Why use a pre-amp? Quite simply, a pre-amp greatly aids in either bolstering the signal of either a mic or line-level device, but it also can add some very helpful signal conditioning that will add “warmth” to the tone a device produces. I use the Presonus TUBEPre not only for microphone applications, but also for adding a touch of warmth to the signal of my acoustic guitar. The difference that it makes in the overall tonal quality that my guitar produces while plugged into an amp is so immense that it has become an essential piece of hardware when I gig or record.
Among the “lower cost,” sub-$100 pre-amps on the market, I believe that the TUBEPre offers the best value. With its standard features, it surpasses many tube-based pre-amps in this price range. Most tube pre-amps just provide drive and gain knobs and perhaps a phantom power switch, but the TUBEPre also includes four extra features that definitely add to its value.
As the name implies, the Presonus TUBEPre is a vacuum tube-driven device. Specifically, the tube used is a fairly standard 12AX7 tube. Here are the extra features that accompany the pre-amp:
- Phase Inverter Switch – I’ve never had to use this, but pressing this switch reverse the polarity of the XLR connection to avoid phase cancellation when two mics operate in close proximity.
- -20db Pad – This is incredibly useful when mic’ing a high output device like an amp so you don’t drive the input signal into distortion.
- 80Hz Rumble Filter – This is very nice feature that will eliminate low frequency background noise such as wind or air conditioners. Since I use mine in my garage, it’s great for filtering out the low frequency drone of my freezer.
- +48V Phantom Power – For those devices that require a constant power source, such as a condenser mic, getting enough power is just a button press away.
I only have one gripe about the TUBEPre, and that is that the meter is completely useless. In my case, once I hit about 9 o’clock on the gain (with Drive set to 11-12 o’clock), the meter becomes incredibly erratic, and tends to peak way too easily. So I tend to rely on my ears, and the clipping alert LED between the drive and gain knobs (which works). Other than this single gripe, it’s all good, and really it’s about the sound anyway.
How it sounds…
Out of the box, the TUBEPre sounds great, adding a very pleasing warmth to your tone, but it sounds even better with a different 12AX7 tube than the cheapo stock tube that comes with the unit. I replaced my 12AX7 with a Mesa Boogie 12AX7 tube, and the already great sound that came out of the TUBEPre sounded even better!
I use the TUBEPre for both microphone and for warming up the signal from my acoustic/electric. In both cases, the resultant sound is very warm and full of texture. My vocals are very clear-sounding, especially when I’m using a heavy-duty cardioid mic, which tends to project a lot of bottom end and at times sound a bit muddy. With that mic hooked up to the TUBEPre, I get a rich, full tone that brings out the subtleties in my voice (though it does pick up those little vocal mistakes ). With my acoustic/electric hooked up to the TUBEPre, it actually helps to brighten out the sound of my guitar, and gives the output much more dynamic range. The net result is that my performance can be a lot more expressive.
As far as driving the tube into clipping, that’s not something that I use it for, but I have done it, and it creates a very interesting effect. The sound is very much pre-amp distortion, but it’s a bit thinner. But as I said, this is not something that I’d do with this unit in any case. Driving the tube into clipping too often and for too long will reduce its life. Tubes ain’t cheap, so I tend to baby this unit as much as possible…
To sum it up, the Presonus TUBEPre is a great addition to your gear if you’re looking to warm up your tone.
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