Golden Age Project GA-800G Large-Diaphragm Tube Condenser Microphone
The classic C800G is the only tube microphone in the world equipped with a semiconductor active cooling system that results in a higher signal-to-noise ratio compared to most other tube microphones. It has a very high-quality modern sound performance.
The Golden Age Premier GA-800G is currently the only microphone to fully reproduce the C800G. It´s appearance and structure, as well as accessories and circuit principles, including its sound character, strictly follows the original design. All of the parts including the power plug and the pin definition of the power supply are the same as in the original C800G.
Even though its based on the original, the circuit board has been upgraded to a ROGERS ceramic circuit board that has superior insulation parameters and offers a more stable performance. The coupling and bypass capacitors has also been upgraded, resulting in a deeper and more exact low frequency performance and a more delicate and transparent high frequency reproduction.
The classic semiconductor active cooling and external cooling system from the C800G is also used in the GA-800G. This is to ensure that the GA-800G has the highest possible signal-to-noise ratio. The tube (a 6AU6) is mounted in an aluminum casing, with the semiconductor cooling chip being attached to the bottom of the case. The temperature of the tube in the GA-800G is the effectively kept down when the GA-800G is in it´s working state, the heat generated by the tube is actively dissipated. The heat that the tube generates is transferred to the reverse side of the semiconductor and transferred to the effective outer aluminum alloy heat sink at the rear of the microphone. This heat sink will then dissipate the heat from semiconductor cooling chip to the air surrounding the GA-800G.
A ROGERS ceramic gold-plated circuit board is used. This type of circuit board is usually used in high-end aerospace communication products, the cost is about twenty (20!) times higher than an ordinary PCB board.
By disassembling a C800G and handing it´s capsule to a manufacturer with more than twenty years of microphone capsule production experience, they were able to produce a capsule that matched the characteristics of the original one. The capsule used in the GA-800G can handle a higher sound pressure level than the original one and it has almost the same sound character.
In order to ensure the tube will have a long life, we are using a NOS CIFTE 6AU6 tube from France, it has a maximum anode voltage rating of about 300V. The tube in this circuit has an anode voltage of 90V and will generate more heat than tubes in many other tube microphones that typically uses voltages between 35-50V. The higher voltage used in the GA-800G increases the heat dissipation so the semiconductor active cooling system is an important element in the design.
The classic 800G uses two 6AU6 tubes as rectifiers for the high voltage rail, they work as pseudo diodes by connecting all grids to the anode that outputs about 290V.
After a lot of listening tests comparing a tube rectifying circuit with a solid state one, we found that we did prefer the sound of the latter so this is what we decided to use. The additional advantage is that there is no need to worry about replacing tubes in the power supply.
Capacitors, resistors and solder:
The metal resistors and electrolytic capacitor from Japan are of special audiophile audio types. The coupling capacitors are Siemens EPCOS from Germany.
The connecting wires inside the GA-800G are oxygen-free copper wires from Japan. The solder is FELDER silver/copper-containing solder from Germany.
Designed for the highest possible sound reproduction quality.
Suitable for vocal recording in studios and film post production houses.
A high sensitivity of -33dB/Pa.
Low noise and low distortion due to built-in cooling system.
Large diaphragm capsule.
Electronically selectable directivity, Omni and Cardioid.
Microphone Type: Tube Condenser
Polar Pattern: Cardioid, Omni
Frequency Response: 20Hz-20kHz
Max SPL: 137dB (Cardioid), 140dB (Omni)
Output Impedance: 100 ohms
Signal to Noise Ratio: 76dB
Self Noise: 18dB (A weighted)