Aurora Audio GTP1 Microphone Preamp

The Aurora Audio GTP1 is a single channel preamp using the same circuitry as the GTP8 units and is basically a GTQ2 minus the EQ part. It is not a clone of anything. It is an Aurora Audio design using their exclusive input and output transformers. The DI is a pair of boot strapped transistors and provides an input impedance of 10 mOhm and an additional 10 dB gain. Guitar pickups will be unloaded and, unlike lower impedance systems, every nuance of the sound will be captured.

The GTP1 can accommodate any signal you care to throw at it, including high-level line inputs. The sensitivity switch provides gain adjustment in 10 dB steps from +80 dB to –10 dB and the level pot allows for fine adjustments of level between +6 dB and -6 dB and also turns down to infinity so that the output level can be turned down and the input gain turned up to get overdriven guitar sounds!

The D.I. input has 10 Megohm input impedance and around 10dB gain. It can be used (to great effect) with musical instrument pickups, but works equally well with high-level signals like a D.A.T. or CD player. If you insert a jack into the front jack socket it will automatically disable the signal from the rear panel XLR.

The GTP1 has a built in switching power supply, custom made to Aurora's specs, with a massive power headroom and can accommodate input voltages in the range of 85 V to 265 V, 50/60 Hz. All metalwork is steel, Aurora don’t use aluminum for anything. Steel is stronger and provides EMF shielding as well as being less prone to damage in transit.

Specifications:

• Input impedance: 1200 Ohms
• Output impedance: <50 Ohms
• DI Input impedance = 10 mOhm
• Noise at +80dB gain, terminated 200 ohms and measured 22 Hz to 22 kHz is <-47 dBu giving an EIN of better than -127 dB
• Frequency response: -1 dB at 20 Hz and >50 kHz
• Distortion plus noise at unity gain at 1 kHz is <0.05% measured 22 Hz to 22 kHz
• Maximum output: +26 dBu