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UAM2

 4  

INTRODUCTION  

 
The UAM2 is a small, high quality audio amplifier that you can plug any line 
level source into and get a whopping 20W out! So if you want, you can plug 
your portable cd player in and run your big ol’ speaker! The board is made so 
that you can mount it directly onto the back of a speaker or just use it as is 
with the mounting holes. It puts out great quality sound with lots of power and 
the active parts are all surface mount! You’ll be amazed when you fire it up, 
20W is going through a tiny TSSOP IC, and it doesn’t even get warm. There 
are 4 gain settings giving you a rough volume adjust, and also a shutdown 
input so you can turn the UAM2 off without disconnecting the power.  
  

 
UAM2 CIRCUIT DESCRIPTION 
 

The UAM2 is built around the Texas Instruments TPA3001D1 audio 
amplifier. It is a 20W audio amp in a 24 pin TSSOP package that we have 
soldered onto the board for you. We know that many of our customers have 
super skills, but we soldered it on for the sake of the ones that might have a 
hard time with a small part like that. All the other parts are left for you to 
solder, and if you have some surface mount experience it should be really 
easy. If this is your first kit, it may be a little challenging, but if you work 
slowly and carefully it should come out all right. The TPA3001D1 is a class D 
audio amplifier. The “D” is the magic behind how a tiny chip can handle 20W 
without going “poof”. If you already know how a class D amplifier works, you 
may skip this section. If, however, this is your first exposure to class D amps 
as it was for me when I designed this kit, keep reading and allow me to 
enlighten you.  
 
 

 
 
 

audio input

reference signal

outp

outn

differential
output

filter

output to speaker

comparator and
switch

Summary of Contents for UAM2

Page 1: ...2V Square board for screw mounting or circular break out board for attaching directly to speaker magnet Line level input Adjustable gain 12dB 18dB 23 6dB 32dB Remote shutdown input Need more audio pun...

Page 2: ...MATEUR RADIO KITS HR Series HF All Mode Receivers DDF1 Doppler Direction Finder Kit QRP Series HF CW Transmitters CW7 CW Keyer QRP Power Amplifiers RAMSEY MINI KITS Many other kits are available for h...

Page 3: ...on 4 Learn As You Build Kit Assembly 6 Parts List 8 Assembly Steps 9 Setup and Testing 11 Troubleshooting Guide 11 UAM2 Parts Layout Diagram 13 UAM2 Schematic 13 Ramsey Kit Warranty 15 KIT ASSEMBLY AN...

Page 4: ...ts TPA3001D1 audio amplifier It is a 20W audio amp in a 24 pin TSSOP package that we have soldered onto the board for you We know that many of our customers have super skills but we soldered it on for...

Page 5: ...t to the speaker The magic of all this is that the circuitry needed to carry out these operations can be digital because all the waveforms are squarewaves the voltage is either high or low on or off u...

Page 6: ...sier but help you to understand the circuit you re constructing For each part our word Install always means these steps 1 Pick the correct part value to start with 2 Insert it into the correct PC boar...

Page 7: ...printed circuit board before soldering The procedure is to take a small amount of glue usually with a pin or toothpick and dab the circuit board in the place where the component will be affixed Be car...

Page 8: ...0K ohm surface mount resistor 124 R2 R3 R4 R6 CAPACITORS 7 1 uF surface mount capacitor C2 C3 C5 C6 C7 C9 C11 2 001 uF surface mount capacitor C14 C15 2 22 uF surface mount capacitor C12 C13 1 47 uF s...

Page 9: ...nt capacitor to the right of R2 4 Install C5 1 uF surface mount capacitor to the right of R3 5 Install C8 47 uF surface mount capacitor just below R7 6 Install C9 1 uF surface mount capacitor above C5...

Page 10: ...l testing for this kit someone soldered it in backwards and well there was an incident The black band indicates the negative lead It s pretty easy to solder in The leads are big ger so it will take a...

Page 11: ...blocks Hear that sound OOOO Feel that chip not get hot AHHH Unless it doesn t work then The long black and red twisted pair wire is for you to connect your speaker to the UAM2 The green screw terminal...

Page 12: ...Hear that sound OOOO Feel that chip not get hot AHHH Unless it doesn t work then TROUBLESHOOTING GUIDE Well this being a surface mount kit and all if something doesn t work it s probably because one o...

Page 13: ...UAM2 13 UAM2 BOARD PARTS LAYOUT DIAGRAM UAM2 MAIN BOARD SCHEMATIC...

Page 14: ...friendly format that is possible As our customers we value your opinions comments and additions that you would like to see in future publications Please submit comments or ideas to Ramsey Electronics...

Page 15: ...and received five extra 1K resistors you can pretty much be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronic...

Page 16: ...NO UAM2 UNIVERSAL AUDIO AMP REQUIRED TOOLS Soldering Iron WLC100 Thin Rosin Core Solder RTS12 Needle Nose Pliers MPP4 or RTS05 Small Diagonal Cutters RTS04 ADDITIONAL SUGGESTED ITEMS Helping Hands Hol...

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