PLA-240ADS Perfect Little Amplifier


New! Compact stereo amplifier with Auto Detect and Switch (ADS)TM designed specifically for use with the variable volume output of music streamers and voice assistant devices like the Amazon Echo Dot (Alexa).  Connect a second source in addition to the Echo Dot.  Automatic signal-detection and source-switching means you hear the source you want, when you want . . . automatically!

  • Whole-House Audio (WHA): Ideal for adding an Echo Dot into a zone or sub-zone. The Dot (or other device connected to the primary input) will interrupt the source coming from the WHA system (connected to the secondary input).  You can hear the Dot even when the WHA system is off.
  • Smart Stereo: Combine an Echo Dot with your favorite speakers to create a "smart speaker on steroids".  Alexa's voice and the Dot's streaming audio take priority over another source connected to the secondary input.

40 watts X 2 into 8 ohms, or 70 watts X 2 into 4 ohms means you can connect one or two pairs of 8 ohm speakers and achieve more than enough volume, even in large rooms.

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See how to combine the PLA-240ADS with our Voice Assistant Mounting kit in our new Hybrid Wireless video.
With its auto-on and ADSTM (Auto Detect and Switch) circuits, the compact PLA-240ADS "Perfect Little Amplifier" opens a realm of possibilities to enhance your audio experience. Here are a few suggestions for how to use this unique amplifier:
Add a source that’s unique to one zone in your whole-house audio system, that can even be used when the system is off. The PLA-240ADS makes a great “smart” zone or sub-zone amplifier. It has twice the power output as the SZA-1 and its auto-source-switching feature allows you to add a source that is only available to that area of the home.
Connect a zone’s Variable output from your whole-house controller (MC-66, Lync 6, Lync 12) into Input 2 on the PLA-240ADS. Connect a source, such as a music streamer or voice assistant device like an Echo Dot into Input 1. In this way, the zone can use the Whole-House Audio system just like any other zone in the house, but whenever the source plugged into Input 1 is active it takes priority and becomes what is heard in that zone.
Imagine adding a music streamer to Input 1 for kid rooms and guest rooms. Let users know that streamer is dedicated just for them and all they have to do is start streaming to it to hear audio in their room. That is, the Whole-House system doesn't even need to be turned on and you don’t need to “teach” anyone how to use the app or keypad.
When combined with an Alexa device (such as the Echo Dot) and your favorite pair of speakers, the PLA-240ADS helps create an awesome stereo system with multiple uses:
Use as your primary stereo system. Think of this solution as a "smart speaker" on steroids.  Compared to an all-in-one smart speaker, you get a more powerful amplifier, your choice of quality speakers that can be spread apart for better coverage and true stereo imaging, and an option to add a second source in addition to whatever the Dot has to offer.
Use as the perfect stereo for teenagers. Most teens want something that performs more like a real stereo system than a plastic stand-alone smart speaker. In addition to the Alexa device, let them add whatever second source they’d like such as a phone, music streamer, game system, TV, etc.. And why is this the perfect solution for you as well? Because you can always interrupt what they are listening to by “intercoming” into the room with Alexa’s drop-in feature. With ADS, the other source is muted so only your voice comes through.  No more shouting to get their attention!
Stream the same source, in sync, throughout your home. Install multiple PLA-240ADS amplifiers and Alexa devices (or other music streamers that can play in sync) throughout your home to create a simplified wireless whole-house audio system.
In addition to ADSTM, the PLA-240ADS also includes an Auto-On feature. Use this option to “set and forget” the amplifier. When no source signal is detected from either source input, the amp will go into sleep mode drawing minimal power. When either source is detected, the amp will automatically power up, and after a few seconds start playing that source.
What you connect to Input 1 doesn't have to be an Alexa device! The PLA-240 works with any two audio sources. Connect a TV and a music streamer to create a stereo system perfect for a guest room (or any room for that matter) that's super easy to use. Want to listen to music? Stream away! Want to watch TV? Turn on the TV. The combination of audio sources is nearly endless. The key is the PLA-240ADS's ability to both auto-power-on and auto-detect and switch between those two sources!
Some notes about setting up the PLA-240ADS:
The PLA-240ADS will switch to the primary source (Input 1) nearly instantaneously whenever the input signal reaches a minimum threshold (around 7mV). The amp will switch back to the secondary source (Input 2) whenever this threshold is not met after a period of time set by the Delay knob (about 0-40 seconds). When both input sources are simultaneously playing, the auto-switching works best when the Input 1 signal is consistently above the threshold.
For the Echo Dot, we recommend setting its volume around 7-10 by default. A setting of 10 (max) is equivalent to a fixed level output from traditional audio devices like a CD player. If you stream music through the Dot at very low levels, you will want to turn off the secondary source input while streaming or increase the Delay time on the PLA-240ADS to prevent the amp from auto-switching back to source Input 2.
For most users, setting the Delay knob to near minimum will work best with Alexa.
Volume is set one time on the amplifier itself, and then adjusted using the source's volume control. Connect your Echo device to Input 1 and play an audio stream at volume 10 set on the device (just say, “Alexa, play my music at volume 10”).  Then, while listening to music, set the amplifier's rotary volume level to the maximum you’d ever want in that room. At that point, you should never have to adjust the volume on the amp again.  Volume for the Echo device is controlled using the Alexa app and by voice, and volume for the other source is controlled by that source (note: to use a TV as one of your sources, the TV must have an analog variable output).


  • 2 stereo RCA inputs; Input 1 is PRIMARY, Input 2 is SECONDARY
  • 40 Watts per Channel at 8 ohms, both channels driven
  • 70 Watts per Channel at 4 ohms, both channels driven
  • Total Harmonic Distortion (THD) .07% at rated power
  • Frequency response 10 Hz - 40 kHz (-3dB, 1 watt)
  • Dimensions (HXWXD): 2 1/4" X 8 3/4" X 7 3/4" (please allow a minimum 1" of space behind amplifier for cables)
  • Auto-on stand-by power: 5 watts

Owner's Manual

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