To download the full 528E User Guide, go to the
528E product page on www.symetrixaudio.com.
Quick Start Guide
528E Voice Processor
Other Notes Of Interest
9
Signal Levels
The 528E is designed around studio/professional line levels: +4 dBu or 1.23 volts. The unit is quiet enough to operate at lower
signal levels such as those found in semi-pro or musical-instrument (MI) equipment (-10 dBu or 300 millivolts).
The microphone input is designed to accept low-impedance microphones. Switchable 48V phantom powering is provided for
suitable condenser microphones. The microphone input accepts signal levels from -60 to -5 dBV (+10 dBV with the -15 dB pad).
The line input is designed to accept nominal line level: +4 dBu.
The output line driver de4 dBm into 600 Ohm or higher balanced loads. An internal switch converts the line level output
to microphone level, or -36 dBu. An unbalanced output is also available via a 1/4” TRS phone jack. This jack is always line-level
and is unaffected by the internal switch.
When using the 528E with HAM radio equipment, it may be necessary to build an “L” pad attenuator in order to level match the
528E’s unbalanced 1/4” TRS output to a HAM radio transceiver’s unbalanced input. The 528E has a level of -2 dBu (-10 dBV)
at it’s unbalanced output which translates to 0.615 volts RMS. The typical HAM radio transceiver has an input impedance of 10k
Ohms so it would be expecting a level of 0.100 volts RMS. Knowing this, one can build an “L” pad attenuator with a 3600 Ohm
series resistor followed by an 820 Ohm resistor to ground. This will give approximately 15.58 dB of attenuation thus providing a
suitable level to the HAM radio transceiver input.
I/O Impedances
The 528E is designed to interface into almost any recording studio or sound reinforcement application.
This includes:
• 600 Ohm systems where input and output impedances are matched.
• Unbalanced semi-professional equipment applications.
• Modern bridging systems where inputs bridge and outputs are low source impedances (voltage transmission systems).
The 528E’s microphone input is intended to bridge a 150 Ohm balanced source. The actual input impedance is approximately 8k
Ohms. 48V phantom powering for condenser microphones is present if the PHANTOM POWER switch has been depressed.
The 528E’s line input impedance is 10k Ohms balanced, and 10k Ohms unbalanced. The inputs may be driven from any source
(balanced or unbalanced) capable of delivering at least -10 dBu into the aforementioned impedances.
The 528E’s output impedance is 200 Ohms balanced, 100 Ohms unbalanced. The output line driver de18 dBm into a 600
Ohm balanced load or +18 dBm into 600 Ohm unbalanced loads.
I/O Impedances
The 528E uses the international standard polarity convention of pin 2 hot. Therefore:
XLR Tip-Ring-Sleeve
Signal
1
Sleeve
Ground
2
Tip
High
3
Ring
Low
If your system uses balanced inputs and outputs, and uses the 528E this way, then the polarity convention is unimportant. If your
system is both balanced and unbalanced, then you must pay attention to this, especially when going in and coming out through
different connector types (like input on an XLR, output on a phone jack).
Further Information
Much more information including an online tutorial, customer submitted settings, frequently asked questions and trouble shoot-
ing information as well as the complete user’s guide can be found on the Symetrix web site at (http://www.symetrixaudio.com).
