NEOLD U17 Plugin Alliance User Manual
- June 13, 2024
- NEOLD
Table of Contents
NEOLD U17 Plugin Alliance
Product Information
The U17 is a unique compressor that was built in 1954 by Allgemeine Telefon- Fabrik in Hamburg for the NWDR broadcasting network. It is considered one of the rarest compressors ever built, with only a few dozen units manufactured. The U17 combines solid-state diode bridge technology with all-tube and transformer-coupled amplification, offering the best of both worlds. It features a discrete soft clipping stage for pleasant coloration and taming heavy transients. The U17 employs six DS62 Germanium crystal diodes and ECC81 double triode tubes for clea voltage controlled amplification. It includes custom iron transformers for audio and sidechain processing.
Product Usage Instructions
Meter
The meter visualizes the intensity and speed of the gain reduction process. It
can also show the input or output level. Use the meter to monitor the
compression levels and adjust accordingly.
Clipper
The clipper section allows you to tame incoming transients and achieve a
louder signal before involving the compressor. You can set the focus of the
effect within the spectrum, making it a useful dynamics tool and sound shaper.
Experiment with different settings to achieve the desired sound.
Compressor
The compressor section offers various controls for dynamic processing:
- Fully Compensated Input Gain: Controls the operating point (threshold) of the compressor. Adjust this to determine when compression should start.
- Torque: Modifies the knee and ratio of the compression curve. Use this control to adjust the aggressiveness of the compression.
- Time Constants: Set the attack and release time constants for the compression. Experiment with different settings to find the desired response.
- Auto Modes: Enable individual auto modes for attack and release. This allows the compressor to automatically adjust the time constants based on the input signal.
- Blend Detectors: Continuously blend the detectors from unlinked to linked operation. Adjust this control to achieve the desired stereo image and compression behavior.
Take time to explore and experiment with the various controls to find the perfect compression settings for your audio.
THE SECRET COMPRESSOR
In 1954, a truly unique compressor appeared on the scene: the U17. Built by
Allgemeine Telefon-Fabrik in Hamburg for the NWDR broadcasting network, only a
few dozen units of this exemplary analog master piece were manufactured,
making this gem one of the rarest compressors ever built.
CROSSING BRIDGES
The U17 combines a solid state diode bridge using Germanium crystal
semiconductors with all-tube and massive trans-former-coupled amplification.
Best of both worlds! The original hardware was intended to provide gentle and
unobtrusive com-pression, and the plugin offers just that in the most
beautiful way… but it also adds a couple of serious setscrews, mutating the
gentleman into a veritable two-face.
DIGNIFIED POWER
A discrete soft clipping stage adds pleas-ant coloration while taming heavy
transients before entering the actual com-pressor, which can blend from gentle
and transparent to straight and aggressive operation with its powerful Torque
control. In fact, the U17 combines everything we love about the golden era of
analog design with a very modern and experienced approach to dynamics
processing.
DIODES
The U17 circuit employs six DS62 Germanium crystal diodes. Four of them are
wired in a bridge configuration to implement the floating gain reduction
circuit which was also used in later units like the U273 or the iconic 33609.
This design was introduced in the early 1950s, when remote cut-off tubes where
the only other option for achieving clean voltage controlled amplification.
TUBES
The audio amplifier as well as the side-chain driver feature an ECC81 double
tri-ode, which is strapped in a clever negative feedback configuration in both
cases to al-low for maximum linearity… the U17 was a broadcast device designed
to improve the SNR in AM transmission paths after all. While the plugin is
based on this beautiful topology, it also offers powerful ways of spicing
compression up with additional grit and harmonic distortion.
TRANSFORMERS
The U17 includes plenty of custom iron: Audio and sidechain are tapped from
the input transformer. The second ECC81 stage of the sidechain amp is loaded
by a ma-jor choke and drives into another iron that feeds the envelope and
time constant gen-erator. An interstage transformer drives the audio amp,
completed by an output trans-former coupled with another choke.
QUICK START
-
Meter
Its main function is to visualize the intensity and speed of the gain reduction process, but it can also show the input or output level instead. -
Clipper
This section allows to tame incoming tran-sients and achieve a louder signal before even getting the compressor involved. You can also set where in the spectrum the effect should be focused, so the soft clipper can be used both as a dynamics tool and as a sound shaper. -
Compressor
The fully compensated input gain essentially controls the operating point (threshold) of the compressor, while Torque modifies the knee and ratio of the compression curve at the same time. Here you can also set the time constants or en-able individual auto modes for attack and re-lease, and continously blend the detectors from unlinked to linked operation. -
Filter
A tilt-style sidechain filter which allows to fo-cus compression on the energy of specific fre-quency ranges, with controls for blending from low pass via completely flat to a high pass filter and for setting the tilt point. It is completed by a switchable sidechain listen monitor. -
Mixer
This section is for blending the processed and unprocessed signals, adapting the output vol-ume, and switching the plugin on or off.
- Shows either input level, gain reduction or out-put level (meter screw changes mode).
- Controls the amount of soft clipping/saturation introduced by the tube amplifier.
- Defines where in the frequency spectrum Density processing is focused.
- Blends between unlinked dual-mono and linked stereo operation.
- Sets the amount of level-compensated gain entering the compressor (threshold).
- Adjusts the attack time of the compressor. Fully clockwise enables auto mode.
- Tunes the release time. Fully clockwise engages individual auto release mode.
- Toggles between monitoring the program audio and the sidechain signal path.
- Modifies the knee and ratio of the compression curve at the same time.
- Crossfades the sidechain filter from low pass via completely flat (=Off) to high pass.
- Increases or decreases the tilt point frequency of the sidechain filter.
- Mixes the dry and processed signals for on-board parallel saturation/compression.
- Amplifies or attenuates the output level, implemented as linear, clean gain.
- Engages or bypasses the entire signal processing chain.
PARAMETERS
Meter
The VU meter displays either input level, gain reduction or output level in
dB. Its mode can be changed with the black screw at the bottom of the the
hous-ing. The reference point is 0 VU = -14 dBFS.
Density
The Density stage is located in front of the actual compressor. It controls
the amount of additional clipping/saturation introduced by the dual stage
ECC81 amplifier. Besides adding pleasant color-ation it also allows taming
heavy transients before entering the compressor stage.
Emphasis
The Emphasis knob controls where in the spectrum the Density processing is
applied. Turning the knob clockwise shifts saturation more towards the high
end of the spectrum, whereas counterclockwise yields more processing in the
lows. The Emphasis filter is neutral (linear) in the 12 o’clock position.
Detector
The Detector knob seamlessly blends between un-linked (U) dual-mono and linked
(L) stereo operation. It is only available on stereo tracks.
Input
This control sets the amount of gain applied to the signal after the clipper
stage, before it enters the compressor. The input gain is fully compensated,
so it essentially controls the threshold of the com-pressor.
Attack & Release
These two knobs set the time constants, which have been carefully selected to
allow for a wide range of compression behaviors, i.e. anything from
transparent and smooth to aggressive, gritty and pumping. The fully clockwise
position (red dot) will put the respective time constant into auto mode.
Monitor
Clicking this lamp allows to monitor the filtered sidechain signal instead of
the default program material. This makes it easy to dial in suitable set-tings
for Shape and Frequency by ear. In addition, the sidechain monitor can also be
used to check external keying signals routed into the U17 via the DAW.
Torque
Torque blends from gentle and transparent to straight and aggressive
operation. This function essentially controls how much the compressor “grabs”
your transients by modifying the knee and ratio of the compression curve,
diving deeply into negative ratios if desired. The default setting (20%)
corresponds to the characteristic of the original hard-ware.
Shape & Frequency
These two controls build a tilt-style sidechain filter which allows to focus
compression on the energy of specific frequency ranges. The Frequency knob
sets the tilt point, while Shape allows to crossfade from low pass via
completely flat (=Off) to a high pass filter.
Mix
This knob blends between the dry (D) and the wet (W) signals and therefore
provides instant on-board parallel saturation/compression.
Output
This control provides linear/clean gain applied to the output signal within a
range from -24 to +24 dB, which allows accurate manual level compensa-tion.
Power
Clicking on the power switch or lamp engages or bypasses the entire plugin.
External Sidechain
The sidechain of the U17 can be fed with an external key signal. Click the
keyhole icon on the right side of the upper toolbar to control the compressor
with any signal you have routed into the U17 via your DAW.
Basic Workflow
Soft clip/saturate with Density and Emphasis.
Compress with Input, Torque, Attack, Release.
Tweak sidechain with Shape and Frequency.
Finish off by adjusting Output and Mix.
System Requirements & Supported Platforms Installation, Activation, Authorization, FAQs
TOOLBARS
- This icon provides a master bypass function for the entire plugin.
- Undo/Redo offers up to 32 steps of your recent settings. Just go back and forth.
- Four individual preset banks which can also be automated in your DAW.
- Copy and paste current settings to/from clip-board or reset current settings to default.
- Click the keyhole icon to trigger compression with any signal routed in via your DAW.
- Opens GUI preferences (set interface size and quality).
- Clicking the Plugin Alliance logo will send you to the PA website via your web browser.
- This icon will guide you to the Plugin Alliance Store via your web browser.
- Brings up the activation dialog for authorizing plugin licenses for your devices.
- Here you will find the manual (requires PDF reader installed) and other useful info.
Version 1.1
References
Read User Manual Online (PDF format)
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