Fredenstein F602 500-Series Tube Compressor

The Fredenstein F602 500-Series Tube Compressor is a true variable transconductance, high performance tool for professional recording and mastering engineers. Featuring the same 6386-LGP tube as the revered compressors of yesteryear, it is designed to deliver modern performance with classic character.

The Fredenstein F602 500-Series Tube Compressor features the original remote cutoff double triode tube used in many vintage designs (Gates, Fairchild, and GE to name a few) called 6386LGP. The signal path is very short and delivers the smoothness you would expect from a great piece of vintage equipment. The innovative transformer-less input circuit yields clarity while the large Lundahl output transformer adds character. Like the Fredenstein F660A, the F602 uses a DSP to continually monitor the 6386 tube and optimise its operating points. This has several benefits including automatic self-test and calibration, but also makes possible greater control range and much faster gain reduction.

There are rotary controls for; Threshold, Ratio (2:1 to 20:1), Make-up Gain, Mix (Blend), Attack (250 uS to 15.5 mS) and Release (12 mS to 5 S). There are buttons for Bypass (true hard bypass), Hard Knee / Soft Knee, Link (up to 10 units) and Meter Mode (VU or Gain Reduction). The LINK switch is also a standby switch allowing to shutdown the tube circuitry if the Fredenstein F602 is not in use while the rack is still powered, therefore extending tube life. The astute reader might notice the exceptional attack and release times that no other “vari-mu” compressor even begins to approach. Usually such fast settings would have a side effect of “thumps” as the gain reduction changes, but in the Fredenstein F602 with the DSP adjusting the tube and maintaining near perfect balance the thumps are eliminated. The MIX control is also interesting. Fully counter-clockwise, a switch engages and only the compressed signal will be on the output. Fully clockwise, another switch engages and only the uncompressed signal (input) will be on the output. Between those extremes, blending is variable, which is typically used to preserve some transients while raising the level of quieter signals. Similarly, when the Release control is fully counter-clockwise a program dependent Auto-Release setting is engaged and when the Threshold control is fully counter-clockwise compression is turned off. Gain reduction is displayed traditionally with a VU meter and a Clip indicator lights if the output reaches +24 dBu. Buttons light when engaged.

Specifications are more than respectable for this type of compressor. Lower distortion, wider frequency response and lower noise compared to units much more expensive. The high current design and unusually low output impedance allows even the most difficult and complex loads to be driven without sonic impact. The hot rod mu. Obviously there is some clever design in this little 500 series unit with a vacuum tube, DSP, MCU control, digital attenuators, high voltage regulators, Lundahl transformer, a discrete line driver and high performance analog throughout. It should also be stressed that it is truly properly engineered, thus uses very high quality parts - besides being built like a tank. Expect it to be reliable and professional. Beyond that, the Fredenstein F602 really sounds quite amazing. A pair of them could be your secret weapon for buss compression and mastering and it won't break the bank. A pair in series is also provides for a very tubular tracking option. Think about it. Due to the high power consumption of about 8W, not all lunch-boxes and racks are suitable for this module. Of course, Fredenstein boxes and racks are well equipped to handle these loads. As all Fredenstein products, the Fredenstein F602 is designed by a German-American team and manufactured in Taiwan.

Fredenstein F602 500-Series Tube Compressor Features

• 500 Series variable transconductance tube compressor
• Features 6386-LGP tube as used in the revered compressors of yesteryear
• Short signal path delivers the smoothness you'd expect from vintage gear
• Modern DSP provides a great control range and fast gain reduction
• Transformerless input circuit and Lundahl output transformer provide both clarity and character
• Threshold, Ratio, Attack, and Release controls make dialing in a killer sound easy
• Automatic release mode adjusts the release time dynamically with source material and input level
• Mix control for parallel compression
• Allows you vary the compression behavior by switching between hard- and soft-knee
• VU meter is switchable between gain reduction and output level
• Clip LED indicates output levels above +24dBu
• 10 units can be linked to form a multichannel compressor
• Standby switch shuts down tube circuitry when not in use to extend tube life
• Hard bypass also works when the compressor is powered down

Fredenstein F602 500-Series Tube Compressor Specifications

• Reference Level: 0 db = +4 dBu (American Studio Standard)
• Make-up Gain: 0 to +20 dB
• Threshold: -25 dB to +9 dB
• Attack Time Range: 250 us to 15.5 ms
• Release Time Range: 12 ms to 5 s
• Compressions Ratio: 2:1 to 20:1
• Frequency Response: 20Hz – 20,000Hz, +/- 1dB
• Distortion: < 0.01%
• S/N Ratio: > 90dB at 0dB Gain
• Input Impedance: > 10 K Ohm
• Max. Input Level: + 24 dBu
• Output Impedance: 20 Ohm
• Max. Output Current: +/- 200 mA
• Max. Output Level: + 26 dBu
• Power Consumption: +16 V +250 mA, -16V -200 mA

Fredenstein F602 500-Series Tube Compressor Includes

• 1 x Fredenstein F602 500-Series Tube Compressor
• 1 x Operating Manual
• 1 Year Warranty