T L Audio User Manual Ebony Series A1 Dual Pre-Amp TL Audio Limited, Letchworth, England. Tel 01462 492090, Fax 01462 492097. www.tlaudio.co.uk email: info@tlaudio.co.
TABLE OF CONTENTS TABLE OF CONTENTS.............................................................................................................................. 1 INTRODUCTION ......................................................................................................................................... 2 WHY CLASS-A?............................................................................................................................................ 2 WHY TUBES?..............................
INTRODUCTION New from TL Audio, The Ebony Series is a sleek looking range of discrete Class A processors designed to heighten your audio experience. The range consists of 3 units, all of which use Discrete Class A circuitry and have an optional tube stage with variable drive putting you in control of how ‘creamy’ or how ‘cool’ your unit sounds.
Why Tubes? Valves - or “Tubes” - have long been associated with excellent audio quality, recognised as adding “warmth” or “depth” to a signal. Driving the valves harder results in an increasing level of mainly second harmonic distortion, which is responsible for the characteristic overdriven valve sound. The Ebony Series feature variable drive valve circuits, which may be switched into the audio paths, or bypassed completely.
The block diagram of one of the channels is shown in fig.1. A discrete Class A electronically balanced mic input amplifier is used, delivering superior audio performance with very low noise, low distortion and wide bandwidth. The mic input is suitable for low impedance (150-600 ohm) microphones, with a gain control range of +16 to +60dB. Front panel switches provides 48V phantom power, and 30dB pad for high output mic applications.
PRECAUTIONS The T L Audio Ebony Series units require very little installation, but like all electrical equipment, care must be taken to ensure reliable, safe operation.
BLOCK DIAGRAM.
INSTALLATION AC Mains Supply. The unit is fitted with an internationally approved 3 pin IEC connector. A mating socket with power cord and mains plug is supplied. All mains wiring should be performed by a qualified electrician with all power switched off, and the earth connection must be used.
in a loss of level and/or increased noise. Good quality screened cable should be used, particularly for microphone or low level sources, to prevent hum or noise pickup. Instrument Inputs. A 2 pin (mono) jack plug is required, which should be wired as follows: - Tip = Signal Phase (“+” or “hot”). - Screen = Ground. Outputs. The outputs are via balanced, 3 pin male XLR connectors.
OPERATION. Microphone Input The 2 XLR mic inputs are at the rear of the Ebony A1. Virtually any low impedance professional microphone can be used. Condenser microphones will require the 48V phantom power button to be engaged for correct operation, but before using Dynamic and Ribbon microphones ensure that the phantom power is switched off.
Tube Stage Drive and Peak LEDs. These LEDs indicate the drive level to the tube, or valve, stage. The Drive LED is a variable intensity indicator, starting to glow when the tube harmonic distortion is around 1%, and being fully illuminated at approximately 5% harmonic distortion. The distortion is predominately second harmonic, unless very high drive levels are used, in which case the tube is eventually pushed into harsher saturation, indicated by the tube Peak LED. Output Peak LED.
GETTING STARTED 1. Having powered up the Ebony A1 and ensured all the gain controls are at minimum connect its line output to the desired line input on your console, recorder or sound card.
SPECIFICATION. Mic Input: Discrete Class A circuitry from input to output (unless Tube stage In). Gain Range: +16dB to +60dB (-14dB to +30dB with pad), Maximum Input level: +10dBu (without pad), +30dB (with pad), Frequency Response: 10Hz to 40KHz, +0, -0.5dB, @ 40dB gain, Distortion (THD + Noise): 0.025%, 20Hz to 20KHz @ 40dB gain, Noise (EIN): -127dBu unweighted, 22Hz to 22KHz, 150 ohm source termination. Instrument Input: Tube input stage, plus discrete Class A circuitry to output.
Tube Stage: Typical Distortion: 1% to 10%, depending on “Drive” level, predominately second harmonic. Noise: -80dBu (22Hz to 22KHz), output gain @ 0dB. Metering: Tube “Drive” LED: Variable intensity over 10dB level range, typically corresponding to 1% to 5% THD. Tube “Peak” LED: Dependant on level and drive, typically corresponding to 10% THD. Output “Peak” LED: +19dBu on output. VU Meter: Switchable to Channel 1 or 2, and Input or Ouput. Nominal calibration: 0VU = +4dBu.
SERVICE Should the unit require service, it must be taken or posted to an authorised dealer with a description of the fault. Please retain the original packing for possible future use, and ensure the unit is suitably protected during transit. The manufacturer cannot accept responsibility for damage caused during transportation. This equipment is supported by a limited warranty for a period of one year from the date of purchase.