Active/Passive Retro-Fit for P-Style Basses
• VOLUME TONE STACK
Works purely passively at all times and is designed to function exactly as the standard Volume and Passive Tone in a
P Style Bass. This is in order that the wonderful stock sounds are always available, with no compromise.
• VOLUME IN PASSIVE (Upper Knob Pushed Down)
When the upper knob is in its down position, the system is bypassed via a high quality relay with gold plated contacts.
In this case, the jack is fed directly from the output of the Volume, exactly as a standard P Style Bass.
• VOLUME IN ACTIVE (Upper Knob Pulled Up)
When the upper knob is in its up position, the active circuit is in activated and the output of the volume feeds the input
to a class A FET input stage. The audio is passed through the active stage and its output feeds the jack with a low
impedance signal.
• PASSIVE TONE (Lower Knob in both Active & Passive Modes)
Acts directly on the pickup at all times, exactly as in a standard P Style Bass, playing a totally familiar role.
The Passive Tone is also extremely useful in the active mode, further allowing the treble content of any active boost to
be suitably backed off or subtly tailored. The Tone Capacitor plugs in, easily allowing different values.
• ACTIVE STACK
• DUAL BOOST KNOB (Upper Knob Pushed Down)
In its centre click, there is additional gain of 2.5dBs with an essentially flat frequency response. (Additionally there is an
option for a slightly brighter sound by setting an internal switch to on, described in the installation set-up.)
Turning it CW gives a mid boost ranging from 0 – 15dBs at frequencies according to the setting of Frequency knob.
Turning it ACW gives a combined boost to the bass and treble spectrum. The lowest level point is set by the Frequency
Knob, but the amount of bass and treble boost varies according to the setting of the Frequency knob. (Not easily de-
scribed in specification terms)
• DUAL BOOST KNOB - DEEP (Upper Knob Pulled Up)
Pulling up the Boost Knob activates a Deep setting. There are four frequency settings for the Deep Boost, set via
switches on the circuit board - 40Hz, 60Hz, 80Hz & 100Hz. The Deep Boost level is also adjustable via a preset trimmer.
NOTE Important:
The Deep switches and level preset are placed on the circuit board such that, if six of the pickguard screws are re-
moved, the pickguard can be eased up in order to gain access for adjustment while the bass is fully playable.
• LOWER FREQUENCY KNOB (250Hz - 2kHz)
The lower outer knob has 41 click positions to set the frequency of operation for the upper knob. Turn ACW for the lower
frequencies and CW for the highest frequencies.
• CHARGING YOUR P-RETRO
• PLUGGING IN THE CHARGER
The P-Retro’s internal battery is charged via its jack socket, and it is important to follow this procedure when plugging
it in. The Battery Pack will normally have some charge when new, but a full charge is recommended after installation.
NOTE - Important:
If the charger is the Universal type, make sure the correct adaptor is inserted in order that it matches your AC Mains
outlet socket. But don’t plug it in to the mains until completion of the following few steps:
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