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Positive Feedback ISSUE45
marsh sound design
as reviewed by Jeff Parks
Richard Marsh has been tied to our hobby for over 30 years, and as such he is a man of many accomplishments. In my opinion, he championed the idea that capacitors and the materials used to make them have a huge affect upon how an audio circuit will sound when all things are said and done. Richard co-wrote a white paper with Walter Jung discussing this very issue called "Picking Capacitors." This interest in capacitor technology lead Richard to design and manufacture his own capacitors that today are the mainstay of many high end audio designs. If you are not familiar with Richard’s work regarding capacitor design, maybe you have heard of his work in designing line conditioning products for Monster Cable, or serving as a technical advisor for The Absolute Sound for many years. It is reasonable to say with such a resume, Richard is one of the icons of the high end audio industry.
Today I am looking at another Richard Marsh design—the Marsh Sound Designs MSD-P2000t hybrid preamplifier. The MSD P2000t is a tube hybrid design utilizing the 5687 tube as opposed to the more commonly used 6DJ8 or 6922. The P2000t uses two 5687 tubes as opposed to the customary four tubes. According to Marsh Sound Design CEO Vern Smith using four tubes as opposed to two tubes makes the circuit more complex and costly to design. One of the design goals in creating the P2000t was to keep the circuit as simple as possible using the best parts while hitting a very affordable price point. To that end Marsh clearly accomplishes that goal. The only inconvenience is the P2000t inverts phase making it necessary to reverse phase at the amplifier output to get the system back into phase.
What captured my interest in reviewing the Marsh P2000t was its classic look. The P2000t is a highly versatile preamplifier due to it multiple inputs and outputs. The P2000t has two RCA outputs for those who would like to run it with multiple amplifiers, five RCA inputs labeled CD, Tuner, DVD, Video, and Line (aux) along with the addition of a complete input/output tape loop. So while I can assume most of us aren’t running a cassette deck or reel to reel tape machine these days, I would venture to guess there are still a lot of you out there with a nice CDR unit. I have one and I use it to burn CDs from my large vinyl collection. If I want to listen to my large vinyl collection on the road recorded CDRs give me that portable option. Yes, I too love to play vinyl like many audiophiles and while LPs are probably the last word in high end listening, you still can’t beat the ease of use of the venerable CD. Along with all of the above features the P2000t makes use of the ever popular IEC connector. With this option audiophiles can play around with different power cords to their heart’s content.
The P2000t is a Class A dual mono tube/ hybrid design where tubes and FETs (Field Effect Transistors) are used an entirely modern circuit called "Trans-Mu" amplification. Without going into the design theory, the goal of "Trans Mu" amplification is to bring out the benefits of the 5687 triode tube in an audio circuit; for example, extremely low noise, wide frequency response, low-distortion, and that uncanny ability that tubes have to "get the music right." Using FETs in the output stage according to Richard Marsh helps eliminate many tube design drawbacks—that being in many cases a woolly bass response, slow transient response, and a rolled off high end. Other advantages of a tube/hybrid design using FETs in the output stage are improved dynamic range, rise time and slew rate, resulting in improved overall control of the musical signal without getting too loose.
Underneath the hood, the P2000t is populated with a parts list one would expect to find in a product that commands a far loftier retail price than that of the P2000t. All internal wiring is proprietary wiring by Monster Cable™. This is shielded to prevent hum and noise. While the main circuit board begs simplicity (no over engineering here), Marsh uses their own proprietary Audio Cap capacitors in all the audio sections. As many audiophiles are aware Richard Mars's Audio Cap™ capacitors is one of the more musically sounding caps available today.
The P2000t also uses its own AC power filter to help eliminate some of that pesky A/C grudge we audiophiles try our best to avoid. In addition, there are separate sections for high voltage and low voltage functions, again, to lower the noise floor of the P2000t. Lastly, the P2000t uses a large high current toroidal power transformer. My experience in the DIY world shows that toroidal transformers have greater bass impact when compared to many OEM conventional transformers. This translates to better overall dynamic range. To top things off in order to dissipate the high heat of the 5687 tubes, Marsh includes heat dissipaters (which clearly resemble Pearl Tube Coolers™) that help the tube run a bit cooler, thus, increasing its useful life. Another added bonus of the tube heat dissipaters is they wrap around the tube itself completely enveloping it. As a consequence these tube heat dissipaters also help cut down on microphonic distortion improve focus, imaging, and soundstaging.
So, how does the P2000t sound? Before I get into the discussion as to what I heard, please bear in mind I replaced the stock NOS Philips JAN 5687 tubes with the more transparent NOS Tung Sol 5687 tubes. More on that subject later in the article.
For starters… I love this preamplifier! It does so many things right it is uncanny. Over the course of the last eight months I have really gotten to know all of this preamplifier’s quirks and strengths. One thing that stands out is that it does not "over do" anything; meaning its bass response is smooth and dynamic without sounding bloated, nor is it too punchy as some tube/hybrid preamplifiers can sound. Midrange is perfect and truly one of the P2000t’s strengths. Highs are smooth with enough detail to articulate the musical message without sounding veiled or thin. There is just enough transparency to the presentation that one can often be fooled that he or she is listening to the "real thing" playing in your living room as opposed to a musical reproduction of the said event. Take for example, Sarah Vaughn from How Long has this been Going On? [JVCXR-0038-2]. I was amazed as to the amount of harmonic richness the P2000t communicates. While being just a bit up front of the accompanying instruments, it really sounded like Sassy was casually sitting on a bar stool next to the piano. No crowding of the voices or instruments within the phantom channel, all were right where they should be layered in a manner that made the presentation quite believable. Sassy’s voice echoed throughout my sound room with such realism it brought me back to a time when I was hitting small jazz clubs like Steamers in Fullerton, California during early 1990s, or at Yoshino’s in San Diego, California during the late 1970s early 80s.
Overall, I truly enjoyed my extended time with the P2000t. As we know all things are not perfect, and so here are my concerns. When I first set up my review sample of the P2000t the tubes were quite microphonic. It wasn’t the usual crackling hiss sound we usually associate with a tube that is beginning to go bad, but rather every time I touched or tapped the P2000t, it would pick up that sound, amplify it, and send it to my speakers. No…, it wasn’t personally distressing or potentially damaging to my speakers, just annoying. As long as I didn’t touch the unit while listening to music the problem subsided, though I could have sworn I heard some ringing. Perhaps the tube dampers/heat dissipaters Marsh is using are not really doing their job! Or maybe there was a clear problem with the tubes that went beyond the ability to dampen the tube through the tube damper/heat dissipaters. I had a problem!
Needless to say, in its present condition the P2000t just didn’t sound right. Speaking with Vern Smith of Marsh and explaining my problem to him, he promptly sent me a new set of tubes to replace the stock Philips JAN 5687 tubes. Gone were the noise, some tube rush, and the pesky microphone issue as mentioned above, all of which was good. What was not good was the musical charm the P2000t had lost upon insertion of the new tubes. Strange as it sounds the replacement tubes were the same Philips JAN 5687 tubes. Maybe in my case the tubes that were sent were a part of a bad lot. I am drawing at straws here, or in other words—guessing! One thing that was for sure, these tubes did not sound the same as the original Philips JAN 5687’s that were sent to me at the beginning of my review period—something was clearly amiss! As this point I was a bit frustrated, on one hand I love the sound of the original tubes, but on the other hand, I could not stand the fact the tubes were acting like a microphone.
So, how did I solve my problem? I went to the internet and did some "tube" research. After completing my research and consulting with a few of my audio buddies, I decided to seek out a couple of pairs of NOS Tung Sol 5687 tubes. Bearing in mind these tubes are readily available at reasonable prices (around $25 per tube) from many web-retailers, I decided I needed these tubes in order to complete the review. Once installed, these tubes improved the sound of the P2000t from a lifeless almost rounded off preamplifier to one that was lively, smooth, and a joy to listen to. The Tung Sol tubes clearly completed the package.
Any other issues…? Just a couple of other quibbles... though the P2000t owner’s manual is specific to the P2000t there is no mention in the manual of how to install, maintain, or trouble shoot the 5687 tubes. From my search on the "net" there were a few complaints regarding the P2000t and its use as a tube preamplifier. In my opinion all of these issues could have been quelled if the manual went into detail as to the joys and quirks of running a tube preamplifier. That said... I believe Marsh needs to understand many end-users of the P2000t are more than likely audiophile novices just entering into our realm. Realizing this, they may or may not have the same set of skills as a more seasoned audiophile who does understand the quirkiness of tubes. Another concern was the need for the P2000t to inverse phase due to the use of only two triodes in its design. On page 11 of the manual it is mentioned, however, I think it needs to be highlighted and in bold print so that it can’t be missed. Other than that I am good.
To wrap things up…, the P2000t is a tube/hybrid preamplifier that offers very near state of the art performance at a real world price of $1500. Though its looks are simple, I find them appealing. Overall the sonic picture of the P2000t is a bit on the euphonic warmer side of neutral—meaning it is more of the "classic tube sounding" rather than "solid-state sounding". I love how the P2000t soundstages, images, and seems to get the music right. This is a preamplifier you could go on listening to for hours without ever experiencing listener fatigue. Numerous times during my extended listening sessions - lasting into the early into morning hours—I would find myself falling asleep. Meaning things sounded so good, I just didn’t want to leave my soundroom for bed!
Although not razor tight, the aural picture is quite convincing and would please almost any audiophile except for those few who have larger budgets, or who are in search for that last bit of transparency and detail. Knowing this, I find that this preamplifier would pair nicely with solid-state electronics or a system that is running a bit on the leaner side of neutral. A mating of the P2000t and its A-400s 200-watt solid-state brother truly could be a great match. Maybe that was Richard Marsh's intention in voicing the P2000t; he voiced it to be complementary to his solid-state amplifiers. Congratulations Richard! You hit it just right. Highly Recommended. Jeff Parks
PS: It was just brought to my attention that all Marsh Sound Design products are being offered factory direct, and for a limited time 30% off of current retail. If you are truly in the market for a preamplifier and you are looking for something that is no fuss and gets the music right, I would run and buy one as soon as possible. Hurry, before Vern realizes he is practically giving the P2000t away at these newly discounted prices. I am sure this offer won’t last long.