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Thursday, March 29, 2012

Class H Power Amplifier TDA1562Q


Several years ago we often hear class of power amplifier. We can make power amplifier in class A, class B or class AB.

Class H Power Amplifier

Class H power amplifiers take the idea of Class G one step further creating an infinitely variable supply rail. This is done by modulating the supply rails so that the rails are only a few volts larger than the output signal at any given time. The output stage operates at its maximum efficiency all the time. Switched-mode power supplies can be used to create the tracking rails. Significant efficiency gains can be achieved but with the drawback of more complicated supply design and reduced THD performance.

IC TDA1562Q is Class H Power Amplifier. Learn more about chip TDA1562Q can be found here.

Schematic diagram of the power amplifier TDA1562Q is shown in Figure 1, the appearance in Figure 2. Has an internal booster circuit elements that allow to develop at 4 Ohm load with power supply 14.2 volts, the power to 70 Watts





Fig.1 Schematic of TDA1562Q Class H Power Amplifier.






Fig.2 Kit of TDA1562Q Class H Power Amplifier.


There should be a reservation - this musical power, and no noise, which usually indicate a modern car audio equipment. Mainly on the presence of these parameters is that when measuring the noise power as a test signal using a rectangular audio signal. Of course, that under this test, power output is possible, but to call it music, hardly anyone turns language.

If the test checks power amplifier TDA1562Q on the noise power in the load 4 Ohm chip developed at the output of 130 watts, which is quite clearly shows that it is much more powerful than the chips used in stereo systems.
As is evident from all the above on the basis of this amplifier can be built quite compact size car for powerful acoustics, and for the sub-woofer. It is not necessary to assemble a fairly labor-intensive converters. Of course the amplifier nonlinear distortion based on the TDA1562Q is slightly higher than the amplifier with transformer-based TDA7294 or TDA7293, but it is still far less than many cheap car amplifiers priced up to $ 150.

Jewel Quest Mysteries: The Oracle of Ur Collectors Edition


The fourth installment to the award-winning Jewel Quest Mysteries series is here. Rupert is back along with his two best friends, Emma and Sebastian. The three heroes are on a quest to find the most coveted jewel board of all, the Oracle of Ur. Can they successfully retrieve the Oracle of Ur?

• Play as Emma, Rupert, and Sebastian
• Explore beautiful locations as you uncover many hidden objects
• Enjoy fun mini-games, solve puzzles, and complete jewel boards



 

 

Wednesday, March 28, 2012

Behind the Reflection 2: Witchs Revenge (Updated)



A witch's quest for revenge spells trouble for a young mother and her son in Behind the Reflection 2: Witch’s Revenge! Guide the mother as she pursues the witch through time and space to save her son from a fate worse than death. Interact with a variety of characters, find useful objects, and stop the witch before it’s too late in this incredible Hidden Object Puzzle Adventure game. Triumph over evil in Behind the Reflection 2: Witch’s Revenge!



 

 

Nancy Drew: Secret of Shadow Ranch


A phantom horse visits Shadow Ranch, leaving a trail of frightening “accidents.” Local legend says the horse has come to avenge the hanging of its master, and that misfortune will befall whoever sets eyes on it. The ghostly horse tramples all hope of a restful ranch vacation for you, as Nancy Drew. You must discover the truth from the ghost stories quickly - you might be next on the list for unearthly revenge!


Download:  Mirror 1:  Part 1 Part 2

Mirror 2:  Part 1 Part 2 Mirror 3:  Part 1 Part 2

 

 

Identify IC TDA7293 and TDA7294 Fake or Original

TDA7293 and TDA7294 is a common feature of the bootstrap capacitor is not installed work as usual, which gives an opportunity for unscrupulous traders to provide fake, counterfeit goods market is the most polished printed for the TDA7294 TDA7293, from the printing on the can identify, find a few different batches of IC for your reference:



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If you can not see it, multimeter test:

TDA7294 pin 11, pin 12 empty legs, open state is insulated

TDA7293 pin 11 (voltage amplification stage output), pin 12 (bootstrap) has a resistance:






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TDA7293 limit voltage 120v

Limit voltage 100v TDA7294

I found that some batches were TDA7294 90V breakdown in the type of IC sound like TDA2030, reaction was slow, boring sound, though not sure whether the fake, but certainly not a good thing!

The breakdown is not more than 90V, the general performance of the midrange and treble sound clear and bright, fast response! Found in different batches of test and origin of the TDA7294 sound even different!

Sound quality not as good as Legend TDA7293 TDA7294, wrong! I found a few pieces of genuine TDA7293 sample tests and found TDA7293 TDA7294 sound much better than that, the biggest feature is bright! Fast! Power foot.

Above are for reference only, are welcome to share and talk about their experiences

Azkend 2 The World Beneath


Journey through the center of the Earth on a fantastic adventure in Azkend 2 - The World Beneath, a captivating ride to remember.
While traveling from Liverpool to New York, your ship was pulled down into the sea by a massive whirlpool. The end seems all but sure yet you open your eyes in astonishment and gaze upon a fantastic world never before seen by the likes of men. It's a magical world with many unbelievable possibilities, but your desire remains to find a way out and make it back home.

Thanks Velocity



 

 

Tuesday, March 27, 2012

Atlantis Trilogy Pack


Get three best-selling puzzle games for one low price! Embark on an adventurous journey around the ancient lands of the Mediterranean in search of the legendary continent of Atlantis. Find a way to bring the Lost Continent back to the surface. Acquire seven mysterious crystals of power to be able to restore the Altar of Poseidon and save the fabled sunken city.  Be the hero the world seeks to unravel the mystery of all times!



 

 

Adore Puzzle


Go on a fascinating tour in Adore Puzzle! Visit well-known European cities without leaving your computer in this fun Puzzle game! Begin your trip in England and explore other countries as you solve more difficult and interesting puzzles. Travel to different countries and solve the puzzles in different game modes. Beat your fastest times as you replay puzzles and master the fun gameplay of Adore Puzzle



 

 

PT2399 Echo, Reverb Effects Schematic Circuit


Brief Description:


IC PT2399 from Princeton Technology Corporation. Pin  15 and pin 16 to form a capacitance by changing the external resistance to change the input frequency response of the inverting amplifier, as the signal input. Pin 8, pin 9, pin 10 form an external pre-emphasis - Compare the source set, the internal microcontroller output DO0 after passing through the circuit compared with the input signal, thus completing the A / D conversion, and then 1bit of data into the microcontroller the Delay Line. 


Similarly, pin 11, pin 12 and pin 7 form to add - Compare source circuit, the signal from pin 12 out. And pin 13 , pin 14 is a separate inverting amplifier, and not directly connected with the internal processing circuitry, it can be used flexibly for the designers.


Pin 6 to control the speed of the internal MCU Delay Line VCO input, changing the voltage can change the delay time, and from pin 5 to monitor the current oscillation frequency. Pin 2 for the internal op amp reference when a single supply source, the integrated circuit is well within 1/2 partial supply voltage, so only the external access to anti-ripple circuit (voltage regulator) to.


PT2399 frequency response within the limits of about 5kHz, and when the input signal when the frequency is higher than 4kHz, sine wave input signal will become somewhat similar to the triangle wave, and in the input signal frequency is greater than 5kHz, it will produce distortion and digital noise. 


Although the guitar signal in the above information on this range is relatively small, but the delay of the chip to deal with these frequency response will be smooth and some distortion.
  

PT2399 input signal amplitude is about 3Vpp signal level higher than this range will be limiting. In the above diagram, the change of pin 15, pin 16 of the resistive and capacitive components, you can change the input frequency response; change components on pin 12 , pin 13, pin 14 of the resistive and capacitive components, you can change the output frequency response. 



The internal structure of integrated circuits based on PT2399, the two parts of the design is the operational amplifier filter design, designers can calculate the actual situation, to not repeat them here.
  

In addition, PT2399 VCO external setting resistors to the minimum, the delay time is 31.3ms, because of this a long time, not suitable for production of chorus or Flanger effects.

For more future information about IC PT2399

Source : http://http://www.avtech.cn/dv_rss.asp?s=xhtml&boardid=4&id=64&page=2







Echo Application Schematic Circuit







Guitar Effect Application Schematic Circuit






Bottom Layout of PCB






Component Layout of PCB

Stereo Audio Power Amplifier 11 Watt using LM4752



Featuring drives 4 Ohm and 8 Ohm loads, single supply operation, compact 7-lead TO-220 package, wide supply range 9V – 40V, internal thermal protection, internal gain resistors (AV = 34 dB), the LM4752 is a stereo audio application circuit of Stereo Audio Power Amplifier 11Watt using LM4752. amplifier capable of delivering 11 Watt per channel of continuous average output power to a 4 Ohm load, or 7 Watt per channel into 8 Ohm using a single 24V supply at 10% THD+N. This stereo audio amplifier is applied mostly in multimedia speakers, stereo TVs, Mini component stereos, and compact stereos.







schemtic digram circuit of Stereo Audio Power Amplifier 11 Watt using LM4752




The following article (well actually datasheet) contains detail information about LM4752 Stereo Audio Power Amplifier 11 Watt description, illustration, schematics and circuit diagrams, specification, key features, application, connection diagrams, absolute maximum ratings, operating ratings, electrical characteristics, test circuit, equivalent schematic diagram, system application circuit, external components description, typical performance characteristics and physical dimension. Here is a quotation from the LM4752 datasheet:


“Proper PC board layout is essential for good circuit performance. When laying out a PC board for an audio power amplifier, particular attention must be paid to the routing of the output signal ground returns relative to the input signal and bias capacitor grounds. To prevent any ground loops, the ground returns for the output signals should be routed separately and brought together at the supply ground.”


Find more about Stereo Audio Power Amplifier 11 Watt using LM4752 here – 22 pages of PDF filetype. (source: national.com). Find also other Audio Amplifier application you might be looking for.

External link:

LM4752 Stereo Audio Power Amplifier 11 Watt Datasheet – www.national.com

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