LUNA Ampex ATR-102 Master Tape Extension Manual

Updated December 16, 2024 21:38

It's Not a Record Until it's Mastered on an Ampex^® Tape Machine

The UAD Ampex ATR-102 Mastering Tape Recorder plug-in and LUNA Extension provides the final "analog polish" to your music, turning your recordings into records. Fully authenticated by the Ampex Corporation and trusted by Platinum‑selling professionals the world over, the ATR‑102 plug‑in faithfully captures the unique dynamics, colorful frequency response, and tape saturation of this industry‑standard Ampex machine.

Add analog polish to your mixes with the most popular professional 2‑track tape machine ever made
Harness classic Ampex tape saturation, selectable tape types, and color to "glue" your mix together
Process your audio through the entire ATR‑102 circuit, including its transformers, amplifiers, and Repro path
Use the ATR‑102 LUNA Extension to produce rich, analog tape‑infused master recordings

The Most Popular Professional 2‑Track Ever Made

With its cohesive sound, punch, and ability to provide subtle‑to‑deep tape saturation and color, the ATR‑102 has remained a fixture in major recording and mastering studios worldwide since 1976.

The ATR‑102 Mastering Tape Recorder LUNA Extension faithfully replicates the unique dynamics, frequency response, and saturation characteristics of the original hardware. Scrutinized and fully authenticated by the Ampex Corporation, the sound of the UAD ATR‑102 LUNA Extension is virtually indistinguishable from its analog ancestor.

Now Fully Integrated into LUNA Recording System

With LUNA Recording System, you can now use the Ampex ATR‑102 as a LUNA Extension, where it's built into the fabric of the mixer without the need to manage separate plug-in windows. This gives you rich, album‑ready Ampex tape tones on LUNA's master fader and buses — with all the authentic dynamics, frequency response, and saturation characteristics of the original machine.

Authentic Calibration Controls and Tape Types

Like the ATR‑102 hardware, the plug-in allows you to choose between various Signal Paths (Input, Sync, Repro), different Tape Speeds / Emphasis EQs (NAB, CCIR, AES) and Tape Formula (GP9, 456, 900, 250) combinations, including home/consumer tape.

Purchasing Ampex ATR-102 Master Tape

You can purchase the optional Ampex ATR-102 Master Tape LUNA Extension from within LUNA's Manage panel. Your purchase of the Ampex ATR-102 Master Tape LUNA Extension includes both the UAD plug-in (Mac/Windows) and the LUNA Extension (Mac only).

LUNA Extension Parameters

The Ampex ATR-102 Master Tape LUNA Extension allows you to choose between different Tape Speeds / Emphasis EQs and Tape Formula combinations, even including home/consumer tape. The Input (Record) Gain knob and the Cal button are the primary controls for regulating levels, and even saturating the tape, and can be used to deliver a heavily colored sound if desired.

Other Ampex ATR-102 Master Tape LUNA Extension features include: 1/4," 1/2," or 1" Head Width, Calibration Level, Biasing, EQ, and Noise Off/On.

Using ATR-102

With the Ampex ATR-102 Master Tape LUNA Extension, you can access the sound and mechanical parameters of an Ampex ATR-102 tape machine, integrated directly within the LUNA mixer buses and the Main track. The LUNA Extension features all of the tone and character of the Ampex circuit design and tape formulas. The Ampex ATR-102 Master Tape LUNA Extension runs natively in the LUNA mixer, and allows for placement of the tape machine either at the end of the processing chain (post-fader) for traditional console to mix down deck signal flow, or before other processors (pre-fader). The Ampex ATR-102 Master Tape LUNA Extension provides dramatically reduced latency and a streamlined, customized feature set compared to the UAD-2 version. The Ampex ATR-102 LUNA Extension retains the head-stacks, speeds, tape formulas and gain and control cards of the UAD-2 plug-in version, but removes some features such as Tape Delay, and user-adjustable Wow and Flutter. Independent L/R control, Manual Calibration (Test Tones, MRL Mode, Distortion Display), user-adjustable Crosstalk, and adjustable Hiss and Hum are also removed.

The ATR-102 can be added to the Master Tape row on a bus or on the Main track. Each Bus track and the Main track may have its own unique Master Tape deck. Set up the ATR-102 by first adjusting Tape Speed, Tape Formula, Cal Level, and Head Width, or select a preset. Note that as you lower the tape speed (i.e. 15 IPS, 7.5 IPS), the tape "sound" becomes more audible. Once this basic setup is made, adjust the Record input gain levels for more or less tape/circuit coloration and saturation. Ampex ATR-102 Master Tape LUNA Extension can be applied pre-fader or post-fader. By default,the extension is applied pre-fader on the Main track, and post-fader on bus tracks.

In the Master Tape Browser, you can set all aspects of the Master Tape deck's sound, including tape speed, head width, and tape formula, as well as bias settings and EQ settings. On the channel in the LUNA mixer or on a Focus channel, a streamlined set of controls (tape speed, head width, and tape formula) is available.

Operational Overview

Famous Tape Sound

The Ampex ATR-102 Master Tape LUNA Extension provides all of the original unit's desirable analog sweetness. Like magnetic tape, users can dial in a clean sound, or just the right amount of harmonic saturation.

Main Track and Bus Tracks

The primary purpose of the Ampex ATR-102 Master Tape LUNA Extension is to obtain tape mixdown sonics within the LUNA environment. To obtain the classic tape mixdown sound, instantiate the LUNA Extension in the Master Tape row on the Main track. To apply the tape sound to buses, instantiate the LUNA Extension in the Master Tape row on each bus.

Multiple Tape Formulas

The Ampex ATR-102 Master Tape LUNA Extension models seven popular magnetic tape formulas. Each type has its own subtle sonic variation, distortion onset, and tape compression characteristics. The tape formulas that can be selected depend on the active tape speed and head width; all tape formulas are not available for all tape speeds and head widths. Lower fidelity types are included to facilitate more signal coloration options.

Multiple Tape Heads

The original hardware machine was manufactured with an interchangeable head block system which enabled the system to be quickly converted to use either 1/4" or 1/2" tape stock by simply swapping out the heads and recalibrating the electronics. As track width increases, subtle improvements to stability, fidelity, and noise become apparent. A popular custom aftermarket tape head is available which enables the use of 1" tape stock, enabling even higher fidelity with its greater track widths. All three tape head widths are accurately modeled and selectable in the Ampex ATR-102 Master Tape LUNA Extension.

Multiple Tape Speeds

All four tape speeds in the original hardware are modeled in the Ampex ATR-102 Master Tape LUNA Extension. Speeds of 3.75, 7.5, 15, and 30 inches per second (IPS) are available. Each speed provides distinct frequency shift, head bump, and distortion characteristics. Higher speeds have higher fidelity; 3.75 IPS has a distinctively "lo fi" character.

Multiple Calibration Levels

Tape machines can be set up with different calibration levels, which entails setting unity gain from input through output based on the magnetic flux (amount of magnetic field) of a given tape formulation. Different calibration levels provide different tape response characteristics for a given level into the recorder. Four selectable calibration levels are available in the Ampex ATR-102 Master Tape LUNA Extension.

Ancillary Noises

Tape recorders have inherent signal noises that are a by-product of the electro- mechanical nature of the machine. While "undesirable" tape system noise is historically considered a negative and was an attribute that pushed the technical envelope for better machine design and tape formulas (and ultimately, "noiseless" digital recorders), noise is still an ever-present characteristic of the sound of using tape and tape machines.

The Ampex ATR-102 models the hum, hiss, wow, flutter, and crosstalk characteristics of the original hardware. These noise components can be disabled.

Modeled Transformer

The original hardware was manufactured with isolation transformers, which can color the signal. Ampex ATR-102 simulates the behavior of the transformers in the hardware.

Automatic Calibration

The ability of a magnetic tape recorder, which has inherently non-linear response characteristics, to accurately reproduce an audio signal with a minimum of noise and distortion requires precise adjustments to the system electronics. The calibration settings are based on the current tape speed, formulation, emphasis EQ, and tape width. The hardware must be meticulously re-adjusted each time a different tape, speed, emphasis EQ, or head width is used (and for system wear and drift, even if these variables are not changed). Ampex ATR-102 Master Tape LUNA Extension has an automatic calibration feature that tunes all calibration electronics with a single button.

Low Level Tuning

Even though automatic calibration is available, the individual controls that adjust calibration are exposed for sonic manipulation. Playback EQ, record (tape) EQ, and record bias can easily be altered for manual calibration and/or creative purposes.

Quick Setup

Set up the extension by first adjusting Tape Speed, Tape Formula, and Tape Head Width. Note that as you lower the tape speed, the tape "sound" becomes more audible. Once this basic setup is made, adjust the Record (gain) levels, for more or less tape/circuit coloration/saturation.

Configuring Ampex ATR-102

You can add Ampex ATR-102 to a Bus track or the Main track. You can configure each instance of Ampex ATR-102 Master Tape LUNA Extension with manual controls and presets.

Assign Ampex ATR-102 to a track

Click the Master Tape insert on a bus track or the Main track, and select the ATR-102.
The primary set of tape machine controls appear in the Master Tape slot, and the Master Tape deck appears in the browser on the left of the screen.

In the Master Tape slot, you can configure the most important features: tape formula, tape speed, and tape head width. You can also toggle the Master Tape deck on and off. You can further configure the Master Tape deck in the Browser on the left of the screen.

Master Tape Deck controls in Browser

To configure Ampex ATR-102 in the Browser:

Hover over the Master Tape insert on a track, and click the box to open the Master Tape Deck.
The Master Tape Deck opens on the left of the screen.
Adjust the controls manually, or choose a Preset to configure the global sound of the Ampex ATR-102

Click the Open (^) button to open the secondary machine controls.

To adjust a rotary tape control, you can click and drag on the control to rotate it to the desired position, or double-click the control to choose from a list of values. You can toggle through push-button controls by clicking the buttons, or toggle switches by clicking them,

Inserting the tape deck Pre Fader or Post Fader

The Ampex ATR-102 Master Tape LUNA Extension can be configured as either a pre-fader or post-fader effect. By default, the Ampex ATR-102 is pre-fader on the Main track and post-fader on buses. On the Main track, the ATR-102 is configured pre-fader to enable modern workflows where a master brickwall limiter or other processor is positioned after it. The Master Tape machine on a bus is configured post-fader by default to apply the sound of the tape after other bus processing. The use of a Master Tape machine on buses allows for sonic exploration beyond what would normally be available with a single mixdown tape deck.

To configure the Ampex ATR-102 Master Tape LUNA Extension as pre or post fader:

Click in the Master Tape row and assign the ATR-102 LUNA Extension to a bus or the Main track,
Hover over the Master Tape slot, and click on •••.
To insert the tape deck pre-fader, select Insert Pre-Fader. An indicator to the left of the option indicates that the option is enabled.
To insert the tape deck post-fader, clear the indicator next to Insert Pre-Fader.

You can also switch between the pre and post fader tape deck location by clicking the option in the Master Tape Browser.

Using presets

The Ampex ATR-102 Master Tape LUNA Extension includes presets created in collaboration with prominent ATR-102 users. The available presets range from Classic and Clean mastering-oriented presets that provide the sound of tape with minimal coloration, to higher-input Pushed presets for mix situations that call for more saturation. Lastly, a collection of Vintage tones are available when distinct coloration is desired.

Primary and Secondary Controls

The graphical interface panel has two modes; Open and Closed. In Closed mode, the primary controls (those that are typically most used) are available on the main panel interface and the tape reels are visible. Additional (typically less used) controls are available on the secondary panel in Open mode. The secondary controls panel is accessed by clicking the button labeled ^ beneath the AMPEX label.

Primary Controls

Meters

The two Meters display signal levels of the extension for the left and right channels. Meter ballistics of the original hardware are modeled. The Meters can be switched to display input or output levels in peak or VU modes.

The extension operates at an internal level of -12 dBFS. Therefore a digital signal with a level of -12 dB below full scale digital (0 dBFS) at the extension input will equate to 0 dB on the Meters when Reproduce is in its calibrated position, which is marked with the "red arrow sticker."

Input/Output

These switches change the Meter to display levels at the input or output of the extension. Input metering is a feature which is unavailable in the original hardware.

Input

When in Input mode, the Meter reflects the signal before the processor.

Output

When in Output mode, the meter reflects the signal level at the output of the extension, which is just after the Reproduce (output) gain.

Record

Record adjusts the signal level into the extension and the tape circuitry. The Record control's available range is -∞ dB (off) to +9.3 dB. The default value is 0 dB.

Tip: Option-click the "RECORD" knob to return the Record value to 0 dB.

Note: The graphical interface panel values, which range from 0 - 10, are arbitrary and do not reflect a particular dB value.

Record is a primary "color" control for the extension. Just like genuine magnetic tape, lower Record levels will have a cleaner sound, while higher levels result in more harmonic saturation and coloration. Higher Record levels will also increase the output level from the extension. The Reproduce control can be lowered to compensate if unity gain operation is desired.

Reproduce

Reproduce adjusts the signal level coming off the virtual tape before the signal is sent to the Meters. The available range is -∞ dB (off) to +9.48 dB. The default value of 0 dB is the "calibrated position" which is marked with a "red arrow sticker." Reproduce is not affected by Auto Cal.

Tip: Option-click the "REPRODUCE" knob to return Reproduce to 0 dB.

Note: The graphical interface panel values for Reproduce, which range from 0 - 10, are arbitrary and do not reflect a particular dB value.

Link

Link adjusts the Record and Reproduce levels reciprocally, so as you turn one up, the other is turned down. Enable this to prevent volume increases or drops when adjusting the Record or Reproduce level.

Secondary Controls

The secondary controls are accessed by clicking the button marked with a ^ beneath the AMPEX label. Conversely, the panel is closed by clicking this button again.

Emphasis EQ

The Emphasis EQ buttons determine the active Emphasis EQ values and the frequency of the Hum noise. NAB or CCIR curves can be selected when the Tape Speed is 7.5 or 15 IPS. When the Tape Speed is 30 IPS, neither value is available (the LEDs are disabled) because the EQ is fixed with the AES emphasis curve, per the original hardware. At 3.75 IPS, only NAB is available (as it is with the hardware).

NAB

When the value is set to NAB (traditionally the United States standard), the Hum Noise frequency is 60 Hz. When set to CCIR (traditionally the standard in Europe and other regions), the Hum Noise frequency is 50 Hz.

Tape Speed and Emphasis EQ were originally practical controls for recording duration versus noise and local standards. Historically, the origin of the tape machine (US or European) dictated the built-in EQ emphasis, but later machines like the Ampex ATR102 had both circuits available.

CCIR

CCIR (also known as IEC1) is the EQ pre-emphasis made famous on British records and is considered the technically superior EQ; many say this EQ was part of the "British sound" during tape's heyday. NAB (also known as IEC2) was the American standard with its own sound. AES is truly standardized at 30 IPS and is the sole EQ found on the Ampex ATR-102 at 30 IPS.

Bypass

Bypass disables extension processing and cleanly transitions between the extension's bypassed and enabled state. Bypass is useful for comparing the processed settings to the original signal. Meters are still active, however, in this state, the Meters indicate signal levels at the input of the extension prior to processing.

Power

This is the Master Tape extension Power control. When set to Off, emulation processing is disabled, the Meters and control LEDs are dimmed, knobs and buttons are disabled, and resource usage is reduced.

Tape Speed

The Tape Speed control determines the speed of the tape transport, in inches per second (IPS). Tape Speed affects the recorder's fidelity and associated "head bump" sonics. Head bump is bass frequency build-up that occurs with magnetic tape; the dominant frequencies shift according to transport speed.

To change the Tape Speed value, click the IPS text values, or drag the knob.

15 IPS is considered the favorite for rock and acoustic music due to its low frequency "head bump" (low frequency rise) and warmer sound, while 30 IPS is the norm for classical and jazz due to its lower noise floor, greater fidelity and flatter response. 7.5 and 3.75 IPS are also available for an even more colored experience, with even greater frequency shift and other artifacts.

Note: The available parameter ranges of Tape Formula, Head Width, and Emphasis EQ are affected by Tape Speed.

Tape Formula

Tape Formula selects the active tape stock formulation. Seven Tape Formulas are modeled in the Ampex ATR-102 Master Tape LUNA Extension. To select the Tape Formula, click the TAPE button to cycle through the available types, or click directly on the Tape Formula value label. The active Tape Formula is highlighted in yellow.

Note: The available Tape Formulas and defaults are dependent on the current Tape Speed and Head values. See Tape Speed, Formula, and Emphasis EQ settings for more information.

Each formula has its own subtle sonic variations, distortion onset, and tape compression characteristics. Generally speaking, the lower the Cal Level for each formula, the higher the signal level required to reach saturation and distortion.

Cal Level

Cal Level automatically sets tape calibration/fluxivity. The Cal Level setting takes care of the setup one would need to make under equivalent hardware operation, and sets the reference tape/flux level without disturbing the (unity) gain of the extension.

To select the Cal Level, click the CAL button to cycle through the available levels, or click directly on the calibration value label. The active Cal Level is highlighted in yellow. The default value is +6 dB.

Because Cal Level affects the operating levels in the extension, it can be used to compensate for overly high (or low) levels at the input of the extension. For example, if the input is too hot, lowering the Cal Level will reduce the signal level without changing Record, which can affect the tape saturation characteristics.

Note: The noise floor is affected by the Cal Level when Noise Enable is active.

As tape formulas advanced, their output level increased, thus lowering relative noise floor. Under normal use, the machine would be calibrated to the tape's output level. However, sometimes the machine is under-calibrated to leave more headroom for a broader sweet spot or to prevent electronics from clipping. Therefore, one can "go traditional" and calibrate to the recommended levels, or select a non-corresponding calibration setting.

As an example, if 456 is the selected Tape Formula and when Cal is set at +6 (6 dB higher than the NAB tape standard), the reference flux level is 355 nWb/m (nanoweber per meter) and is 10 dB below the point where THD reaches 3% (referred to as the maximum operating level). Therefore, with a 1 kHz test tone at -12 dBFS sent to the extension, with Tape Formula set to 456, Cal set to +6, and Auto Cal enabled, output levels of the extension will match the input level and fluxivity on the tape will be 355 nWb/m.

The tape manufacturer's recommended calibration settings for each Tape Formula are shown in the table below.

Tape Manufacturer's Recommended Calibration Levels

Tape Formula	Calibration	Flux Level
111	+0 dB	77 nWb/m
35-90	+3 dB	251 nWb/m
250	+3 dB	251 nWb/m
456	+6 dB	355 nWb/m
468	+6 dB	355 nWb/m
900	+9 dB	502 nWb/m
GP9	+9 dB	502 nWb/m

Tip: The Ampex ATR-102 Master Tape LUNA Extension default presets bank offers a variety of preset Tape Formula, Tape Speed, CAL level, and EQ configurations that are commonly used for recording with each of the popular Tape Formulas.

Head Width

This control specifies the active tape head model. Head Widths of 1/4," 1/2," or 1" can be selected.

To select the Head Width, click the HEAD button to cycle through the available values, or click directly on the value label. The active Head Width is highlighted in yellow.

Note: At tape speeds of 3.75" and 7.5" only the 1/4" head can be used. At these speeds, the 1/2" and 1" heads cannot be selected.

Tape Reels Animation

When the secondary controls panel is closed, the graphical tape reels "spin" if the LUNA transport is running.

The tape reels animation can be disabled by clicking the capstan graphic. Re-clicking the capstan will re-start the animation.

Auto Cal

The Ampex ATR-102 has individual calibration controls for adjusting sync (record) EQ, reproduction (playback) EQ, and record bias, which are used to compensate for the inherent non-linearities of tape systems. On the hardware, these controls are typically adjusted to calibrate the system for optimum response compensation due to tape nonlinearities whenever the tape formula, tape speed, emphasis EQ, or head width are changed.

When the Auto Cal (Automatic Calibration) ON button is clicked, the calibration EQ and bias controls are automatically adjusted to their "flat" calibrated position for the currently active Tape Formula, Tape Speed, Emphasis EQ, and Head Width. The Auto Cal ON LED illuminates green when the calibration parameters (Shelf EQ, HF EQ, Repro HF, Repro LF, and Bias) are in their calibrated position.

Auto Cal is OFF by default. When Auto Cal is ON, the calibration parameters (Shelf EQ, HF EQ, Repro HF, Repro LF, and Bias) change values whenever Tape Formula, Tape Speed, Emphasis EQ, or Head Width is modified. When Auto Cal is OFF, the calibration parameters do not change values when Tape Formula, Tape Speed, Emphasis EQ, or Head Width is modified.

Important: Any calibration settings made manually are lost when Auto Cal is activated. Consider saving manual settings as a preset before activating Auto Cal. After Auto Calibration occurs, the automatically adjusted parameters can be modified to any other value if desired. If a calibration parameter is adjusted while Auto Cal is ON, the ON LED illuminates in red instead of green, indicating that the system is no longer in the calibrated state. If the moved controls are subsequently returned to their original position, the LED will return to its green state, indicating the unit is back in calibration.

Tip: To return any of the individual calibration controls to their "flat" (calibrated) position, click the label text adjacent to the control (or, simply re-click Auto Cal to return all calibration controls to their "flat" position).

Record EQ

The Record EQ controls (HF EQ and Shelf EQ) are applied in the tape recording circuit and affect tape saturation characteristics. They compensate for common residual HF loss due to bias optimization and system filtering, and affect HF content in the signal prior to the tape non-linearity.

HF EQ

HF EQ provides high frequency emphasis in the signal recorded to tape.

Shelf EQ

Shelf EQ is another control (in addition to HF EQ) provided to compensate for tape nonlinearity. Although adjustment of this control is not part of the Ampex factory calibration procedure, it can be used for customized manual calibrations or creative purposes.

Repro EQ

The Repro EQ controls (Repro HF and Repro LF) are post-head controls for tape playback calibration. They affect the signal coming out of the tape circuitry in both Repro and Sync modes.

The Repro EQs are used as filters to shape the frequency response of the system in maintaining a flat response and enable compensation for any tape frequency loss or head wear.

Repro HF

Adjusts the tape playback high frequency content when Path Select is set to Sync or Repro.

Repro LF

Adjusts the tape playback low frequency content when Path Select is set to Sync or Repro.

Bias

This control adjusts the amount of bias in the record signal. Bias is defined as an oscillator beyond the audible range applied to the audio at the record head, allowing for adjustment of the record behavior. Ideal bias voltage settings provide maximum record sensitivity and low distortion. Intentionally overbiasing is a common technique especially for "tape compression" which produces a warmer, gently saturated sound. Underbiasing can also be used to add distortion and other nonlinear responses, similar to gate chatter or cold solder joints; extremely low voltages may even cause audio to drop out entirely.

Bias voltage, HF/Shelf EQ, and Emphasis EQ (CCIR, NAB, AES) all work together to provide a linear response to the recorded signal. The "flat" (calibrated position) is determined by tape speed, tape formula, emphasis EQ, and head width.

Noise Enable

This is a global enable control for the Hum and Hiss effect. When Noise is enabled, a preset level of Hum and Hiss is added, depending on the tape speed .

Tape Speed, Formula, and Emphasis EQ settings

This table includes all the combinations of tape speed, head width, tape formula, and Emphasis EQ.

Speed (IPS)	Head Width	Form. 1	Form. 2	Form. 3	Form. 4	Emphasis EQ
30	1"	250	456	468	GP9	AES*
30	1/2"	250	456	900	GP9	AES*
30	1/4"	250	456	900	GP9	AES*
15	1"	250	456	468	GP9	NAB
15	1"	250	456	468	GP9	CCIR
15	1/2"	250	456	900	GP9	NAB
15	1/2"	250	456	900	GP9	CCIR
15	1/4"	250	456	900	GP9	NAB
15	1/4"	250	456	900	GP9	CCIR
7.5	1/4"	250	456	35-90	111	NAB
3.75	1/4"	250	456	35-90	111	NAB

When the tape speed is 30IPS, the NAB and CCIR indicators are both powered off to indicate that AES emphasis EQ is used.

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It's Not a Record Until it's Mastered on an Ampex® Tape Machine