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TP-2
Streaming Video introduction to the
TP-2
All-in-one, dual
channel, Tube Pre with Optical Compression and multi-format Digital Output is designed to provide sound
enhancement for any recording application. Similarly, the new Dual Tube
Preamp Board with Optical Compression (TPB-2) offers the same
functionality in a user-installable option to enhance Korg's D32XD and
D16XD recorders. Both incorporate a specially tuned version of Korg's
Valve Force vacuum tube circuitry (made popular in the Triton Extreme and
Electribe SX/MX) to add analog tube warmth and richness, as well as
optical compressors that offer a quick response.
Valve Force Tube Circuitry
Uses a special
version of the widely acclaimed Valve Force circuit used in the ElecTribe
“X” series and the TRITON Extreme.
The most popular and
versatile tube in use, for a reliable and predictable sound; round and
full with that classic tube presence.
Optical Compression and Limiting
Fast or slow
response/release time; Variable threshold/sensitivity knob
Optical compression
provides
fast response without adversely coloring the sound. Excellent dynamic
control remains entirely in the analog domain, to deliver a warm, rich and
robust tone.
Two Channel Operation
Two independent
channels can function as two separate units. Link function ties them
together for processing stereo sources
Extensive Gain Control
48 dB of Gain
Trim; 26 dB Pad; plus Hi-Z Switch
Accommodates a wide
range of source levels – from a direct guitar output to a high end mic –
ensuring the tubes & compressor always work at optimum level
Low Cut Filter
6 dB
per octave below 70 Hz
Switch-able filter
prevents low frequency signals from muddying up the mix and/or overworking
the compressor.
Multi-Format Balanced Inputs
also accepts
unbalanced inputs
Balanced ¼” TRS and
XLR Inputs with switch-able +48 Volt phantom power and phase-invert switch
Balanced Analog Outputs
Balanced ¼” TRS and
XLR Outputs
44.1 kHz; 48 kHz; or 96
kHz sample rate outputs
S/P DIF Format.
Provides a direct connection to other digital gear; or use as a stand
alone A to D converter
Sleek, Smart Styling
Convenient table-top
design delivers pro-results in any set-up, without hogging desk space
Dual Output Level Faders
Provides just the
right level signal to make your other studio gear sound its best
Sexy, Analog, Backlit VU Meters
What more can we say?
Preamp basics
Before the signal from a
microphone or instrument is introduced to a mixer or recording device (PRE),
this device raises the level (AMP lifies) of this signal.
Gain
The foundation of
accurate sound reproduction and recording is understanding gain. Anything
you can do to increase the level of the signal before it is processed and
recorded will improve the sound quality. The idea is to get as much
difference in gain as possible between the ambient noise floor and the
signal, without squashing it at the top when you run out of headroom. By
increasing the gain, you are also increasing the sensitivity of the
microphone (or instrument pick-up), allowing it to capture more of the
delicate and subtle shadings that contribute to the unique sound of the
recorded source.
Equalization (EQ) will
have a more pronounced effect on a signal with proper gain – because there
is simply more audio information to work with. Effects will also be
enhanced when working with a signal having a proper gain structure.
Dynamics will be improved, allowing you to create a final mix that has
more depth and clarity.
Despite what you’ve
heard, nothing can be done downstream to compensate for a low-gain signal.
Normalizing tools will only affect the portion of the original signal that
was accurately captured. It will add more level, but it will not enhance
the signal. The evil step-sister of Gain is Noise. Simply turning up the
volume may ultimately raise the noise floor as well.
Vacuum Tubes
The TP-2 uses a pair of
12AX7 tubes in a modified version of the Korg Valve Force circuit. Tubes
are electronic, but they are also mechanical devices. Due to their design,
tubes create a compression of the audio signal naturally and, like other
mechanical devices – a piano, for example – they behave along the lines of
some natural laws. When you drive a tube hard, and get it near (or at) the
clipping point, the resulting distortion occurs along the natural overtone
series, producing a musically relevant type of distortion. Plus, a tube
outputs a smooth and continuously changing signal, unlike a digital
signal. By achieving this combination of added gain, compression and
tonality in the analog domain, the sound that is finally captured by your
digital recorder will be better sounding and closer to the original
signal.
Application
In general terms, the
benefits of using a preamp will be more readily apparent when working with
critical acoustic sources – lead vocals, acoustic guitar, flute, hand
percussion, etc… While a mic pre (microphone preamp) can enhance any
source, it is not likely that you will use it on every mic used for every
track of your recording. However, the increased response of the tracks
recorded using a mic pre will allow those tracks to really shine and stand
out in a mix.
Compression
Compression is a form of
automatic gain control.
What it does:
It prevents loud signals from “clipping”, by reducing their level before
any clipping occurs.
What it does not
do:
It does not raise the level of soft signals. Some compressors have a
circuit parameter called “makeup gain” which returns the level to normal
(by raising it back up) after the compressor lowers the level, rather than
depending on the compressor’s “release” characteristics to return the
signal to its original level.
What it sounds
like it is doing:
Because the level of loud passages is reduced, it sounds as if the softer
signals are getting louder.
The compressor allows
you to keep as much of that increased gain as possible at all times,
without overdriving the input of any device to the “clipping” point. This
combination allows the microphone to operate efficiently, capturing sound
clearly at a variety of levels, while preventing any sudden spikes or
level peaks from clipping, and ruining an otherwise perfect recording.
This arrangement also keeps the signal to noise ratio optimized, so less
noise is introduced into the final recording.
Optical Compression
To make these gain
adjustments at lightning speed – eliminating compressor “breathing” and
“pumping” - and to prevent the compressor circuit from coloring the
sound, the TP-2 uses a photocoupler in concert with the vacuum tubes in an
Optical Compression circuit. By not relying on any additional hardware,
Optical Compression is able to respond faster and more smoothly to abrupt
level changes, and provides fairly transparent processing. Another
important characteristic of optical compression versus other methods is
the release stage. An optical compressor has a fairly fast release up to
approx. one-half of it’s level, and then it slopes off more gently. This
two-stage release characteristic is what makes them sound so smooth, and
is a much-called-for sound for vocals and acoustic instruments.
It is still possible to
“drive” the tubes a little hotter by raising the Gain Trim control, and
then increasing the compressor sensitivity to provide more gain reduction.
This provides the typical “saturated tube” sound, purposefully adding more
second and third order harmonics to the original signal.
Digital Conversion
After you have enriched
your sound with all the audio benefits of the tube preamp and optical
compression, you can use the TP-2’s internal ADC to provide a high-quality
digital audio output to the rest of your recording or reproduction system.
The TP-2 features a bit depth of 24, and the sample rate of the S/P DIF
output can be set to 44.1 kHz, 48 kHz, or 96 kHz and is available in both
Optical and Co-Axial formats. Analog outputs are also provided.
TPB-2 (for use in the
D16XD and D32XD)
The TPB-2 provides the
exact same tube preamp and optical compression feature set that makes the
TP-2 ideal for so many applications. Unlike the self contained TP-2, the
TPB-2 is a user installable option for the Korg D16XD and D32XD. Both are
two channel units, and the controls can be linked for stereo operation.
Both are equipped with ¼” and XLR inputs, an input trim knob, 26dB pad,
phase reverse, phantom power, a low-cut filter, Hi-Z switch for
guitar-level sources, fast/slow release time switch, gain reduction LEDs,
compression sensitivity knobs, and two sexy blue analog meters.
Owners Manual (pdf)
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