Parallel single-ended A300 pure Class A true electron tube amplifier, high-fidelity Bluetooth 5.0

The current tube is Beijing FM30.

The Russian product name of FU29 is FY29, and the American product name is 829B. It is a composite tube that encapsulates two Cambodian emission quadrupoles in the same glass shell. It is used in a power amplifier with the same parameters in a parallel single-ended output. The unit with the same parameters in a tube is used in parallel. The filament voltage of FU29 is 6.3V, the current is 2.25A, the screen voltage is 600V, the curtain gate voltage is 200V, the zero signal screen current is 40mA, and the full signal current is 110mA. The gate bias voltage is -18V, and the optimum load impedance from the screen pole to the screen grid is 13750Ω. The output power (effective value) reaches 10W when the parallel single-ended is used. The circuit of this machine is simple, and a composite tube 6N3 is used as the pre-amplifier, so that a single channel with a 6N3 and a FU29 can complete the power amplifier task, and has a single-ended pure A power output of more than 10W. The actual thrust and hearing are better than 300B. The machine is small in size and unique in shape, but the thrust is strong. Do not use the power of general transistors or digital power amplifiers to compare the actual thrust of this kind of tube power amplifier, because of the high supply voltage and unique output structure, the output internal resistance change of high and low frequency signals is relatively small, and it has good low frequency driving ability. And the sound is soft and smooth, warm and delicate. This is also the reason why the tube power amplifier has not been completely replaced after the emergence of many new technologies.

At present, the production date of this batch of domestic electronic tubes we have received ranges from six years to eight years. The meticulous workmanship is amazing. It is hard to imagine that we could have completed such fine and complex products ourselves in that era, and the consistency is very good. The specific test has been compared with the EL34 and 300B, which are relatively highly recognized by the market. We think the sound of FU29 is remarkable, and it is not inferior to these internationally renowned famous tubes at all. Our domestic products have also had good products to be proud of. From the previous FU32 tube power amplifier we made, we have achieved good sales in both domestic and international markets, and the return and repair rate is basically zero. It can be seen that in any era, as long as it is a good and excellent product, it will be recognized by the market and users. We will continue to work hard!

We originally thought that such tubes should have a relatively large stock in the domestic market, but when we made the FU32 power amplifier, we found that it was not what we had imagined. As the number of tubes available on the market decreased, merchants continued to increase prices, and we were forced to adjust the sales price several times. The FU29 tube used in this machine is the same. When we started searching, we found that there were many sellers selling, and each had a lot of inventory. When we actually bought it, we found that there were only a few really in stock, so the number of tubes we actually got was not much, and the machines we could make would not be too many. Players who like it can start early, and this may disappear one day

This machine is suitable for pushing general bookshelf speakers and some floor-to-ceiling speakers with high sensitivity. The machine has added a new Bluetooth 5.0 receiver module to facilitate wireless connection of portable devices such as mobile phones.

The schematic diagram of this machine is as follows:

external dimensions: 194 Width X159 Height X311

Output power: 10WX2 (pure Class A, equivalent to Class A and Class B 50W thrust)

Accessories: 220V power cord 1 FM30 * 2, 6N3 * 2

Weight: With packaging, the courier fee will be charged at 10KG.

The whole machine quality assurance for two years. The tube is all in-line quality assurance for 3 months (burning filament, cracked screen is not within the scope of quality assurance)

Price of a separate chassis: $150 (including switches, knobs, and power seats)

The large knob is the volume control. POWER on the left is the power switch, and BLUE on the right is the Bluetooth control switch.