no complete consoles were ever sold
commercially. However, Bill Putnam himself built a few full-fledged desks for
his own studios, complete with fabricated frame, power supply, metering,
and buss/effects routing options.
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Although very few desks were built from 610 modules, their contribution to
the history of recorded music is enormous. Ray Charles, Frank Sinatra and
The Beach Boys were a few artists captured with the 610 at United/Western
as part of landmark recordings such as “Sounds in Country and Western Music,” “Strangers In The Night,” and “Pet Sounds,” respectively.
One of these 610 desks is the famous Wally Heider “Green Board.” This extremely well-built example was originally fabricated by Frank DeMedio for
Wally Heider’s Remote Recording Service in the early ‘60s. Wally originally
handled many of the live recording dates booked by Putnam. This console recorded and mixed some of the greatest performances of the era, from many
live shows with the “Rat Pack,” to recording the very last concert under the baton of Igor Stravinsky in Los Angeles.
With the Wally Heider Green Board alone, the list of records using the 610
is staggering. Here are but a few notable acts recorded with the Green
Board: Duke Ellington, Elvis Presley, Johnny Cash at Folsom Prison, Fats Domino, Little Richard, Cream, The Beach Boys, The Doors, Janis Joplin with Big
Brother & The Holding Company, The Who, The Grateful Dead, The Steve
Miller Band, Moby Grape, The Byrds, Jefferson Airplane, Booker T. & the
M.G.s, Otis Redding, Eric Burdon and The Animals, Simon and Garfunkel,
and The Jimi Hendrix Experience (live at the Monterey Pop Festival, where he
first set his guitar on fire!).
In the early ‘70s, long before this one-of-a-kind desk's historical significance
could be anticipated, Neil Young bought the 12-channel board from Wally
Heider. Young immediately moved it to his Broken Arrow Ranch. He installed
the desk in his barn, which he used as a recording studio, and employed it to
record his seminal record “Harvest” and may other classic albums. The Green
Board remains at Broken Arrow Ranch, and is still in use today.
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The original Wally Heider “Green Board” console
containing 12 vintage UA 610-A preamplifier modules
The modern Universal Audio 2-610
Dual Channel Tube Preamplifier
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