. Various Neve BA716-BA717 EQ free download

File name Neve_BA716-BA717_EQ.pdf

BA716/717 INFORMATION GENERAL - (SEE FIGURE l) BA716 and 717 are fixed together to form a sandwich assembly mounted near the centre of the channel or rev modules. A single l6 way flying flatcable connector connects BA716 to a header on BA7^0. BA716/717 form a four band fully variable (parametric) equaliser which may be switched into the Channel or Mixdovn signal paths. The high frequency and low frequency bands may be switched from a peaking to a shelving characteristic When used in a Rev module the EQ may be switched into the Rev Send path (or Delay Insertion path if "INS" button on BA752 is pressed) or the Rev Return path. USER CONTROLS Frequency controls : one per band, marked 30Hz - 300Hz ; 200Hz - 2kHz ; 0.8kHz -8kHz ; 1.5kHz - 15kHz. Set band centre frequencies. Boost/Cut controls : one per band, marked LOW, MID 1, MID 2, HIGH. Set band boost or cut over range +l8dB. button : When out, low band response is bell shaped. When in, lowband response is shelving. button : When out, high band response is bell shaped. When in, high band response is shelving. "CH" button : When out, EQ is available in the Mixdown path. When in, EQ is available in the channel path. "IN" button : When out, EQ is bypassed. When in, EQ is inserted in the signal path. NOTE ; As with all parametric equalisers, a certain amount of overlap of frequency ranges is provided. Careless use can thus result in ridiculously high gains at certain frequencies which may cause oscillation. DETAIL See ET10209 (circuit diagram), EB2036U (channel module block diagram), and figure 1. The BA716/717 parametric equaliser may be considered to consist of five separate sections, each of which is physically split between the two printed circuit boards: a) In/Out switching and LED indicator switching b) Low band EQ section c) Mid 1 band EQ section d) Mid 2 band EQ section e) High band EQ section All the EQ sections are connected in series. INPUT/OUTPUT AND LED SWITCHING Switch SI ("CH") on BA717 and S2 ("IN") on BA716 enable the equaliser to be switched into either the Channel or the Mixdown signal paths, and to be either in circuit or bypassed. One pole of each switch is used to switch LEDS mounted remotely on BA7^o. IC1 on BA716 is a non-inverting buffer amplifier. LOW BAND EQ SECTION BA717 : IC1 amplifiers a, b, and c, form a Two-Integrator loop filter whose frequency is tuned' by RV1 (30Hz - 300Hz). The filter has a fixed "Q" of 1 and its input is provided by IC2a on BA7l6. Two outputs are taken from the filter to a summing amplifier ICld, one filter output and ICld output then going to the shelving switch (SI on BA716). BA716 : IC2b is used as an inverting summing amplifier to combine the filter output, selected by SI with the input signal from IC1 buffer. RV1