Yorkville SMAP3000 free download

File name Yorkville-SMAP3000 pwramp.pdf

3000 HIGH EFFICIENCY STEREO POWER AMPLIFIER WORLD HEADQUARTERS CANADA Yorkville Sound 550 Granite Court Pickering, Ontario L1W-3Y8 CANADA Voice: (905) 837-8481 Fax: (905) 837-8746 U.S.A. Yorkville Sound Inc. 4625 Witmer Industrial Estate Niagara Falls, New York 14305 USA Voice: (716) 297-2920 Fax: (716) 297-3689 SERVICE MANUAL Quality and Innovation Since 1963 Printed in Canada VERSION 1.50 October 1998 IMPORTANT SAFETY INSTRUCTIONS AUDIOPRO AP-3000 SERVICE MANUAL M1012 "THE INPUT BOARD" The input board processes the audio signal from the input jacks to the voltage amplifier board, (M1011). INSTRUCTIONS PERTAINING TO A RISK OF FIRE, ELECTRIC SHOCK, OR INJURY TO PERSONS. INSTRUCTIONS RELATIVES AU RISQUE DE FEU, CHOC ЙLECTRIQUE, OU BLESSURES AUX PERSONNES. Each channel consists of a balanced gain stage, defeatable bass boost filter, and a preemphasis filter network. The balanced input, (XLR Jack) and unbalanced input (phone jack) are wired in parallel to the input of a balanced operational amplifier, (U1). The gain of this stage is 1.6 (4dB) balanced and 1.6 (4dB) unbalanced. Resistors R1, R5 along with capacitors C1 and C2 form a radio interference elimination filter. Switch S1 selects a flat or bass boosted frequency response. The bass boost filter provides a 20Hz high pass, high Q filter response with a +4dB peak at 55Hz. The filter consists of a tee network on the input of U1A along with R9, R10, R11, C5 and C6. The gain is 1 (0dB) in the passband, (above 100Hz). Operational amplifier U3B is a high pass shelving filter with a +2dB shelf above 20KHz. This filter provides the preemphasis required to obtain a flat frequency response (to 20KHz) on the power amplifier output at full power. M1011 "VOLTAGE AMPLIFIERS AND SYSTEM CONTROL" This board contains: · Voltage amplifiers to drive the current amplifiers on the M1002 boards. · The front panel volume control circuitry. · The EMS control system with its associated circuits: Pre clipping and line current sensing heater circuits. · Clip and activity LED's. Driver circuitry for the amplifier disable relay (used during amplifier turn on, turn off, thermal shutdown and current limiting). Circuit Explanation: Refer to the schematic of M1011 as the sections of the circuit are explained. The audio signal enters the board from M1012 through connector MS4. The two channels are marked "L" and "R" for left and right. The signals are to be considered as differential sources and therefore are marked as L+, L-,R+ and R-. Since the left channel has the same topology as the right channel we will only look at the left channel. The signal ("L+") at the terminal block (MS4) passes through the front panel level control (P1) and the desired level enters the inverting input of U1. Op amp U1 is an inverting amplifier with a set gain of 2.40 (7.6dB). Built around U1 is a dual purpose circuit controlled by a voltage divider consisting of R15, R16, R17, R18, R19, R20 and R21. The voltage divider sets two reference le