Universal Audio Amplifier Ramsey Electronics Model No. UAM2 Need more audio “punch” for a project? Build your own powered speaker or juice up that audio kit with this high quality audio amp. Maximum 20 Watt screaming output for any application; lower gain settings with the change of a jumper. • Whopping 20W output at 18V. • Runs on 8V to 18V DC. • SNR: 102dB at 15W into 8Ω, 18V 95dB at 10W into 4Ω, 12V • THD + N: 1% at 15W into 8Ω, 18V .
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Ramsey Publication No. UAM2 Manual Price Only $5.00 KIT ASSEMBLY AND INSTRUCTION MANUAL FOR Universal Audio Amplifier TABLE OF CONTENTS Introduction to the UAM2 .................................. 4 UAM2 Circuit Description .................................. 4 “Learn-As-You-Build” Kit Assembly ................... 6 Parts List ........................................................... 8 Assembly Steps ................................................. 9 Setup and Testing ....................................
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.
First, your audio input is compared to a high frequency reference signal. This generates two squarewave outputs. These outputs change phase in response to the audio input. audio input > 0 audio input = 0 volts When the audio input is 0 volts, the two outputs are nearly in phase and the differential voltage is almost zero most of the time, just little spikes.
RAMSEY Learn-As-You-Build KIT ASSEMBLY There aren’t that many solder connections on the UAM2 printed circuit board, but you should still practice good soldering techniques. • • • • • Use a 25-watt soldering pencil with a clean, sharp tip. Use only rosin-core solder intended for electronics use. Use bright lighting; a magnifying lamp or bench-style magnifier may be helpful. Do your work in stages, taking breaks to check your work.
be installed by holding it with tweezers in contact with the “tinned” trace and re-heating the solder (see the associated diagrams). Another commonly used technique is to glue the surface mount components to the 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.
UAM2 PARTS LIST Sort and “check off” the components in the boxes provided. We do our best to pack all our kits correctly but it is possible that a mistake has occurred and we missed a part. Please note that physical descriptions of parts are for those currently being shipped. Sometimes the parts in your kit may have a different appearance but still have the same values.
UAM2 PC BOARD ASSEMBLY STEPS Let’s start with the surface mount components first, and do the big through hole parts last, except for J3, which we will install as a reference part to get our bearings. You want to be careful about how much heat you apply to the teeny parts. Just get the tabs and circuit board pads hot enough to get the solder to flow. We have also given you extra caps and resistors in case you torch them. The one really tough surface mount part has been installed at the factory for you.
18. Install L1, surface mount ferrite bead, under D3. 19. Install C2, 1 uF surface mount capacitor, under L1. 20. Install C13, .22 uF surface mount capacitor, to the left of C2. 21. Install R1, 51 ohm surface mount resistor, to the left of C13. 22. Install C3, 1 uF surface mount capacitor, to the left of R1. 23. Install R6, 120K ohm surface mount resistor, down and to the left of C3. 24. Install C1, that big ol’ beast electrolytic surface mount capacitor.
SETUP AND TESTING Well, setup and testing for this kit is really easy. Just plug in a line level or even headphone level audio source into J3. Use J1 and J2 to set the gain. Use the chart below: J2 J1 Gain(dB) ON ON 12 ON OFF 18 OFF ON 23.6 OFF OFF 32 ‘ON’ means the jumper block is on the pins, and ‘OFF’ means it isn’t. Start out at minimum gain to test.
SETUP AND TESTING Well, setup and testing for this kit is really easy. Just plug in a line level or even headphone level audio source into J3. Use J1 and J2 to set the gain. Use the chart below: ‘ON’ means the jumper block is on the pins, and ‘OFF’ means it isn’t. Start out at minimum gain to test. Plug your 8-12V power source in, connect a speaker to J5 and J6, and feel the awesome power of your UAM2!!!!!! If everything works ok, crank the gain up to max by pulling out both jumper blocks.
UAM2 MAIN BOARD SCHEMATIC UAM2 BOARD PARTS LAYOUT DIAGRAM UAM2• 13
CONCLUSION We sincerely hope that you will enjoy the use of this Ramsey product. As always, we have tried to compose our manual in the easiest, most “user 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 Inc. Attn. Hobby Kit Department 590 Fishers Station Drive Victor, NY 14564 or email us at: techsupport@ramseymail.
The Ramsey Kit Warranty Please read carefully BEFORE calling or writing in about your kit. Most problems can be solved without contacting the factory. Notice that this is not a "fine print" warranty. We want you to understand your rights and ours too! All Ramsey kits will work if assembled properly. The very fact that your kit includes this new manual is your assurance that a team of knowledgeable people have field-tested several "copies" of this kit straight from the Ramsey Inventory.
TABLE OF CONTENTS Introduction to the UAM2 .................................. 4 UAM2 Circuit Description .................................. 4 Parts List ........................................................... 8 Assembly Steps ................................................. 9 Troubleshooting Guide..................................... 11 UAM2 Parts Layout Diagram ........................... 13 UAM2 Schematic ............................................. 13 Ramsey Kit Warranty ...........................
