Genz-Benz 12.2 Manuale Utente

PREAMP VOLUME CONTROL – This control sets the volume of the preamp after the input and FET channel gain 

stages and before the EQ controls.  Use this control in conjunction with the GAIN control and the MASTER VOLUME 

control for your overall output level.

GAIN SWITCH (LOW/HIGH) – This switch sets the gain sensitivity for the TUBE channel.  It works both like an Active/

Passive switch and like a gain boost switch.  The amber LED indicates that the HIGH setting is selected.  The difference 

between the LOW and HIGH gain positions is approx. 10dB.  Since there is a GAIN switch provided for each channel this 

allows the player to set different gain structures for the FET or TUBE channels.  

If warm, clean tube tone is desired, we recommend that the LOW setting be used for basses with hotter output or active 

pickups (generally most basses using one or two 9 volt batteries to power their on-board preamp or those with an output 

sensitivity over 1 Volt) and the HIGH gain setting be used for basses with lower output or passive pickups.

If tube compression, growl, or all-out distortion is desired then the HIGH gain setting may be used regardless of the 

pickup sensitivity.  The “hotter” the pickup output, the more tube distortion can be achieved.

PREAMP GAIN CONTROL – This control sets the input sensitivity gain of the 12AX7 tube preamp after the GAIN switch.  

The design of the TUBE GAIN control allows you to set your tone from rich, clean tube tone, to mild tube compression, to 

warm tube growl, to all-out aggressive tube overdrive.  The volume of the signal is then controlled by the TUBE preamp 

VOLUME control and also the MASTER VOLUME control.  The higher the GAIN settings are, the lower the channel 

VOLUME will need to be set, so as not to overload the EQ network.

Note: It is generally recommended when using heavily distorted tones with a tweeter loaded cabinet, that you reduce the 

high frequency settings on the amp or cut the tweeter level control of our cabinet.

O/L LED – In the TUBE channel, this LED senses the condition of the input signal after the GAIN control and also 

senses and warns of possible clipping in the EQ network.  The O/L circuit does not sense distortion or overdrive in the 

tube.  Your ears are the best judge of that for your desired tone.  The O/L sensing circuit is very dependent upon the 

output of the bass instrument pickups, the GAIN and VOLUME settings of the TUBE channel and the amount of EQ used 

i.e. the more radical the EQ boost and volume level of the preamp VOLUME control, the more possibility of an overload 

condition.  If overloading of the TUBE channel is occurring, adjusting the preamp VOLUME and/or preamp GAIN controls 

down will reduce or eliminate the over-load condition and adjusting the MASTER VOLUME control up will return the 

overall loudness. 

NOTE:   It is OK for this LED to flash occasionally with your hardest notes played and it may flash even if the FET 

channel has been selected for use.  This is normal and is due to the mixing topology for the 2 channels.

PREAMP VOLUME CONTROL – This control sets the volume of the preamp after the input and TUBE channel gain 

stages and before the EQ controls.  Use this control in conjunction with the PREAMP GAIN control and the MASTER 

VOLUME control for your overall output level.

ACTIVE EQUALIZATION (both channels) – The SHUTTLE

®

MAX 12.2 contains two active 4 band equalizers (one for 

the FET and one for the TUBE channel) each with 2 sweepable parametric midrange frequency networks (LOW MID and 

HIGH-MID) that offer 15dB of cut or boost with a bandwidth of approximately 1 octave wide.  These are slightly over-

lapping filters to provide ultimate flexibility.  Parametric filters are typically (but not always) used to reduce or remove 

offending frequencies in the instrument’s pickup response, or to boost response to achieve a particular voicing.  Spend 

some time experimenting so that the process becomes creative as well as corrective.

LOW FREQUENCY CONTROL – The LOW frequency EQ section is an 80 Hz shelving curve with 15dB of cut or boost.

LOW-MID FREQUENCY FILTER -- The center frequency of the LOW-MID filter is continuously user adjustable from 120 

Hz to 2 KHz with a single control.  The LOW-MID GAIN control sets the amount of level (cut or boost) for the specific 

frequency set by the LOW-MID FREQUENCY control.  

HIGH-MID FREQUENCY FILTER -- The HIGH-MID frequency is continuously user adjustable from 300 Hz to 5 KHz with 

a single control.  The HIGH-MID GAIN control sets the amount of level (cut or boost) for the specific frequency set by the 

HIGH-MID FREQUENCY control.

HIGH FREQUENCY -- The HIGH frequency EQ section is a 4 KHz shelving curve with 15dB of cut or boost.

NOTE: These equalizer networks are similar to those found on professional sound consoles and are very useful tools.  

These active equalizers are very wide response type filters and a little “tweaking” goes a long way.

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