Power Amplifier
Upshock Home Audio knows it is important to get the most out of your dollar these days. There is no reason to overpay for Home Audio Receivers so we have put together a list of our favorite products at some of the best prices anywhere. We have done the searching for you and have compiled the results on each page. If you are unable to find the receiver other audio piece you are looking for on this page, use the search box for best results.
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 SHERBOURN model 7 2100A 7 CHANNEL x 200 WATT POWER AMPLIFIER XLR and RCA INPUTS $499.99 (1 Bid) Time Remaining: 1d 16h 18m |
 Marantz MM7055 5 Channel Power Amplifier with 140W per channel Reference Series $989.00 Time Remaining: 4d 21h 11m Buy It Now for only: $989.00 |
 Yamaha HTR 5250 Home Theater Power Receiver Amplifier 250 Watts $134.99 Time Remaining: 4d 10h 52m Buy It Now for only: $134.99 |
 PYLE 350W 2CH DIGITAL HOME HOUSE THEATER POWER AMP AMPLIFIER RECEIVER NEW $118.80 Time Remaining: 1d 23h 45m Buy It Now for only: $118.80 |
 PYLE 350W 51CH DIGITAL HOME HOUSE THEATER POWER AMP AMPLIFIER RECEIVER USB SD $138.80 Time Remaining: 20d 1h 47m Buy It Now for only: $138.80 |
 350W 51CH HOME STEREO RADIO RECEIVER POWER AMP AMPLIFIER w USB SD 2 MIC INPUTs $136.80 Time Remaining: 20d 1h 48m Buy It Now for only: $136.80 |
 Harman Kardon Signature 21 5 channel Power Amplifier MADE IN USA Excellent $499.00 Time Remaining: 3d 8h 45m Buy It Now for only: $499.00 |
 Sony Power Cinema VCR Integrated Amplifier SLV AV100 Works Great $85.00 Time Remaining: 24d 15h 27m Buy It Now for only: $85.00 |
 NHT Controller + NHT Power5 Amplifier $1,688.00 Time Remaining: 29d 17h 56m Buy It Now for only: $1,688.00 |
 RDX D 7 SURROUND SOUND AMPLIFIER RECEIVER 51 CH POWERED HOME THEATER SYSTEM $400.00 Time Remaining: 7d 15h 50m Buy It Now for only: $400.00 |
 Crown Audio XLS 2500 Professional Power Amplifier BNew Sealed Fast Ground Ship $559.00 Time Remaining: 17d 9h 9m Buy It Now for only: $559.00 |
 Pioneer VSX D903S 8 Channel Receiver Power AMP Dolby Pro Logic Parts Repair $59.99 Time Remaining: 1d 8h 14m Buy It Now for only: $59.99 |
A few items from Amazon
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LP-2020A+ Lepai Tripath Class-T Hi-Fi Audio Mini Amplifier with Power Supply $21.00 This Lepai Tripath-based mini audio amplifier is ideal for both home and car audio applications. The amplifier's TA2020 amp chip is a 20W/ch continuous average two-channel Class-T Digital Audio Power Amplifier IC that incorporates Tripath's proprietary Digital Power Processing technology. Class-T amplifiers offer the audio fidelity of Class-AB amps combined with the power efficiency of Class-D amp... |
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Pyle Home PCA2 2X40-Watt Stereo Mini Power Amplifier $33.23 The PCA2 mini stereo power amplifier from Pyle provides up to 40W of power on each channel at 4 Ohms. Connect your inputs using the RCA jacks, and output an amplified audio signal over standard speaker push jacks. It’s compatible with any audio or computer device--you can even hook up an iPod using a 3.5mm to RCA jack converter. A master volume control on the front lets you adjust the gain, and ... |
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Pyle Home PTAU45 Mini 2x120 Watt Stereo Power Amplifier with USB/CD/AUX Inputs $231.99 Pyle PTAU45 Home Amplifier is perfect for powering any stereo system. Complete with USB, CD and AUX inputs, and 2 x 120 watts of power -- this simple to use and durable amp has bass and treble controls, a slick blue LED output level display, L/R RCA inputs, and 4 speaker outputs. Using sophisticated circuitry and premium components for uncompromising musicality -- this product is famous for delive... |
How does ohm's law apply to the amount of speakers that can be supported for a power amplifier (PA)?
I read that alot of Power Amplifier (PA) has 8 Ohms circuitry. And that supports well for 2 speakers. Then when you add 2 more, it drives the amplifier to work harder because it reduce down to 4 ohm which is dangerous for most PA. Why is that?
In the days of vacuum tube amps, the speakers were driven by output transformers and the impedance level was important to get maximum power transfer. Modern transistor amplifiers use transistors to directly feed voltage into the speaker, and they will drive a wide range of loads. Where ohm's law comes in, the current into the speaker is the drive voltage divided by the speaker impedance:
I = V/R
The power dissipated in the speaker and in the amplifier is proportional to I^2. If R gets too low, the current can rise to excessive levels, dissipate too much power, and cause overheating of the amp output stages or the speaker voice coil.