Heritage Audio DMA-73

Description

Features • 80dB Class A Microphone preamplifier, HI-LO selectable minimum input impedance, balanced and floating. High gain positions show a higher impedance, ideal for old ribbon mics. • 50Db Class A Line preamplifier, bridging input impedance, balanced and floating. • All discrete Class A Ultra High Impedance J-Fet Direct Input on a high quality Neutrik Jack. The DI circuit is ahead of the Mic Input transformer, so the transformer is on when in DI mode. • Class A single ended, 2N3055 driven, high headroom output stage. • Individual Neutrik gold plated XLR connectors for microphone and line inputs. • Gold Plated Neutrik XLR output. • PAD: 20dB Mic input attenuation ahead of the input transformer to avoid overloading it. • HI PASS FILTER: Active all discrete Class A 3rd order Bessel, 80Hz Hi Pass Filter. 18dB/octave slope. • OUTPUT control to allow overloading of the preamp. • External linear PSU to avoid electromagnetic radiation into the audio transformers ( a.k.a. hum ). • Carnhill Input and Output transformers. • 3 gain stage, genuine B283 gain card modular construction. • Marconi style knobs and vintage style engraved pushbuttons. Specifications • Microphone input impedance: HI, 1200 Ohm minimum, LO, 300 Ohm minimum. Higher gain positions gradually have greater impedances, optimum for lo gain ribbon mics. Input is Carnhill transformer balanced and floating. • Line input impedance: 10K Ohms bridging, Carnhill transformer balanced and floating. • DI input impedance: Greater than 2 Megohms, unbalanced. • Output impedance: Less than 75 Ohms, Carnhill transformer balanced and floating, to drive a load of 600 ohms (factory terminated). • Maximum output: Greater than +26dBm into 600 ohms. • THD: Less than 0.025% at 1 Khz, less than 0.05% at 100Hz. • Frequency response: 20Hz ( +0.3dB ) to 20Khz (-0.2dB) • Maximum gain: Slightly greater than 80dB • Noise: Less than -100dBm. • Power consumption: Less than 200 mA @24VDC

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