Blue 315 MKII
Isomorphic Mastering Equaliser
The extreme left side of the panel houses switches for Eq In/Out and Power, apart from these the
two channels, mounted one above the other, are identical as are their controls. Starting from the
right hand side of the module:
Input Level sensitivity is controlled by three sets of rotary controls, first a rotary switch for the
course sensitivity with 5dB steps, secondly another rotary switch for the fine sensitivity in _dB
steps and finally a continuously variable control with ±1dB range which is only in circuit when the
Vari push switch has been pressed and is illuminated.
Filters
There are two rotary switches for the High and Low pass filters, with a fixed slope rate and
switched selection of turnover frequency.
EQ
The first section of the Eq is for the low frequency section. This is a shelving variety with
switched rotary controls for frequency , boost , cut , Q ( bandwidth ) along with a frequency range
push button switch .
This stage can also be switched from shelving to a fully parametric bell stage .
The next two section, HMF and LMF are identical except for their frequency ranges. All the
controls on these fully parametric stages are multiposition rotary switches. The boost and cut
controls have the same sensitivity as the LF section , with frequency and bandwidth rotary
switches for each stage.
The last section of the Eq is a high frequency mirror of the first i.e., another shelving/bell stage with
rotary switches for boost , cut ,
Q ( bandwidth ) and a frequency range push button switch .
The link switch , when engaged , allows both corresponding upper and lower EQ push button
functions to be switched in and out simultaneously E.g., engaging the low-mid parametric stage high
range switch on the upper channel will cause the corresponding lower channel low-mid parametric
stage high range switch to be engaged . Pressing either switch again will cause both to be switched
off .
Phase , Overload & Master In
Below the filter switches there is a Phase Reverse switch and an Overload indicator, which will
light whenever the signal level reaches or e20dB, which is 6dB prior to the onset of
clipping.
The left hand end of the panel houses two further large push switches, the uppermost of these is
the Power switch, which is lit when the unit is active.
The lower large push switch is the Eq In/Out switch . This has two modes of operation, the switch
will latch, electronically, when pushed putting the Eq in-circuit and light the LED, a further push
will unlatch and take the EQ out and the module back to bypass (this is a relay bypass). An