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500 Series Preamps, Times Three

BAE 1073 MPL, Sonic Farm Silkworm, Meris 440

The 500 Series format has certain limitations that are a challenge for module designers. These include tight spaces in which to put large components, plus low power supply voltage and current draw. But over time, manufacturers have thought this out, gotten over the problems through meticulous design, and made some excellent preamps. The three units grouped here fall into this category and are some of the best around. Reviewed below are the BAE 1073 MPL, Sonic Farm Silkworm and Meris 440 microphone preamps. Each offers a solid design, great features and excellent sonic performance.

BAE 1073 MPL

This great-sounding unit is solidly built, hand-wired, and bare bones in design. Features include Class-A electronics, Carnhill St. Ives transformers, DI input, and separate switches for Mic/Line, phantom power (illuminated), and polarity flip. Input is gained via the large rotary knob at the top in 5dB increments with a completely variable output gain knob. There is an impedance switch on the back of the unit that allows you to choose either 300 or 1200 ohms. Being on the back, you’re probably going to set it and forget it, but it’s nice to have the option. I set mine to 1,200 ohms, and it always sounded great.

The first use was on a male lead vocal recorded with a U 67 through the BAE 1073 MPL and an Empirical Labs Fatso Jr. I set the Fatso to Buss, Tranny and adjusted it, so I was getting 3 to 5 dB of gain reduction at the peak. The sound was beautifully warm, tame at the top without being dull, and carried a full midrange tone that flattered this male vocalist. I used the same chain to shoot out three different mics: a 251, a U 47 and the U 67. The 251 was very sibilant, while the U 47 was better but didn’t have the full midrange of the U 67, so I went with the latter.

Next I used the BAE to record a bass guitar using an A Designs REDD DI. Because of the gain the REDD offers, I was able to use the line input of the 1073 MPL—the combo sounded fantastic. On another session, I recorded a Fender Jazz bass using the DI input on the front of the unit that, again, sounded beautiful. The bass had a rich and full tone, not needing even a hint of EQ.

On other sessions, I used the unit to record snare and then kick drum. For both applications, I used some EQ from a 500 Series API unit and the pair was a winner in both applications. My favorite preamp for kick and snare is the Coil CA-286, which I reviewed in Mix’s September 2015 issue. But the 1073 MPL is a close second, and much more affordable.

The unit tested had the impedance switch on the back of the unit, which is so impractical that it might as well not be there at all. However, you can purchase a version with the impedance switch on the front of the unit for $950. That aside, the unit sounds great as a preamp or line amp, and although it doesn’t have extra features found on competing preamps, it is a winner. If you’re looking for a classic, great-sounding preamp that will be in your 500 Series rack until the Apocalypse, this is the one.

Product Summary




PRICE: $899

PROS: Solid build, sonically excellent, line/mic switch.

CONS: Version with impedance switch on front of unit is $50 upcharge.

Sonic Farm Silkworm

Silkworm is Sonic Farm’s first 500 Series product, and it is packed with features. On the inside, there are Cinemag 100-percent high-nickel transformers at the input, and another, steel transformer switchable, at the output. On the front, the large white knob at the top provides access to a full 66 dB of gain, and after that it gets interesting.

The “Vibe” section offers a three-position switch that is best explained by the designers. “This switch is a complex impedance manipulator that makes the mic interact with the input transformer. S, P and W stand for Smooth, Present and Warped. Present is linear; Smooth has a slight top-end roll-off, and Warped has a presence peak between 3 and 7 kHz depending on the mic impedance.” The designers say this feature will most affect dynamic moving-coil mics, ribbons less, and transformerless condensers hardly at all. Lots to remember, but that’s the depth of tweaking you can apply to your signal. Next is a High, Low, and Medium gain switch that is self-explanatory, plus there is a separate pad switch. This kind of gain control means this unit will handle most anything.

Other switches toggle Mic or Instrument input, phantom power (illuminated), polarity, and a toggle for solid-state or transformer-driven output. At the bottom is the DI input, and that’s pretty much all you can fit into a single 500 Series rackspace.

I used the Silkworm across a broad range of applications from vocals to percussion, drums, guitars and bass. Whenever I had a “problem,” I found myself switching over to the Silkworm to help fix it. Yamaha Subkick too hot for other preamps? The Silkworm’s pad and three-position gain switch were the solutions. Bass amp miked with an AKG D112 not round enough? The Silkworm’s output transformer and Vibe switch gave me many options for my sonic palette. This preamp is a sound tweaker’s dream. On a lead vocal, recorded with a simple Shure SM7, the Silkworm provided the extra gain I needed for this mic that has a notoriously weak output. Plus, once I experimented with the Vibe and output transformer, I could access many sonic options without having to reach for an EQ.

If you’re a sonic “fiddler,” meaning you try anything to get it right before Record, then this is your preamp. The features are no BS. Each one is solidly designed and thought out. How they got all this into a 500 Series unit, that sounds good as well, is unbelievable. What you can believe is that you’ll love this unit on many varied types of inputs for years to come.

Product Summary

COMPANY: Sonic Farm

PRODUCT: Silkworm

PRICE: $700

PROS: A sound tweaker’s dream. Great features and sound.

CONS: None found.

Meris 440

The Meris 440 first caught my eye because of its integrated guitar pedal effects loop option. I’ve been experimenting with integrating pedals into my +4dB workflow from Pro Tools for other reviews in Mix, and I thought that the Meris 440 was brilliant. The main features of this well-made preamp include up to 60 dB of gain provided by a large input gain knob and a second output knob, both completely variable. The output trim (-27 dB to +12 dB) happens before the output transformer to preserve its secondary impedance. Other features include a 12dB per octave HPF starting at 80 or 200 Hz, 3dB of high-shelf boost at 4 or 7 kHz, a -20dB pad, polarity, and illuminated phantom power switch. As with the Silkworm, there are Cinemag transformers at the input and output, but unlike the Silkworm, the output transformer is not switchable. The two TS jacks at the bottom of the unit are where the I/O happens for guitar pedals. The return jack doubles as a DI input—a nice touch.

I first used the 440 for a range of applications where the guitar pedal I/O wasn’t needed. Not engaging this gave me a chance to first see what it could do as a preamp alone. It is a standout. When used to record bass, kick, snare, acoustic guitar and percussion, the Meris 440 sounded excellent. The HPF is well centered at 80 and 200 Hz—I tried both when recording acoustic guitar, settling on 80 Hz. I’m always swearing at those who choose 100 Hz as a starting point, as it takes out too much of the good tone.

Next, I used an Earthquaker Devices Hoof fuzz pedal patched across the input of a bass amp miked with a U 47 FET microphone. The clean DI input recorded through another preamp married nicely with the 440’s fuzzed-out input. It was nice to have the pedal in the control room as the bass player was in another room. I could see this unit sitting nicely in the home studio rack of a guitar player who wants to keep his pedals on the desktop with short cable runs. Having the plugs at the front of the preamp is an excellent idea.

Another great feature is to use the 440 as a re-pedaler from your DAW. Set the unit to unity gain by setting the -20dB pad to on, the gain knob completely anti-clockwise, and the output knob to 10 o’clock. Send your DAW track to the input of the unit and use the Send/Return jacks to go to your favorite pedal. The affected output of the 440 can then be re-recorded back to your DAW on a fresh track.

The only item on my wish list would be that the +3dB boost would be centered closer to 2 kHz, which for me is the money frequency for guitars. That said, if you’re on a budget and want a great preamp with some solid extras, including the ability to quickly add guitar pedals to your workflow when recording or mixing, this is your best buy.

Product Summary



PRICE: $549

PROS: Affordable, great sound, solid build, versatile effects loop and DI.

CONS: No line input for re-amping guitar effects from your DAW.

Kevin Becka is Mix’s technical editor.