GOLD SERIES

F600A

Your Working Horse

The F600A Compressor is truly a novel and unique compressor. It does not use VCAs, FETs, Optos, remote-cutoff (vari-mu) tubes, diode bridges or pulse-width switching. It uses a pair of digital controlled attentator/amplifiers for gain reduction and make-up gain. Thus it gives a unique sound that is extremely useful regardless of which other compressors one might own. It has been described as exceptionally smooth, clean and capable of extreme output levels.

The F600A is a high performance tool for professional recording and mastering engineers. It comprises of a analog gain control circuit and a digital side-chain based on two DSPs. This technology can easily achieve more than 20 dB of gain reduction while maintaining very low distortion. Up to ten units can be linked together to form a very accurately matched multi-channel compressor.

Familiar controls include; Threshold, Compression Ratio (1:1 to 100:1), Attack and Release times (dB/linear), and Make-Up Gain. A button selects RMS or PEAK and Hard-Knee or Soft-Knee, another selects Link and another button is used for Bypass. A tunable high pass filter can be tuned from flat up to 4 kHz (!). The F600A can be used as De-Esser, or on a lathe, as a cutting speed limiter. It also uses an analog VU meter to traditionally display gain reduction.

If placed in a Fredenstein Bento 6D or 10D, settings will be automatically displayed on the Bento's LCD display which makes accurate recalls a breeze.

The F600A features a fully externally and internally balanced signal path with much lower distortion than conventional compressors. This simply translates to noticibly cleaner punchier sounds. And it doesn't sound “digital” and doesn't sound like plug-ins – it's still analog. The extreme low output impedance with its high current design allows even the most difficult and complex loads to be driven up to +26 dBu without sonic impact. Yeah, it's unique.

  • A high-performance compressor for pro recording and mastering engineers
  • Exceptionally clean, smooth sound
  • Unique circuit with 2 digitally controlled analog attenuator/amplifiers for gain reduction and make-up gain
  • DSP-based digital side chain
  • Hard-Knee and Soft-Knee operation
  • Achieves over 20dB of gain reduction and can be driven to extreme output levels
  • Compression Ratio with settings from 1:1 to 100:1
  • Highpass filter tunes up to 4kHz, turning the F600A into a highly effective De-esser
  • Link up to ten F600As to create a precision-matched multi-channel compressor
  • Analog VU meter
  • In a Fredenstein Bento 6D or 10D 500 Series rack, settings automatically displayed on the Bento's LCD display for accurate recall
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F601A

Most Versatile Preamp

The F601A is a versatile high performance professional microphone preamplifier. It is the only mic-pre that allows the engineer to choose whether to use the input transformer, as well as, whether to use the output transformer. Each has a switch and is gain compensated for easy comparisons.

The premium Lundahl transformers used are very transparent, which means these switches only tend to have a subtle sonic effect and whichever combination is choosen the performance is always exceptional. Often the benefits of transformers relate to noise rejection and galvanic isolation but with some penalty in absolute distortion and frequency response, but with Lundahls, the benefits can be useful and the penalties tend to be very minimal.

The F601A uses a fully discrete Class-A gain stage with an innovative Zero-Negative-Feedback design. This improves low frequency and transient reproduction dramatically and delivers detailed high frequency information without being harsh. This preamplifier has been described as truly silky, smooth and warm and yet, tends to be very fast and detailed.

Controls include; Gain (0 to 78 dB !), Input Impedance (1000 or 300 ohm), Low Cut Filter (60 Hz), Phantom Power and Polarity. It also has a front panel DI Input for instruments. Output level is displayed with a conventional VU meter.

Behind the front panel, controlling gain and other functions, the F601A incorporates a few dozen high quality sealed relays controlled by a 32 bit MCU. If placed in a Fredenstein Bento 6D or 10D, settings will be automatically displayed on the Bento's LCD display which makes accurate recalls a breeze. It also means better matching when multiple F601A's are used for stereo or surround.

The F601A's very low noise, intrinsically low distortion and wide frequency response will provide exceptional sonic results. It outperforms “classic” microphone preamplifiers by a wide margin. This isn't your grandfather's mic-pre.

  • A high-performance preamp for pro recording engineers
  • Discrete Class A gain stage with unique zero-negative-feedback design
  • Individually selectable Lundahl input and output transformers
  • 78dB of gain (with input transformer engaged)
  • Polarity reverse, 48-volt phantom power, and 60Hz highpass filter
  • lo-Z switch lowers the input impedance to 300 ohms to optimally match up with your ribbon and dynamic mics
  • Incorporates high-quality sealed relays controlled by 32-bit microcontroller
  • 32-bit CPU stores your parameters in nonvolatile memory
  • Install it in a Fredenstein Bento D chassis and all parameters will be displayed on the Bento LCD screen
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F602

VariMu In Perfection

The F602 Compressor is a true variable transconductance (often falsely called “variable mu”) high performance tool for professional recording and mastering engineers. The F602 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 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 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 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 F602 is designed by a German-American team and manufactured in Taiwan.

  • 500 Series variable transconductance tube compressor
  • Features the same 6386-LGP tube as the revered compressors of yesteryear
  • Short signal path yields the smoothness you'd expect from vintage gear
  • Modern DSP provides a greater control range and faster gain reduction than historic units
  • 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 your source material and input level
  • Mix control makes parallel compression a piece of cake
  • Vary your 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 unit is powered down
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F609

Full Tube Preamp

The F609 is a professional tube microphone preamplifier, using two double-triodes, one ECC802S (12AU7) and one ECC803S (12AX7), in a single 500 series rack module. It provides an +160V power-supply to avoid starving the tubes. The F609 uses high quality American made input and output transformers.

The main feature of the F609 is the combination of the Input Gain knob (0 to +70 dB) plus Output Gain Knob, plus all-tube signal path. The output level control allows to change the characteristic of the amp and to run the first stages all the way up to distortion and it is genuine old-school tube distortion. The sound is very smooth with a big, well defined low-end. This little module can rock with the best of them.

The F609 is particulary interesting paired with the F602 tube compressor, if you happen to like high end vintage flavors and genuine tube character. It also pairs nicely with the Artistic Compressor and Artistic Leveller for traditional 70's style tube mic-pre into solid state FET or Opto compressor chains. Some engineers chain all three.

Additional features are: 20db Pad, polarity control, phantom power, a two stage low-cut filter, and a standby mode to preserve the tubes if not in use. The traditional VU meter is standard.

Not all racks can supply the 250 mA that the F609 requires, but any of the Bento series are well suited to provide that.

  • An endless range of vintage tube character
  • Employs two double triodes: ECC802S and ECC803S
  • Custom gainstage using the Input and Output Gain controls
  • Premium American-made input and output transformers
  • 20db pad, polarity reverse, phantom power, 2-stage highpass filter, and standby mode
  • Requires 500 Series rack capable of supplying 250mA (Bento series racks are recommended)
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F610 UE-1

Universal Entzerrer

The Fredenstein F610 Universal Entzerrer UE-1 is a digital controlled stereo analog quad band equalizer and 30 band spectrum analyzer in a double wide 500 series cassette.

For the first time in a 500 series module, we were able to implement a high resolution 3.5” LCD color display including a capacitive touch controller, thus welcoming the 500 Series to the 21st century.
The four filters are all identical and each can be tuned from 20 Hz to 20 KHz. The encoder rotary frequency knob allows access to about 190 different frequencies per filter, while the USB interface allows for 1 Hz frequency resolution. The maximum filter gain is +/- 16 dB. In case more gain is needed, additional filters can be set at the same frequency for a ridiculous up to 64 dB boost or cut. The Q-factor of each filter can be varied from 0.4 to 7.9. The gain can be adjusted from -16 dB to +16 dB in 0.25 dB steps, clearly fulfilling the demands of modern sophisticated mastering. The Filter 1 characteristic can be changed from band-pass to low-shelf and Filter 4 to high-shelf.
In addition, a variable 2nd order low-cut filter with a range from 20 Hz to 975 Hz is provided as well as a “Color” function giving a tube-like sound. The hard bypass allows for quick evaluation of the eq'ed results.
The 30-band spectrum analyzer features a 60 dB dynamic range with select-able sensitivity from +6 dBu to + 24 dBu in 6 dB steps. The choice to feed either the input or the output signal to the analyzer adds to the versatility of the F610.
Up to 99 complete settings can be stored in the internal non-volatile memory and a Micro-USB interface provides complete control from a connected host computer via RS232 over USB.

The F610 UE-1 name is an homage to the classic K&H UE-100. “Entzerrer” is the German technical term for equalizer.

  • 4-band EQ with variable Q
  • High-resolution 3.5" color LCD capacitive touch-controller display
  • 30-band spectrum analyzer
  • Each band features ±16dB of gain and a variable-Q range of 0.4 to 7.9
  • Filters 1 and 4 may be switched from bandpass to low shelving and high shelving, respectively
  • Variable 2nd-order highpass filter with a range of 20Hz–600Hz
  • Color function imparts tubelike vintage flavoring
  • Hard bypass allows for quick comparison of dry and equalized signals
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HD MicPre

12Hz–700,000Hz

The Fredenstein HD microphone preamplifier utilizes a completely new approach to microphone level amplification.
With 96 kHz/192 kHz sampling rates becoming very popular while tracking, studios are still using equipment which cannot provide the frequency response or bandwidth provided by modern A/D converters.
The HD Pre overcomes these limitations especially for wider bandwidth sources such as acoustic instruments.

It is the preferred choice for classical recordings and Jazz recordings as well.
Besides incorporating a fully discrete signal path and a Class-A balanced output stage, the HD Pre uses a revolutionary current amplification circuit, which neutralizes limiting internal transistor capacitance.
As a result, the HD Pre features an unprecedented bandwidth of over 900 kHz.

  • Overcomes the limitations of conventional preamps with an entirely new approach to mic-level amplification
  • Frequency response: 12Hz–700,000Hz (+/-1dB)
  • Ideal for wider bandwidth sources such as acoustic instruments
  • Fully discrete signal path
  • Balanced Class A output stage
  • Innovative current amplification circuit that neutralizes limiting internal transistor capacitance
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HD Reference & Commander

High End Dual MicPre & Remote

The HD REFERENCE Microphone Preamplifier can be described as unique, revolutionary, and among the best performing mic pre's of all time.
Well almost unique. The internal topology was first introduced in the 500 Series Fredenstein HD PRE which features the new current mode, true class A, zero negative feedback, 100% balanced circuit that uses 54 discrete premium transistors for gain. The HD REFERENCE goes a step further with 72 transistors and a +/- 24 volt power supply. The HD REFERENCE is also designed to be remote controlled (or not) and offers 1 dB gain steps shown clearly on the front panel.

Technical performance can only be described as extreme or exceptional. Extreme low noise (EIN - XX dB), exceptional low distortion (.XX% at 60 dB of gain), extreme bandwidth (-3dB down at 900kHz) and is can deliver +30 dbu at the outputs. And while it sports the holy grail, grand combination of high end specifications, The HD REFERENCE also out-performs typical tube pre-amplifiers in the area of smooth transition into saturation, due to the absence of negative feedback and the fast recovery inherent in the topology. In other words, it goes from pristene to 3 dimensional through rich and then power house depending on how hard one drives it.

Features include 1 dB stepped gain from 0 dB to +64 dB (using high reliability relays) indicated with a large 7 segment LED display. 3 high pass filter frequencies, 3 impedance settings, phantom power and polarity switching. Details like, automatic muting while phantom power is changing, to prevent thumps and damage to monitors is built in. There are also a pair of Direct Inputs for instruments with low noise discrete JFET inputs (2 meg ohm) and 0 to 40 dB of gain.

And then by adding the COMMANDER remote control we can reap the benefit of keeping the mic pre close to the mic, while still keeping control of all the features the HD REFERENCE provides. By keeping the cable between the mic and the REFERENCE HD short, we can preserve the fragile mic level signals and send a robust line level signal any reasonable distance to the converter, console or compressor. The Commander and REFERENCE HD connect with a standard mic cable. The COMMANDER additionally has a LOCK button that can prevent tampering at the remote preamp.

  • 2-channel microphone preamp with 64dB of gain
  • Fully discrete signal path and Class A balanced output stage achieves a true-to-life sound
  • Current amplification circuit eliminates internal transistor capacitance, providing 920kHz of bandwidth
  • Experience warm, natural sound via zero-negative-feedback topology
  • Transformerless design won't color your sound
  • Digital displays allow you to set your gain level in accurate 1dB steps – great for setting up stereo pairs
  • 7-segment LED meters make monitoring your levels easy
  • 3 impedance settings optimize the preamp for your mic
  • 3 highpass filter frequencies eliminate unwanted low-frequency rumble
  • Phantom power and polarity reversal
  • Discrete JFET inputs for your guitars and other high-impedance sources
  • Optional HD Commander remote control is available for keeping the preamp close to your mic (sold separately)
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F200

Dual MicPre + Stereo FET Compressor

The F200 is a two channel microphone preamplifier and a two channel FET compressor with Stereo link capability. The mic-pre and compressor are connected in series. The output mixer allows the user to select only the mic-pre or the compressor . In addition, a wet/dry (compressed/ uncompressed) mix can be performed.

The mic-pre section features a switchable 20db pad, a low-cut filter, phase reversal and P48 phantom power. The maximum gain of the mic-pre is +60 dB, the minimum gain with pad activated is 0 dB. In case the unit is used as a compressor only, the input is able to handle +20dB signals and is fully compatible with line level signals. At a mic-pre output level of greater than + 24dbu a clip indicator will light up. The high impedance Direct Input (DI) is compatible with balanced and unbalanced signals.
The compressor section features rotary controls for Attack Time, Release Time and Compression Ratio as well as a Stereo link switch. The VU meter is switchable, either the compressor gain reduction or the output level can be displayed. All switches have dedicated LED indicators.
For easy touring and recording around the world, the F200 has a built-in universal power supply ranging from 90Vac to 240Vac, 50 -60 Hz.
As all Fredenstein products, the F200 is designed by a German-American team and manufactured in Taiwan.

  • 2-channel microphone preamp and compressor
  • 2 completely separate processors — use them individually or combine them into dual channel strips
  • Separate mic and compressor output levels for effortless parallel compression
  • Mic preamp features 60dB of gain and a 20dB pad, highpass filter, polarity reversal, phantom power, and DI
  • Compressor includes controls for attack time, release time, compression ratio (from 2:1 to 20:1), and stereo link
  • Experience warm, natural sound via zero-negative-feedback design
  • Clip Led for the mic-pre turns on at +24 dBu output levels
  • VU meter displays compressor gain reduction or output level
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F676

Old High End Sound New Style

The Fredenstein F676 Microphone Preamplifier is a valve (tube) based preamp with a fully balanced signal path throughout. It features transformers on the input and output. The F676 uses a DSP to control the operating points of the tubes, guaranteeing perfect working conditions all the time.

The final result is a tube preamp with a very pleasant sonic footprint, lush smooth highs without being harsh plus very detailed mids and lows. The physical footprint is also very well suited for many desk-top situations where it can be conveniently put within arm's reach.

Control functions include 0 to 76 dB of gain in 1 dB steps along with a 20 dB pad. It also includes the usual Phantom Power, Polarity and High Pass Filter switching and 2 impedance settings (1K ohms and 200 ohms). The F676 has a few unusual controls; one for setting Fully Balanced or Single Ended circuitry and another that injects DC into the output transformer. Each is intended for creating desirable vintage characteristics beyond what the basic tube / transformer topology does. The F676 also allows for saving and recalling 99 User Presets.

The LCD graphically displays Peak output level and Gain settings. It also displays tube currents while it self-calibrates so that you can be confident that the unit is working optimally.

The name F676 is an homage on the famous German V76 tube microphone amplifier which was the sonic inspiration for this unit. The F676 will make a positive difference in your studio.

  • Modern re-imagining of the legendary Telefunken V76 mic preamp
  • High-quality input and output transformers deliver the sonic imprint that you'd expect from a top-shelf piece of vintage gear
  • Modern DSP provides performance beyond the basic tube/transformer topology
  • Front panel LCD screen displays your peak output level, gain settings, and more
  • Store up to 99 presets for easy repeatability
  • Experience warm, natural sound via zero-negative-feedback design
  • Features 76dB of gain, a 20dB pad, highpass filter, polarity reversal, phantom power, and DI
  • Self-calibrates for easy maintenance
  • 100% analog signal path
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F660

Take A Faichild To The Next Level

The Fredenstein F660A Limiting Amplifier is a valve (tube) based compressor and limiter with the same very short signal path as the famous Fairchild 660/670. It uses the exact type of tubes, the 6386 LGP, as the Fairchild and 4 of them per channel like the Fairchild.

Fortunately, new production tubes are available today, since original tubes are hardly sold anymore. The four tubes form a single stage push-pull Class A amplifier and the whole signal path consists only of a T-type input attenuator, input transformer, Class A tube amplifier and finally the massive output transformer. At this point the similarities end.

The F660A uses a DSP to control the operating points of the tubes, guaranteeing perfect working conditions all the time. The side chain amplifier is designed with semi-conductor components since it “only” generates the control voltage for the tubes. The final result is a compressor with the compression characteristics of the Fairchild, but with an extended frequency response, lower noise and lower distortion. The perfected tube buss compressor.

The front panel provides immediate access to the most used controls; Make-Up Gain, Compression Threshold, and Release Time. There are 6 Release Time settings designed to mimic the original Fairchild switch. The 3 encoders also function as push buttons for Bypass, Sidechain High Pass Filter and Stereo Link.

The LCD screen is used to set more parameters such as, Attack Time (6 Attack Time settings), Metering range plus choices of RMS, Peak and Hold settings and a Calibration mode. The F660A also allows 99 User Presets to be stored and recalled which is quite a feature in a mastering situation, especially because the F660 self-calibrates for the most part plus has an easy method for complete exact calibration so repeat-ability is a non-issue.

The old Fairchild 660 is a classic compressor with some highly desirable compression characteristics but perhaps some shortcomings with regards to pure fidelity. The F660A combines the sought after character of the original with audio performance well suited for modern production and mastering. But sorry, no maintenance worries, no lost lows and highs, and no old Bakelite knobs and no scratchy pots and switches. It just sounds right.


 

  • Modern update of the legendary Fairchild 660/670 compressor/limiter
  • Features the same 6386-LGP tubes and short signal path as the original
  • Modern DSP provides extended frequency response, lower noise, and less distortion than historic units
  • Front panel LCD screen provides access to your most-used parameters
  • Store up to 99 presets for easy repeatability
  • Experience warm, natural sound via zero-negative-feedback design
  • Fast attack time catches short transients for full limiting
  • Adjustable DC threshold allows you to select between 0.5 and 5V
  • Sidechain for avoiding compression in unwanted frequency ranges
  • Self-calibrates for easy maintenance
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MixCube

Summing Mixer with up to 32 Channels

The Fredenstein MIX CUBE is a compact answer to the question of mixing in the box or mixing out of the box with a solution born of thinking outside of the box.
The MIX CUBE is a high quality digital controlled analog mixer that can be configured as 8X2, 16X2, 24X2 or 32X2 while only needing about 6.3” (16cm) by 6”3 by 6.3” inches of desk space.

It features a front to back balanced audio path with a fully discrete output stage. The MIX CUBE can be thought of a remarkably compact, extreme performance, purist analog mixer for the digital age.
Each of the channels has gain control in 1⁄2 dB steps, pan, cut and solo. Any set of channels can be controlled by one of four fader groups. The master mix also has gain control, balance and cut. Presets can be easily saved and recalled.

The 4 Fader Groups provide a convenient way of controlling multiple channels. For example, one could assign 10 drum channels to Group 1, (indicated numerically below the channel and with a color change) and adjust the level or mute or solo just the drums. Also, in the Audio Menu, all channels can be increased or reduced by 3 dB or 10 dB steps. One can easily find the optimal level to drive the mix buss and outboard processors.

The MIX CUBE also has MIDI ports and a USB port to allow full remote control. For example, a low cost moving fader MIDI controller can provide a traditional tactile interface for the MIX CUBE. Alternatively, A DAW can control the MIX CUBE via MIDI or USB and provide a fully automated mix in the analog domain while the digital to analog converters operate at their optimum levels.

The MIX CUBE has a 4.3” 480x272 pixel full color TFT graphics display that clearly shows levels, pans, groups, etc. 3 Encoders and 3 buttons give the engineer quick access to any control.

  • High Quality Summing Mixer
  • Upgrade from 8 channels of summing up to 32 channels
  • Digital controlled but fully balanced analog signal path
  • Remote controllable with any MIDI controller or DAW via MDI or USB
  • (4.3”) 480 x 272 pixel color TFT display to show settings
  • MUTE, SOLO, PAN
  • Frequency response from 2Hz up to 80kHz
  • Store and recall up to 9 settings (or songs)
  •  
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