Studio Projects VTB-1 V Series Tube Microphone Preamplifier
Solid state design with a totally discrete circuit makes for a winning sound

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Studio Projects VTB-1 (Click image for larger view.)
Every day that goes by it seems that a couple of hundred bucks buys more and more for recording studio owners and musicians. In the last two years, Alan Hyatt of PMI Audio in Torrance, Calif., has been designing and introducing award-winning Studio Projects microphones, and has made it clear from the start that the company is partnered with 797 Audio in Beijing, China to deliver affordable quality audio products to the masses. High praises of the large-diaphragm condenser mics quickly spread and continue to be the biggest microphone buzz on the internet. Even many of the skeptics, wary of hype, have themselves been converted into satisfied customers who turn around and spread the good news. With stunning microphones and compressors this side of dirt cheap on the market, the missing link in the low-cost signal chain has still been a truly great microphone preamplifier.

Out of the Box

When I first received the VTB-1 from Alan Hyatt for review, I somehow didn't want to like it. Lucky me. There are some things I don't like. I don't like the name, and I can't remember it. Something like the V1 would have been more fitting and in line with the company's other products. I also expected a little more from Studio Projects in the way of packaging and cosmetic design. It looks like a $200 mic pre. No more, no less. As we were patching in the unit to the DAW, I didn't like that the XLR jacks in the back of the VTB-1 don't lock the XLR mic cables into place. I'd like to see a 19" rackmount version with dual VTB-1's in the near future. The V2, perhaps. A quirky perk is an indigo-blue light that glows inside the VTB-1, which is quite apparent in low-level lighting. Nothing wrong with a little atmosphere enhancer.
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I spoke with Alan Hyatt recently and he said, "When I approached the designer, my request was to build the ultimate low-cost microphone preamplifier." The VTB-1 is solid state using a totally discrete circuit. What is surely to make high-brow recordists scoff is the "Tube Drive," featuring a variable drive to a 12AX7 tube utilizing a starved plate — the same technology used in your good ol' stomp box. About the tube option, Alan said, "This was something we wanted to include to give more options and not limit the mic pre to just one sound."

An important feature not to be overlooked is a mic loading switch on the back which offers switchable impedance between 50/200 Ohm. We didn't have a ribbon mic handy, and we totally phased testing a dynamic, but I'm hearing from respected engineers that the switch actually works quite well. Also crammed into this mighty mite is a front-panel DI and a rear-panel 1/4" TRS insert that acts as a splitter box allowing for simultaneous output of one solid-state signal and one post-tube signal.

In Use
I drove on a beautiful day along the shores of the east coast to a studio I've been designing. I want to thank Mark L for providing his studio and another set of ears to test the VTB-1. In hindsight, I would have liked to have had a chance to "burn in" the box by leaving it powered on for a week.

Although the Tube Drive is variable, for the sake of economy, I only recorded separate passes for each instrument in five different positions. One at SS, the solid state position — which sits at 7 o'clock on the dial. The signal is not introduced into the 12AX7 tube at this stage. We took a second pass at 9 o'clock, third pass at high noon, fourth pass at 3 o'clock and the last pass cranked — which lands at about 5 o'clock.

We decided to add tracks to a song already in-progress to not only get an idea of the additive quality of the VTB-1 over several tracks, but also to compare it to tracks that had been recorded with an HHB Radius 40, a channel strip I have recommended highly in the past couple of years.

Studio Projects VTB-1 V Series Tube Microphone Preamplifier
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The first audition was with a Taylor acoustic guitar miked with an Oktava MC012 with a cardioid capsule running straight to the VTB-1 and into the DAW. No compression, no EQ. We recorded five passes, the first one at the SS setting. The first thing I noticed — even though we were riding the gain levels high — was that the VBT-1 itself was dead quiet. No hum, no hiss, no RF noises. As we made each guitar pass and cranked on the tube-drive knob, the presence of the tone increased. After we got to the passes that were near the end of the scale, things just started to sound dirty. Not unlike an amplifier that gives you about 75% of usable power before it starts to crap out. Nevertheless, Studio Projects leaves it up to you as to how much you want, and I'm sure there may be applications for the higher tube settings that I haven't yet investigated. Mark and I both agreed that the guitar sounded best around 9 to 12 o'clock.

Next up to bat were some vocal tracks cut with a Studio Projects C1 microphone. During the first pass on the SS setting, it was clearly apparent that this preamp is serious. We continued doing passes and cranking up the dial each time. Each pass was clearly adding more warmth to the signal. All the passes sounded stunning until we reached the last quarter of the dial. High noon seemed to be the sweet spot . [an error occurred while processing this directive] Number three in line was a Danelectro bass plugged directly into the DI on the front panel. We tracked the bass with no compression and no EQ. Even though the sound of the bass didn't sit as well as if it were compressed, it nevertheless accurately brought out the tone of the bass on the SS setting and really came to life at 9 o'clock. In all fairness, I'd have to say the explorations into the DI aren't conclusive as I'd need to set up the entire chain for the bass. But I heard nothing objectionable, and the bass came through with nice, full frequencies.

VTB1 SPECIFICATIONS
Maximum Gain:
Mic In to Bal Out: 72dB (60dB preamp gain, 12dB output gain)
Line In to Bal Out: 42dB (30dB preamp gain, 12dB output gain)

Phase response (20-20kHz, either input): <+/- 15 degrees

Input Impedance:
Mic Input (Rear switch in 200 ohm position): 2000 ohms
Mic Input (Rear switch in 50 ohm position): 300 ohms
Line Input (Front panel TRS jack): 1.5 meg ohms

Distortion/Noise(THD + Noise):
-20dBu input-Mic; 0dBu input-Line
Both measured at +15dBu output
Mic or Line In to Bal or Line Out: <0.0015% (Blend set full CCW- no tube)
Mic EIN: -128dBu (150 ohm source, 60dB gain)

Output Impedance:
Male-XLR Balanced Output: 100 ohms (50 ohms each leg)
TRS Line Out: 300 ohms (Impedance Balanced)


Insert Jack(TRS):
Nominal level approx 0dBu
Located between SS preamp stage and tube/output stage
Tip = Send: 50 ohms output impedance
Ring = Return: 7500 ohms input impedance

Frequency Response (20-20kHz, ref 1kHz):
-20dBu input, +15dBu output
Mic In to Bal Out: +0 /-0.25 dB
0dBu input, +15dBu output
Line In to Bal Out: +0 /-0.5 dB

Last up was a Yamaha grand piano miked with an AKG 414 on the omni setting. In this case, the SS setting was the way to go. Again, beautiful. Nice and transparent and easily sounding as refined as mic pres I've used on many high-end solid-state consoles. We also listened to some additional passes with the 70Hz high-pass filter engaged and it did the job cleanly and effortlessly. A high-pass filter can be an important tool to have at the preamp stage, and I'm glad to see Studio Projects included this feature.

Critical Listening
After recording all the different passes, we began listening back. We soloed tracks, listened to them in context with drums and other tracks recorded earlier and also A/B'ed the VTB-1 passes with the same parts recorded with the Radius 40.

Auditioning every pass was like bringing up a different quality. All of the first three passes sounded great — so it's more of a matter of deciding which setting would help the track best sit in the overall scheme of the recording. After selecting what we felt were the best passes on each take, we did some A/B'ing. I must say, as much as I like the Radius 40, the difference of the VTB-1 was surprising. In technical terms, the VTB-1 completely blew the doors off the Radius 40. I have been a long-time user of high-end and mid-range TL Audio products, and though I have never felt the mic pre on the Radius 40 is outstanding, as an overall tube-hybrid front-end for a project studio at $600 or under, it's hard to beat. After hearing the VTB-1, I've changed my mind.

The difference in sound between the units could be compared metaphorically to the the Radius 40 sounding like a drop of ink on a piece of paper with bleeding around the center spot. The VTB-1, on the other hand, sounds more like a defined, deliberate mark with little to no bleeding around the edges, even as the dial is cranked and the tube pushed harder. The sound of the VTB-1 is warm without sacrificing definition.

I have never heard a mic pre under $1,000 that sounds and acts like the VTB-1. The missing link in the price versus performance chain has arrived! Next time we'll be raising the bar by running the VTB-1 against Neve and API mic pres — two of the heaviest hitters in the audio industry. I've heard through the grapevine from some trusted industry sources that the VTB-1 recently took a little run with an Avalon 737 and didn't exactly lose the race.

Last Word
The heavens are surely smiling on Studio Projects and its rapidly growing user base. Considering the various new ventures the company has, including one with the legendary microphone-modification wizard, Stephen Paul, to bring Stephen's first microphone to market, there seems to be no end in sight for Studio Projects as they continue to smash through sonic performance barriers. If you're looking for your first external pre, you've found it. The question of whether to buy a solid state pre or a tube pre is history. If the pres you have didn't run you over a thousand dollars, you're not getting the sound that this unit delivers.

The VTB-1 is one of the most versatile mic preamps I have ever used, with a wide variety of sonic treatments, from transparent to beautiful warmth to bordering on tube insanity. If I was limited to recording an entire project with only one pre, I would seriously consider the VTB-1 for the task. The VTB-1 is certain to join the ranks as one of the most innovative audio products of recent memory.