M-Audio Tampa Preamp/Compressor

Richard Alan Salz
M-Audio Tampa Microphone/Instrument Preamp and Compressor

Ah, Tampa! Just the word conjures up visions of sunny beaches, and (somewhat) surfable waves. M-Audio would prefer however, that the word Tampa should instead call to mind their newly designed preamp/compressor! Does this silicon and steel Tampa measure up to its eminently pleasurable namesake?
Looking at the Tampa from the front, arranged left to right are the following; A power toggle switch, a 48 V phantom power toggle switch and indicator LED, a Neutrik XLR/1/4” trs combi-jack, and instrument/mic toggle switch, a four position microphone impedance rotary switch, a rotary gain pot, a 20 B boost toggle switch, a low cut toggle switch, a compressor in/out toggle switch and LED, a rotary threshold pot for the compressor, a rotary ratio pot, a rotary attack pot, a rotary release pot, an analog vane meter indicating gain reduction, an analog vane meter showing output level, an LED to indicate clipping, a phase reversal toggle switch, a 20 dB pad toggle switch, and a four position rotary switch to select the sampling rate.
Viewed from the rear, the Tampa sports a 12VAC push on power supply input, a balanced output on an XLR connector, an additional balanced output on ¼” TRS, an AES EBU digital output on an XLR connector, and a S/PDIF digital output on an RCA jack.
Viewed from a short distance away the M-Audio Tampa looks very impressive, sporting vintage style knobs, twin round meters, and snazzy looking toggle switches all wrapped up in a brushed metal package. Look a little closer (perhaps popping open the cover) and a different picture emerges. Slightly sharp-edged metal work, flimsy cheap-feeling plastic push-on knobs, and most disturbing of all, switches and pots mounted directly to the circuit board and completely unsecured otherwise.
The most moderate tug on any of the pots or switches actually deflects the leads that attach to the board, and the circuit board itself. With the exception of the Sample Rate and Input impedance pots, which are secured by nuts and washers to the front panel, all of the pots have about 1/8” wiggle room in each direction. This is an almost certain recipe for eventual failure. Even the very cheapest of equipment has nuts or standoff collets that secure the pots and switches to the front panel and prevent circuit board deflection. For a unit of this price, the omission is inexcusable. I have seen clock radios that have been constructed in a more sturdy fashion.
The Tampa provides analog XLR balanced and 1/4-inch TRS outputs, simultaneous output is possible, useful for sending a signal to two places at once, such as to a headphone amp and to a mixing board. DAW users can take advantage of this feature for latency-free monitoring. Additionally, both S/PDIF and AES/EBU digital outputs are available.
Temporal What?
Temporal Harmonic Alignment is the buzzword of the day, when it comes to the Tampa’s preamp section. The obvious question? Quite simply, what is Temporal Harmonic Alignment? M-Audio isn’t saying. During conversations with several M-Audio personnel, I never was able to ascertain exactly what THA is, exactly what it does, and by what method of circuitry it has been implemented. Piecing together the various information I was able to gather, my best guess is that it introduces a phase delay to some of the harmonic distortion components. According to M-Audio, this makes for a more “tube-like” sonic presentation. Since the THA circuitry is not switchable, there is really no way to evaluate this claim. Is the Tampa’s sound due to the THA circuitry? Who knows!
I checked out the Tampa (actually a pair of them) on a variety of sources. All testing was carried out using the following equipment for monitoring and recording: Neotek IIIc console, Urei 809 and Fostex NF-1 monitors, DAV Electronics Broadhurst Gardens (solid state) microphone preamp, Peavey VMP2 tube preamp, the excellent Radial JD-7 distribution amp/DI, MCI/Sony JH-24 multitrack and Studer A 80 RC master recorders.

Director’s Cut
I recently got the chance to test the Radial JD-7 distribution amp/ DI box, which turned out to be one of the better DI’s that I have heard recently, so naturally this was the sonic benchmark that I compared the Tampa to. Where as the JD-7 was definitely on the neutral side (in a good way), the Tampa tended to push the sonic image much further forward, especially when driven hard. I would attribute this to the wildly rising distortion that the Tampa exhibits at high output (or operating levels, should you chose to use the output pad). According to the graph that is printed in the Tampa’s operation manual, distortion looks to be hovering around the 5% mark at the unit’s maximum analog output. To the Tampa’s credit however, this distortion isn’t terrible sounding in the way that other low-buck gear can be. Just the same, you should keep in mind that the Tampa will start sounding dirtier as the levels increase. I found the compressor to sound very nice on bass (especially with the Moses Graphite J-Bass I was using) firming up the bottom, and generally staying out of its own way. I achieved the best results with the ratio set to about 2:1, the attack set a little bit shy of 11 o’clock, and the release set at about 3 o’clock in rotation.

Just Say AHH
I set up a classically trained vocalist whose voice is very smooth and balanced, in front of a Microtech Gefel M71KMT (which is a somewhat dark sounding cardioid microphone) which I have used on her vocals several times before. I wasn’t crazy about what I heard, although I was able to vary the sonic qualities of the presentation a bit by using the variable impedance feature on the Tampa. Just the same, I found the overall sound to be a bit lifeless possessing a “whiteness” or slightly metallic edge. I switched to an Audio Technica 4060 tube microphone, which seemed to better gel with the preamp, providing a truer sonic picture of reality. I also felt that the sound was lacking a little bit in terms of the apparent size of the image. In my experience, I find that this phenomenon usually correlates with anomalies in the midrange response of the device.

During a recent session with a folk influenced male singer I once again tried the Tampa with the M71KMT, again it was no dice. But, I did get a pretty nice sound using an Audio Technica 4040. This combination seemed to provide a sound with lots of sonic cutting power. The slightly metallic presentation of the Tampa really enhanced the vocal track lending a little bit of excitement. Doing a quick comparison with the all-tube Peavey VMP-2 to check out M-Audio’s assertion that the Tampa was “tube-like” quickly showed that it was nothing of the sort. The Peavey sounded much rounder and smoother, completely lacking the metallic edge of the Tampa. That’s not to say that the Tampa is bad and as a matter of fact we ended up using the Tampa for that particular track. On the first sample of the Tampa that I received, I noticed a somewhat disconcerting phenomenon. Upon application of the phantom power, the woofers on my monitors moved out to their full excursion and then back in again, over the course of about two seconds. This indicates the presence of DC current at the output of the Tampa. The second sample was much better in this respect, and only exhibited a small “blip” upon the application of the phantom power option.

The Beat Goes On…
I set up my AKG D12e in the studio’s 22” GMS maple kick drum (fitted with an Evans EQ 2 batter head, and a cutaway resonant head which is basically just keeping the drum’s hardware from rattling) and substituted the Tampa for the solid state DAV Broadhurst Gardens No. 1 preamp I often employ on the kick channel.

While the Tampa did a nice job of presenting the snap of the beater, the overall kick drum seemed to lack bottom end as well as a sense of “punch” relative to the sound of the DAV preamp which presents the drum with most all of its visceral power intact. The overall presentation just didn’t sound like my bass drum. I especially felt that the leading edge of the transient was not reproduced faithfully. Could be due to residual effects of the Temporal Harmonic Alignment’s effects on the phase coherency of the signal?

On a brighter note, when I dialed in a 2 ms attack, (approximately) a 500ms release time, and a 2:1 ratio on the compressor I was pleased with the overall vibe of the kick track. It was like the compressor returned the excitement that the preamp missed!

Using a pair of Tampa’s, I mic’d the studio’s GMS kit from up above, four or five feet in front of the bass drum in OTRF configuration using a pair of Audio Technica 4060 tube mics. Initially I left the compressor switched out of the signal path, but as with the kick drum described above, I found the sound to be much more compelling with the compression switched in. This time, I set the compressor to a 1ms attack (which is its fastest setting) and increased the ratio to approximately 4:1. In general the resultant sound was reasonably full bodied in timbre, and had a decent, though not stellar, amount of depth of field (to borrow a photographic term). Just for fun I swapped the Gefels for the 4060’s and found that they seemed to work much better in the capacity of drum mics than they did for male or female vocals when paired with the Tampa, though the 4060’s still seemed to be a better match.

Using the same set up as above, I pulled the mics back into the room, about 15 feet from the drum kit. I was less pleased with the results, as a sense of “hollowness” seemed to develop. Whether or not this was some form of phase cancellation induced by the THA circuitry, or just a sample-to-sample variation between the two units I am unsure. One thing that I did notice though was that there is the distinct sound of static when you turn the gain control quickly, especially when it is past 12 o’clock in its rotation. My initial feeling that it was the sound of DC current passing through the potentiometer was confirmed by M-Audio, who noted that it was caused by the preamps servo not responding quickly enough to the change in gain. To avoid this noise, just turn the pot slowly!

String Me Along
I used the pair of Tampa’s combined with the Audio Technica 4040’s in neck/sound hole arrangement on a friends Martin D-18. Don’t tell my friend, but his is not one of the better D-18’s I have ever heard! It tends to be kind of “tizzy” sounding, and requires a dark sounding microphone, in order for it to have any body at all. Not surprisingly I found the sound with the 4040’s to be over bright and strident. I substituted a pair of beyer dynamic M88tg’s and was much happier with the warmer and more present presentation. I really liked the sound of the Tampa’s compressors in this instance, using a fairly low threshold and low gain reduction ratio. This was my favorite application for the Tampa, getting a really nice “radio” sounding acoustic track.

The Tampa was also pretty good when it came time to put it (along with the ubiquitous Shure 57) in front of a guitar amp. Using a “vintage” 57 (circa 1985 or so) I mic’d my Silverface Vibrolux reverb (driven by a Paul Reed Smith CE-24) to good effect. I was able to get sounds ranging from fairly open to faux “wall of sound” by using (and abusing) the compressor. Especially on guitar tracks the Tampa’s compressor does offer the user a glimpse at why people tend to covet vintage (and non-vintage) optical compressors. While most people wouldn’t mistake the sound of the Tampa for a well-designed tube preamp (even an inexpensive one like the VMP-2), the sound was nice and full sounding, mostly lacking the metallic edge that I had noticed on some of the vocal tracks I recorded with the Tampa.

Digital Output
The digital output of the Tampa sounded quite a bit better than the (admittedly) behind the curve converters in my Sony A6 DAT machine, and was not that far shy of the good sounding converters in the MOTU 1296. I was impressed by the relaxed and transparent sound of the converters, and definitely appreciated the switchable sampling rates (44.1, 48, 88.2, and 96K) that were available.

I wasn’t impressed however by the physical proximity of the digital output (primarily the AES-EBU XLR output) to the analog outputs. Since they are more or less side by side, I am concerned about potential mis-wiring mishaps (especially in a dark rack situation) and perhaps more importantly the possibility of noise being radiated into the analog circuitry, especially since the digital section is on the same PC board and not shielded in any manner. There is no way to turn the digital section off when it is not being used, and surprisingly there is no provision for using the Tampa with an external master digital clocking source.
What’s the Frequency Kenneth? – The M-Audio Tampa offers a good sounding preamp and compressor, as well as a smooth sounding 96K capable analog to digital converter (with both S/PDIF and AES/EBU digital outputs) in a nice looking package. The inclusion of a digital output is especially valuable for DAW users who would like to bypass their consoles or converters. While the Tampa does sound pretty good and have a very full feature set, I feel that its construction quality leaves much to be desired. I would not recommend the Tampa for use in any installation where its controls might be subjected to rough use or falling objects. With a redesign of its packaging (and switchable THA circuitry, please) the Tampa could very well be a contender.

Product Summary
M-Audio Tampa
Microphone Preamp/Compressor
MSRP $799

EM Meter –
Features – 4
Sound Quality – 3
Construction Quality – 1.5
Value – 2.5

Pros – feature rich, interesting colorations, versatile metering, very good DI
Cons – shoddy build quality for price, no external digital clock input, wall wart

Manufacturer –
Web www.m-audio.com

Tampa Specifications

Frequency Response 20-40000 Hz (+/- .25 dB)
Distortion .5 at 10VAC
Maximum Gain 66dB
Low Cut -12 dB per octave below 80Hz
Input Impedance Mic Input 2400/1200/600/300 ohms
DI input 100K unbalanced 200K balanced
Output Impedance 600 ohms
Compression Ratio 1.1/1 to 10/1 continuously variable
Attack Time 1ms to 11ms continuously variable
Release Time 250ms to 5 seconds continuously variable
Mic EIN -127 dB
Signal to noise ratio 110 dB
Dimensions 19.5 x 4.5 x 3.5 inches
Input Connectors XLR/TRS combi-jack w/48v power
Analog Output Connector 3-pin XLR male balanced TRS ¼” balanced
Digital Output Connector AES/EBU on XLR male, S/PDIF on rca
Sampling Rate 96/88.2/48/44.1 kHz at 24 bit
Supplied Accessories AC adaptor wall wart type