The Forssell Technologies SMP-2 is an extremely high-quality, sonically neutral two-channel microphone preamplifier designed for the most demanding applications.
Housed in a 1U rack mount enclosure, the SMP-2 captures musical performances when utmost accuracy and superior honesty is required.
The Forssell Technologies Inc SMP-2A is a 2 channel, transformerless, Class A discrete JFET microphone preamplifier housed in a single space rack chassis. Each channel on the SMP-2A has front panel mounted controls for gain, output muting, polarity reverse, and phantom power on/off. The mute, polarity, and phantom power switches each have LED indicators which illuminate when the switch is pressed in to indicate that the switch is on. The gain control is variable from minimum to maximum gain in 24 stepped positions. Bicolor LED level indicators are also present for each channel. These LED indicators show green with the output signal level is above -5 dBu, and red when the signal level reaches +24 dBu, which is 2-3 dB prior to clipping. A power on/off switch and LED are also located on the front panel.
The rear panel contains the two input and one output XLR connectors per channel. All XLR connectors are wired Pin #2 hot. There is an input XLR for phantom powered mics (labeled P48), and one for non-phantom powered mics (DC) such as ribbon, dynamic, or externally powered condenser mics. There is also an IEC AC power connector and fuse holder on the back panel. The fuse holder is integrated into the IEC power connector and uses 5x25mm slow blow fuses. There is a spare fuse located within the fuse holder. The fuse type is 250 ma time-delay or time-lag fuse. If your preamp is wired for 230 VAC, then please use a 100 ma time-delay fuse.
An AC line voltage switch is located inside of the SMP-2A. Please refer the SMP-2A to a qualified technician to change the line voltage setting.
Operation of the SMP-2A is very simple and should be intuitive for most users. Microphones are connected to the SMP-2A preamplifiers via female XLR connectors to the rear panel, and
the preamplifier outputs are connected to male XLR connectors. Each channels input and output XLR connectors are located next to each other and correspond to the channels as laid out on the front panel.
Phantom power is applied to the P48 input XLR when the phantom power switch is pressed in. It is a good habit to apply phantom power AFTER a microphone is plugged into the XLR connector on the SMP-2A to prevent a voltage spikes appearing at the input of the preamp circuitry. The phantom power supply voltage on the SMP-2A is +48 VDC and is a high current robust design to provide consistent phantom power voltage to all inputs regardless of the number of phantom powered mics plugged into the SMP-2A.
No phantom power is present on the direct coupled input (DC) XLR even if the phantom power switch is pressed in on the front panel. PLEASE NOTE... only one of the two input XLR connector can be used at any given time. The unused XLR should have no cable plugged into it.
Gain control on the SMP-2A variable from a minimum of +6 dB to a maximum of +68 dB (or +74 dB if high gain option is installed) in 24 steps. The gain control use high quality Elma switches for long life and good signal switching qualities. The gain setting for each position are shown on the front panel graphics.
The SMP-2 circuitry features an all Class A discrete JFET design with a gain range of +6 to +68 dB in 24 switched steps.
Each channel has P48 Phantom powered inputs and Direct Coupled (DC) inputs for microphones that do not require P48 power.
Front panel signal level indicators are provided for each channel to indicate -5 dBu dBu output level (green) and output clipping (red).
Level indicators are single bicolor LED.
Polarity Invert, Output Mute and Phantom Power (P48) switches for each channel are also located on the front panel along with LED status indicators for each switch. Audio connectors on the rear panel are high-quality Neutrik XLR connectors with gold-plated pins.
Minimum Gain: +6 dB
Maximum Gain: +68 dB or +74 dB (optional)
Input Impedance: 13k ohms
EIN (Max gain): better than -128 dBu (22 Hz to 22 KHz, unweighted), typically -130 dBu