RECORDING PreSonus M80 - Eight Channel Mic-Preamplifier w/ Stereo Summing Bus - PreSonus M80 - Eight Channel Mic-Preamplifier w/ Stereo Summing Bus By Kurt Foster Aug 9, 2004, 15:06 <img SRC="http://www.recording.org/e-mag/uploads/presonus_m80_dw_jpg_small.jpeg"> 8 channel full featured mic pre! The market

PreSonus M80 - Eight Channel Mic-Preamplifier w/ Stereo Summing Bus By Kurt Foster
Aug 9, 2004, 15:06

8 channel full featured mic pre!

The market for microphone preamplifiers has really heated up in the past 18 months. All of a sudden, everyone has an opinion to offer or is asking the pundits "What about the (fill in the blank) pre? We get lots of questions at Recording dot ORG asking for advice and pointers towards great sounding "affordable" mic pres and lots of replies offering recommendations. It can get very contentious as to what is good and what isn't. In the end the answers are not as simple as one might think. Much of what makes a great pre is very subjective and what might be one persons treasure, is anothers junk.

The mic pres from Presonus, get nods of approval and are recommended very often by those who inhabit the budget / price conscious camp. Live sound contractors have told me that the Presonus M80 is a great way to bring mics into mobile recording systems they are using on location for "board tapes" or artist references. Some touring acts record all their performances and no one really knows the destiny of these recordings. In the off chance that a gem may be uncovered, in terms of a performance, these FOH engineers, want to be sure that the recordings they hand over at the end of the show, are up to snuff. The M80 has been receiving high marks in this application. But how will the Presonus M80, retail (Price:$2299.95), stand on its own in a situation where there are other (some very expensive) choices? I decided to take the M80 for a "test drive" to see if I could ferret out the answer.

DESCRIPTION

The PreSonus M80 is housed in a two rack space, steel chassis with a high quality blue anodized front panel. Each channel is full featured, with low noise, balanced input transformers, 48 volt phantom power switch, phase reverse switching, -20-dB pad, HPF at 80 Hz., "IDSS warmth control" and led metering. The M80 features a stereo mix buss with pan controls on each channel, for placing any channel into the M80's main stereo buss output. A high gain output headphone jack is provided for monitoring of the main bus.

The "IDSS control" on each channel adjusts the drain current on the input FET amplifier, altering the even harmonic levels of the signal used to adjust the harmonics of the signal from absolutely pure (no harmonics) to simulation of the effects of tape saturation and tube "warmth" according to PreSonus.

PreSonus M80 front panel

The rear panel of the M80 features XLRF and TRS instrument inputs using Neutrik combo connectors and XLRM output connectors for each of it's 8 channels. Each channel is equipped with separate balanced send and return jacks for inserting your favorite processors. It is refreshing to see the inserts on the M80 as dedicated balanced send and receive jacks rather than the customary TRS send / receive affairs we are all used to. One may use the send without interrupting the signal flow, for diverting the signal off to another mixer for latency free monitoring or perhaps to send to another recorder as back up for example. There are too many applications for this jack to mention them all here, suffice it to say this option offers a lot of flexibility, just use your imagination. For additional flexibility, the user may plug line sources into the insert return jack. Mix output connectors are balanced XLRM. There are XLRF connectors provided on the main buss as well to accommodate aux inputs. These connectors may be used to "stack" two or more M80's.

PreSonus M80 rear panel

Power is provided by an external power supply via a 5 pin XLRM connector. The M80 is suited not only as a pre amp for mixing but can perform double duties as an analog summing mixer for 8 channels of DAW at mix time.

UNDER THE HOOD

The PreSonus M80 is built in the USA. I "popped the top" of the M80 and was very surprised at what I saw. In general terms the inside was well laid out and neatly done, comprised of what appears to be five sub assemblies. I couldn't be exactly sure without disassembling the whole unit which I choose not to do.

The construction is "through the board" type, which makes repair in the field (by a qualified tech of course) much simpler than construction using surface mount methods. This kind of build quality not only insures serviceability in your neighborhood but also guarantees that the M80 will be serviceable long after it is out of production. Kudos to PreSonus for this! I had high hopes that the unit I received would have the much touted Jensen transformers but I was disappointed to see that it did not. Too bad, I understand the Jensens really provided a chunky tone which I diid not hear from the unit I received.

IN USE

I usually record on my DAW, shooting for levels around -12 to -6dB on the digital scale. I found it very difficult to reach these levels with the M80 with the inputs of my Alexis AI3 converters set at +4. Pushing the level higher the pres ran out of headroom fast and began to distort horribly. I found myself forced to record tracks at a lower level than I am used to or to kick the sensitivity of my AI3's down to -10. A look at the owners manual stated nothing in regards to loads or termination recommendations so I assume this was not the problem. I am puzzled why the levels didn't seem hot enough. While overall, this didn't present a huge problem for me, I thought it was worth mentioning here.

I first used the PreSonus M80 as front end on a drum recording session. Using a D112 or D6 on kick drum, SM 57 or Beyer 201's on the snare, Audio Technica Pro 35's on the toms and AKG 460's and 451's on the cymbals / hat, the M80 delivered clean sound without a hint of sonic signature. I know there's transformers in there but i really can't tell from the sound of the M80. The IDSS feature (to my ear) was really not a bonus. I don't care much for intentionally induced harmonic distortion and in use, I found the sound of the M80 to be more pleasant without this feature dialed up. Cymbal tracks recorded though the M80 were accurate in playback and recorded as they sounded in the room. On snare and toms the sound was predictable, perhaps a bit overly clean (for my tastes) when compared to other high end offerings I have in my pre amp rack.

As a direct input for bass and electric guitars, I once again found the M80 to be squeaky clean. Adequate, even good but not exactly what I personally like. Acoustic guitar tracks recorded with both a pair of Studio Projects C4's and then vintage AKG 451's, were a bit "woody" sounding to my ear and lacked the "girth" and "dimension" some well known vintage and "boutique" mic pres exhibit.

On vocals with a Neumamnn U87, Audio Technica 4033, SP C3 mics the sound was as before, accurate and more than less, unremarkable. That is to say while I cannot fault it, it didn't make me jump up and down and say, "Oh JOY! Goody goody goody!" But when I tried the M9, the new "affordable" fixed cardioid pattern LD tube condenser mic offered from CAD, the sound just jumped to life! Some things are a match made in heaven and in this case I think I may have discovered one of them. The M9 sounds very good on its own however, even through the cheap pres found on a digital studio like the KORG D1600, so this is not a surprise to me.

Speaking of the D1600, as we all know the pres in these types of recorders are pretty dismal. They can really leave a lot to be desired, both in terms of sound and features. I took the M80 along with me for a session I had booked at a friends studio where a pair of D1600 is used in tandem allowing 32 tracks, 16 at a time. Using the M80, even through the KORG mic / line inputs (turned all the way down) really made a big difference. The M80 pres were much more focused and accurate, with a better high end definition although less harsh. The M80 is absolutely an improvement in this type of application.

CONCLUSION

To be fair, I should mention some the pres I compared the M80 are two to eight times as expensive as the PreSonus is on a per channel basis. I think for many home recordists stuck with the featureless pres found in small table top mixers or in all in one "Porta-Studio" recorders, will find the mic pres offered in PreSonus M80, an improvement in audio quality and in flexibility due to the inclusion of phase reversal, pad, hpf and phantom power on every channel. The addition of the stereo mix buss is a real bonus allowing mixing of multiple channels to a recorder and allows the M80 to perform multiple duties in the studio, a real plus for those wo are looking for ways to be sure every dollar is well spent and put to work. In this context, the Pre Sonus is a very good value. Now the home recordists stuck with only four channels with phantom power on their porta-studios, can play with more condenser mics and fool around with techniques in stereo micing, Decca Trees and MS encoding, that require phase control and more channels than they have available to them. Because the M80 features includes pads unlike the porta studios and Mackie type mixers, the home and remote recordist can use extra hot mics (like the ATM Pro35's) and if they like, even dial in a little "grunge" into the signal with the IDSS control. In mix down, the DAW user may use the M80 as an eight channel analog summing mixer, avoiding the degradation that so often accompanies mix down in the digital 2 buss of DAWs.

The PreSonus M80 has already gained wide acceptance among FOH mixers as a convenient tool for archiving live performances. Now it is making inroads into the home project studio market. I advise you to check this 8 channel mic pre out if you are looking for some affordable mic pre options. It may be for you, just what the doctor ordered.

Features

Plug microphones and instruments directly into the Neutrik (TM) combo connectors
Feed the inputs of a digital audio workstation with the M80's eight discrete outputs
Mix any of the eight channels to the mix bus/fold back system
Use for live remote/straight to two track recording
Chain multiple M80s together via the auxiliary inputs
Optimize valuable rack space and performance

Number of Channels	Eight
Dynamic Range	>120dB
Noise Floor @ Bus	-90.2dBu
Noise Floor @ Main Output	-96.4dBu
Number of Channels	Eight
Noise Floor @ Channel Output	+24dB gain, -88.2dBu
Headroom	+28dBu
Frequency Response	+/- 0.5dB, 10Hz - 60kHz
Crosstalk	<82dBu @ 10kHz
Channel Gain, Mic Input	+24dB to +60dB
THD + Noise (No IDSS)	0.0024%
THD + Noise (Max IDSS)	0.500%
Input Impedance	1.3k Ohms
Output Impedance	51 Ohms
Master Output Control (Bus)	-72dB to +10dB
Metering	Full Scale
Send Output Impedance	51 Ohms
Return Impedance	10k Ohms
Internal Operation Level	0dBu = 0dBu
Input Connectors	NeutrikTM Combo Connector
Output Connectors	XLR
Send Connectors	1/4" TRS
Return Connectors	1/4" TRS
Power Supply	External, Toroidial, Linear Supply
Power Requirements	100V AC to 120V AC or 200V AC to 240V AC
Main Connection	IEC Receptacle
Size	2U Rack, 19" x 3.5" x 7"
Weight	13 Lbs.

www.PreSonus.com

(p) 2004 Kurt Foster

Kurt Foster has been involved in music and recording for over 35 years. He owned and operated KFRS, a 2000 sq. ft. commercial analog and digital recording facility in the San Francisco Bay Area beginning in late 1980's through the 1990's recording and working with greats such as Brownie McGhee, cult following guitarist, Kenny "Blue" Ray, Jackie Payne (Johnny Otis Band), Nik Turner (of Hawkwind) Polo Jones (of Michael Jackson, Peter Gabriel, Whitney Houston) and individual members of The Doobie Brothers, Tower of Power, Huey Lewis and The News and The Tubes. He is retired to Cedar Flat, Oregon but continues to be active in recording, artist development, procuring recording contracts for new talent, music publishing, writing both music and music related articles as well as serving as a Moderator and Review Editor for a popular online recording forum, Recording.Org.