Dizengoff Audio Type 47 Microphone Amplifier

Presenting the Type 47 mic preamp from Dizengoff Audio. The Type 47 is an upgraded version of the D4 mic preamp. It features a number of upgrades to the original D4. It uses large, hand-wound signal transformers based on early EMI designs for improved frequency response and low end. It adds user-selectable input trim capability. It adds improved internal and external shielding thanks to our latest next-gen enclosure technology.

The Dizengoff Audio Type 47 is a tribute to a rare and much loved British tube console from the 1960’s.  The original circuit was designed by the Recording  Engineering  Development Department as a replacement for the Siemens V72S amp cards used in an earlier British console.  It featured three gain settings (+36, +40, and +46), and a ‘fine trim’ knob that allowed the user to trim gain by a few dB.  

The Type 47 has expanded that range from +20 up to +60 using a 12 step rotary attenuator. It also adds a rotary Input Trim, allowing the input signal to be padded down between 0 and -18dB. Like the original design, the Type 47 also has a ‘Fine Trim’ control allows the user to fine tune the gain by 2-4dB depending upon the gain switch setting.

The sound is huge and open–heard on albums recorded by The Beatles, Pink Floyd, and The Zombies between 1964 and 1968.  It has incredible detail, and the kind of wonderful coloration that only an EF86 pentode can deliver.  It’s often considered to be the sound of John Lennon’s “Revolution,” which used two console channels in series to achieve an overdriven sound.

Signal path transformers are custom wound, right here in house.  They’re based on the transformers used in the original, but they take advantage of modern materials. The input transformer is made of Metglas Amorphous alloy, and the output transformer is a lo-nickel (50% nickel) for excellent fidelity.

The power supply is internal.  It’s built around a Japanese Nippo Steel R-core power transformer.  It has extremely high efficiency and low noise compared with traditional E-I core transformers and plays a significant part in achieving the Type 47’s low noise performance.

The enclosure makes use of a type of copper laminated polymer material known as G10. In testing, it was shown to offer superior shielding and noise reduction compared to traditional steel or aluminium enclosures. It's paired with a powder coated aluminium faceplate.

Features

• 2U flat black copper/polymer chassis with aluminium face plate coated in ANSI 61 Grey

• IEC power inlet

• XLR input and output

• DI input

• 12 position stepped gain control, 20-60dB

• Trim control, for fine adjustment of gain

• 4 position rotary input trim control, 0 to -18dB attenuation

• +48v phantom power

• phase reverse

• dimensions, 3.5" tall x 19 wide (faceplate) 3.45" tall x 6" deep x 17" wide (enclosure body)

Specs

• Frequency response 20Hz-60kHz

• THD+N at 1Khz: 1%,+4dBU, 10-24kHz bandwidth

• S/N -90dBA at maximum (+60dB) gain, 10-24kHz bandwidth