Elliptic Equalizer for Mastering with 12dB/Octave Slopes
Mastering Insert Switcher, Passive, Fully-Balanced, Two Insert with Flip
Precision MS Mid Side Matrix
Phono Transfer System
Stereo Width Controller Board
Dual Class-A II Line Driver and Headphone Amplifier Board
Buy JRC and THAT Corporation Audio ICs
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"MTC-IFGO" is Offered as A Bare Circuit Board, PC Board with ICs, or Assembled and Tested Shown Above.
The KA Electronics
Input-Gain-Filter-Output, "MTC-IGFO," is a
Mastering Transfer Console front-end with Swiss Army Knife flexibility.
What does the MTC-IGFO do?
The MTC-IGFO has a fully-balanced line receiver, individual Left/Right or
Stereo Mute, a -5.5 to +5.5 dB gain stage designed for 23 step switches, +5dB
gain boost, four relay-selected high or low pass filter stages (12dB/octave) and
balanced output for driving an insert chain.
Multiple IGFO boards can be
cascaded to add additional filters. The MTC-IGFO coupled with an
insert switcher create a high-quality transfer console at low cost.
Relay filter selection eliminates costly multi-pole switches.
Second-order filters require two switch poles per channel. A stereo transfer
console with stepped switches requires two 4 pole switches to control both the
high and low pass filters. A tape-to-vinyl transfer console, often requiring
identical modulation plus preview channels, requires 8 pole switches. The cost
of tuning a single pair of low and high pass filters by varying its component
values is high.
The MTC-IGFO uses a different approach with active filter
stages for each filter frequency. Costly rotary switches are replaced by
multiple active filter stages with their outputs switched by low-cost
double pole relays. A unique insert chain places only the selected filters in
the signal path. With the MTC-IGFO, a single pole rotary switch can tune several
Filters customized for your unique workflow.
MTC-IGFO board has four stereo filters which, according to assembly and jumper
placement, can be all high-pass, all low-pass or two high-pass and two low-pass.
On-board jumpers allow the second two filters to be fed from the input or the
output of the first two filters for band-pass combinations of high and low-pass.
Multiple MTC-IGFO boards can be cascaded to expand the number of filters
available. Two boards provide eight filter frequencies in various combinations
of high and low-pass such as 4HP/4LP, 2HP/6LP, 6HP/2LP or 8 of all one type.
Multiple boards may be cascaded actively in single-ended or fully-balanced
configurations or passively to avoid additional circuitry.
example high-pass filter frequencies are 20, 30, 40 and 50 Hz. Common low-pass
frequencies are 12, 14, 16, 18, 22 and 27 kHz. (Second-order 12 dB/octave
Q=0.707) The filters are unity-gain Sallen-Key topology with custom frequency or
Q set by the builder. Configuration of the filters to either low or high-pass
response are done by component placement during assembly. Example filter
configurations and component values are provided in the documentation.
Example 20/30 Hz high-pass and 22/27 kHz low-pass filter using a single
20/30/40/50 Hz high-pass and 12/14/16/18 kHz filter for
tape-to-vinyl transfer using two MTC-IGFO boards.
Balanced outputs drive the Insert Chain.
has fully-balanced THAT1646 OutSmarts
line drivers to feed the insert chain. When feeding cascaded boards the THAT1646
may be bypassed to provide unbalanced active or hard-wire connections to the
preceeding board's filters.
The MTC-IGFO has numerous jumpers to provide
Swiss Army Knife features.
One set of jumpers bypasses the active inputs
and outputs to passively cascade boards. A second set of jumpers allows the last
two filters to receive thier inputs from the first two rather than the input to
allow combinations of high and low pass.
An optional on-board relay
voltage regulator is available for unregulated or higher voltage supplies. Five
current-limited outputs are available for LED switch illumination of Filter On ,
+5dB gain, and Left/Right/Stereo Mute.
The KA-Electronics MTC-IGFO is sold as a bare PC board, a "kit" including
semiconductors, or an assembled and fully-tested module.
A Mouser Electronics Project Manager
is available for DIY builds of the MTC-IGFO.
Other items from KA-Electronics RockmoreLabs:
Bare PC Board
Bare PC Board Including ICs
(2 THAT1246, 2 1646, 2 OPA2134, 4 NJM2114.)
Assembled and Tested EEQ-12 Board
Buy it on