SPL / IRON Red

A new compressor that combines traditional vintage tube compressor technology with SPL's unique 120V technology.

*This product requires an AC115V 50/60Hz outlet. Please note that it will not function correctly with a standard household outlet (AC 100V) without voltage boosting.

Threshold

The Threshold setting determines the level at which the compressor begins to function. The compressor activates for signals exceeding the set value. The compressor does not activate for signals below the Threshold level. It can be finely adjusted using the 41-step potentiometer.

Tube Bias

The Tube Bias setting switches the voltage applied to the vacuum tube crits in three stages.

Increasing the voltage applied to the crits reduces the signal from the vacuum tube cathode to the atom, resulting in stronger compression. The signal after setting the Threshold, Rectifier, Side Chain EQ, Attack, and Release parameters is sent to this criterion.

Attack

Attack sets the response time of the compressor. This is the time until compression begins to take effect for signals exceeding the set Threshold value. Six settings are available, from Slow to Fast.

*Note: The attack time for IRON is not shown because it changes depending on the settings of other parameters.

Release

Release sets the speed at which the compressor process is released when the signal falls below the Threshold. Similar to Attack, six settings are available, from Slow to Fast.

Rectifier

Rectifier allows you to select one of six different control characteristic curves. The first five positions offer the characteristic curves of pneumatic, silicon, and LED. Each of these characteristics affects the attack and release times, with timeless response characteristics ranging from 0.1ms to 5s. The final position, a combination of germanium and silicon, offers a faster timeless response of 0.2ms to 300ms.

Side Chain EQ

Side Chain EQ allows you to influence the compression response within a specific frequency range. For example, cutting the low frequencies will make the compressor less responsive to kicks and basslines. Similar effects can be achieved with other frequencies. Boosting a certain frequency band will make the compressor more sensitive to that band. Sidechain filters affect only the control signal, not the actual audio. The IRON's site-chain EQ has a 6-step switch, allowing you to select Off, 4 presets, and an external site-chain signal. In the Off position, the internal capacitor cuts frequencies below 20Hz, and positions 2-5 are filtered using preset curves. When an external site-chain signal is selected, the IRON compressor is triggered by the signal input to the jack on the IRON's rear panel.


Auto Bypass

When objectively evaluating processed material, the Auto Bypass function allows you to automatically switch between the original signal and the processed signal at set intervals, rather than manually. This is a significant advantage, as it allows for more focused evaluation without moving from your monitoring position.


AirBass / Tape Roll-Off

In most cases, mastering is the final stage in music production, and excessive modification or processing of the audio signal is undesirable. For this reason, we have prepared a combination of two types of boost filters and a 120V SUPRA overhead amplifier.

...AirBass: A musically balanced filter with powerful bass and bright, silky treble.

...Tape Roll-Off: A filter based on the frequency characteristics of the tape machine. Effective for audio signals with excessively boosted high frequencies due to natural high-frequency roll-off.

Main Features


? Mastering compressor using SPL's proprietary 120V technology


? Parallel dual-tube circuit



? Custom-made Lundahl high-level dual-coil Mu-Metal transformer



? Independent feet-forward optical isolator within the variable tube bias control circuit




? Rectifier circuit for achieving 6 control characteristics



? Logistic relay for complete linking of the two channels