ISA One User Guide FA0187-01
Warnings & Cautions THE APPARATUS SHALL NOT BE EXPOSED TO DRIPPING OR SPLASHING, AND NO OBJECTS FILLED WITH LIQUIDS, SUCH AS VASES, SHALL BE PLACED ON THE APPARATUS VENTILATION SHALL NOT BE IMPEDED BY COVERING THE VENTILATION OPENINGS WITH ITEMS, SUCH AS NEWSPAPERS, CLOTHS, CURTAINS ETC. NO NAKED FLAME SOURCES, SUCH AS LIGHTED CANDLES, SHOULD BE PLACED ON THE APPARATUS MAINS LEAD - THIS EQUIPMENT MUST BE EARTHED AND FITTED WITH THE CORRECT LEAD FOR THE COUNTRY OF OPERATION.
Contents 1. Warnings and Cautions......................................................................................................... 2 2. Contents............................................................................................................................... 3 3. Getting Started and Powering Up ......................................................................................... 3 4. Front Panel ........................................................................................
Front Panel 14 1 3 4 2 5 8 9 6 20 15 13 16 21 7 10 22 11 12 17 18 19 . Gain dial: selects the gain of the input in stepped values of 10 . Trim dial: allows an additional 20dB of gain to be applied to a mic or line signal . Activates a gain range of 30-60dB across the stepped Gain dial (the default is 0-30dB) . Phantom Power switch: supplies +48V to the MIC input on the rear panel 5. Inverts the phase of the signal 6. Activates a high-pass filter 7.
Input Pressing INPUT steps through each of the three inputs, as indicated by the corresponding LEDs. When the Mic LED is lit, the microphone input is active etc. An XLR input for a microphone, as well as both XLR and TRS 1/4” inputs for line-level sources, can be found on the rear panel. A TS 1/4” input for an instrument (DI) is available on the front panel. Mic input gain With the Mic input selected, the user has access to the full gain range in 10dB steps from 0dB to +60dB (yellow legend).
Phase Pressing PHASE inverts the phase of the selected input to correct phase problems when using multiple microphones, or when incorrect wiring polarity has occurred. Insert Activating the INSERT switch (illuminated when active) breaks the signal path of the channel, so that the signal sent to the first ADC Input and the analogue output on the rear panel is the signal received at the INSERT RETURN connector (on the rear panel) rather than the direct mic, line or instrument signal.
Cue mix Activating the CUE MIX button sends the signal connected to the rear panel CUE MIX INPUTS to the headphones. When in cue mix mode, no inputs can be heard in the headphones. This facility means that, in a low latency environment, a monitor mix can be fed from a desk into ISA One to provide a suitable cue mix for the recording artist.
LED Meters If wanting to calibrate the LED meters, the PEAK METER CAL dial on the rear panel can be used. In the default state, with the dial in a central (‘detented’) position, 0dBFS is equal to +22dBu. Rotating the dial in either direction sets a new value for 0dBFS from +18dBu (fully anticlockwise) to +26dBu (fully clockwise). Rear panel 1 13 9 10 11 12 6 5 8 3 2 4 7 . Optional ADC (digital conversion card) . Microphone (XLR) Input . Line-level (XLR) Input .
Analogue inputs The MIC I/P (XLR) and LINE I/Ps (XLR and ¼” TRS Jack) can be used to connect an analogue source to ISA One. If a microphone is connected to the MIC I/P, phantom power can also be supplied by making sure MIC is selected using the INPUT switch on the front panel, then activating the +48V switch. If you are unsure whether your microphone requires phantom power, refer to its handbook, as it is possible to damage some microphones (most notably ribbon microphones) by providing phantom power.
The optional ADC can convert two separate channels of audio. The second of the two channels received at the ADC Input is determined by a connection on the rear panel. With no signal connected to EXT I/P, the second channel is fed from the DI (Instrument) input on the front panel. Connecting a signal to EXT I/P makes that signal replace the instrument as the second channel going into the ADC.
AES/SPDIF Connector Configuration The 9-pin D-type connector labeled AES/SPDIF can be configured either as an AES or S/PDIF dedicated output using the AES/SPDIF switch next to it. When operating the connector in AES mode, an AES cable is required. When operating in S/PDIF mode, the S/PDIF RCA cable should be used, which automatically sets the output stream to consumer mode.
Digital Output Front Panel Controls Clock Select Lock LED Ext Sync Clock Select Pressing this switch allows you to select between sample frequencies of 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, and 192kHz. EXT Pressing EXT allows the ISA One to be slaved to an external word clock source.
Recording a line-level source To record a line-level signal with ISA One, carry out the following steps: . Connect the line-level signal, using either an XLR or a ¼” TRS Jack cable, to the appropriate LINE I/P on the rear panel . Select LINE as the input source using the INPUT switch . Set the gain of the line signal using the two dials on the front panel and observing the VU meter or left-hand LED meter.
If only wanting to record guitar then this 2-channel facility can be used in a similar way. Only, in this instance, the AMP Output on the front panel is used to feed the direct instrument signal back into the amplifier, and the microphone is used to record the amplified guitar. This way, the clean direct guitar and the amplified guitar can be recorded on separate tracks (see diagram 3 in the Signal Connections section).
Switchable Impedance: In Depth Explanation Dynamic moving coil and condenser microphones Almost all professional dynamic and condenser microphones are designed to have a relatively low nominal output impedance of between 150Ω and 300Ω when measured at 1kHz.
Signal Connections Recording an analogue vocal signal through a desk with backing tracks DESK Line I/P Stereo O/P Cue mix switch active Mic selected as input In this low-latency environment, the vocal can be sent to the desk, mixed with the backing tracks and then a stereo mix be sent back to the ISA One, via the cue mix inputs.
Recording an analogue guitar signal using both inputs In this instance, should you want to record the signals digitally, the stereo output of the optional digital card (if installed) will mirror the MAIN and DI outputs (left and right respectively). If recording through a desk or other low-latency environment, a stereo mix with backing tracks and guitar can be sent back to ISA One’s CUE MIX inputs to allow a latency-free headphones mix for the guitarist (as in diagram 1).
• Frequency response at maximum gain (60dB) = -3dB down at 16Hz and -3dB down 118kHz • CMRR=98dB (Channel 1, 1kHz, maximum gain with +24 dBu input) • Crosstalk Channel to Channel: with 10dB@1kHz input to chA, chB output =104dBrA.
Front and Rear Connectivity Analogue Channel Inputs: Mic input: XLR x 1 Line input: XLR x 1 and TRS x 1 Instrument input TS Jack x 1 External ADC input: TRS Jack x 1 Return: TRS Jack x 1 Analogue Channel Outputs: Send: TRS Jack x 1 Balanced line output: XLR x 1 DI output: XLR x 1 DI through: TS Jack x 1 Analogue Channel Additional I/O: Cue mix left input: TRS Jack x 1 Cue mix right input: TRS Jack x 1 Headphones output: ¼” TRS Jack x 1 Warranty All Focusrite products are covered by a warranty against manuf
