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Millennia Media HV-37

Dual Preamp Unit Brings Clear Sonics, High Gain Ribbon Mode

The HV-37 has a Ribbon mode offering +10 dB more gain.

The fundamental design philosophy behind everything that Millennia Media produces is that for certain types of recordings, the gear shouldn’t get in the way of the sound. When trying to capture true sonic reality, the use of warm, colorful, harmonic-generating circuitry lies to our ears and changes our interpretation of the sound. This effect, at times, can be pleasant and “musical”; however, when skilled musicians are playing expertly crafted instruments in a great-sounding room, there is no need for extra musicality, and instead accurate capture is preferable.

The original Millennia HV-3 excelled at this goal and became a favorite for orchestral and other acoustic recordings. When a circuit of comparable sonic transparency was packed into 500 Series unit, the HV-35 created a good amount of buzz. Now, conceivably out of a desire to accommodate engineers who haven’t bought into the whole 500 Series craze, the HV-37 offers a pair of HV-35-like circuits in a single-rackspace unit with a built-in power supply.

On the Surface

The rear panel of the HV-37 features a pair of XLRs for input and a pair for output. Aside from that, there is an IEC Connector to feed the internal switching power supply. The front panel features two sets of controls, one for each of the two channels. The buttons, lights and connections are the same as those found on a single HV-35. Each channel has a ¼-inch TS input jack for instrument connections, a button to toggle between the rear XLR input and the front-panel instrument input, and a +48V phantom power button (runs at a true 48V ±2VDC). Switches avoided in earlier Millennia designs, to avoid the potential impurities imparted by contacts and relays, are now available on the HV-37. These include a polarity flip and an 80Hz rolloff.

The whole gain-adjusting structure is a slight departure from the earlier offerings in this line. Instead of the 36-position stepped gain circuit, there is a continuously variable gain trim with “high gain jump near full clockwise.” Not many sound sources required that amount of gain boosting, however, it made a noticeable difference when I throttled the pre to record Foley sounds. Like all of the other HV-3s, the HV-37 has such high input headroom that there is no conceivable need for a pad on the input. The -15 dB pad instead attenuates the output of the unit to avoid clipping AD converters downstream when hot signals are passing through.

The HV-37 conforms to the Millennia notion that even the best transformers will add some amount of coloration to the passing audio. Because of this, the HV-37’s tranformerless amplifier uses an AC-coupled circuit with a series of capacitors to block the DC phantom power current. When there is no need for phantom power, the “ribbon” button bypasses the AC-coupled circuit and switches to simpler DC-coupled circuit path from input to output. This path is intended to be even more transparent than the phantom-power-ready path and comes with an added 10 dB boost to help bolster moving coil and ribbon-type dynamic mics.

In Use

When using the HV-37 to record acoustic guitar with a pair of Mojave MA-101a mics, the preamps really shined. The image was realistic, and the upper midrange was wide and open. The amount of detail in the top end was very impressive. Compared to a more colorful API 212 pre, which pushed a bit of midrange, it seemed that the less crowded–sounding Millennia lent itself to a clearer and fuller bottom end, as well. Using the same setup on a brass section, the overall sound was impressively detailed, with a realistic stereo image. While the sound collected was a little on the edgy side, this might have been an honest reflection of the loud brass in a small room.

I used the HV-37 with a Neumann TLM 127 to record Foley cloth sounds, and even with the preamp cranked to full volume, I never heard any noticeable hum or circuit noise. It was as clean as could be, and the sound from that combo was fantastic. I would listen in the studio and come back to the control room to hear a virtually identical sound. Other than a time using the Benchmark MPA-1, I’ve never heard a preamp exhibit such transparency when recording Foley. My only complaint was that despite the extra gain boost attained with the preamp maxed, I was still wishing for about another 10 dB when recording low-level Foley sounds.

Connecting a guitar to the front-panel instrument input was an interesting experience. I was impressed by all of the complex information in the top end that I had never noticed before. The sound was snappy and tight all around. My only problem was that circuit was a bit lacking in personality. It wasn’t very musical until I processed the signal with a plug-in, or re-amped it through an actual guitar amp. I shot it out against a Chandler Limited Little Devil, and it felt like both were equally open in the midrange, but the Little Devil warmed up the lows and added a little personality to the top end. Overall, this seemed to be a more inspiring tone. However, when I connected a bass to the HV-37, it did a great job of displaying a full bottom end while letting the intricacies of the top end distinguish themselves. If you’ve been looking for a solution to clarify a muddy instrument, this might be just what you’re looking for. Beyond that, though, the biggest strength of the HV-37 would be the fact that once re-amped, the clarity of the circuit really shone through and really made the amped guitar pop through the mix.

I did experience one hang-up when recording a guitar with hot pickups through the front-panel jack with the guitar’s volume controls all the way up and the gain control of the preamp all the way down. Even when engaging the pad, fast, loud power chords were still clipping the converters on a number of interfaces that I connected to the output of the HV-37. I fed the signal to the line-level input of my Sound Devices USBPre2 and pulled back the input gain, and heard sparklingly clean sounds. To that end, it seemed that the preamp itself wasn’t distorting, but the output was too hot to be A/D converted cleanly without another volume control in between.

By the Numbers

Despite the fact that opening the chassis of the HV-37 revealed a pair of HV-35s with a switching power supply, we shot the HV-37 against the HV-35 on the APx525 and predictably found nearly identical results. The most significant difference, however, was that the HV-37 exhibited roughly 10 dB of improved signal-to-noise ratio over the HV-35 powered by an original API Lunchbox. This proved that the build and the isolation of the power supply from the amplifier circuit seemed to be very well executed.

Should I Buy One?

As far as a no-nonsense mic preamp for recording orchestra or live performances, Millennia’s 2-channel HV-3C prices out about $400 higher than the HV-37 and offers stepped input control, ensuring precise stereo matching. The HV-3C also boasts marginally better specs on paper. On the other hand, if you’ve been after the Millennia sound but have been turned off by the lack of typical conveniences on the HV-3C, like the roll-off and the polarity flip, then this is the box for you. The ability to capture reality now and flavor it to taste another day is a commodity that is easy to appreciate, and the HV-37 provides the perfect go-to preamp to achieve that goal.

Brandon Hickey is a Chicago ex-pat engineer specializing in studio recording, post-production.


COMPANY: Millennia Media


PRICES: $1,439.99 street

Pros: Clean, transparent sound with high headroom.

Cons: Continuously-variable gain control rather than a stepped control.

Try This

When recording guitars plugged directly into the HV-37, it was beneficial to have the guitar feeding an actual amp as well. Feeding the guitar to a record track in Pro Tools to record the dry sound, and then outputting that track from a USB interface to a Reamp could produce some serious latency in the amped sound. Instead, most modern USB interfaces have an option to feed analog input signal (pre the A/D process) to a hardware output. This zero-latency monitoring option would be perfect for this Reamp application.

***The Audio Precision tests of the two channels of the HV-37 confirmed Millennia’s specs of 65 dB of gain and extremely low inter-channel cross-talk. Click here to download.

***Here the HV-35 in an original API lunchbox was on the left analyzer channel, and a channel of HV-37 was on the right. All specs match except note that the signal-to-noise specs favor the HV-37. Click here to download.