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 Tube Amp Class A SE 6G2P Drive 6P6P Bamboo Casing + 4 Inch Full Range Bamboo Speaker Cabinet
Tube 6p6p (or 6v6) is specifically designed and developed power output tube for the audio field, sound performance had been proved since it hit market, whenever savored carefully, nostalgic thoughts immediately felt.
Make this power amplifier is based on the classic circuit of 6p6p (6v6) power tube, and we select HIFI components and parts to create this Class A single-ended tube amplifier, sound satisfactory by users, we would like to share it with all fans!
Also the 4 inch full range speaker cabinet is made of bamboo.
The music source of demo video came from desktop music player foobar2000, and the notebook is connected with a Bluetooth 4.2 receiver with vacuum tube 12au7 as a buffer.
The Moon Represents My Heart from IWISTAO 3 inch Range Speaker Solid Wood Labyrinth Cabinet
Man voice of The Moon Represents My Heart from IWISTAO 3 inch Range Speaker Solid Wood Labyrinth Cabinet
This speaker cabinet is made of solid wood. Built-in a labyrinth structure, it can enhance the low-frequency radiant energy, make low-frequency dive deeper, effectively overcoming insufficient bass of commend full range speaker cabinet, make the speaker cabinet the full-frequency be more full and rich.
Also, there are 2 demo videos for the middle and bottom speaker, but they were drove by two difference type preamplifier.
The middle with a 6080 tube preamplifer
The bottom with a passive preamplifier
Their cabinets are labyrinth structure but also there are some differences as below.
The up's structure as below, and the left is for 3 inch full range speaker unit (the right is for 4 inch one).
The middle's structure as below, and the left is for 4 inch full range speaker unit (the right is for 3 inch one).
The demo video for IWISTAO 3-4 Inch Full Range Empty Speaker Cabinet Labyrinth Solid Wood Strengthening Bolts Inside
This speaker cabinet is made of solid wood with strengthening bolts inside. Built-in a labyrinth structure, it can enhance the low-frequency radiant energy, make low-frequency dive deeper, effectively overcoming insufficient bass of commend full range speaker cabinet, make the speaker cabinet the full-frequency be more full and rich.
IWISTAO Vacuum Tube Amplifier 300B Kit Single-ended Class A No soldering 6F3 Preamplifier DIY Kits HIFI
Vacuum tube 300B is a mysterious vacuum tube with a long history, and don’t know how many music fans are fascinated. I still don’t know how many people are struggling to find its real voice. The audiophiles think that 300B is a female voice representative. But our 300B kit circuit is the embodiment of the sound of rigidity and softness. It is not only an attentive and charming woman, but also an iron and tender prince charming.
There are also rumors that the low frequency of 300B is not good. From an electrical point of view, the internal resistance of 300B is only about 800 ohms, which shows its damping coefficient is very good. Why is the rumors so? This is depended on the quality of the power supply, time constant of the circuit design and other reasons.
In fact, 300B tube is the best way to reflect the original atmosphere of music, because the tube’s characteristic curve distribution is excellent, coupled with second-harmonic sense of hearing, the mouth shape of the singer, the low-frequency tension of the chest resonance, its dynamics can be said to reach the perfect state, if regardless of the power, hundreds of thousands of transistor world-famous machines are difficult to surpass in the same power range as the 300B. From the acoustic point of view, the sound of the 300B tube amplifier is more expressive and richer, musical sense.
Our vacuum tube 300B kit has a unique acoustic and electrical regulatory concepts from the design to the selection of the output transformer.
The vacuum tube 6F3 is a relatively unpopular composite tube, which is quite a 12ax7+6p14 inside. Because of the large inventory, the price is related low, but its performance is extremely excellent, especially when it is connected as triode tube, which output internal resistance is particularly low, and linearity is good, driving 300B is absolutely no problem. In addition, many senior enthusiasts will inevitably ask, why use large loop feedback? This is our consideration of sound and stability. The large loop will sacrifice the transparency of mid and high frequencies. However, in order to improve the weakness of the low frequency of the tube, adopt the large loop can will make the internal resistance of the 300B tube amplifier lower, so that its overall sound balanced.
The FU33 electron tube is a direct-heating thorium carbide cathode glass triode, the anode cooling method is natural cooling, the maximum anode dissipation power is 350W, the maximum operating frequency is 30MHz, and the output power is 1000W. It is mainly used for oscillation in industrial high-frequency heating equipment and amplification in radio equipment.
This tube can be used interchangeably with the 833A/C type electron tube produced in the United States.
Vacuum tube FU33 is a high-power triode, usually used in communication equipment, with the characteristics of high voltage resistance. Some data of FU33 are indeed very scary. For example, the maximum anode voltage can reach thousands of volts, the maximum anode dissipation power is about 300W, and the filament current can reach 10A, which is very harsh on power supply. It seems that using FU33 to make power amplifiers is not an easy thing, but why use it? A senior audiophile said, "This vacuum tube has good pressure resistance, good sound, strong three-dimensional sound field, strong dynamic output of Class A, and freely retractable."
The DIY project spent a lots of efforts from at least 6 months ago, and now finally finished.
Here, we attached some data of vacuum tube FU-33 for you information.
Basic Parameters
Filament Voltage ……………………………………………… 10 V
Filament Current ……………………………………………… 9.4---10.6A
Inter electrode Capacitance
Grid Plate …………………………………………………… 5.5--7.1 pF
Grid Cathode ………………………………………………… 10.1—14.5 pF
Cathode Plate ………………………………………………… 6.4—10.6 pF
Amplification factor……………………………………………… 31.5-38.5
Operation Frequency …………………………………… 30MHz
Anode DC Voltage…………………………………………… 3kv
Anode DC Current ……………………………………………… 415Ma
Grid Current ……………………………………………… 40-70mA
Grid Impedance ………………………………………… 3.5/5 kΩ
Output power ……………………………………………… 1000W
Application ……………………………………………… broadcast communicate and High- frequency hearting.
Cooled style …………………………………………… wind cooled
Limit using parameter
Maximum filament voltage: 10.5V
Minimum filament voltage: 9.5V
Maximum anode DC voltage: 3300V
Maximum anode power dissipation: 350W
Maximum grid power dissipation: 20W
Mechanical Parameter
Weight: (approximately) 0.6Kg
Installation method: vertical, anode lead up
Cooling method: natural cooling
The highest temperature of the shell: 225℃
The highest temperature at the sealing joint: 200℃
High temperature at the terminal: 200℃
Use requirements and precautions
1. When using electronic tubes, there should be no more than one limit value parameter. Exceeding the limit value is not allowed even for a very short time.
2. The lead wires connected to the electrode of the electron tube must be in good contact with the electrode, otherwise an arc will be generated, and the electrode will be melted through, causing the tube to leak.
3. The electronic tube should be handled with care during packaging, storage, transportation, and replacement to avoid damage.
4. When the electron tube is working, the ventilation should be good, the surface temperature of the electron tube should not exceed 145 degrees Celsius, otherwise, the glass bulb should be blown to cool.
5. Note: When the anode dissipation power is greater than 300W, the glass bulb is blown and cooled.
Applications
More details for vacuum tube FU33 (813A/813C), please find here.
