Sunday, March 3, 2013

IWISTAO HIFI 2x100W Bluetooth4.0 Power Amplifier Audio NE5532 Preamplifier 2SA1941/2SC5198 APT-X

 IWISTAO HIFI 2x100W Bluetooth4.0 Power Amplifier Audio NE5532 Preamplifier 2SA1941/2SC5198 APT-X


This is a HIFI Bluetooth Music Amplifier that adopts To shiba 2SA1941 and 2SC5198 transistor, and support Bluetooth 4.0, its output power is up to 2x100W. There is two modes of signal input, Bluetooth and 3.5mm AUX line-on two modes, you can select by yourself.


IWISTAO HIFI 2x100W Bluetooth4.0 Power Amplifier Audio NE5532 Preamplifier 2SA1941/2SC5198 APT-X from IWISTAO HIFI MINIMART1 on Vimeo.


The HIFI Bluetooth music amplifier is designed as class AB with full structure of separated components and parts, and scientific, rational PCB layout and strict sound adjusted so that it performs distinctive sound. And add distortion servo circuit in the circuit design, so when large dynamic come, its performance is leisurely, unhurried. Meanwhile, its amplified circuit adopts NE5532 as a preamp, and T oshiba tube as power amplifier stage, these two parts complement each other. In addition, it builds amplifier speaker protection circuit inside to protect your speakers. Cooling system is made of blackening treatment process of heat sink, and a fan that connected with heat trace wire to the heat sink with forced cooling.


Brushed aluminum panels, black metal housing, it is noble and elegant. It is adopted that transformers toroidal with all copper, high efficiency and low leakage, which provides powerful current, thus providing better, more pure sound. As a HIFI Bluetooth desktop amp, front panel has a third selection for signal input, Bluetooth / PC / AUX; and there is tremble and bass knob for tone adjustment and AUX input jack.


Also there is bass and tremble adjustment knob on the front panel.


More details, please find 

Thursday, December 6, 2012

Development Story of Portable Speakers System

Development Story of Portable Speakers System 


When popular style is becoming a trend, portable speakers begin to become popular as same as street dancing a couple years ago. Features of portable speakers is compact, portable, and quality sound to meet needs of people's daily lives, such as learning, entertainment, leisure, etc. It can play portable media such as SD card, TF card, USB disc and so on. Music signal as MP3 or WMA which are stored in these media above mentioned, and those music signals will be decoded by decoding circuit inside through digital-to-analog conversion, and then they will be amplified by power amplifier circuit to drive speakers for playback. Wistao technology released several products to markets.


Portable Speakers System

Portable Speakers System


Stereo Portable Speakers System

Stereo Portable Speakers System


Stereo Portable Speakers System

Stereo Portable Speakers System


Speaking broadly, portable speakers is small in volume and distinguish itself from those larger HIFI home theaters, music centers, 2.0 or 2.1 multimedia speakers, etc.. General it’s volume are relatively small and can be easily put in bag, using storage card or wireless signal to play music media, and getting power from battery; its main advantages is portability. Not only indoor but outdoor can play normally. But anyway, it is a class of active loudspeakers. We will explore its development story from portable view.



Stereo or speakers were not considered as portable before transistor hit market. Perhaps you might also see some antique tube radios or phonographs working with horn speakers from film and television; they were generally to be placed somewhere in room like living room or reading room. If present electronic products compared with it from volume view, it will be described as a small sorcerer in the presence of a great one due to its bigger volume. By the way, you can find a computer at that time, which volume was larger as a building. With transistor application, electronics product’s volume became smaller and smaller, thinner and thinner. Last 1950s and 1960s, Sony used transistor technology to make radio and instant hit in the United States, opened U.S. market. And later Sony developed an innovative products Walkman, which could be said is an "originator" of portable speaker. It is an analog audio player based on tapes. After then CD emerged, it marked advent of  digital age, is " 0 " and " 1 "era, which greatly improved sound quality of audio playback.CD avoid mechanical wear as tape player due to its non-contact signal reading technology, also avoid distortion of the signal source. After two or three decades, Internet age was coming. Industry found a 640M CD disc that can be stored only ten to twelve tracks, CD disc capacity is limited and does not facilitate transmission within networks, so they developed music compression format technology firstly --- MP3 format, that did not affect the sound quality of  music, and track capacity became smaller from 30 to 40 megabytes of CD format to only a few megabytes of compressed MP3 format for a same track, so it’s transmission within internet network becomes very easy. During this period, portable CD player based on a CD disc media called Discman emerged; its music is listened by headphones. And MP3 player was also hit market as portable music devices, but it needs to use headphones to listen.



With popularity of desktop PC, multimedia speakers have become a standard of the computer active speakers, but it can only be accompanied by the computer around as much less as portable. During the period, a variety of digital products such as SD card, TF card, USB disk were be developed, and their storage capacity was also growing; Large capacity rechargeable battery and LSI Class D amplifier were adopted on portable speaker, it made portable powered speakers miniaturization, which also led to emergence of digital portable speakers, to achieve a truly "portable", which is digital portable speaker today.



Technology continues to progress, and it has also changed our lives. With advent of powerful decoder chips, portable speakers’ feature also is becoming more and more powerful, many functions have been added to portable speaker, lyrics display, repeat, breakpoint memory, multi-format music player, etc.; while added bass enhancement technology to speakers’ cavity, it can reproduce familiar quality sound as HIFI speaker.




Saturday, December 1, 2012

Mud Is Gone

Mud Is Gone 


Most of us might experience to hear poor music with poor audio devices. Now, you can put them away.Do you recall the voice of the teacher from The Peanuts cartoon, by Jim Shultz? The students responded with "yes, sir" and "I understand, sir". How they understood "woh woh...wah woh woh wah...woh" has always vexed me deeply. Take that now into the portable Bluetooth speaker market, and many speakers follow the same muddy but  Wistao Bluetooth speaker, "woh wah" approach to reproducing the music, games, movies and speakerphone calls we strive to access everyday.

The human ear is capable of picking up a certain range of sound frequencies. Research shows this range to be 20hz to 20Khz. Sound is measured and perceived in frequency (pitch) and intensity (loudness). Frequency is measured in hertz or hz. What does all this techie talk mean and where am I going with all this?

High definition or high fidelity (hifi) audio comes down to one word...clarity.
Here are some real world examples of sounds we hear everyday and the general frequencies they produce (and we perceive):
  • Rumble of thunder = 50hz to 250hz
  • Average size dog bark = 500hz
  • Leaves rustling = 800hz to 4Khz
  • Bird chirp = 4Khz to 6Khz
  • Human voice = 150hz to 8Khz
  • Human voice through a telephone = 300hz to 4Khz
We like to break the sound spectrum into 4 easy bands, or frequency ranges:
  • Low band= 20hz to 200hz
  • Low-Mid band = 200hz to 800hz
  • Mid-High band = 800hz to 4Khz
  • High band = 4Khz to 20Khz
These bands may look familiar to you, more commonly known as EQ. Car stereos, home stereo systems, and most portable audio devices have some sort of EQ capability for you to adjust the sound bands to your liking. Many of these devices use terms like bass, mid, and treble.

Our anti-"woh wah" campaign deals with the mid-high and high bands of portable speakers and Bluetooth speaker, or any speaker for that matter. I believe these two upper bands are the most sensitive hearing ranges for humans. This is where the clarity and presence of speech occurs. The tone or warmth of speech is in the low-mid band. Without good reproduction of these upper two bands, the clarity or high fidelity sound is lost...gone...outta here...trapped in the land of woh-wah. Many speakers do not consider the top of the high band either (8Khz and up). This is that range of brightness and sizzle, that I call "air",that gets forgotten many times and brings an added clarity to your audio sources. What good is a speaker (or speakerphone) that doesn't accurately reproduce the most sensitive range of hearing for humans? It is my strong belief that a speaker should accurately reproduce the human voice first (with high band emphasis and "air"), then more full-range, musical content second.

As you hunt for a great speaker solution, be aware of these ranges of sound, especially the mid-high and high bands. I have come to appreciate the detail and high band clarity of a well-engineered speaker over one that can create that huge "thump" of bass. Especially a speaker that you can fit in your hand or toss in your backpack.

So, travel with caution on your audio journey, declare clarity as king, and watch out for the mis-engineered speakers from the muddy land of "woh- wah".