?? how does the ibp work ??
The IBP phase shift circuitry works by running through two passive symmetrical all pass filters. It works entirely in the analog domain. All pass filters are like high pass or lo pass filters as in your EQ or speaker crossover network, but only the phase is affected not amplitude. The IBP has relatively flat amplitude response well past 96kHz. In most but not all cases at least two all pass filters are needed to recreate what is necessary to correct a phase problem or emulate phase shift in nature. One filter is used for the bottom of the frequency spectrum. The other is used in series for the top, creating a somewhat linear phase vs. frequency response. This is because you need to create a phase curve that is approximately twice the phase shift when you double the frequency. So for 45 degrees of phase shift at 40 Hz you need approximately 90 degrees of Phase shift at 80 Hz for it to sound natural. I say approximately because every situation is different with sound bouncing around, EQ added (with corresponding phase shift), phase response of speakers, microphones etc. Phase curves in nature have many variables that determine the amount of phase shift vs. frequency.
The switch Phase adjust 90 degrees /180 degrees selects between one or two series all pass filters in circuit. Phase center lo/hi selects between a higher bandwidth phase adjust utilizing one all pass filter for lo and the second for hi frequencies or a lower bandwidth phase adjust which uses both all pass filters for the lo frequencies. The IBPs electronics are for buffering and gain make up only. The IBP is entirely balanced and symmetrical from input to output. The output transformer in the ibp allows you to plug freely into balanced or unbalanced circuitry without any interface problems and also allows you to lift the ground.
The DI section puts a very high impedance input circuit specifically designed for instrument pickups ahead of the phase adjust circuitry. This hi impedance presents no load on your pickups allowing you to hear the full tonality of your instrument. The gain of the DI section can be varied from 12 to 26 dB of gain. The buffered out put is tapped after the instrument input circuit, before the phase adjust circuit, and can be used independently, even when the IBP is used in line level mode.
The re-amp output will bring the +4dB db output to guitar level (about -14dB)and is tapped after the phase adjust circuitry and after the transformer. It is the same output as the line output but at a lower level and higher impedance. The re-amp output and line out share the same transformer, they are not intended to be used at the same time. The earth lift switch on the front panel lifts the ground of the line out xlr pin 1 and the sleeve of the re-amp output jack. If you are installing the ibp in a rack and will be extending the reamp output jack to a remote location use a stereo jack and plug with 3 conductor wiring. This will allow the earth lift switch to function correctly whether using the re-amp or line output.
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