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Fredenstein Preamp/Compressors

500 Series Units With a Digital Edge

I’m a big fan of 500 Series audio gear. It’s a great way for anyone to affordably start a collection because there’s no need to re-buy the power supply for every unit in your rack. There are a lot of preamps and processors to choose from, and manufacturers are stretching the format in novel ways.

Fredenstein Professional Audio—a team of German and American designers who manufacture gear out of Tapei, Taiwan—offers a range of 500 Series units that not only work in any basic enclosure, but also offer an extra digital component when run in their affordable Bento 6D, or Bento 10D enclosures.

For this review, I got the Bento 6D six-space 500 Series host unit plus a pair of F600A solid-state compressors.

Bento 6D

The Bento 6D ($499) came loaded with the units mentioned above with slot 6 empty. Before applying power, I wondered about the rectangular, blue LED screen on the right of the unit. I first thought it had something to do with the integrated power supply, a great feature not usually found in popular 500 Series enclosures. But upon power up, I quickly found that when I moved a knob or switch, even when jumping from unit to unit, that the screen displayed the changes in white-on-blue letters. Change from soft to hard knee, apply phantom power, adjust the threshold or gain, and the display responds accordingly. I quickly got used to this, especially since the units use every bit of available real estate, positioning knobs, switches and labels very close together.

The display is easily readable, even in low light, and will make anyone needing glasses for close-up work shout, “Freedom!” On the back, in addition to XLR in/outs and Aux in/outs on each slot, the Bento offers audio linking, compressor bus linking, a ground flip, an on/off switch, and a standard IEC connector for power. The Bento has a quiet fan that kicks on when the unit needs cooling, which is noted by a fan On indicator on the LED panel with a Temp readout in Centigrade.

F609 Preamp

The F609 preamp ($599) uses “American made” input and output transformers and squeezes two tubes into a single vertical space—an ECC802S and an ECC803S. Front panel features include separate input and output gain controls, allowing you to play with distortion; a three-position low-cut filter switch (Off, 50Hz or 100 Hz); a -20dB pad; polarity switch; a standby/on switch; phantom power; single clip LED; DI input; and a slick looking circular VU meter. The phantom power and standby switches come with a single LED indicator, and the VU meter will not light up unless the unit is “on.”

I used the preamp first on a male lead vocal with great results. Despite the fact that the mic was a Shure SM7B, the top was very open, and the vocalist’s lower range, which was prominent, sounded great. The vocal was “there” without needing EQ during tracking. In fact, on subsequent uses, I got used to staying away from any EQ at all, relying solely on mic placement and selection—as it should be.

I next used the preamp on kick drum. The mic was an AKG D12 VR, a great active dynamic mic that has a three-position EQ switch tailored for kick. The signal was punchy and just needed pairing with a Yamaha SKRM-100 Subkick to bring up the 50Hz range. Last, I used the F609 to record a Martin acoustic guitar with a Neumann U47 FET placed just where the neck joined the sound hole. Once again, the instrument needed no EQ help and sounded great.

F600A Compressor

The F600A compressor ($549) boasts low distortion and an internally balanced signal path. The gain control circuit is analog but the sidechain is digital based on two DSPs. Features include three dual-concentric knobs offering threshold/gain, release/attack and ratio/HPF. The highpass filter is sweepable from off to 4 kHz, giving you some serious options when trying to crush just the top end of a signal. The release ranges from 1 ms to 128 ms, while the attack is variable from 1 ms to 32 ms. I would like to have seen these attack/release ranges extended higher for some lazier applications like vocals, especially at lower tempos.

Its sidechain is very sophisticated, using two LED lit switches to range from peak or RMS, at hard or soft knee. I found this useful for subtle changes of compression when recording transient material like handclaps or snare drum. The unit uses the same circular VU meter as the other F Series units.

I had a pair and quickly put them to use on a stereo acoustic guitar recorded with a U67 on the low end and a KM84 near the neck. It was easy to gang them in stereo by flipping the Comp Bus switch on the back and the link switches on both units. I adjusted the F600A’s attack/release, sidechain options, ratio and threshold but could never get it to sound better than the raw mic feed. In this case, I believe with more leeway on the length of attack and release, I could have finessed the track a bit better.

However, on snare drum, I was able to really play with the sidechain and LPF to get some very interesting and musical results. I was able to quickly crush down on the top end of the snare by setting the sidechain at 2 kHz, which brought out the beef of the snare, and then blended in the snare bottom mic to bring out the upper frequencies. It was educational playing with all the options: RMS, peak, sidechain, and the quick attack times.

No Noisy Neighbors

Being a skeptical guy, I was curious as to why slot 6 in my Bento 6D was unoccupied. There are reasons why manufacturers use external power supplies in audio, one of them  being electrical noise introduced to the audio path. So, I put our Stanford Research SR-1 audio analyzer on the job to see if that would be a concern. The first test was to run a Total Harmonic Distortion (THD+N) test on the F600A compressor set in slot 2, with the threshold set to maximum to take the compressor out of play. THD+N was tested with the output gain on three different positions; 0dB Brown, 7.5dB Blue, and 15.5dB Purple (see the two graphs on page 74). At maximum gain, the noise was just under a meager 0.006. For the second test, the F600A was moved to slot 6, closest to the power supply, and the noise moved a hair to just over 0.055. So much for healthy skepticism—the figures are great with little to no noise introduced to the audio coming out of slot 6, and all that comes in a box that costs $499 with the digital option, and $319 without.

I’ve not seen a lot of gear manufactured in Taiwan, but if my experience with the Fredenstein units is any indication of what can be, then bring it on. The fit, build and sound are tops, the American/German collaborative design excellent, and the digital readout afforded with the Bento 6D makes it a must-have companion piece. I purposely never look at the price until the end of a review, but I was surprised that the cost of these units is right in line with the competition, even a bit below. So, if you’re looking for great sounding 500 Series preamps and processors plus a bit more, Fredenstein has some gear you’ll want to see and hear. 

Kevin Becka is Mix magazine’s technical editor.