Text preview for : LYNX manual.pdf part of Lynx Lynx power amp complete schematics and manual
150 Watts pr. Channel into 8 Ohms
275 Watts pr. Channel into 4 Ohms
400 Watts pr. Channel into 2 Ohms
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Audio Circuit Denmark
www.audio-circuit.dk
Power Amplifier Main PCB v2.1 and v2.2
Quick Assembly Guide v.1.2
16.11.2003
LYNX
Contents 1. Introduction and Specifications 2. Circuit Description 3. Component Lists 4. PCB-Layout and Silk Screen 5. Hardware and Connectors 6. PCB assembly and first test 7. Power Supply 8. Schematics
Disclaimer
The LYNX Power Amplifier are intended as a non-commercial diy-project, and it is therefore builder's responsibility to assure that assembly and wiring are made correct, and that suitable components are used. Audio Circuit Denmark can therefore under no circumstances be held responsible for any incorrect information or documentation, damages to persons and material, loss of money or what so ever.
LYNX Power Amplifier by Audio Circuit Denmark www.audio-circuit.dk
Page 1
1. Introductions and Specifications
Introduction This project had only one goal. To create a rock-solid and powerful sonic Power Amplifier like those used in recording studios. However, if you are fond of the deceased mighty and "muscular" power amps from Phase Linear, SAE, GAS and Dynaco etc. you may be intrigued by this project as the result is very close to those. Components Components shown in the schematics are only suggestions. The circuit has shown good characteristics and have produced a clear sound, when build with low cost components. So with this circuit you have the possibility to either build a low cost dynamic Power Amplifier or a Studio Class Power Amplifier. Technical Specifications: With the use of a heavy Power Supply combined with a large Capacitor Bank, the LYNX Power Amplifier are able to deliver loud and clear sound, and have shown capable of handling loads down to 1 Ohms without any instability. Specifications rated at +/- 55 Volt DC Supply Voltage with 2x22.000 uF capacitor bank: Output Power: 150 Watts pr. Channel into 8 Ohms 275 Watts pr. Channel into 4 Ohms 400 Watts pr. Channel into 2 Ohms DC to 300 kHz Better than 110 dB (20 Hz to 20 kHz Less than 0.001% from 20 to 450 Hz raising to less than 0.05% at 20 kHz Greater than 700 from DC to 400 Hz
Frequency response: Signal-to-Noise Ratio: Harmonic Distortion THD: Damping Factor:
The amplifier can run with supply voltages from +/-35 to +/-70 Volts DC without changing any resistor values.
2. Circuit Description and Schematics
Circuit Description The input signal from a Pre-Amp or a Volume Control is applied to the Inverting Input (Pin 2) of the U101 Opamp through a low-pass filter (R102 and C101), while the feedback signal (determent by R120 and R121) is applied to the Non-Inverting Input (Pin 3) of the U101 Opamp. U101 makes the first low Voltage Gain, and provide low output impedance to the Voltage Amplifier stage Q101 and Q103 (Positive Voltage Amplification) and Q102 and Q104 (Negative Voltage Amplification). The signal is then feed to the Current Gain Stages, which are build-up as "Three Deep Darlington" (TDD) circuits, each consisting of one Pre-Driver (Q106 and Q107), one High Power Driver (Q110 and Q111) and the Output Transistors (Q112 to Q119). The Bias circuit consists of Q105, C104 (decoupling), R113, R115 and a Potentiometer R114, which allows the Bias to be adjusted. The +/-15V DC Supply to U101 are provided by R122, ZD101 and C105 (Positive Supply) and R123, ZD102 and C106 (Negative Supply). A Current Limiting Circuit (R124 to R127, C109 and C110, D103 to D108 and Q108 to Q109) is fitted to protect the output stage from delivering high currents above safety level. The use of C105 and C106 allows high current peaks (dynamic peaks) on the output without limiting the output current. Only if the current flow continues above "safety level" the capacitors are charged and Q108/Q109 limits the output current by lowering the signal to the Pre-Drivers. If you are afraid of DC-Voltages on the input (from the outputs of your other equipment) you can add a 47uF/10V NP-capacitor to the input in series with R101. On the last page you see the full schematics for the LYNX Power Amplifier.
LYNX Power Amplifier by Audio Circuit Denmark www.audio-circuit.dk
Page 2
3. Component List
LYNX Power Amplifier main PCB v.2.1 and v2.2 (updated 16.11.2003) Item
R101, R105, R105, R120 R102 R103, R104 R107, R108 R109, R110 R111, R112 R113 R115 R116, R117 R118, R119 R121 R122, R123 R124, R125, R126, R127 R114 C101, C104 C102, C103 C105, C106 C107, C108 C109 U101
Description
10K, 0.25W 1M8, 0.25W 820R, 0.25W 1K, 0.25W 3.3K, 0.25W 330R, 1W 1K8, 0.25W 220R, 0.25W 180R, 1W 4R7, 2W 390R, 0.25W 2K7, 2W 100R, 0.25W 4K7 potentiometer 100pF 33pF 22uF, 50V 0.1uF 100pF OPA627
Mfr./Type
Alternatives
Notes
1% 1% 1% 1% 1% Non-Inductive 1-5% 1-5% Non-Inductive Non-Inductive 1-5% Non-Inductive 1-5%
Cermet, Bourns WIMA FKP 2 WIMA FKP 2 VISHAY MKP 1837 WIMA FKP 2
Equivalent Equivalent Equivalent
10-24 turns
Non-Polarity Equivalent Equivalent OPA27 Low DC-Offset opamp
Q101, Q108 Q102, Q109 Q103, Q107 Q104, Q105, Q106 Q110 Q111 D103, D104, D105, D106, D107, D108 ZD101, ZD102
MPSA42 MPSA92 MJE350 MJE340 MJE15032 MJE15033
Philips Philips Fairchild Fairchild Motorola Motorola
Equivalent Equivalent Equivalent Equivalent Equivalent Equivalent
1N4148 15V Zener, 1W
Equivalent
Output Stage (not on PCB)
Item
R131, R132, R133, R134, R135, R137, R138, R139 R139 R140 C110 L101 Q112, Q113, Q114, Q115 Q116, Q117, Q118, Q119 D109, D110
Description
0,33R, 5W 2R7, 5W 10R, 5W 0.1uF 2uH MJL21194 MJL21193 1N5059
Mfr./Type
Alternatives
0,22R, 5W
Notes
Non-Inductive Non-Inductive Non-Inductive
VISHAY MKP 1837
Equivalent 20A rating Equivalent Equivalent Equivalent On main heatsink On main heatsink
Misc. (Power Supply and external connectors not included)
One L-shaped Aluminium Profile 20 x 20 mm (0.79" x 0.79"), L: 100 mm (3.94"), thickness: 3 mm (0.1") or more. Two large heatsinks for output transistors (C/W 1 at 100 W for normal use) Suitable isolation pads for Q105, Q106, Q107, Q110, Q111 and Q112 to Q119 and heat-conducting paste. TO-220 heatsinks for Q106 and Q107, e.g. K25-004 from Austerlitz (C/W 15 at 4.0 W). Terminal Blocks for easy wiring and suitable wires etc. Various suitable screws, bolts, washers, nuts and insulation bushes for secure attachment of PCB and transistors.
LYNX Power Amplifier by Audio Circuit Denmark www.audio-circuit.dk
Page 3
4. PCB-Layout and Silk Screen
The LYNX main PCB v.2.1 Silk Screen and PCB-Layout Original board size: 100 x 80 mm (app. 3.94" x 3.15") = one half of a Euro-Board.
LYNX Power Amplifier by Audio Circuit Denmark www.audio-circuit.dk
Page 4
5. Hardware and Connecters
Main PCB v.2.1 fitted with L-Profile, TO-220 heatsinks and Terminal Blocks. IMPORTANT NOTE! Q105, Q106, Q107, Q110 and Q112 MUST be fitted with insulation pads and bushes to prevent any electric connection between the transistors and the L-Profile and heatsinks. Apply heat-conducting paste before attaching the transistors. The PCB are to be thermal attached to main heatsink by the L-Shaped Profile using suitable bolts, washers and nut and heat-conducting paste!
L-shaped profile, size 20x20 mm (0.8"x0.8") Length: 100 mm (3.94"). Thickness: >3 mm (0.13") Holes for Support bolts
Terminal blocks Lead 5,08 mm
TO220 Heatsink Terminal block Lead 2,54 mm Terminal block Lead 5,08 mm
TO220 Heatsink
Holes for support bracket if used in mobile equipment
Positive Signal Current Limiter
Feedback
Negative Signal Current Limiter
To Base Terminals of Q112, Q114, Q116 and Q118
To Base Terminals of Q113, Q115, Q117 and Q119
Positive DC-Supply
Negative DC-Supply
Power Supply and Signal Gnd
Audio Input
LYNX Power Amplifier by Audio Circuit Denmark www.audio-circuit.dk
Page 5
6. PCB assembly and first test
Please read carefully before you start assembling the PCB!
- Check for correct board size and version (v2.1 and v2.2) - Check carefully the PCB for broken or shorted tracks - Check for missing, bad or misplaced drilled holes
L-Profile
Start by attaching the L-shaped pre-drilled Aluminium Profile to the PCB using the two fastening bolts. Use suitable washers and nuts etc. Carefully bend the pins and attach the three transistors Q105, Q110 and Q111 to the PCB and L-profile with suitable bolts, washers and nuts. Use suitable isolation pads and bushes, and heat-conducting paste!
Components
Components should easily be soldered in if you use following order: 1. 0.25W resistors (all) according to the part list Always measure the resistance of each resistor before attaching it to the PCB! 2. Jumper J1 and the Bias potentiometer R114 3. Zeners ZD101 and ZD102 and all diodes D103 to D108 Raise Zeners app. 5 mm from the PCB, as they can get warm 4. Opamp U101. Be careful to inset the opamp correctly. Note that pin 1 is marked on the silk screen and by a square pad on the PCB 5. Small transistors Q101, Q102, Q108 and Q109 6. Capacitors (all) 7. 1W and 2W resistors (all) Raise resistors app. 5-10 mm from the PCB as they can get warm 8. Large transistors Q103 and Q104, and Q106 and Q107 with fitted heatsinks Make sure that the heatsinks on Q106 and Q107 are not touching other components! 9. The terminal blocks (if used) Check and double-check all solderings!!
Preparing the first test
Do the first test with no output stage connected! In fact, if you replace each of the two driver emitter resistors R118 and R119 with 0.33 Ohms resistors, you have a complete small 40 W Power Amplifier. Connect a regulated +/-40 to 70 Volt DC-Supply to the +Vcc and Vee terminals of the PCB. Positive Supply to the +Vcc terminal and Negative Supply to the Vee supply, using a 0.5 to 1A fuse in each supply line. Connect the Power Supply GND to both the GND and the Input terminal on the PCB, and your oscilloscope to the F/O terminal on the PCB.
First test
Switch on the Power Supply and observe the oscilloscope for any signs of oscillation on the F/O terminal. Also check that no component gets hotter, than you are still able to touch it. Verify that the Zener-stabilized supply to U101 are +/-15VDC.according to GND. Measure the Bias Voltage across R118 and R119, and adjust the Bias trimmer R114 for app. 300 mV across each resistor. Check that the DC-Voltage on the F/O terminal is below +/30mV. If DC-Voltage on the F/O terminal exceeds +/-30 mV, you may have to check all resistors values and check for faulty transistors etc. Please note that values above +/-30 mV can be normal, if you are using an Opamp (U101) with an internal DC-offset >1 mV, as this DCoffset is amplified 25 times! Apply a low level signal (e.g. 100 mV/1kHz sine wave) to the Input terminal and observe the F/O terminal. As the amplifier has a gain of app. 25, you should now see a clear 2.5V sine wave. If you observe any crossover distortion, then adjust the Bias trimmer R114 until distortion disappears. Slowly raise the Input Signal level until the amplifier clips, while checking for abnormal signal handling or oscillation on the F/O terminal.
LYNX Power Amplifier by Audio Circuit Denmark www.audio-circuit.dk
Page 6
7. Power Supply
Recommended Specification
Rail Voltages: Transformer rating: Capacitor Bank: +/-40 to 70 Volt DC with common ground 500 to 800 Watts per channel 2x15.000uF (minimum) with 2x100nF parallel
To Power Amplifier
AC main LYNX Power Amplifier by Audio Circuit Denmark www.audio-circuit.dk Page 7
Main PCB
+Vcc +Vcc
Output Stage
R122 2K7 2W D109 1N5059
R109 3K3
R111 330R 2W
C107 100nF Q106 MJE340 D103 1N4148 Q112 Q112 Q114 Q118 Q112 Q110 MJE15032
ZD101 15V 1W
Q103 MJE350
C102 33pF R113 1K8
Q120 MJL21194
Q101 MPSA42 Q105 MJE340 D105 1N4148 C105 22uF 50V R126 100R F/O R114 4K7 D107 1N4148 R127 100R R119 4R7 2W C106 22uF 50V -CL R125 100R Q113 Q113 Q113 Q115 -CL F/O R129 0R33 5W R131 0R33 5W R118 4R7 2W R128 0R33 5W R124 100R C104 100pF D106 1N4148 R116 150R 1W Q108 MPSA42 +CL +CL
R105 10K
R101 10K
7
R107 820R
R103 1K
2
R130 0R33 5W
R132 0R33 5W
R134 0R33 5W
L101 2uH Speaker
Input
-
6
+
3
C101 100pF R117 150R 1W D108 1N4148 Q109 MPSA92 R115 220R D104 1N4148 C103 33pF Q107 MJE350 Q104 MJE340 Q111 MJE15033
R102 1M8
C109 100pF
4
U101 OPA627
Gnd
R108 820R
R104 1K
R133 0R33 5W
R135 0R33 5W R137 10R 5W C113 0.1uF Q119 MJL21193 Q117
R136 2R7 5W
Gnd
R120 10K
R121 390R
R106 10K
Q102 MPSA92
C108 100nF R112 330R 2W
ZD102 15V 1W
D110 1N5059
R123 2K7 2W
R110 3K3
-Vee
-Vee
Schematic notes
Date Date Date Ini Project Client Copyright
18.06.2003
Rev
08.09.2003
Rev
11.11.2003
Rev
JD
2.1
Chk Chk
LYNX Power Amplifier
3.0
Chk
Public
3.1
Dept. Title File name Drawing No
Audio-Circuit Denmark
Sheet
Unless otherwise designated: All resistors in Ohms, 1%, 0.25 Watt Capacitors in uF, 100 Volt Q106 and Q107 fitted with TO-220 heatsinks Q105 and Q110 to Q119 placed on main heatsink R139, R140, L101 and C131 are placed on Speaker Binding Posts
R&D
LYNX Amplifier v2.2E
LYNX_v2-2_Overview
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