Yamamoto Sound Craft EQB-01 Vacuum Tube Phono Equalizer Amplifier

The circuit of the EQB-01 amplifier was completely reviewed and the SN ratio of the amplifier was greatly improved.



EQB-01 is a unique circuit method using a five-pole tube for amplification.

Divide the ripple filter of the power supply from the rectifier circuit separately for each stage and supply each stage from the independent power supply. Rectification circuits improve regulation by double wave rectification. The ignition of the heater of the vacuum tube Telefunken 6AK5W has provided an independent rectification circuit for each of the six vacuum tubes, eliminating interference with each other's vacuum tubes. In addition, the amplifier circuit maintains the same method as the basic circuit, and by resetting the operating point to the optimal point, it achieves a large gain and reduces noise.



Equalizer amplifier gain is high-gain type, 58 dB. Normal equalizer amplifier gain is about 34 dB, so it is 24dB larger than the standard setting. SN ratio achieved 110dB due to 2.3mV residual noise in that state. The gain is obtained from only two vacuum tubes, so there is no lack of information because it is very simple. Generally, it is a CR-type circuit configuration that is disadvantageous to the SN ratio, but it proves that depending on the usage method it gets a fairly good SN ratio. The maximum output is about 28V, so it can support not only MC cartridges, but also large MM cartridges and high power MC cartridges. Actually, the MC cartridge YC -03S,YC-03M is directly connected to the level that can be used without using a boost transformer. Since the output of the YC-03S is 0.25mV, most MC cartridges can be used directly. The MC cartridge's sound is high in freshness and greatly improves the amount of information. In addition, the input impedance of the equalizer part of the amplifier such as the company's CA-03 is 100Ω optimal.
The EQB-01 is CA-03 a configuration that omits the line amplifier from the CA-03L and omits the input volume and selector switch. The substrate also improves sound quality by gold plating the thickness of copper foil to 70μ
Equalizer Amplifier

Maximum output	28V
Frequency Characteristics	30-15kHz/+-0.5dB
Input Impedance	47kΩ,1kΩ,100Ω
Output Impedance	4.8kΩ
Amplification rate	58dB/1kHz
Residual noise	2.3mV
S/N ratio	110dB
Size	420(W)290(D)94(H)mm
Weight	6.3kg

Delivery may take 1-3 months for almost order-made production.