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Kemo M033N 18 Watt Universal Mono Amplifier Module
How would a 9v battery work with this amp? What do you estimate would be the wattage out from the amp to the speaker?
A 9 volt battery will technically power this amplifier although most 9 volt batteries have a fairly low mAh rating, which means they will not last very long.
Date published: 2013-12-26
What volume knob and power supply to use with this amp?
NOTE: Uploaded image is chart of the SMALLER version of this amp.1) What volume knob from the PE catalogue should i order?-> the speaker driver will be 8 ohm.-> the diagram for a possible PE volume knob does not show the same connections as the diagram from Kemo?= how sould the L-pad volume knob be connected or can it simply not be used at all?PE l-pad volume knobhttp://www.parts-express.com/pe/showdetl.cfm?partnumber=260-2522) I'm looking to install this amp + power supply inside a very small cabinet. So the power supply should be as small as possible. preferably no larger than 5x5x8 cm. But smaller would be even better. Any suggestions?Thanks.
I've uploaded the wiring diagram for this amplifier. You will want to use a 10k Audio Tapering Potentiometer (PE 023-610) hooked as shown in the diagram. I believe you are confusing L-Pads and Audio Potentiometers. They are similar devices but used for different applications (See Note 1 Below for more info).If you are looking for a small form internal power supply I suggest a Li-Po or Li-Ion battery packs either 11.1 or 14.8. I also suggest some kind of smart charging system for them. Overcharge and imbalance charging is not a desirable outcome for your device and personal safety. Be warned that this approach is not economically friendly but has high energy density for a small package. (Design is mostly weighing out trade-offs)Too keep with the small form factor idea, you could use an external supply (ie Wall Wart or Brick). Then you wouldn't have to house any electronics other than a jack to plug into. I have listed some products that fall in line this approach. (My suggest power supply cannot be listed below, however the PE# is 129-145)Best of luck on your project.NOTE 1:L-Pads and Audio PotentiometersL-PadThe L-Pad is used to connect to a speaker, normally used in passive crossover design (Commonly to attenuate a Tweeter output to match that of the woofer). These hand high level audio signal, thus the high power ratings. Also are selected based on speaker nominal impedance (4 or 8 ohm). Some designers used fixed L-Pads in crossovers (simply two resistors) as to the variable made reference to.An audio potentiometer:Audio Potentiometers come in two flavours; Linear and Logarithmic (otherwise know as Audio Taper). The names refer to how the resistance changes when you turn the knob. Linear Pots increase in resistance in a direct relationship to turning. Audio Taper Pots try to mimic how we naturally hear attenuation of volume. (Audio taper are generally more desirable for volume control).These devices work on line level signals (so low power). These are selected based on the input impedance of your device.
Date published: 2013-04-29
Will this amp work with rotary encoder & blue tooth?
rotary encoder, product id: AA-AA11117blue tooth, product id: BT-1AI am interested in using this amp with both AA-AA11117 (as external volume control knob) and the BT-1A to make it work with my iphone via bluetooth.In the Q&A i cant find any answers to this.1) will the volume control knob work with the Kemo M033N 18 Watt Universal Mono Amplifier Module2) will the bluetooth device BT-1A work with the Kemo M033N 18 Watt Universal Mono Amplifier Module3) how should i power the bluetooth and the amp.- seperately?- what power supply?Thanks in advance,Bjorn.
This will work with the bluetooth adapter, unfortunately it will not work with the encoder.
Date published: 2013-04-24
How to get mono sound from a stereo input.
I have one of these that I got last year but have not been able to wire it correctly. I want to get an iPod stereo signal and reproduce sound in one bookshelf speaker. If I take a 3.5mm plug and feed the amp the positive and negative signals from the iPod it sounds really strange. I know I'm doing something wrong. Any help would be greatly appreciated.
If you only see two wires out of your iPod stereo connection, you are missing the grounding wire(s). You are connecting Right Channel to the positive input of the amp and Left Channel to ground input. There are two possibilities:1. I suggest trying to separate the wires further. They are most likely surrounded by the ground wire (3.5mm TRS have really thin wires). Once you see all the wires you can then use one channel to hook up to the amp. For example the center part of the black wire to positive input and the surrounding part to the negative input.2. Then again you might have missed the green wire or striped it off when taking off the outer connector. If this is the case, just tie either red or black (not both) to the positive input and green to the negative input.If you would like to mix Left and Right Audio into your amps input you will need an op amp summing circuit. However(depending on the input impedance of the amp) I have built simple resistive summers. Put two 470 ohm resistors on the red and black wires of iPod output cable. Tie the ends together and place a 20k ohm resistor between that point and the green wire. The Positive input to the amp would be where all the resistors are tied and Negative would still be the green wire.I hope this helps and best of luck
Date published: 2013-08-07
Power supply for several of these
I would like to build a portable four channel amplifier using these. What kind of power supply would be able to handle powering anywhere from 1-4 of these. If each one is routed through an SPST so that any can be on or off at a time, is there a power supply that would be able to handle that without needing extra components to rectify the power based on need?
These small amplifiers do not draw a lot of current, so any 12-20v supply that has 4-5 amp output should power these without issue.
Date published: 2012-10-30
What would one use as a power supply for this amp?
This amp is rated to work with anything that is 8-20VDC with a minimum current draw of 800 mA. We offer a wide varaiety of power supplies that will work well. I have one listed below that is a good match.
Date published: 2013-07-20