IWISTAO Blog is the official platform of IWISTAO HIFI MINIMART, dedicated to high-fidelity audio and DIY electronics. We focus on tube amplifiers, output and power transformers, speaker enclosures, and Bluetooth audio technologies, including HiFi Bluetooth speakers, headphones, and tube-based acoustic systems. The blog shares product insights, technical knowledge, and practical guides for audiophiles and audio builders worldwide.
IWISTAO HIFI Bluetooth 5.1 Stereo Decoder Qualcomm QCC5125 Hardware Decoding Bluetooth Optical Inputs APT-HD LDAC
Overall sound performance of this decoder is full of simulation, its vocals are rich in emotion, and the performance of slow music is also very good, full of vinyl flavor.
IWISTAO FU29 vacuum tube pull push amplifier with Bluetooth wireless connection
This FU29 vacuum tube named FY29 in Russian, and named 829B in American. It is a composite vacuum tube in which two Cambodian tetrodes are packaged in a same glass shell. It is generally used in power amplifiers with push-pull output, which can reduce tube selection and matching trouble. FU29 filament voltage is 6.3V, current is 2.25A, screen voltage is 600V, curtain grid voltage is 200V, zero letter screen current is 40mA, full letter current is 110mA. The grid bias voltage is -18V, the optimal load impedance from the screen to the screen grid is 13750Ω, and the output power (effective value) reaches 44W when the signal is full. In order to further simplify the circuit, this unit uses a composite tube 6N2 for preamplification and phase inversion, so that a single channel can use 6N2 and a FU29 to complete the power amplifier task, and it has 40W power output.
It is small in size, unique in shape, but strong in driving force. Do not use the power of general transistors or digital power amplifiers to analogize the actual driving force of this tube power amplifier, because the high supply voltage and unique output transformer’s structure, its output internal resistance change for high and low frequency signals is relatively small, and it has a good low frequency driving ability. And the sound is soft and smooth, warm and delicate.
This is why the tube amplifier has not been completely replaced after the emergence of many new technologies.
The video demo the manufacturing process for IWISTAO empty speaker cabinet made of HDF board. Step by step as below.
1. Smooth cutting with uniform density board
2. Precise hole cut by CNC
3. Environmentally friendly woodworking glue
4. Strong and durable enclosure with air nail reinforcement
5. Rosewood grain leather, all hand-painted
I remember everything from IWISTAO 12 Inch Full Range Speaker Unit without a baffle
The speaker is one inch large and one inch strong, small speaker unit to listen details, and large speaker unit to listen energy. Large-caliber speaker unit have a wide sound field, which is unmatched by small-caliber speakers. The speaker cone frame adopts aluminum die-casting structure, the paper cone is a leather-edge suspension paper cone, and its magnetic circuit adopts a symmetrical magnetic circuit structure with a short-circuit ring, and the magnet adopts Y35 aerospace magnetic outer magnet.
The performance of speaker unit is deep and full in low frequency, beautiful and lyrical in the midrange, clear and bright and elegant in the treble, and full of penetration, also its vocal performance is very outstanding. It is a good match with the tube amplifier, such as 300B, 2A3, EL34, KT88, etc.; Because the speaker unit’ sensitivity is high, the output power of 3 to 5W can produce very good sound. At the same time, it is also suitable for transistor power amplifiers.
This is a tube preamplifier with tube rectifier and linear pre-amplifier stage that is made of tube 6N8P as preamp and tube 6Z5P as tube rectifier.
Designed as a modified non- negative feedback amplified outstanding circuit, and adopt HIFI components manufactured, to ensure that the volume of cases in any accurate sound field , rich layering; high frequency is slim and sleek, beautiful sounds. Singer’s dental and the slightest breathing switched sound could be heard clearly, music rich, sensual fruity, sweet vocals.
Adopting two-stage direct-coupled amplifier circuit, strong vacuum tube flavor, deep extension at both ends, and large dynamic range.
The chassis is made of red walnut wood, 20mm thick solid wood rather than veneer, with rose gold mirror stainless steel top plate, appear luxury.
