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Desktop Amps item created by ETAHL, Apr 27, 2011
Pros - excellent sound for the money; will drive speakers
Cons - some potential issues with hum
REVIEW: Musical Paradise MP-301 MK2 vacuum tube integrated amp
I received a review loaner of the MP-301 Mk 2 from Garry at Musical Paradise in Canada. I had a good experience previously with the original MP-301, and had reviewed it favorably a couple years ago. I was anxious to try the improved MP-301 Mk 2, for several reasons:
It has a switch between speakers and headphones, an important feature which the original lacked;
It had two inputs, with a switch;
It uses 6SJ7 driver tubes, which I have a lot of nice NOS varieties I got from the time I owned the Darkvoice 337;
I liked the look of the amp from the prototype pics I saw. Here are some pics I took:
The MP-301 Mk2 is all pentode – two power pentodes (6L6, EL34, or KT-66) and two sharp-cutoff pentodes for the driver tubes (6SJ7, 6SK7, or 6SD7). Garry advised me that the MP-301 Mk 2 is designed primarily as a speaker amp, and asked me to test it with speakers, which I did, as you will read below. That said, I review products mainly on head-fi, and so the focus of this review was on headphone use.
The MP-301 Mk 2 is designed in Canada, but build in China. This does help keep the costs down. The amp is output transformer coupled, which means that it delivers more power to low impedance headphones than a typical OTL (output transformerless) tube amp will. MP provided the following specs for the headphone output:
output power (True RMS) for headphone is 1.53W for 32ohm, 0.79W for 62ohm, 0.16W for 300ohm, and 80mW for 600ohm
So the amp provides the most output for lower impedance headphones. However, as you will read below, it is most prone to some potential hum with lower impedance headphones. If you plan to use low impedance headphones (below 50 ohm), there is a mod that Musical Paradise will do to better accommodate low impedance headphones. Future versions will apparently offer a switch for headphones of different impedance.
For those thinking of using the MP-301 Mk 2 to drive headphones like the HE-6 or AKG K1000 from the speaker taps, I was told by Garry from Musical Paradise NOT to connect any headphones in this manner. He said this could cause output transformer damage, since the transformers are not designed for such high impedances. So I did not try that.
One other thing I think should have been included is a power on LED. Other than the switch and the glow of the tubes (which in spite of my clever pics don’t really glow all that brightly), there is no indication that the amp is on.
Adventures in Tube Rolling
Those who know me or who have read my other reviews know I almost never use stock Chinese, Russian, or any current production tubes even for one second. I have a large collection of NOS tubes and almost always find these to be better.
So I first powered up the amp with my best shot – Mullard EL34 power tubes and Tung-Sol mesh-shield 6SJ7GT’s from WWII. Unfortunately, I was greeted with an unacceptable level of hum. I decided to run the amp in for a few days in hopes this would go away. But it did not. Low impedance headphones were worse than higher ones. The hum was barely noticeable with 600 ohm Beyers (but the MP301mk2 is not really a good choice for 600 ohm Beyers due to the relatively low power delivery at that impedance). It was a little too audible with the LCD-2. It was totally unacceptable with the Edition 8.
I tried two other sets of Tung-Sol 6SJ7GT, but no change. I then tried some Sylvania 6SJ7WGT, and they were a little better, but not better enough. I then gave up on the EL34’s, and swapped in some Tung-Sol 6L6WGB power tubes, but that did not really do much to reduce the hum.
So I ordered a pair of 6SK7GT's, which Garry from Musical Paradise suggested might have less hum than the 6SJ7GT. I put these in, and I still had just a bit more hum with headphones even with the Sylvania's than I really find acceptable, although otherwise the sound was excellent. So I continued on. I put the stock driver tubes in, and there was almost no hum with any headphones. This was using NOS Tung-Sol 6L6 output tubes.
Encouraged, I tried another pair of really nice NOS 6SJ7GTs - Raytheon Bantals. Success! Another pair of totally quiet tubes. I'm not sure exactly why some of the NOS driver tubes I tried would be quiet - two of the pairs I used had been used in my DV337 when I had it and were completely silent in it. But at least the stock driver tubes work perfectly, and so do the Raytheons. The stock preamp tubes are really pretty decent sounding. The Raytheon 6SJ7GT's I am using now are a little smoother in the treble, and just a little warmer overall. But given the difficulties in getting quiet NOS preamp tubes, I think my recommendation to people would be to upgrade the power tubes, leave the stock preamp tubes in there, and see how you like the sound, and if you like it, leave it! The stock preamp tubes with the NOS Tung-Sol 6L6WGB tubes I put in sounded very good.
It’s still a bit disappointing that three pairs of NOS 6SJ7 and one pair of 6SK7 tubes all hummed unacceptably. Also, one of the stock power tubes I received was bad - loose base, and was crackling badly when used. There was, however, no hum with the stock power tubes either, confirming my suspicion that the driver tubes are what are prone to hum problems. The power tubes had NO impact on the hum issue at all. Changing them did NOT help, at all. ONLY changing the preamp tubes helped. So of multiple pairs of preamp tubes, only the stock tubes and one pair of Raytheon 6SJ7GTs were quiet. And I do not believe there is any magic to the Raytheons – it was just luck, I think, that this pair was quiet in the MP-301 Mk2. I'm not exactly sure why, although I do know that this type of sharp-cutoff pentode is prone to hum in audio applications. Too bad - it's a great sounding tube, but given the hum problems, it may not be an ideal choice in a low power audio amp.
Anyway, with my NOS 6L6 tubes and the either the stock preamp tubes or the Raytheon 6SJ7GT’s, the MP 301 mk2 worked well and sounded good. I could finally get to the review!
Sound - Headphones
Again, the MP-301 Mk2 isn't designed primarily to be a headphone amp - it's more designed as a speaker amp with the convenience of headphone use. But with the right tubes and headphones, it's a very good sounding headphone amp, especially for the money.
The MP-301 Mk2 was actually at its best driving the LCD-2 and the new Hifi-Man HE-500. It has enough power to deliver all the volume I needed with either of these headphones. It’s putting out about 1.5 W into the HE-500’s 38 ohms, and about 1W at the LCD-2’s impedance. Given their sensitivity rating, that is plenty of juice for all but the nuttiest headbangers. You can forget about using the HE-6 with these though – not enough power for those. The Beyer T1 and HD800 also sounded pretty decent, but the only reason the T1 worked well is that they are super-efficient. The MP-301 Mk2 only musters 80 mW into 600 ohms.
I really liked the sound with any of these though, and the basics of what the MP-301 Mk2 offered with headphones sonically was pretty similar. The overall sonic picture is one of a soundstage that is well defined, with good lateral placement, but that is deeper than it is wide. The midrange is definitely vacuum tube based. The 6L6 has a well-deserved reputation as being good sounding for being a fairly powerful tube, and I found the all-important midband to be generally clean, just a bit in the rich side, and perhaps just a little but forward in the lower mids at times.
Female vocals were very good – in fact ALL vocals were very good. Strings sounded sweet but had the right amount of both body and string. I especially enjoyed some of my favorite female-fronted goth metal with the MP-301 Mk2. The new album from Sirenia, “The Enigma of Life”, was highly enjoyable, and Ailyn’s sometimes delicate and sometimes powerful vocals were well presented. I also enjoyed the wonderful new recording from Alison Krauss and Untion Station, Paper Airplane, quite a bit on the MP-301 Mk2, for the same reasons. Diana Krall’s sultry semi-hushed vocals on “Black Crow” from “The Girl In The Other Room” were just beautifully rendered, and was the attack of her piano. In fact, this excellent recording was well rendered in general by the combination of the MP 301 Mk2 and the HifiMan HE-500. Also, the stunning performance of “Loser” from the recent Gateful Dead release of their 1989 concert in Philadelphia “Crimson, White, and Indigo” was very well rendered, with both Garcia’s voice and guitar sounding exactly as they should.
Bass performance was good. Bass weight in the mid and upper bass was pleasing. The MP-301 Mk2 does not plumb the absolute depths, and bass is a little looser than the best, but like other pentode/transformer coupled tube amps I have, it is better than many OTL amps in terms of bass definition. Still, if you are a bass texture freak, this isn’t the amp for you. There was plenty of weight to Phil Lesh’s bass on the aforementioned “Loser”, but I know that recording super-well, and there was some depth and definition missing.
Same up top. The treble is sweet, and never harsh at all, but compared to better amps, it lacks a little detail and extension. I preferred the MP-301 Mk2 with the HifiMan he-500 over the LCD02 for this reason – the LCD-2 plus the MP-301 Mk2 at times could seem a little dark. Many know I do NOT find the LCD-2 to be dark sounding on its own, but when the amp is a little dark, which the MP-301 Mk2 is, IMO, then the LCD-2 will not “cover” for this.
I spent a little time comparing the MP-301 Mk2 to the WooAudio WA6, which is the closest amp I current own to the MP-301 Mk2 in terms of price and topology. In terms of its use as a headphone amp, the MP-301 Mk2 is not really competitive to the WA6. Which is NOT to say the MP-301 Mk2 isn’t good, but the WA6 is simply much better as a headphone amp. As well it should be – the WA6 will not drive speakers, and is more than 2 times the price of the MP-301 Mk2! Still, treble and bass extension and definition on the WA6 were audibly better, no doubt, as was soundstage width. Still, let’s recall that the MP-301 Mk2 is $260! It’s really important to keep that in mind when considering the above. What the MP-301 Mk2 delivers for $260 is impressive, indeed.
Sound – Speakers
I had given my original version MP-301 to my son to drive a pair of B&W DM601 S2 bookshelf speakers. I thought that sounded great. He wanted something with remote and iPod integration, though, so I bought him a Cambridge Audio integrated unit. I dropped the MP-301 Mk2 back into that system for a little bake-off.
First of all, the MP-301 Mk2 had no problem driving the DM601’s to nice levels in my son’s bedroom. Earsplitting, no, but plenty loud enough for my wife to yell at me to turn it down! I noticed very little hum with speakers, and even then only with my head fairly close to the speaker, and of course no one actually uses speakers like that
The sound with speakers was basically as I described above – the overall sonic signature wasn’t different. The sound was very pleasing overall, and really very good for the price. Kind of amazing, actually. I preferred the sound from the Musical Paradise over the Cambridge Audio One+, which offers more features but is more than twice the price of the MP-301 Mk2. There are limits to how much volume you can get out of the MP-301 Mk2 with speakers, and I wouldn’t even try to use it with tower speakers in a big family room. But with moderately efficient bookshelf speakers in a modest sized room, the sound was quite good, and definitely competitive with other speaker amplification options for such applications.
I have always said that reviewing budget products is tough. It’s relatively easy to pick out and focus on their problems, and not spend enough time on their strengths. It’s no different with the MP-301 Mk2. Musical Paradise has worked hard here to keep the cost of this product down, and given its price, it sounds very, very good. It’s actually great that you can get this much good sound for this price, and from speakers or headphones!
That said, there are some concerns, for sure - it's unfortunate that it seems to be very sensitive to the tubes used in it. This was kind of frustrating, although one can avoid such issues by just using the stock tubes. That said, several users also have received bad power tubes (me included). And while it is quietest with high impedance headphones, it delivers the least power to these. Being transformer coupled should enable it to handle lower impedance loads, but it has the most hum issues with these. And the fit and finish was nice in some ways, but only fair in others (the lettering/stenciling on mine was somewhat poor).
Still…you cannot expect perfection for this price. That you don’t get it should come as no surprise. You do get an amp that sounds quite good, and will do a decent job with many speakers and headphones (though not all).
So…do I recommend the MP-301 Mk2? Sure I do. I recommend it for people on a budget, who have moderately efficient bookshelf speakers in a modest sized room, and/or headphones between 40 and 300 ohms, and who are not dying to spend all their time and money tube rolling. In that context, the MP 301 Mk2 is a stone cold bargain, and a fine little amp.
Pros - Sound quality, size, build, dynamics, deep rich bass and everything in between
Cons - Early adopters dealing with hum and lack of proper headphone impedance choices
I own the first version and loved it but MK2 blows that unit away. Deeper, richer bass thats tight and well defined. Amazing how good it sounds, if I paid 2K for an amp and you gave me this unit for that 2K I'd be a happy, happy camper!!! This is a no brainer especially if your on a budget, its a special unit and your chance to get one is now before the race is on. I was given this as a gift and what a gift!!!!!