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icecubeman 5th December 2011 09:09 PM

Art pro mpa ii
ART PRO MPA II is two channel tube preamp with great options for shaping sound. First of all, it is one of very few in its category with impedance control for each channel. Impedance is very interesting function and very versatile, because it doesnt affect directly the impedance in microphone, only signal that comes into preamp. I found a lot of new colours for many microphones just tweaking this one. MPA has also TRS input and can react as DI. If you use it this way, impedance is fixed so you cannot use impedance knob, but you have option to setting high pass filter. Every channel has its own phantom power button, +20 gain button which you often use in studio applications especially on vocals, accoustic guitars or other dynamicaly wide sound sources.

The most discused button of this device is High Plate button. By pressing this, MPA leaving starved plate function and tubes became really hot hjghfgg It means, preamp operates as real tube preamp. After pressing this button please wait minute or so, it is time needed to warm up tubes gooof. After testing starved and nonstarved operation I must say, High Plate button is always ON on my device heh. You will be surprised how dramatic the difference in sound is.

Of course first step you must make is to change tubes in preamp. It comes with some Chinese stock tubes, that has almost no bass and really bad highs. As for tubes, swtich it for some NOS or some "in production" ones. I am using tubes from JJ Electronics and they are amazing!!! As for outputs options, there is two versions of MPA - standard and digital. I decided for standard version, because after a lot of searching I found relevant opinions on bad quality of AD convertor in digital version. So I am connecting MPA to my much better converter through TRS connectors. Everything is working like charm.
In this price range you can hardly find any nonstarved tube preamp with that kind of build quality and sound quality.

ivmike 16th December 2011 03:49 PM

I've been using an ART PRO MPA II for a few years now and I am really impressed with it.

Initially, I purchased it on the advice of my local sound tech as I was looking to add quiet gain to a pair of Apex 205 ribbon mics that I had purchased. After a short burn-in time (for the 12AX7 tubes/valves) I begun to track; the difference was significant and very pleasant. The tracks were smooth, clean and sat beautifully in the mix; the drums "came alive" and no longer had that basement-studio sound to them.

The features on this unit alone should push the price much higher than it's current street price of $300 (or less); where else can you get a pair of real high-voltage tube preamps with step-less impedance selection, phantom power, a mid/side option(!!), step-less low-cut (hi-pass) filter, that can also double as a great bass DI (through the hi-Z input) for this kind of money? Not only that, the tubes are easy to replace, should you wish to alter the tone of the MPA II (currently, a pair of NOS Sylvania long plate tubes reside in my MPA II).

This is easily the best tube/valve pre-amp out there for under $1000; it's not just for hobbyists, but is designed as a professional tool. This is a worthy investment for anyone that is serious about taking their home recordings to the next level.

Jawsman 17th December 2011 06:51 AM

My review
Well, I purchased mine with the A/D and found right away they skimped on the tubes. I changed them out with some Tung-Sols to actually give me some consistancy in performance. My output would vary not only in level, but tone as well until I switched. I found that after I did that, it worked much better. Now that I had that solved, I tried the digital end of it...ugh. The A/D converter on this thing, first off, takes some time to send a useable sync signal to anything if it sends one at all. Sometimes I have to turn the sync rate knob a few to the left/right of the rate that I'm after for my interface to lock. I'm sure that a master clock would help though, but for now, that little trick will have to work. Now that's out of the way, the sound out of the A/D converter is exteremely week and tinny...and and very lack-luster.
Now not all is lost. The analog side of this guy isn't at all bad. Though I have to crank my input gain up to the next to highest click just to get the signal-to-noise ratio to a decent level and the meters to register, I then have plenty of headroom to get all the output gain I need.
Over all, you get what you pay for, but I suggest saving up for a UA Solo 610 or a Grace Design or whatever. It's worth the extra few $$$ over this price range of preamps.

collinTHEbrewer 24th January 2012 07:44 PM

Art Pro MPA II
This preamp is great! I got it off ebay used for a little over $200.

At first glance, you will notice that this preamp is well built, feels very solid, and looks professional. Already, it's a high rating in my book for a home studio.

Next, the features are superb. The Pro MPA II has plenty of options. Since it's a 2-channel amp, it can be run as two independent channels or as one stereo channel with master volume controls. There's also an MS mode for recording in the MS configuration. Very flexible!

My favorite control is the impedance knob which adjusts the input impedance of the amplifier. It is very useful for revoicing a mic if it's just not meshing well wish the sound source to provide more clarity or maybe a warmer tone. This is a great option for the beginner studio owners who have a limited mic selection. One mic can be given new voices!

As far as sound quality goes in comparison to other preamps, I would give the Pro MPA II a 7. It's a great amp, but don't be deceived by the tube technology! It's a solid state amplifier with a tube used for voicing. The main source of amplification is an OPAMP, but a very high quality one. But here's what I did...

I replaced the original Chinese 12AX7s with some NOS Phillips 12AU7s that really cleared up the preamp! It was a pretty good investment for the matched pair, but it really took the sound from a solid 7 to a 9. Not to mention, it was very easy to do.

I would recommend this preamp as a must-have for project studios and home studios. Maybe some professionals looking for a different sound could use it to!

Kell Sound 14th January 2013 04:15 AM

Another ART Pro MPA II Review
Clearly this preamp is not one that you will make you sell your 1073's for. As sound on sound reminded us, if you use a preamp properly, you will get good results out of almost any one you choose. But let's not get into comparing hi-end and budget preamps. Let just take a look at a pre that has gained attention lately.

Front Panel

Good sized knobs give you control over the usual array of parameters as well as some less common features typically reserved for pricier units. The top row of controls have a gain pot which amplifies the signal before hitting the tube, an impedance control which can affect the tone on dynamic or ribbon mics, and an output control to tame the signal before hitting the A/D (I will go ahead and assume you are recording digitally). To the far right you will also find a Stereo / Dual switch which will link the output control of both channels to channel one's output pot, and turns channel two's output control into a pan pot. Neat.

Along the bottom row you have a High Z input on each channel (try driving a bass hard with this) followed by a low-cut filter. This is a tame filter by most standards as it's only a single pole filter (6 dB/octave) so don't hesitate to use this before you get in the box. Each channel also has four buttons in common a +20dB gain, +48V phantom power, Plate voltage, and a phase inverse button. The +20 dB gain gives you an extra boost before the signal hits the tube, allowing you to get a driven tube sound on quieter sources. The phantom power and phase invert are self-explanatory, but feel free to google them if you want to know more. The plate voltage is a great feature which changes the behaviour of the tubes, giving you a cleaner signal with a higher headroom. Center on the unit you will also find the Mid/Side Matrix button which will decode your mid/side mic setup into a stereo left and right signal.

In the middle of the unit stands the metering, which includes two VU meters for the output levels (0 VU = +4 dBu) and an 8 LED segment tube warmth meter which lets you know how hard the tube is being hit by your signal.

A quick peek inside reveals just what one might expect. A clean, well laid out circuit board and two 12AX7 preamp tubes. The tubes are a basic Chinese 12AX7 and are a good place to start when looking at modifying this mic pre. For the purposes of this review I will be using the stock tubes. All samples have been made after the preamp has warmed up for at least half an hour which is where I stopped noticing a difference (or maybe just got impatient).

How Does It Sound

In use I found the pre to be pretty straight forward to operate. While recording I always had the +20 gain button pushed in. It makes sense though, why else would I choose a tube pre unless I wanted to get some tube sound. The addition of the tube warmth meter made it easy to set my gain control. With it tickling the yellow I knew I had some headroom before things would get a little out of control.

I recorded a handful of sources and was pleased with the overall sound quality and nothing really stood out to me as an issue. The HPF being 6bd/oct meant that you could throw it on and take a tasteful cut out of the low-end junk without worrying about destroying the body of some lower notes. The plate voltage did in fact give more headroom before the tube saturated, but I found I never really wanted that. Perhaps if it was my only preamp that might be a benefit, but for me it was a feature just for the sake of having another item on the features list. The inclusion of the +4 / -10 output again was another feature I would never use, but provides a good service to those running directly into some consumer gear like computer line-inputs, iPhones, etc. One thing to note is that adjusting the input impedance will cause a change of gain, so be mindful of this as you adjust your impedance.

At first when I was listening back I could hear very little difference between the impedances. Which isn't to surprising given the 300 oHm output of the SM57 being right in the basic range of this preamp. Honestly I was expecting more difference (you will find a greater difference on a ribbon mic than dynamic). However as I was about to give up on finding a difference I noticed a recording I had done a few days earlier as a warmup with my own playing. At the end I hit a sudden chord and the lower impedance had far more bite to it. Cool. So while this guitar part may not have been the best for demonstrating the variable impedance, there is a difference. Play with it!

All and all I was impressed with the preamp. It had a pretty good overall sound quality on the sources I recorded. Due to the other material recorded not yet being release I could only provide examples of the guitar track presented here. While it would not be my first choice of pre, with a couple of higher end options being my go-to's, it would always be a consideration. The combination of an expansive feature set and a low price point make this a no brainer for anyone looking into an inexpensive pre.

Check out the review on my blog for audio samples.
ART Pro MPA II Review - Kell Sound

warlordpriest 2nd April 2013 10:19 AM

ART Pro MPA II - My impressions
I know there's a lot of love for this unit but in my experience it offers too little of a real improvement in the sound. If you're buying something for the tube sound, you might get a 5% improvement.
Not that I didn't upgrade the tubes, either. I put in some long plate gold pin tubes and it did sound clearer and slightly more pleasing approaching soft clip levels, but it just wasn't a GREAT improvement. So why bother.:tut:
There is a cheap feel about the knobs which doesn't lend to longevity, because this thing is so finicky to set up, you're going to do a lot of knob twisting.
My unit doesn't seem to be very accurate as far as output goes. There is a big difference between the output of the two channels, so you have to do a lot of tweaking to get the levels matched. When the levels are matched on the unit, the output of the two channels is Very different.
In my opinion, this is NOT pro gear, because pro gear is accurate, easy to set up, fast to work with and offers a dramatic improvement in the sound. That said, it does seem to impart a little more life to digital sources, although you may have to strain your ears to hear it.
I couldn't recommend this unit to anybody. Buying it was a good learning experience, but I'd rather get rid of it than waste any more time with it. I think if you really want the tube sound you're going to have to spend a lot more $!

Noobs 1st July 2013 06:17 AM

ART Pro MPA II - Noobs' thoughts
This mic pre was added to our home studio in an effort to improve vocal recordings & add a bit of warmth and character to D.I instruments (prior to this, everything was going straight into an M-Audio Profire 2626 --> Logic 9). We went for the non-digital unit, mostly because it was cheaper but also because we dislike acronyms like S/PDIF, ADAT, AES/EBU etc.

Straight out of the box, vocals were noticeably more "lively" & we appreciated the tweakability of the unit. The +20dB, plate voltage & variable impedance controls allowed us to cater for our fairly basic array of microphones with the turn of a knob/push of a button & we've made some some stellar vocal takes with a RODE NT1-A through this unit. The settings can be dialed to pick up every nuance of a vocal take or be focused on a specific aspect/tonal range of a performance, which we have found very useful for creating different "flavours" and enhancing the dynamics of a track.

The high-z input has become an indispensable feature for recording at home & is particularly effective on bass. Where we previously used the direct out of an Ampeg SVT-3 PRO as a pre-amp, we now track bass through the Pro MPA with better results (less tonal option options, but significantly more warmth and a much purer signal - the players' dynamics and the tonal qualities of the instrument are much more prevalent). Likewise, the unit adds the same warmth and purity to synth (and it's stereo!) and makes a D.I guitar sound bearable when micing a cab isn't an option/you can't be bothered.

More recently, we replaced the stock Chinese tubes with the Mullard equivalent & the difference is pretty satisfying. However, as I find with most tube upgrades, it's not a mind-blowing, can't-live-without-it kind of difference, just a touch more boldness (particularly in the low-end), a slightly more "throaty" character and a bit more clean headroom. That said, experimenting with a few different tubes is essential to fully appreciating the sound quality and potential of this unit.

Finally, it will come as no surprise given the low cost of these units that the components & build quality leave a bit to be desired. On our unit, the VU meter on channel 2 only turns on occasionally & the gain control on channel 1 doesn't always work with the high-z input. Looking inside the unit you will find wires and cables are not soldered, but sheathed to their connectors inside little plastic covers, most of which have slipped away, leaving them connected via good will and hope alone. Fortunately, the majority of components are easily accessible and a fault can be identified by anyone who dabbles in electronics.

For us, this unit is ideal. The price is right & the sound is a vast improvement on where we were previously. Most importantly, I can live with the downfalls of the unit - which isn't something I can say about most of the "cheap alternatives" I've come across over the years. As a home studio for ourselves & our friends, I can't foresee us upgrading anytime soon.

ocgarza 21st July 2013 04:43 AM

Solid budget tube preamp with lots of options
I give the MPAII a big thumbs up kfhkh for: quality build, affordability, flexibility and it's a good sounding tube preamp.
I use one at work for the TV channel I manage and one at home (the reference model with the blue lights that was on sale for $100 at Musicians Friend recently - what a steal!).
Yes there is a learning curve to finding the "sweet spot" for the sound you like but it's worth it. And be sure to take notes! We are getting serious about our audio quality and use large condenser mics and dynamic mics for a lot of our audio work.
This preamp is much better quality than those in the mixer we were using.
Like others have already posted, we use the preamp with the 20db pad "in", the tube voltage plate engaged and phantom power engaged when needed.
To get the tube sound we like with the large condenser mics, we keep the output low, impedence set to the mic output, and with the input gain turned up.
Two things we do that might be different from your work flow: we go straight into a digital recorder from the preamp out and there is a lot of signal that comes from the preamp. We might look at other tubes when time permits, but could find no fault with the stock tubes that came with the unit.
OC Garza

philsaudio 9th April 2016 04:45 PM

What can I say I like it.

I wish it had an insert with an insert bypass button.

The Mid Side comes in handy.

Picture of the inside.