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PC - Applied Research Tube MP Review

Manufacturer: Applied Research and Technology
Product: Tube MP Studio - - Preamplifier, Direct Box
MSRP: $159.00

In a project studio or home studio based on a DAW, coupled with multi-track software, all one really needs is one good preamplifier, a good mike and some patience. While there are widely available low-cost, small mixer boards with preamplification, there is plenty of room for a dedicated, higher-quality preamplifier. I received the Tube MP for review from Applied Research and Technology with considerable anticipation. I looked forward to hearing the sonic quality of this external preamplifier, particularly with its tube enhanced hybrid design. In addition, I was very curious to use the direct inputs on this little box.


  • 24-bit/96kHz recording
  • Dyn.Range >100dB (20Hz to 20kHz)
  • Freq.Resp. 10Hz to 20kHz (+0,-1dB)
  • THD <0.1% (typical)
  • Maximum Gain 70dB (XLR to XLR typical), 60dB (1/4" to XLR typical)
  • Maximum Input Level +14dBu (XLR), +22dBu (1/4")
  • Maximum Output Level +28dBu (XLR), +22dBu (1/4")
  • Input Impedance 2k ohms (XLR), 840K ohms (1/4")
  • Output Impedance 600 ohms (XLR), 300 ohms (1/4")
  • Power Requirements 9 VAC @ 700ma (typ)
  • Dimensions 5.0"D x 5.5"W x 2.0"H
  • Weight 1.5 lbs
As you can see from the image above, the Tube MP has a variety of controls on its face. These include variable input/output controls, switches for phantom power, phase reversal, and +20dB input gain. The unit also has a input meter on top. The back of the Tube MP features 1/4" unbalanced and balanced XLR inputs and 1/4" unbalanced and balanced XLR outputs. A 9v power supply provides power to a jack on the back as well. In addition, there is a level meter that lights up when the power is turned on.


I first noted its considerable heft (1.5 lbs), given its small size (5" x 5.5"). Its black metal design is attractive and is clearly well-built. The preamplifier is self-powered with a 9v transformer that plugs into a wall socket - - no other setup is necessary. Simply, hook up your source to its input, route its output to your soundcard via the outputs and you are set to go. Careful adjustment of the input and output levels is critical to achieving an optimum preamplified signal. The Tube MP can be adjusted in several ways to accommodate different input signal strengths and power needs. For instance, the Tube MP can be used with dynamic or condenser microphones, electric/bass guitars and any line level instruments such as a synthesizer keyboard. The combination of its preamplifiers coupled with High-Z capability and very wide input gain, make it a very versatile and useful addition to any studio.


I first tested the microphone inputs with both condenser and dynamic microphones I have in my studio. I found the adjustments were quite easy, particularly using the level meter on top of the unit. The meter was very accurate - - when it ran into the "red" overdriven area, I noticed the signal had a distorted, overdriven sound to it. I next tested the instrument level preamps by plugging in my Gibson SG electric guitar into the preamp, then playing around with the settings. I got a very satisfying "hot" clean signal into the PC - - even though the signal level coming off of an electric guitar are typically very low, I did not need to use the +20 gain switch to get adequate signal. I found I could still overdrive the signal from the guitar - - this preamplifier is sensitive and powerful. However, small, discrete adjustments were easily made via the controls to optimize the preamp signal.

I did try the +20 settings just for thoroughness, turning down the input knob to compensate. I found that the gain setting did indeed raise the level of the input signal but also some of the noise - - a low-level hiss, noticeable but not distracting. I preferred the sound of the normal gain levels.

Acoustic Guitar

I plugged in one of my Marshall 2003s into the microphone input, turned on the phantom power and recorded some acoustic guitar tracks. I was particularly interested in comparing the sound of the preamp as it compared to the preamps of my Aardvark Direct Pro 2496, of which I am rather fond. I have been able to get a wonderful "woody" tone with the DirectPro with very careful microphone placement. My guitar, an old Gibson Gospel, has a very rich, deep tone on the bass and brilliant highs. I expected this preamplifier to provide a rich full-sounding tone that would accentuate the woodiness of my guitar - - given its tube-based architecture. I was not disappointed. I noticed that the sound quality was quite clean with a warm, fat tone to the bass. However, since it was a mono signal, as compared to the stereo microphone placement I prefer to use, the sound quality was not as well-rounded between highs and lows as I am able to achieve with the DirectPro. So, I recorded a mono track with the DirectPro to be fully fair and used these tracks for comparison. (Perhaps if I had had two Tube MPs to play with it would have been different). Nonetheless, it sounded very good on the acoustic guitar.


I next used the preamp to record some vocals. Using the same microphone, I recorded some vocal tracks on some songs I am working on. I was very pleased with the sound quality for vocals. The tube presence was evident but not dominant, providing a rich-sounding fat tone. This was particularly noticeable on the quieter portions of the vocal parts.


I see this unit being very portable so long as you have adequate 9v power, the quality of the preamplifiers is first-rate and will provide high-quality signals to any soundcard. It would be useful for providing good preamplified signals to a laptop in the field, assuming power is available for the 9v supply.

The only downfall of this preamplifier is that it is mono only. If it were stereo, capable of two microphone inputs? Killer, totally killer. As it is, in the DAW world, you simply need record one mono track, copy it and separate the two to get an adequate stereo effect. However, there is nothing like true stereo. At this price though, I cannot see a similarly good-sounding two channel, stereo preamplifier being available.


The only difficulty I had at all using the preamp involved a sensitive 1/4" output jack. I found that when fully inserted, the sound was a bit distorted. I had to partially pull the plug out to get a full signal to the soundcard. This made it susceptible to any movements of the preamplifier. This occurred with a replacement cable as well, neither of which I have had any trouble with in the past.


As advertised, the Tube MP is designed to be a replacement preamplifier for the preamps that are installed in lower-priced mixer boards. As compared to my mixer, this preamplifier is noticeably quieter and cleaner. In sum, it is superior to the preamplifiers on my Spirit Folio mixer. As compared to the preamplifiers in my DirectPro, they are really two different animals. I preferred the DirectPro on the acoustic guitar, given the natural fullness of the instrument. As to vocals, I preferred the Tube MP - - the tube technology lended a warmth and fullness to my vocals that was superior to the DirectPro.


The Tube MP delivers on its promises - - it functions admirably as a direct input for instruments, provides clean and warm preamplification for both microphone and line inputs. It sounds good and costs little. For virtually any application needing a single preamplifier, be it professional or home studio, it is easy to see why this one is the sales leader.