Related Manuals for ROSTEC LMA2
Summary of Contents for ROSTEC LMA2
- Page 1 ROSTEC LMA2 Microphone and Line Preamplifier ROSTEC LMA2 High Performance Microphone and Line Preamplifier...
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Page 2: Table Of Contents
ROSTEC LMA2 Microphone and Line Preamplifier Table of contents General description Front page……………………………………………………..…. 1 Contents ………………………………………………………..2 General description ……………………………………………… 3 Analog Inputs ……......…………………………… 3 Analog outputs…………......……………………… 4 Insert points…………......……………………..4 Digital outputs…………......……………………… 4 Clock input and output…......……………………… 5 Peak meter…..………......……………………..5 Power Supply…………......………………………... -
Page 3: General Description
ROSTEC LMA2 Microphone and Line Preamplifier Features General description The LMA2 is a 2 channel ultra low noise and ultra low 2 microphone inputs via the 25 pin D-sub distortion mic/line preamplifier designed with the female connector at the back panel ... -
Page 4: Analog Outputs
The SPDIF output is unbalanced, impedance 75 ohms, 1 Volt no load, 0.5 V into 75 ohm. The LMA2 features a high-end 2-channel 24 bit 192 kHz When connecting 2 pins on the 9 pin D-SUB connector, AD converter with impressive specifications. -
Page 5: Clock Input And Output
This is one of the basic reasons for the exceptional sonic quality of the LMA2 digital interface. When the LMA2 is connected to a host computer via USB, the sampling frequency is controlled by the The meter operating system, or it is selected from within the DAW. -
Page 6: Operational Description
ROSTEC LMA2 Microphone and Line Preamplifier Operational description Insert point switch Instrument/line input The toggle switch controls the bypass function of the insert point. The insert point exists electrically between the analog output of the preamp and the input of the digital circuit. -
Page 7: Input Gain Adjust
ROSTEC LMA2 Microphone and Line Preamplifier The button selects the digital functions: OFF led on: All digital functions are disabled. USB led on: The unit is communicating via USB. AES led on: AES/SPDIF from AD converter circuit. Indicates that the LMA2 is locked to external word clock. -
Page 8: Front Panel Quick Guide
ROSTEC LMA2 Microphone and Line Preamplifier Front panel quick guide... -
Page 9: Back Panel Quick Guide
ROSTEC LMA2 Microphone and Line Preamplifier panel quick guide Back... -
Page 10: Back Panel Connector Pin-Out
ROSTEC LMA2 Microphone and Line Preamplifier panel connector pin-out Back... -
Page 11: Remote Ground Connection For Line In
"receive" the environmental noise. This additional noise signal is fed into the balanced input of the LMA2 at the negative input terminal, canceling out the noise signal at the positive terminal without affecting the sound signal from the instrument. -
Page 12: Mechanical And Electrical Specifications
ROSTEC LMA2 Microphone and Line Preamplifier Mechanical and electrical specifications Analog circuit: Mic input impedance: 6 kohm Line input impedance: 1 Mohm/60 pF Max input level balanced, mic or line: +30 dBu Max input level unbalanced, line: +24 dBu Max input level balanced, direct input: +30 dBu... - Page 13 ROSTEC LMA2 Microphone and Line Preamplifier Clock system: Word clock input, BNC, unbalanced, unterminated (1.5 kohm), min. 0.2 Vpp, max. 10 Vpp. Word clock output, BNC, unbalanced, impedance 75 ohm, 5 Vpp no load, 2.5 Vpp into 75 ohm. Word clock frequencies: 44.1k, 48k, 88.2k, 98k, 176.4k, 192k.
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Page 14: Technical Section
Impulse response The above snapshots show the ideal step impulse response of the LMA2 analog circuit. When subjected to steep transients (in this case a 1 kHz square wave with 5 nsec rise time), there is no ringing and no overshoot. There is only total control. -
Page 15: Unwanted Hf Feedback
ROSTEC LMA2 Microphone and Line Preamplifier Unwanted HF feedback and oscillation in studio installations It may seem risky to install a piece of equipment witch exhibits such fast speed and high gain at the same time in a studio environment. Normally, when the input signal path and output signal path of a amplifier with high gain and high frequency response passes too close to each other, high frequency oscillation may occur. -
Page 16: Analog Classical Distortion Analysis
ROSTEC LMA2 Microphone and Line Preamplifier Classical distortion analysis There has always been great focus on distortion, when it comes to judging audio equipment. It can be argued, that any distortion product (2nd, 3rd harmonic etc) below -60 dB is inaudible, simply because the distortion tones are a consequence of the incoming tone, and thus are always masked by it. -
Page 17: Digital Classical Distortion Analysis
ROSTEC LMA2 Microphone and Line Preamplifier Analog in @ microphone input. Digital out @ AES output (identical to USB output) THD+Noise versus frequency. Of the analog circuit + the digital circuit. Range 20 Hz - 20 kHz @ -0.1 dBFS. -
Page 18: Digital Fft Distortion Analysis
ROSTEC LMA2 Microphone and Line Preamplifier Distortion in depth analysis. FFT (Fast Fourier Transform) A more detailed picture of the distortion characteristics can be seen using FFT analysis, which allows the magnitude of the individual distortion components to be quantified. FFT analysis has the advantage of being able to remove random noise in order to reveal the distortion component only. -
Page 19: Analog Crosstalk Analysis
Analog in @ microphone input CH1. Analog out @ analog direct output CH2 The balanced nature of the LMA2 really pays off. The crosstalk is below -120 dB in the main part of the spectrum. Only above 10 kHz is a slight increase can be seen, reaching approx. -115 dB at 20 kHz Note: This is a linear and unweighted measurement. -
Page 20: Hum And Noise
ROSTEC LMA2 Microphone and Line Preamplifier Hum and noise Using an analog power supply with an oversized toroidal transformer and linear regulators could be cause for concern. However, not to worry. The carefully designed power circuits create an electromagnetic quiet environment, free from the usual radiation pollution from a switch-mode power supply, and the true balance nature of the analog circuits really pays off.
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