PRIMARE A32 Power Amplifier Service Manual

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1 PRIMRE Power mplifier Service Manual

2 . Technical Description.. Error codes.. Bias djustment.. Schematics.. Technical Specifications. onfidential! This document is not allowed to show for third part without written permission from Primare Systems B. This document is subject to change without notice. uthor: Bjorn Holmqvist Primare Systems B bjorn@primare.net

3 Functional Description Features The Primare power amplifier is a fully balanced design, this means that the negative speaker terminals are active, not ground as on an unbalanced design. When performing measurements, test equipment (such as udio Precision) that can handle balanced amplifiers must be used. The input impedance is K and the gain is db. It is possible to obtain just above 0 undistorted watts at an R load (both channels driven). The frequency response are flat, the will drop down only -db at 00Khz. Standby The is equipped with two standby modes, where standby mode is the power save mode. In power save mode only the standby circuit will be powered by the small standby transformer placed on the digital PB. Digital control and monitoring When power is first applied and the standby button on the front panel are pressed down the are going to initiate the startup sequence. Relay K will be turned on where after a small delay will follow before relay K goes active to disable the inrush limiters. t the same time bias are turned on by shutting down the voltage supplied to the optocouplers on the amplifier channels. fter a 0 second startup delay for the amplifier to settle down the speaker relays are turned ON. During the startup sequence all safety parameters such as D-offset and fuses will be monitored, if an error is spotted the amplifier will refuse to start and the standby LED will flash rapidly to indicate that an error has occurred. The error code can be read out by pressing the error check switch (SW). Description of the error codes can be found on the next page. If the standby switch is pressed when the amplifier is in operate mode it will go to standby mode, which means that bias and speaker relay will be switched off. The standby LED is going to half light intensity to indicate that the amplifier is in this standby mode. If the standby button are pressed down for more than one second the amplifier are shutting down into standby mode which means that bias, speaker relay and the two power relays K, K are switched off. Only the standby circuit is still powered consuming just a few watt of energy. Temperature protection When temperature has reached 0 centigrade at the temperature sensors the speaker relay and bias are going to be switched off, when the temperature have decreased 0 centigrade the are going to be restarted. In practice this will mean that the warmest part of the heatsink will be around -0 centigrade when over- temperature protection cuts in.

4 General Protection During operation mode D-offset, fuse, temperature and -loss are constantly monitored, any abnormal function from these will immediately disengage the speaker relay and the standby LED will start to flash rapidly indicating that an error has been spotted. The error code can be checked by pressing the error check button (SW), if more than one error at the same time a repeated press of the button will display the next error. D-offset and over temperature will automatically resume to normal operation after a delay if the error recovers. Fuse error will not (latch), here the amplifier must be turned off and the fuses replaced before normal operation is possible. Trigger. If a.mm teleplug are connected to the left trigger input (the right connector is the output) the function of the standby button are being changed to only be able to turn the amplifier into standby mode directly. The standby button cannot turn the amplifier on while the trigger is connected (trigger mode enable). The circuit will trigger at.v and are highly immune against disturbances. The trigger are only able to control the amplifier between operate and standby mode. RS The RS port can be used for firmware upgrading as well as controlling by restron compatible RS codes. Fuses Due to the large capacitance of the electrolytics bank, turn off the mainspower and wait minimum minutes before replacing a blown fuse. Make sure to replace a blown fuse with exactly the same type and value. Error codes LED Nr Error ll OK 0 0 D L+ 0 0 D L- 0 D R+ 0 0 D R- 0 Fuse Rch 0 Fuse Lch Overheated

Bias djustment ritical for the adjustment are that the mainsvoltage is 0V or 0V exactly. The temperature in the facility must be constant during the adjustment procedure.

5 Bias djustment ritical for the adjustment are that the mainsvoltage is 0V or 0V exactly. The temperature in the facility must be constant during the adjustment procedure. Use the Bias test points and potentiometers (R, R) to adjust bias on each channel. The lower potentiometer is accessible thru a hole in the bottom of the amplifier. Bias test points ompare the voltage drop over all of the emitter resistors.

6 These steps describe the Bias adjustment procedure, which is the same for both L& R channels.. Switch the amplifier on or if it has been on burn-in (test), disconnect input signal and loads. The amplifier must be in operate mode, bias will be switched off in standby.. Let the amplifier run for h, without input signal.. djust the bias to mv measured on JP, JP or JP, JP.. heck the maximum difference (voltage drop) over emitter resistors (R, R, R, R, R, R, R, R, R0, R, R, R, R, R, R, R). The difference between them should not exceed mv. Higher difference might be due to a faulty transistor or Emitter resistor, also check and that the screw are tightened.. Wait h.. Measure the bias and if needed readjust to mv measured on JP, JP or JP, JP.. Wait h.. Measure the bias and if needed readjust to mv measured on JP, JP or JP, JP.. Wait h. 0. Measure the bias and if needed readjust to mv measured on JP, JP or JP, JP. Repeat step - until the bias are stabile.

7 D P P S T00m SW 0V SW0-0 T nf/v X TRNSFX K RELY DPDT Q BV D BRIDGE 00U/V D LL +.VD R 0K 0N 00n U LD0V Vin DJ Vout +.V R K S SW-SPDT +.VD 00n 00U/.V Standby mode S N R 0R 00N Q B 00N K R R 0R +.V D LL D LL PB R K D LL R K D LL R K 00N R 0R PHONEJK STEREO SW J J PHONEJK STEREO SW D P P P R NT R R NT R R NT R NO N OIL N0 N OIL D BDYD R 0R Q B R 0K SW BL/UNBL +.V R N R N +.V 0V P0 0V P P To mains Transformer u/v +.VD 00N 0 00N +.VD 0N R 0K Q nf/v X R 0R NO N OIL N0 N OIL R 0K Q K RELY DPDT R K Q D BDYD +.VD BV R 0R +.VD Q R 0K B R K R K 00U/V 0 J ON0 0 +.VD J ON0 00N PB 0 U V + GND V+ TOUT - RIN + ROUT - TIN V- TIN TOUT ROUT RIN SW MXEE PIN ON P PIN ON P 00N 00N 00N 0 00N F PIN ON P NMF0 F NMF0 PIN ON P D KB RS P HEDER PB B R0 K BV BV LL LL LL LL LL LL D P HEDER +.VD B J Bias R SPK Relay R XLR/R R +V R GND R Temp R Temp R Fuse R D-heck+ R D-heck- R J Bias L SPK Relay L XLR/R L +V L GND L Temp L Temp L Fuse L D-heck+ L D-heck- L 0 ON0 0 ON0 D R 0K D R 0K 0 00U/.V D LL D R 0K D 00U/.V R 0K D0 00U/.V R 0K D LL R 0K D p X MHZ LL D LL 0p 0 U P.0/IB/D0/D0 P./I P./OD/D0 P./O P0.0/MP/KBI0/D0P0./INB/KBI/D0 P./O/D00 P0./IN/KBI/D P./OB P0./INB/KBI/D P./RST P0./IN/KBI/D VSS P0./MPREF/KBI P./XTL VDD P.0/XTL/LKOUT P0./MP/KBI P./INT P0./T/KBI P./INT0/SD P.0/TXD P./T0/SL P./RXD P./MOSI P./SPILK P./MISO P./SS PLP 0 +.VD 0 U SER SRLK SRLR RLK E V GND LV SW SW-B O0 O O O O O O O Q R 0R R0 R heck error R K R0 K R K R 0K D D0 D R0 K LED LED LED R R R R R 0R R 0R R R +.VD R 0R D LL 00U/.V 00U/.V D LL 00U/.V Title Size Number Date: -Nov-00 Sheet of File: :\WORK\..\P00-D.SH Drawn By: Revision

9 B D D B Title Number Revision Size Date: -Dec-00 Sheet of File: :\WORK\..\P00-.SH Drawn By: Q S0 Q S0 Q BD Q S Q S0 R K Q S Q S00 R K R 0K R 0R R 0R D N D N 0.U R K R K R K R0 K Q0 S0 R K R K PF Q S0 Q S0 Q S0 R R R K R 0R R0 K R0 K P D N D N 0.U R 0R R 0R R 00R R 0R R K R K R K R 0K K E Q OPTOISO Q BS0 R 0R R 0R R K R K Q S R R R R 0.U 0U/V R 0R R0 0R R 0.R R 0.R R R R0 R R R R R Q0 S Q S00 R 0.R R 0.R R R R R R R R R S. S. 00N 00N R0 K R K 0.U 0 U R M +V -V 0.U 0.U 00U/V 00U/V R R 0.U R 0R BIS Q SK QB SK +0V -0V U TL0 R K 0 N JP 00U/V 00U/V Q S Q S00 R 0.R R 0.R R R R R R R R0 R Q S Q0 S00 R 0.R R0 0.R R R R R R R R R R K R00 K R 00R R K R 00R R K R0 K R0 K 0P 0P 0P U OP UB OP U0 OP U0B OP S SW SPDT SB SW SPDT S R K R K R0 K R K R0 K R0 K R R R R Q S0 Q S0 Q BD Q S Q S0 W R K Q S Q S00 R K R 0K R 0R R 0R D N D N 0.U R K R K R K R K Q S0 R K R K P Q S0 Q S0 Q S0 R R R0 K R 0R R0 K R K P D N D0 N 0.U R 0R R 0R R0 00R R 0R R K R K R K R0 0K K E Q OPTOISO Q BS0 R 0R R 0R R K R K Q S R R R R 0 0.U 0U/V R 0R R 0R R 0.R R 0.R R R R R R R R0 R Q S Q S00 R 0.R R 0.R R R R R R R R R 00N 00N R K R K 0.U U R M +V -V 0.U 0.U 00 00U/V 0 00U/V R R 0.U R0 0R BIS Q0 SK Q0B SK +0V -0V U TL0 R K N 0 00U/V 0 00U/V Q S Q S00 R 0.R R 0.R R R R R R R R R Q S Q S00 R 0.R R 0.R R R R0 R R R R R 00U/0V 00U/0V 00U/0V 00U/0V 00N 0 00N R0 0R R0 0R 0U/V 0U/V +V -V Vin GND OUT U Vin GND OUT U Q S Q S R K R0 K 0U/V 0 0U/V D V D V 0U/0V 0U/0V +0V-POWER -0V-POWER +0V-POWER -0V-POWER +0V-POWER +0V -0V -0V-POWER 00N +V +V -V -V -V +V 00N 00N 00N 00N 00N 0U/0V 0U/0V JP 0 00U/V 0 00U/V 0 00U/V 0 00U/V 0 J ON0 BIS SPK-RELY FUSE-ERROR R 0K R 0K FUSE-ERROR D-HEK + D-HEK - D-HEK - D-HEK + Q B D N00 R0 0R/W S RELY-SPDT R0 00K R K SPK-RELY Q B D N R 00K R K XLR/R +V R 00R XLR/R R 0K R0 0K N N +V 0 00U/0V 00U/0V 00U/0V 00U/0V 00U/0V 00U/0V U/0V U/0V 00N 00N 0 00n 00n 00n 00n RV KTY OUT(+) OUT(-) 00N 00N 0N R 0R R 0R R 0R R 00R R 00R R 00R GND XLR+ XLR- R IN R-GND 00U/0V R K R K R K R K JP JP R0 0R R 0R R 0R R 0R

11 P D P D 000/V 000/V 000/V R k P D BRIDGE P D P P BRIDGE 000/V 000/V 000/V R k P P P D 000/V 000/V 000/V R MRS P B BRIDGE P0 B D P P BRIDGE 000/V 0 000/V 000/V R MRS P Title Size Number Date: -Dec-00 Sheet of File: :\WORK\..\P00-B.SH Drawn By: Revision

13 Performance Data 000V Torodial Transformer. total of uf electrolytes in the powersupply. Dual set of Speakerterminals for each channel. Balanced (R) and Unbalanced (XLR) inputs. Input impedance K, R and XLR Output Power (both channel driven): x0w Ohms load 0Hz-0Khz x00w Ohms load 0Hz-0Khz THD+N below 0.0% in both cases. Frequency response: 0Hz-00Khz 0.dB Noise, below 00dBV THD+N: K 0W R load below 0.0%. Gain: db unbalanced, 0dB balanced. Trigger input range: -V.

An Ultra Low Resistance Continuity Checker

An Ultra Low Resistance Continuity Checker By R. G. Sparber Copyleft protects this document. 1 Some understanding of electronics is assumed. Although the title claims this is a continuity checker, its