WARM AUDIO EQP-WA Tube Amplified Program Equalizer Instruction Manual

: June 6, 2024
: WARM AUDIO

Table of Contents

NOW LET’S GET STARTED!
HIGH-FREQUENCY CONTROL
HARDWARE CONTROLS — REAR PANEL
TECHNICAL SPECS
A BIT OF HISTORY
WAXING PHILOSOPHICAL
HOOKUP DIAGRAMS
HOOKUP DIAGRAMS
RECALL SHEETS
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

EQP-WA
TUBE AMPLIFIED PROGRAM EQUALIZER
Instruction Manual

THANK YOU!
Thank you for purchasing the Warm Audio EQP-WA mono program equalizer. We feel this product offers the best in terms of the sound, function, and vibe of classic premium equalizers from the analog era of recording. We cut no corners when it comes to what goes into our products, and the EQP-WA is no exception. We’ve chosen the highest quality input and output transformers, and inductors by Cinemag Transformers. The EQP-WA features selected high-quality vacuum tubes, potentiometers, switches, and rugged construction. We are confident you will love recording with the EQP-WA.

WELCOME BACK TO THE WORLD OF ANALOG
Though digital technology and software have made great strides in their performance in recent years; we still feel that nothing compares to the level of articulation, depth, realism, and responsiveness of a well-built piece of analog gear. When you hear the bottom-end presence and top-end detail of quality analog gear, the difference can be astounding. The cost of most boutique analog equipment is financially out of reach for many recording artists. Our mission is to change this, and introduce as many people as we can to recording and mixing with real, dedicated hardware. Whether this is the first piece of outboard gear you’ve ever purchased outside of a recording interface, or merely the first in a long time; we thank you, and welcome you back to the world of analog.
Bryce Young
President
Warm Audio
Austin, Texas USA
REGISTER YOUR EQP-WA
Before we begin, please take the time to visit www.warmaudio.com to register your product. To ensure you receive proper and uninterrupted warranty support for your product, please register your unit within 14 days from purchase.

WARRANTY STATEMENT

Warm Audio warranties this product to be free from defects in materials and workmanship for one year from the date of purchase, for the original purchaser to whom this equipment is registered.

This warranty is non-transferable.
This warranty is void in the event of damage incurred from unauthorized service to this unit, or from electrical or mechanical modification to this unit. This warranty does not cover damage resulting from abuse, accidental damage, misuse, improper electrical conditions such as mis-wiring, incorrect voltage or frequency, unstable power, disconnection from earth ground (for products requiring a 3 pin, grounded power cable), or from exposure to hostile environmental conditions such as moisture, humidity, smoke, fire, sand or other debris, and extreme temperatures.

Warm Audio will, at its sole discretion, repair or replace this product in a timely manner. This limited warranty extends only to products determined to be defective and does not cover incidental costs such as equipment rental, loss of revenue, etc. Please visit us at www.warmaudio.com for more information on your warranty, or to request warranty service.

This warranty applies to products sold in the United States of America. For warranty information in any other country, please refer to your local Warm Audio distributor. This warranty provides specific legal rights, which may vary from state to state. Depending on the state in which you live, you may have rights in addition to those covered in this
statement. Please refer to your state laws or see your local Warm Audio retailer for more information.

NON-WARRANTY SERVICE

If you have a defective unit that is outside of our warranty period or conditions; we are still here for you and can get your unit working again for a modest service fee. Please visit us at www.warmaudio.com to contact us about setting up a repair or for more information.

With the proper care, your Warm Audio gear should last a lifetime and provide a lifetime of enjoyment. We believe the best advertisement we can have is a properly working unit being put to great use. Let’s work together to make it happen.

NOW LET’S GET STARTED!

HARDWARE CONTROLS — FRONT PANEL

Bypass Switch
Located on the bottom left-hand side of the faceplate is the bypass toggle switch. This switch engages or disengages the equalizer section of the EQP-WA. By design, it is not a true bypass; but merely takes the EQ circuitry out of the audio path. More on this is discussed later in the manual.

Power Switch and indicator bulb
Located on the bottom right-hand side of the faceplate is the main power toggle switch. This turns the unit on, and power will be indicated by the adjacent power indicator
bulb.

Boost and Cut – Low Frequency’ selector
The rotary switch selects a frequency in the low to lower midrange bands for boost, cut, or even simultaneous boost and cut to create a desired texture effect to the selected band.

LOW-FREQUENCY CONTROL

‘Boost’ (low frequency)
Controls the amount of gain applied to the band selected by the low-frequency selector with a range from zero (unity gain) to +12dB.

‘Cut’ (low frequency)
Controls the amount of attenuation applied to the band selected by the low- frequency selector, with a range from zero (unity gain) to -18dB.

HIGH-FREQUENCY CONTROL

Bandwidth
The bandwidth knob varies the width of the high-frequency boost and cut controls from a relatively sharp Q (affecting the least surrounding frequencies) to a somewhat broader Q (affecting a larger area of bandwidth). A sharp Q is considered useful for more surgical work, such as boosting or cutting a specific overhead piece or octave of an instrument; while a broader Q is more natural and musical, for gentler tone shaping of instruments or program material.

Boost knob
The boost knob controls the amount of boost applied by the high-frequency boost selector, from zero (unity gain) to +18dB.

Boost High-Frequency Selector
This rotary switch selects the high frequency to be boosted by the boost knob.

Cut knob
This knob controls the amount of attenuation applied by the high-frequency cut selector, from zero (unity gain) to -14dB.

Cut High-Frequency Selector:
This rotary switch selects the high frequency to be attenuated by the cut knob.

HARDWARE CONTROLS — REAR PANEL

Power
The EQP-WA requires a 3-pin, grounded IEC cord, and should ship with the power cord appropriate for the territory in which it is sold. Voltage is selectable between 115v and 230v operation, from the rear voltage selector switch. Power input is via a standard fused IEC power receptacle with built-in fuse access, chassis mounted on the rear of the unit. Power is turned on and off via the toggle switch labeled ‘ON/OFF on the right side of the unit’s front panel.

Audio Connections
The EQP-WA has both XLR and ¼ inch TRS balanced inputs and outputs, rear chassis-mounted, operating at line level. Unbalanced connection is also possible via a ¼ inch TS cable. It is not advised to connect both input connectors or both output connectors at once.

Tube Gain Adjust
Located next to the output section, this control provides for approximately 6db of adjustable gain in the tube makeup amplifier, generally between -3 and +3dB. This will allow users to match two units for stereo use with either a test tone or source material, or to match one or two units for unity gain within a particular setup. At fully clockwise (when facing the rear of the unit), the control is essentially bypassed and the EQ has its original default level. At fully counterclockwise, the EQ will be at full attenuation.

Aside from its technical purpose, this feature allows for some additional creative use. For instance, hotter bus material can benefit from the slightly improved headroom and transparency of pulling down the tube gain lower. Conversely, solo instruments and vocals (acoustic guitar or female vocal, for example) can benefit from the added tube roundness and girth of having the tube gain pulled up higher. As with anything, let your ears be the final judge of how to use this feature.

TECHNICAL SPECS

Tube Equalizer based on the classic “Pultec” EQP-1A
CineMag USA transformers
Premium high voltage 12AX7 and 12AU7 tubes
CineMag USA inductor EQ section
EQ section is bypassable – signal still passes through tubes and transformers for the warming effect
No insertion loss – loss restored by tube amplifier
XLR and TRS transformer balanced inputs
XLR and TRS transformer balanced outputs
Flat frequency response from 20 Hz – 50 kHz
Boost and Cut controls can be used simultaneously for phase effect
Low frequency boost – 20, 30, 60, 100, 200, 400, 800 Hz – 12 db
Low frequency cut – 20, 30, 60, 100, 200, 400, 800 Hz – 18 db
High frequency boost – 3, 4, 5, 8, 10, 12, 16 kHz – 18 db
High frequency cut – 3, 4, 5, 10, 20 kHz – 14 db
5 added frequency points for greater flexibility
Switchable 115/230 volt IEC power inlet
Dimensions: 19 x 3.5 x 6 inches – 2RU rack-mountable

A BIT OF HISTORY

Most early recording consoles had very primitive equalization capabilities, often consisting of only two knobs. These consisted of either a simple ‘tone control’ type shelving equalizer, or a ‘low’ and ‘hi’ control knob with a fixed frequency center. One of the most significant advancements in early studio recording came with the advent of dedicated equalizers. The invention of dedicated equalizers inspired desk manufacturers to start putting more comprehensive equalization into their desks. This addition, more than any other, brought about what we would consider the modern recording desk.

Many of the earliest outboard equalizers were passive devices, operating in a purely subtractive manner, requiring a preamplifier (either in the form of outboard gear or routed back into an unoccupied channel of the console). Not only did the equalizer lose the signal level by performing equalization; but often caused ‘loading loss’ merely by being patched in, resulting in added noise, hum or buzz, and loss of tone or high frequencies. By the time an equalized signal was preamplified again and passed through additional console circuitry, the signal-to-noise ratio was often worse off. This made EQ difficult to use without negatively affecting the signal quality.

What followed next was the innovation that brought the use of EQ into the mainstream, known as active equalization.
‘Active equalization’ allowed an EQ to be patched into a mixing desk for the first time without the fear of ‘insertion loss’, added noise, or loss of fidelity. Finally, EQ could be performed risk-free. Most analog equalizers manufactured today use some form of solid-state electronics to apply their boosts or makeup gain. The earliest incarnations of these equalizers, however, used vacuum tubes, along with large input and output transformers, as required by most high voltage tube circuits. This type of design imparts a ‘sweet’ character that many modern designs fail to reproduce. Though many modern EQs have a generous amount of features, few offer the warmth and richness, or the natural and forgiving qualities of the classic designs.

In the early days of recording, distance mic recording was more common than the close-mic technique.
Large rooms tend to ‘even out’ a sound stage, eliminating the need for much of the corrective EQ used in modern production. As close mic recording became the accepted norm for superior track isolation, the need for equalization became much more apparent to recording engineers. Early studios began to utilize what many termed the ‘Tamla/ Motown’ technique (named after the famous record label and studio), whereby an instrument or voice is ‘manipulated’ to some degree via equalization in order to sit well within the context of a mix. Today, this is a nearly inseparable part of the art and science of modern music production.

WAXING PHILOSOPHICAL

WHEN TO EQ?

This is a question that deserves thought. In some cases, EQ can be intuitive. One of the simplest examples of corrective EQ would be in treating the human voice; adding top end to a vocal that needs articulation, or adding bottom end to a vocal that appears thin. In all cases, one should listen thoughtfully and let the material tell you what it needs. Ultimately, one should EQ when a signal requires help to fit naturally and compliment a mix.

Most musicians and artists would say they want their voice or instrument to sound as natural as possible; however, there are many acoustic factors that can affect one’s perception of how an event sounds. What most artists and engineers desire is for an instrument to sound natural or, in an idealized way, closer to the artist’s intention. Most artists expect their recorded material to perform well in the context of a mix without covering other performers or getting covered up. Using an outboard equalizer should typically be viewed as much of a way to make corrective changes as it is to make creative changes. The reason for this is that microphone placement, room acoustics, the settings of the instrument or amp, and a whole host of other variables are always applying their own unique type of EQ to a signal, some of which may be outside of your control and undesirable.

As a general rule, one should do most EQ after applying compression; though there are exceptions, such as taming a problem frequency in advance of a compressor to allow the compressor to respond more naturally. In this situation, one might consider subtractive EQ prior to compression, and additive EQ post-compression. The most notable exception to this rule is in stereo mastering, where EQ should precede final compression and limit, to prevent any chance of peak overages.

TIPS ON USING YOUR EQP-WA

The EQP-WA is a program equalizer by design, which means, though quite capable on individual instruments, it especially shines on complex, full bandwidth material; i.e. complete mixes or instrument groups. It is especially good with providing a final tone balance and adjusting the relationship of the midrange to the low and high-frequency bands in the finished material. As with all equalization, listen for what the source material calls for, and reference back to the original (unaltered) source often to maintain perspective.

HOOKUP DIAGRAMS

In this example, a microphone is feeding into a preamplifier, which feeds into the EQP-WA via a balanced XLR patch cable, which feeds in the LINE LEVEL input of your
recording interface/recorder.

Note: it is important to use a line-level input on your recording device as opposed to a microphone or instrument-level input.

HOOKUP DIAGRAMS

In this example, the EQP-WA is being routed as an insert into a recording device. This is useful for using the EQP-WA as an “analog plug-in” or insert for mix-down. The recording device is feeding the EQP-WA with a balanced 1/4” cable via a line output.
Then, the recording device is capturing the EQP-WA via a LINE LEVEL input.