gbSoundlab TubeMUv2 User manual

TubeMUv2 | User's Guide
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Tube MUv2
VARIABLE-MU EMULATION COMPRESSOR
Classic compressor / Stable compressor
User's Guide

TubeMUv2 | User's Guide
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TABLE OF CONTENTS
CHAPTER 1 – INTRODUCTION
1.1 Welcome
1.2 Product Description
CHAPTER 2 – CONTROLS
2.1 “COMPRESSION/THRESH TRIM/SIDE FILTER/RATIO/STABILIZER/TYPE”
2.1b “RESPONSE CURVES”
2.1c. “GAIN REDUCTION AND SIDE CHAIN SCHEME”
2.2 “VUMETER/LIMITER/OUTPUT/GR - LEVEL”
2.3 “MIX/POWER/MAKEUP”
2.4 “QUALITY SELECTOR/RESIZE /PRESETS”
CHAPTER 3 - OPERATION GUIDE
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Chapter 1 – Introduction
1.1 Welcome
Thank you for purchasing this gbSoundlab product. We advise you to take the time to
read this manual to get the best performance from TubeMUv2.
1.2 Product description
TubeMUv2, It is a vintage compressor, with many improvements with reference to the
first version and, which emulates the RMS generated in this type of device equipped
with variable «MU» factor valves, these being designed in principle for radiofrequency.
The gain variation is achieved by polarizing the "grids of the first two triode or pentode
valves" with a negative voltage. The higher the signal amplified by the internal
sidechain circuit, the higher the control voltage, and therefore the greater the gain
reduction. The uniformity of the signal is given by its "Feedback" control circuit and for
this reason, this type of processor has the hallmark of musicality.
These compressors behave completely differently from the others, such as the Optical,
VCA, FET, and Diode Bridge, the latter also very similar to the “Variable – Mu” but with
greater distortion
Several new controls have been incorporated into this second version of TubeMU,
achieving greater flexibility in adjusting any sound source. Now we can choose
between the response of an older conventional compressor “CLASSIC” or another with
greater precision “STABLE”. We can also select the compression upwards “UPWARD”
or downwards “DOWNWARD”. The latter is the most similar to the response of
variable mu valve compressors.
With TubeMUv2, we will obtain a uniform compression, thanks to the emulation of the
sidechain and the feedback curve of the MU-variable models, generating a smooth
cohesion, to embellish any track or final master.
TubeMUv2 retains part of the architecture of the first TubeMU, but is now more
tamed and cleaner for the demands of today's production. A second compression
section has been implemented to free up the low frequencies, or simply make use of it
creatively, depending on how STABILIZER is set. In addition, a quality control based on
the number of samples per period has been implemented.
TubeMUv2, is for sure the most malleable compressor in your tool drawer. And don't
worry if you don't know if it will be optimal for this style or that. TubeMUv2 is an all-
rounder.

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Chapter 2 – Controls
2.1 – COMPRESSION / THRESH TRIM / SIDE FILTER / RATIO / STABILIZER / TYPE
COMPRESSION: It acts by amplifying and, at the same time, compressing the input
signal.
THRESH TRIM: It is key in the “COMPRESSION” adjustment. With it we will adjust the
sensitivity of the sidechain signal detector. It has a range from 0 to -24dB.
STABILIZER: Adjusts the crossover frequency of the parallel process for low
frequencies. It is dedicated to the “STABLE” selection only.
SIDE FILTER: Select the working frequency of the sidechain. The adjustment is
intuitive, depending on the amount of low frequencies that we want to compress, or
exclude from the process. It is active, in both “CLASSIC” and “STABLE” modes.
TYPE: It allows us to adjust the compression up “UPWARD” and the compression down
“DOWNWARD”. The latter is very linear, with a very smooth and progressive curve.
UPWARD, is more oscillating.
RATIO: Compression ratio, with a range of 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1,
30: 1.
ATT: Attack adjustment from 0 to 100ms.
REL: Release adjustment from 25 to 100ms.

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2.1b – RESPONSE CURVES
Downward compression
Upward compression

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2.1c – GAIN REDUCTION AND SIDE CHAIN SCHEME
We can observe in the diagram, the differences between the adjustment of
"CONPRESSION (1)
” and “THRESH TRIM (2)”. The input control itself generates the compression, by
having topology (Feedback). In this way, it collects the output signal and re-injects it to
the side channel, which provides enough negative voltage to bias the grids of the first
MU-variable tubes.
THRESH TRIM adjusts the amount of negative tension, giving a balance between the
incoming signal and the side channel control tension. Thus, with very little input signal,
we can generate a high compression, or on the contrary, adjust so that with a high
input signal, we can reduce the compression level.
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2.2 – VUMETER / LIMITER / OUTPUT / GR - LEVEL
VU: With “LEVEL” signal measurement and “GR” gain reduction options. The “green (-
10dB)” mark gives us the most stable and intense point. We can also compress almost
to mute, for parallel compressions with great sustain.
LIMIT: Toggles between two options. The first consists, in circuitry (VCA), soft. The
second (SOFT CLIP), as a barrier for percussion, buses and complete mixes. It really
always depends on the type of sound material and, of course, the production approach
that we want. Either type can work fine. If we don't need a gimmicky sound, any soft
limiting is more than enough.
Below the switch we have a lamp, which indicates, long before the area (Clip) in white,
the beginning of the soft limiting process. The red color indicates that we are forcing
its entry.
OUTPUT: Its implementation is arranged "POST LIMITER" to be able to reduce or
increase some dB.

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2.3 – MIX / POWER / MAKEUP
MIX: It executes a balance between the dry and wet signal (DRY - WET),
achieving a comfortable parallel compression adjustment.
MAKEUP: Recovers signal losses caused by compression. It is positioned at the
entrance of the final limiter, thus favoring the pressure adjustment at its entrance.
POWER: Starting up and shutting down TubeMUv2.

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2.4 – QUALITY SELECTOR / RESIZE / PRESETS /
QUALITY SELECTOR: It gives us the option to select between four different types of
processes related to the number of samples that we will host in each clock period. The
lower the number of samples, the higher the CPU consumption and therefore the
better the resulting quality.
Standard, locates 128 samples per period.
Good, locates 16 samples per period.
Best, locates 8 samples per period.
Excellent, locates 4 samples per period.
RESIZE: It gives us the possibility to adapt the size of TubeMUv2 to any screen. We can
adjust in steps from “50, 75, 100, 125, 150, 175, 200%
gives us the possibility to adapt the size to any screen.
We can adjust in steps from (75, 90, 100, 110, 125, 150).
This is the way to access the TubeMUv2 manual.
PRESETS:
It gives us a factory guide and the possibility to save any user settings.
st = STABLE
stm = STABLE MASTERING
cl = CLASSIC

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Chapter 3 - Operation Guide
Way of working with TubeMUv2
The pre-settings are a good start to understand its operation in a few minutes. The
parts are defined and very intuitive.
However, one way to understand its processes is to start like this:
VU / GR – LEVEL: Select the switch, in “GR”.
COMPRESSION: Act clockwise to amplify the signal and compress it.
RATIO: Adjust from 2:1 to 5:1 for moderate compression.
Adjust from 5:1 to 30:1 for gimmicky and parallel compression.
TYPE: Selecting “DOWNWARD” we will obtain a smooth and very linear
compression, like the old Mu-variable compressors.
Selecting “UPWARD” we will achieve greater oscillation in the
audio signal.
CLASSIC / STABLE: The response of “CLASSIC” is more pumping, but we can help
ourselves with “SIDE FILTER” to reduce the range of bass that we
want to exclude in the response of the side chain.
On the contrary, “STABLE” implements an architecture for
processing low frequencies and, thus, delivering a response
devoid of oscillations.
ATT / REL: We can adjust the attack and release of the compressor.
QUALITY: Try the most suitable for your work. For example, with the
selector in “Good” mode, you will notice greater precision in the
hits and attacks.
MAKEUP: Reclaim gain with this control, and also inject signal by adding
pressure to the final limiter.
OUTPUT: Compressor general output setting. We will reduce or amplify
the signal depending on the compressor settings.
Happy Work !
© Copyright 2021 Germán Bou / gbSoundlab - All Rights Reserved