Peavey's previous foray into tube microphone preamp design yielded the critically acclaimed VMP-2, a great-sounding and affordable dual-channel Class A unit. Now, the Mississippi-based manufacturer has added an even more affordable unit to its prorecording line: the single-channel TMP-1 Class A tube mic preamp. Because I often use and really like the VMP-2, I jumped at the chance to check out the TMP-1.
Like the VMP-2, the TMP-1 boasts Class A tube design throughout its signal path. It has fewer features than its predecessor, however, which is no surprise given the preamp's remarkably low price.
The TMP-1 is a 1U rackmount box with a modern, no-frills look. The faceplate has a silk-screened blue-to-black fade, a depiction of two tubes, and large white lettering. From left, the front panel provides an 80 Hz low-cut switch, an input-level knob, a five-step LED input meter (-6 dB, 0 dB, +6 dB, +12 dB, and Clip), a 24V Phantom Power switch, a power-indicator LED, and a power On/Off button. The TMP-1 lacks an attenuation pad, a polarity-reversal switch, and an EQ (aside from the highpass filter).
The highpass filter, which is designed to eliminate low-end rumble, has a steep 12 dB-per-octave slope starting at 80 Hz (despite the incorrect mention in the manual of a 40 Hz highpass filter with a 6 dB-per-octave slope). The unit's Gain knob is marked 0 to 10, like a guitar amp's, rather than marked with decibel calibrations. The LED is a helpful addition and more than many preamps offer. According to Peavey, you can achieve the best signal-to-noise ratio by keeping the signal between the meter's +6 dB and +12 dB range.
One thing that irks me is the TMP-1's 24V phantom power. Peavey confirmed that the lower, nonstandard voltage helped cut costs, but phantom power is not the place to skimp on a preamp designed for professional use. Although most condenser mics work with as little as 9V phantom power, many microphones require 48V to operate at optimum level. Moreover, the TMP-1 does not provide an LED to indicate that phantom power is on. That is a concern because the Phantom Power button is easy to push, yet it's difficult to tell at a glance whether it's engaged.
OUT THE BACK, JACK
The TMP-1's rear panel is as simple as they come. A combination input jack allows for balanced XLR and unbalanced ¼-inch connections. The XLR input (recipient of the phantom power) is transformer balanced. My only beef with the jack design is that it doesn't provide a locking mechanism for securing the mic cable.
The unit has two discrete output jacks: a transformer-balanced XLR and an unbalanced ¼-inch. Also located on the rear panel is the receptacle for the included IEC power cable, which is detachable.
RACKED AND READY
Like the VMP-2, the TMP-1 employs readily obtainable tubes: a 12AX7 at the input stage and a 12AT7 at the output. Despite the VMP-2's better specs and bigger feature set, I thought it worthwhile to conduct a comparison test between the two preamps. I also put the TMP-1 head-to-head against a couple of more-expensive, solid-state preamps that I'm well acquainted with, just to draw a better bead on the TMP-1's sound quality.
I tested the TMP-1 in the controlled environment of Guerrilla Recording in Oakland, California, and on location recording gigs. I used Monster Cables and recorded direct to a Panasonic SV3800 DAT. In the studio, I routed signals through a Soundcraft Spirit Studio console; on location, I used a Mackie 1202-VLZ.
I used a variety of microphones to test the TMP-1, including Baltic Latvian Universal Electronics (BLUE) Dragonfly and AKG C 3000 B large-diaphragm condensers, an Oktava MK 012 small-diaphragm condenser, and a Shure SM57 dynamic mic. Sources included female and male vocals, acoustic guitar, dumbek, and key chimes.
I also tested the unit as a direct injection (DI) box for recording bass guitar — an application curiously absent from the manual, considering that the unit offers an unbalanced ¼-inch instrument-level input. Interestingly, the DI box was my favorite use for the TMP-1. The tone, albeit a bit on the bright side, was smooth, clear, and present, not boomy or indistinct. The TMP-1 may well prove a winner as a preamp for bass rigs.
IN THE CONTROL ROOM
When plugged in and turned on, the TMP-1's transformer put out a troubling 60-cycle hum. That was a moderate distraction in the control room, though, fortunately, the monitoring levels in the room effectively overrode the hum during recording, making it less of an issue.
Another curious thing happened: after the unit had been on for half an hour or so, the -6 dB and 0 dB LEDs lit up, despite no signal being present. Thinking the unit defective, I obtained a second TMP-1 from Peavey. With that unit, only the -6 dB LED lit up (though the 0 dB LED flickered occasionally). Fortunately, the LED gremlins didn't seem to affect the unit's sound.
The TMP-1's self-noise level is fairly prominent. The noise wasn't a problem when recording loud sources that provided a fairly hot input (strummed steel-string guitar and dumbek, for example). However, it was appreciable when recording quieter sources that required greater amplification, such as soft vocals and light, sparse percussion. Moreover, using the TMP-1 with a somewhat noisy mic compounded the noise.
Although the TMP-1's overall tone is fairly close to the VMP-2's, the TMP-1 doesn't quite measure up sonically. For one thing, the TMP-1 is about 7 dB higher in self-noise than the VMP-2, and it produces a noticeable high-end hiss. Because of that, the TMP-1 would not be my first pick for recording quiet sources.
Depending on which mic I used, the differences in tone between the two preamps changed, particularly in the highs. Overall, the TMP-1 sounded brighter than the VMP-2 (especially with the Dragonfly). I was impressed, though, by how good both preamps made the SM57 sound.
In comparison with the more expensive preamps, the TMP-1 sounds somewhat harsher, more sibilant, and not quite as warm and detailed; again, the TMP-1 is noisier. Keep in mind, however, that those preamps cost two to three times as much per channel, so that's not exactly an apples-to-apples comparison. (The comparison helped me to get a better idea of the TMP-1's tonal qualities.)
Because the TMP-1's overall sound is somewhat thin, I preferred not to engage the unit's highpass filter for most applications. Nonetheless, the filter is a welcome feature in case of severe rumble, and it could also prove to be helpful when recording particularly boomy sources.
When powering the Dragonfly, the TMP-1's 24V of phantom power reduced the mic's output by about 6 to 8 dB (as compared with the VMP-2, which provides the standard 48V phantom power). If I had not been doing a direct comparison, the deficiency might not have been so noticeable. Decreasing the phantom-power voltage reduces the mic's sensitivity, however, and additional gain is required to make up for the loss; if the preamp is noisy to begin with, the noise level is only going to increase.
The TMP-1 is an affordable, single-channel Class A tube mic preamp with a tube signal path from input to output and a simple, uncluttered design. Although it lacks the tone warmth typically attributed to tube gear, the TMP-1 provides a sonic personality different from those of standard solid-state board preamps. If you have a few extra dollars and want to increase your studio's palette of sounds, give the TMP-1 a listen.
I have a couple of concerns. One, it's noisy enough to be problematic when recording quiet sources (or when used in tandem with a noisy mic). It also provides only 24V rather than standard 48V phantom power — a cost-cutting maneuver that reduces the unit's appeal and usefulness for professional recording.
If you're a bass player, check out the TMP-1 as a DI box and as a preamp for your rig. It could prove your most affordable route to a clear and present bass sound.
Input Connectors(1) Neutrik Combo (transformer-balanced XLR; unbalanced ¼")Output Connectors(1) transformer-balanced XLR; (1) unbalanced ¼"Maximum Gain55 dB (mic); 40 dB (line)Maximum Input Level+55 dBu (mic); +40 dBu (line)Maximum Output Level+18 dBMFrequency Response20 Hz-20 kHz (+0, -3 dB)Dynamic Range120 dBEquivalent Input Noise-106 dBVTotal Harmonic Distortion<0.2% @ maximum gain (40 Hz-40 kHz)Hum and Noise66 dBV @ 40 dB gain (unweighted)Signal-to-Noise Ratio>66 dBV @ 40 dB gainPhantom Power24 VDCTubes12AX7 (input); 12AT7 (output)Filter80 Hz highpassMetering5-step LED (input)Power Supplyinternal (IEC jack)Dimensions1U × 9.875" (D)Weight8.4 lbs.
tube mic preamp
FEATURES2.5EASE OF USE5.0AUDIO QUALITY2.5VALUE3.0
RATING PRODUCTS FROM 1 TO 5
PROS: Affordable. Transformer-balanced I/O. Great as bass DI box. Provides ¼-inch input, five-step LED input meter, and 80 Hz highpass filter.
CONS: Noisy. Provides only 24V phantom power. No indicator LED for phantom power. No attenuation pad, polarity reversal, or locking mechanism on XLR input jack. Somewhat thin sounding and lacking in warmth and low end. Skimpy manual. Mysterious LED-meter malfunction.