In the Studio with the Soundelux USA U99

With the mind-boggling number of companies making condenser microphones in 2017, it can be easy to forget that not all that long ago, the options for a top-tier tube mic were limited to a small handful. Among those options, the larger, historic companies came out with tube/solid–state hybrid microphones and "reissues" of their classic designs that had little, if anything, to do with the mics they purported to emulate.

It’s even easier to forget that as far as what’s available today, few people have been involved in the business of building microphones longer than David Bock.

While working on the tech staff at Hyde Street Studios in 1980s San Francisco, it was under Garry Creiman (also the man behind the restoration of Tiny Telephone Oakland’s Neve 8068) that Bock learned the basics of microphone repair. Maintaining the studio’s aging fleet of classic microphones lent some valuable insight into what made the prized vintage mics tick and what was generally the first thing to go wrong under the hood.

After another four years as "day tech" at Ocean Way, Bock partnered up with the post-production company Soundelux to found Soundelux Microphones in 1995 while continuing to service and restore vintage microphones for his own clients.

Focused on replicating or improving upon the "big" vintage tube condenser microphones that Bock experienced, Soundelux did quite well, selling a respectable number of mics to top studios worldwide while retaining the boutique, handmade quality that popularized them in the first place.

After the post-production company was sold to a third party, the new owners decided that they didn’t want to be in the microphone business, and Soundelux Microphones abruptly closed down in 2006, paving the way for Mr. Bock to start producing a few of the models under his own Bock Audio brand.

One Soundelux microphone that didn’t make the jump to Bock Audio was the U99, which went through a few revisions during its production from 1999-2006 before going into temporary retirement. With an announcement and release at Winter NAMM 2017 in Anaheim, David Bock reintroduced the U99 under the Soundelux USA brand, a sister company to Bock Audio.

After multiple failed attempts to nab one of the supercool, retro-styled Soundelux USA t-shirts at that show, we got David to agree to send us a U99 to beat on back at Reverb HQ.

Tech and Specs

You can find a lot of the spec info and dealer jargon from marketing press releases and the like, so we’ll keep this fairly brief.

The Soundelux USA U99 is a large diaphragm tube condenser microphone with a continuously variable polar pattern from omnidirectional to cardioid through figure-of-eight. The capsule employed is a K67-type of German origin — a dual-backplate design as used in the Neumann U 67 that’s quite popular with "clone" companies and DIY builders. This capsule does have an inherent high-frequency lift to it, which is balanced out electronically in both the U 67 and the U99.

Soundelux U99

The tube is a NOS EF732, a subminiature pentode used in a number of Bock’s other designs, with the audio path ending on a large core output transformer selected for its sizeable headroom before distortion at low frequencies.

The microphone’s electronics are well-fed by a fully linear, high voltage N470 power supply, which also houses the rotary control for polar pattern. The U99’s output level is quite healthy, and the self-noise is low enough to be a non-factor in nearly all situations.

Had I not any previous experience with older Soundelux or Bock microphones, perhaps I would have been surprised at the construction, build quality and heft of each component in the box. The microphone itself could double as a nightstick, the power supply’s rugged case a brick in a wall.

The included shockmount is of the threaded variety, which I personally prefer to mounts that clip around the body of a microphone. A roughly 20-foot cable gets its own storage box, coiled to a size that nears the diameter of a basketball in order to preserve the structural integrity of the cable over time.

In Situ

My first encounter with the new U99 came at the Reverb office during a video shoot with LA-based harpist Lara Somogyi. While her personal instrument, a Camac "Big Blue" Electroacoustic harp, leans heavily on complex electronics and pickups piped into stompboxes, the acoustic sound of the harp is absolutely stunning.

I wanted to capture the natural sound of the harp and blend it in with the heavily mangled sound coming out of her amp, and the shiny new Soundelux USA U99 in the Reverb office raised its proverbial hand to be placed on a stand for the job.

While there’s nothing to stop you from firing up the mic and getting started, the base and body of the U99 hold a gaggle of inset switches to further tailor the tone of the microphone and open it up to a wider variety of applications. In addition to a -20dB pad for use in front of loud amps and drums, there’s a three-position switch for high-frequency contour that boosts, attenuates, or leaves alone the treble end of the spectrum, as well as the handy "FAT" switch from Bock's U195 FET microphone. The corner frequency of the high-frequency cut is also selectable on a two-position "HI / LO" switch on the side of the microphone, letting you go from dark to darker.

With the U99 at a bit of a distance — six to seven feet from the harp — the "FAT" and high-frequency boost switches were employed to balance out what is naturally lost as you move any microphone back from a sound source. I dialed the polar pattern halfway between cardioid and omni and got back to the chair to hear what was coming through.

This was the first time I noticed the notable, highly welcome midrange texture that I believe to be unique to this microphone. Harmonic content that — if it was present in the room, was certainly not all that audible — became a major sonic focal point on this harp track.

With the lows and highs lifted on the mic itself, the perceived "reach" of the U99 at this distance was one I'd equate to an AKG C 12 or the few Brauner VM1 KHEs I've had the pleasure of using, and this is not exactly a small feat.

Little-to-no "close up" detail (fingers scraping across the strings, the harp’s pedals being pressed down and let go) was lost among the more reverberant capture when the microphone was pulled back from the harp, and both extremes of the frequency range remained prominent and present. I briefly entertained the idea of trying a couple different switch positions before deciding that what ain't broke ain't a candidate for fixing.

I boxed up the mic after the video shoot and carted it back to my not-exactly-humble home studio for further testing. I have a decent amount of higher-end microphones of all types, both vintage and contemporary, that I know like the back of my hand but picked one in particular as the control for my U99 experimentation — one of my Sony C-38Bs.

Listen to the samples below to hear the U99 in action and how it compares to the C-38B.

Yes, it's a transistor-based microphone with a totally different capsule and electronic design than the U99, but it's a mic that I use regularly in just about every application, and it's one that doesn't have too much of its own personality. The C-38B is "clean" without being some sort of sterile measurement microphone, and since I wanted to try the U99 in front of a lot of different instruments, the Sony made for the best option to see what the Soundelux microphone was really doing.

I put both microphones up on a single mic stand with an additional Latch Lake Xtra Boom attached, allowing me to position both mics in close quarters without needing to wrangle two separate stands, then simply aimed them at each instrument you’d find in a standard 3-4 piece rock band arrangement and cut a short song.

Rupert Neve Designs 511 mic pres were used for both mics on every sound source with the high-pass filter and "silk" disengaged. Toggling a couple mute groups in Pro Tools allowed me to switch which microphone was in the mix for each individual instrument or across the whole song.

1970s Tama Royalstar kit with Sabian cymbals

Starting with the drums, a 1970s Tama Royalstar kit with a 22" bass drum and some old Sabian cymbals, the mics were positioned a few feet in front of the kit at roughly ear-height and more on the ride cymbal/floor tom side. Doing single-mic drum recording from this position gives you good impact from the bass drum and floor tom without having too much hi-hat in the mix, being that the hats are furthest from the microphone.

With the U99 set to "FAT" with the high-frequency switch up the middle, my first thought was that this wasn’t exactly a fair fight. The lowest octave of the bass drum was almost non-existent in the C-38B from this distance but was loud and clear on the U99. Not that the Sony doesn’t sound good here — trust me, it does — but the C-38B would have needed a close bass drum mic for the best balance while the U99 simply did not.

Bass response aside, the midrange texture of the U99 that I first heard on the harp session was once again the star. With the Soundelux mic, each drum — particularly the snare — somehow sounded closer to the microphone and poked through with a subtle richness and aural umami that could not be replicated by strapping an equalizer on the Sony. A little additive EQ could get the bottom end of the two mics playing the same sport, but midrange command of the U99 does not live in any outboard device or plugin that I’ve got.

Bass and guitar amplifiers were next, using my main rig for both. I have an old pre-Bogen Challenger PA/phono amp from the 1950s that’s been converted into a guitar amp with two distinct channels and voices. One is a sort of hybrid between a Fender Deluxe and Bassman, the other gets into higher gain Marshall territory, and I use an ABY switch to get one or both. This amp goes into an open-back Analog Outfitters 2x12 ORGANic cabinet with old Hammond speakers in it. It sounds old, and it sounds very good for both guitar and bass.

‘70s Univox violin bass copy

First up was the bass guitar, a ‘70s Univox violin bass copy with flatwounds and a very predictable, familiar sound. I twisted the knobs to get a bass-heavy, slightly grungy sound out of the amp to anchor the track and placed the microphones about 6 inches off one of the speakers and a couple inches off the center of the cone.

The U99’s "FAT" switch on the proved to be a little over-the-top here, and the sadistic part of me that thinks microphones should have more switches wished for the low-frequency rolloff that’s present on the U195 to work in tandem with the "FAT" option. I opted to leave the bass response on the U99 flat, matched gains at the mic pres and went ahead with the take.

Tonally, the story here was mostly the same as with the drums and the harp, though the midrange magic on the U99 was less pronounced at this closer distance, perhaps being overshadowed by the gigantic low-end thump I was getting. 5kHz-and-up treble capture was also quite pronounced on the Soundelux mic, with pick attack being more clearly audible than on the C-38B which, for the first time in recent memory, came off as dark and hazy to my ears.

Before getting into the electric guitar track, I moved the mics from one speaker to the other and briefly swept them around to find the most balanced sound out of both mics. The amp was set up on the brighter, more "Marshally" channel and gained up to the very first point of crunch from the neck pickup of my 1965 Gibson Firebird III. I wound up with the mics only about 2 inches off the speaker, just above the center of the cone.

1965 Gibson Firebird III

Even on the neck pickup, the amp was a little on the trebly side, so I opted for the high-frequency cut switches on both microphones. The high-frequency cut on the U99 with the side switch in the "LO" position got the treble response of both mics very close and wonderfully dipped out the slightly ice-picky qualities that can come with putting a condenser microphone this close to a guitar speaker.

For chorded parts in context with the drums and bass, I actually prefered the the more even-keeled sound of the C-38B in this case, with its leaner low end that more easily fit the guitar track into the mix. Single-note or lead parts, and the script flips to favor the U99 for its ability to shoot the track out front a little more.

Soloing the U99 track, however, showed once again that this microphone has a large character that would absolutely work for the song had I not been comparing it to a microphone that was doing this specific job slightly better. After printing a take, I got curious and pulled the microphones back to about a foot out from the amp, set the high-frequency responses back to flat, and once again the U99 was the bar-none favorite.

In the interest of getting one non-amplified sound into this test, and seeing as my piano was about three weeks late for its seasonal tuning and touch-up, I pulled out a dreadnought acoustic guitar (Recording King RD-T16 with a torrefied top, a great studio instrument) to lay a chorded rhythm bed under the chorus. Acoustic guitar is one of my favorite uses for the C-38B and one application in particular where I remember the original EF86-equipped 2000s Soundelux U99 sounding stellar.

Recording King RD-T16

I changed things up here and set both microphones to omnidirectional and then engaged the high-frequency boost on the U99. I situated mics about two feet back from the guitar, with the capsules pointing in between the hole and neck/body joint — my prefered starting point for a balanced tone from a dreadnought.

Even on this decidedly "background" track, I had a clear favorite, which was not the expectation I had before I hit red. The low-frequency pickup and general capture of the room in omni was fairly close between both microphones, but that’s where the similarities ended.

Boosting the highs on a condenser microphone is not something I’ll often do, but in this case, it was just what the doctor ordered with the U99 to get this acoustic track to situate itself on top of the mix without getting in the way, especially with the delicious midrange-centered "velvet" that is apparently inherent to the microphone regardless of polar pattern or distance.

It was a similar story when I got to vocals. I’m a tenor-to-alto with what I’ve been told is a sultry tone (much easier to listen to than to look at, I guess), and 90% of the time I go for a softer delivery rather than belting or going for tons of power. Because of this, my voice lends itself very well to condenser microphones, with my favorites being good U 67s and very good Telefunken ELA M 251Es. However, I cannot stand the C-38B on my voice, and for that reason I decided to put it away and just deal with the U99 for all vocal parts.

The U99 gets billed as something of a U 67 replacement due the capsule and "all-purpose" nature of the mic, but I must say that’s doing the Soundelux microphone a bit of a disservice. There is something completely different going on when road meets the rubber, especially on a vocal.

When set to cardioid, the U99’s proximity effect from about 8 inches away on my voice was a touch more subtle than my recollections of U 67s at the same distance. I quickly decided I’d take a couple more steps back from the mic, flip on the "FAT" switch, and have a listen while running through a take.

The thing that sets the U99 apart from the U 67 on a vocal is undoubtedly the "reach" I alluded to before. Being able to step back from the mic and still have a focused, "close" sound is not something I’ve been able to do with a U 67, and the added benefit of being able to bump up the low end on the U99 with the mic at greater distances adds a whole other level of utility.

Toggling back and forth between the "all Sony" and "all Soundelux" mixes was essentially a towering reiteration of everything I’d found up while cutting the song. The U99’s sound has more thunder, sex appeal and polish and the "all Soundelux" mix with the faders at unity sounded much closer to finished product than the "all Sony" mix.


I’ve been fortunate enough to set hands and ears on a staggering number of microphones throughout my life — old and new, incredible and terrible. While I can likely be considered some sort of microphone fetishist, the amount of same-old-same-old design recycling, lookalikes, and the neverending string of models that have "47" in the name for some reason have soured me to the point where it takes quite a bit for me to be genuinely impressed by a new microphone offering. The Soundelux USA U99 has crossed that threshold, and I plan on selling a few dead-weight mics in my locker to pick one up for my place.

With the U99 being one of those mics you can just leave on a mic stand and point at whatever comes through the door, the return on investment should happen quicker than you’d initially think."

While $2,600 is nothing to sneeze at for a single microphone and will probably be out of the budgetary stratosphere of budding engineers or home studios, it’s worth noting that other microphones of similar build quality and featureset either cost twice as much or don’t even really exist.

One of the most popular tube mics in this weight class, the Manley Reference Cardioid, costs a couple bills more and offers only a cardioid pattern and a much less versatile, less pliable sound. With the U99 being one of those mics you can just leave on a mic stand and point at whatever comes through the door, the return on investment should happen quicker than you’d initially think.

More importantly, it’s built by a man with decades of experience building microphones who truly listens to what he’s doing and cares about how the end product turns out.

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