Difference between revisions of "AudioAmp380"
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[[FILE:AudioAmp380-3D.png]] | [[FILE:AudioAmp380-3D.png]] | ||
− | == Design == | + | == Design Features == |
* Pre-amp plus power amp | * Pre-amp plus power amp | ||
− | * 50 Ohm input impedance | + | * 50 Ohm input impedance matches Product Detector outputs |
− | * Gain trimmer potentiometer on preamp | + | * 0-10x Gain trimmer potentiometer on preamp |
* External mount gain potentiometer | * External mount gain potentiometer | ||
* [https://www.ti.com/lit/ds/symlink/ne5534.pdf NE5534] Pre-amplifier | * [https://www.ti.com/lit/ds/symlink/ne5534.pdf NE5534] Pre-amplifier | ||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
* [https://www.ti.com/lit/ds/symlink/lm380.pdf LM380] 2.5W Audio Power Amplifier | * [https://www.ti.com/lit/ds/symlink/lm380.pdf LM380] 2.5W Audio Power Amplifier | ||
− | + | * 12V nominal power | |
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | |||
− | * 12V nominal | ||
** 10-22V | ** 10-22V | ||
− | * Fits into 80x50x20mm extruded aluminum enclosure | + | * Fits into standard 80x50x20mm extruded aluminum enclosure |
− | + | ||
+ | === Pre-Amplifier (NE5534) === | ||
+ | |||
+ | * Low-Noise Operational Amplifiers | ||
+ | * Internally fixed gain of 50 (34 dB) | ||
+ | * Equivalent Input Noise Voltage 3.5 nV/√Hz Typ | ||
+ | * Unity-Gain Bandwidth 10 MHz Typ | ||
+ | * Common-Mode Rejection Ratio 100 dB Typ | ||
+ | * Wide Supply-Voltage Range ±3 V to ±20 V | ||
+ | ** Used as single supply | ||
+ | |||
+ | === Audio Power Amplifier (LM380) === | ||
+ | |||
+ | * Wide Supply Voltage Range: 10V-22V | ||
+ | * Low Quiescent Power Drain: 0.13W (VS= 18V) | ||
+ | * Voltage Gain Fixed at 50 (34 dB) | ||
+ | * High Peak Current Capability: 1.3A | ||
+ | * Input Referenced to GND | ||
+ | * High Input Impedance: 150kΩ | ||
+ | * Low Distortion | ||
+ | * Quiescent Output Voltage is at One-Half of the Supply Voltage | ||
== Controls == | == Controls == | ||
− | * RV1 - trade-off | + | * RV1 - trade-off gain/bandwidth - Tune for best sound |
− | * RV2 - volume control (after preamp and before LM380 Amp. 1x5 header | + | * RV2 - volume control (after preamp and before LM380 Amp). 1x5 header wire to external pot |
− | + | ||
− | * J2 - Audio Out | + | == Jacks == |
− | * J3 - Power | + | |
+ | === J1 - Audio In === | ||
+ | |||
+ | * 50 Ohms input impedance for radio applications | ||
+ | ** Output of Product Detector stage | ||
+ | ** R1 = 51 Ω | ||
+ | ** RV2 = 500 Ω pot | ||
+ | * Optional [https://en.wikipedia.org/wiki/Line_level#Line_in Line Level Input] | ||
+ | ** The impedance of a line input is typically around 10 kΩ | ||
+ | ** R1 = 10 kΩ | ||
+ | ** RV2 = 50 kΩ pot | ||
+ | * RCA jack | ||
+ | |||
+ | === J2 - Audio Out === | ||
+ | |||
+ | * 8 Ohm speakers | ||
+ | * RCA | ||
+ | |||
+ | === J3 - Power === | ||
+ | |||
+ | * 10V-22VDC | ||
+ | * 5.5mmx2.5mm DC jack | ||
+ | |||
+ | == Measurements == | ||
+ | |||
+ | * MHS-5200A Signal Generator | ||
+ | ** 200 mV | ||
+ | ** 100-10KHz | ||
+ | ** Drives 50 Ohms | ||
+ | * Adjust Trimmer CCW for full gain | ||
+ | ** With adj screw to the right side | ||
+ | * [[Benchtop Power Supply DPS3005]] | ||
+ | ** 12V | ||
+ | ** 20mA with volume control fully down | ||
+ | ** 300mA with volume control fully up (3.6W) | ||
+ | |||
+ | == Rev 2/3 Schematic == | ||
+ | |||
+ | [[file:AudioAmp380-Rev3_Schematic.png]] | ||
+ | |||
+ | == Revision History == | ||
+ | |||
+ | === Rev 1 Rework === | ||
+ | |||
+ | ==== Rev 1 Schematic ==== | ||
+ | |||
+ | * (Before rework) | ||
− | + | [[file:AudioAmp380-Rev1_Schematic.png]] | |
− | + | === LM380 Equivalent Schematic === | |
− | + | [[file:LM380_Equiv_Schematic.PNG]] | |
* Issues | * Issues | ||
− | ** | + | ** Pre-amp opamp has + and - reversed |
** Also hooked up the feedback to the wrong input | ** Also hooked up the feedback to the wrong input | ||
− | * Replace R1 with jumper | + | * Replace R1 with wire jumper |
− | * Replace C9 with jumper | + | * Replace C9 with wire jumper |
* Remove C2 | * Remove C2 | ||
* 5 Cuts | * 5 Cuts | ||
Line 55: | Line 107: | ||
[[file:U2-2_3_Rev1_Rev2_Cuts_Jumpers.png]] | [[file:U2-2_3_Rev1_Rev2_Cuts_Jumpers.png]] | ||
+ | |||
+ | * Jumpers on rear side | ||
[[file:AudioAmp380_Back_Jumpers.PNG]] | [[file:AudioAmp380_Back_Jumpers.PNG]] | ||
+ | |||
+ | === Rev 2 === | ||
+ | |||
+ | * Schematic C5 was 100uF, should be 100nF | ||
+ | ** Fixed on prototype | ||
+ | * Footprint wrong on C2 (older rev 2 was ordered) | ||
+ | ** 10uF can be fit onto the card | ||
+ | * Didn't have any 100uF cap to use at C9 | ||
+ | ** Used 47uF - power bypass = OK value | ||
+ | |||
+ | === Rev 3 === | ||
+ | |||
+ | * Fixed C3 footprint already | ||
+ | * Fixed C5 footprint back to 0.1" small cap footprint | ||
+ | * Card works | ||
== Videos == | == Videos == | ||
+ | |||
+ | * Charlie Morris ZL2CTM design | ||
[[file:ZL2CTM_Schematic.PNG]] | [[file:ZL2CTM_Schematic.PNG]] | ||
<video type="youtube">GlT0HbvcmrM</video> | <video type="youtube">GlT0HbvcmrM</video> | ||
+ | |||
+ | == Panel Cutouts == | ||
+ | |||
+ | [[file:AudioAmp380_Panel_Cutouts_Rev3.PNG]] | ||
+ | |||
+ | * [http://land-boards.com/AudioAmp380/AudioAmp380_Panel_Cutouts_Rev3.pdf Panel cutout] (PDF File) | ||
== Assembly Sheet == | == Assembly Sheet == | ||
− | [[LM380 Rev 1 Assembly Sheet]] | + | * [[LM380 Rev 1 Assembly Sheet]] |
+ | * [[LM380 Rev 2 Assembly Sheet]] | ||
+ | * [[LM380 Rev 3 Assembly Sheet]] |
Latest revision as of 20:36, 29 March 2022
Contents
Design Features
- Pre-amp plus power amp
- 50 Ohm input impedance matches Product Detector outputs
- 0-10x Gain trimmer potentiometer on preamp
- External mount gain potentiometer
- NE5534 Pre-amplifier
- LM380 2.5W Audio Power Amplifier
- 12V nominal power
- 10-22V
- Fits into standard 80x50x20mm extruded aluminum enclosure
Pre-Amplifier (NE5534)
- Low-Noise Operational Amplifiers
- Internally fixed gain of 50 (34 dB)
- Equivalent Input Noise Voltage 3.5 nV/√Hz Typ
- Unity-Gain Bandwidth 10 MHz Typ
- Common-Mode Rejection Ratio 100 dB Typ
- Wide Supply-Voltage Range ±3 V to ±20 V
- Used as single supply
Audio Power Amplifier (LM380)
- Wide Supply Voltage Range: 10V-22V
- Low Quiescent Power Drain: 0.13W (VS= 18V)
- Voltage Gain Fixed at 50 (34 dB)
- High Peak Current Capability: 1.3A
- Input Referenced to GND
- High Input Impedance: 150kΩ
- Low Distortion
- Quiescent Output Voltage is at One-Half of the Supply Voltage
Controls
- RV1 - trade-off gain/bandwidth - Tune for best sound
- RV2 - volume control (after preamp and before LM380 Amp). 1x5 header wire to external pot
Jacks
J1 - Audio In
- 50 Ohms input impedance for radio applications
- Output of Product Detector stage
- R1 = 51 Ω
- RV2 = 500 Ω pot
- Optional Line Level Input
- The impedance of a line input is typically around 10 kΩ
- R1 = 10 kΩ
- RV2 = 50 kΩ pot
- RCA jack
J2 - Audio Out
- 8 Ohm speakers
- RCA
J3 - Power
- 10V-22VDC
- 5.5mmx2.5mm DC jack
Measurements
- MHS-5200A Signal Generator
- 200 mV
- 100-10KHz
- Drives 50 Ohms
- Adjust Trimmer CCW for full gain
- With adj screw to the right side
- Benchtop Power Supply DPS3005
- 12V
- 20mA with volume control fully down
- 300mA with volume control fully up (3.6W)
Rev 2/3 Schematic
Revision History
Rev 1 Rework
Rev 1 Schematic
- (Before rework)
LM380 Equivalent Schematic
- Issues
- Pre-amp opamp has + and - reversed
- Also hooked up the feedback to the wrong input
- Replace R1 with wire jumper
- Replace C9 with wire jumper
- Remove C2
- 5 Cuts
- 4 on front
- 1 on back
- 5 jumper segments on back
- 2 nodes
- Jumpers on rear side
Rev 2
- Schematic C5 was 100uF, should be 100nF
- Fixed on prototype
- Footprint wrong on C2 (older rev 2 was ordered)
- 10uF can be fit onto the card
- Didn't have any 100uF cap to use at C9
- Used 47uF - power bypass = OK value
Rev 3
- Fixed C3 footprint already
- Fixed C5 footprint back to 0.1" small cap footprint
- Card works
Videos
- Charlie Morris ZL2CTM design
Panel Cutouts
- Panel cutout (PDF File)