December 2005

Dynavector 507 MkII
An Engineering And Sonic Marvel
Or
The Terminator Of Tonearms
Which Ever You Prefer

Review By Scott Faller
Click here to e-mail reviewer

  In the world of truly high-end audio, I am really surprised that this one has slipped by so many reviewers. Like you guys, I surf and read about all things audio. I'll happen across reviews and read them, trying to relate my own experiences to the piece of gear that others write about. Just like you guys, I read and salivate over some overtly cool pieces of gear out there.

I get lost fantasizing about either owning or reviewing things like the ultra cool looking Shanling tubed CD/SACD player and other unreachable items. One that immediately comes to mind for me are Classic Audio's, Hartsfield reproductions. Although I've only spent a nickels worth of time with them at a show, I was so taken by their sound, I can't get them out of my head (read = John, send me a pair for review, please!). Other gear that gives me a chubby are the ultra cool tube amps like the Electron Luv stuff and any number of turntables that are out there. I guess in the end, I'm just a died in the wool, low powered valves and vinyl fan.

Well, a few months ago I finally broke down and bought myself a killer turntable in the Opera LP5. Again, in the world of true high end audio, this thing is a screaming deal. The trouble with an ultra-fi turntable like the LP5 is you need a great arm to mate to it. Sure, I could have mounted one of my spare Rega RB-250's to it but that would be like hubcaps on a Ferrari. No offense to the Roy Gandy intended by any stretch, but a high end table like this needs a stellar arm (and cart) as its mate.

Enter my old mate Geoff. Geoff has been one heck of an influence on some of the gear I've chosen to review of late. Besides getting along famously, I trust Geoff's ears implicitly. It seems we hear the same way, so when he says a piece is going to sound like ‘this', nine times out of ten, its going to sound just as he described. Geoff suggested that I contact Dynavector and see if they would be interested in having the 507 Mk II reviewed. Sure enough, after a few emails, Masaaki from Dynavector had a 507 packed up and was shipping it to the States.

Tonearm Construction

As you probably already know, there are three basic tonearms that are designed and sold around the world today, a gimbaled arm (like a Rega), the unipivot arm (like the Hadcock) and the parallel tracking arm (like the Air Tangent). Of those three, the gimbaled arm is probably the most popular arm sold today. When you look at the Dynavector 507 Mk II, it doesn't fit in any of those three profiles. Dynavector calls this design a Bi-axis, inertia controlled, dynamic balance arm.

There are a few fundamental design concepts that come into play with this design. Lets talk about the Bi-axis concept first. The DV507 has a single bearing at its horizontal pivot point. Protruding out to the sub arm where the cartridge is located is an inverted structural channel (or beam) machined from aluminum. This main arm is attached to the horizontal bearings. When you look at the pic, on top of the main arm at the pivot point is a graduated scale. These graduations correlate directly to the combined weight of your headshell and cartridge. You weigh that combination, then slide the main arm counterweight to the matching graduation and lock it in place. This provides a simple yet extremely effective way to uniformly load the horizontal bearing. This is completely opposite the typical gimbaled arm, which is always asymmetrically loaded due to cartridge force weighting. That means the front side (or cartridge side) of your bearings are going to see more friction than the back (or counterweight side) of the bearings. Eventual result being horizontal drag and (most probably) horizontal tracking errors as the bearings wear. Now, don't slam me for that one guys, this is simple science, no matter how you want to look at it.

Dangling out at the end of the main arm is your actual arm tube (or sub arm) and vertical bearing that also houses a torsion loaded, tracking force adjustment. On the left side of this pick you see an ‘old school' bayonet mount for a headshell (more on that later). In the center is the cartridge tracking force adjustment that measures in 0.2-gram increments. On the right side of the pic is what appears to be a counterweight. What this devise does is to help control resonance produced from the cartridge and arm tube. The machined rod that the sub-weight mounts to isn't rigidly affixed to the sub-arm. Inside is some sort of rubber(ish) damping material that helps absorb arm resonance's. Think about that for a second. Dynavector could have used a simple torsion spring to adjust the cart tracking weights but they discovered the addition of this devise helps to control the unwanted resonance generated from the cart/sub-arm. In turn they have incorporated it into the design and are using it (not only) as a resonance control device but also a counterweight for the sub arm. Again, more solid engineering at work here. The DV 507 comes with three separate weights to precisely match your combined cartridge and headshell weights.

Below we'll take a look at some of the tractability issues Dynavector addresses but here, lets take a little closer look at the sub-arm. The arm tube of the DV507 has increased in diameter more closely resembling the diameter of the old DV501 arm tube. Another look at the left side of that pic shows you a short, stubby arm tube. In fact, the arm tube measures just under 0.75-inch not inclusive of the bayonet mount. With the head shell mounted, the total length of the sub-arm is just at 3 ½ inches from stylus to pivot point.

As you can see, the design uses a detachable head shell. For many, you might think this to be counterintuitive, but it really isn't when you think about it. The ‘joint' that is introduced isn't any different from so many arms out there that are sold with replaceable arm tubes to mate for a given cartridge compliance. Some of those same arms have a similar ‘joint' positioned back at the pivot point. When fitted, the head shell and sub-arm combination are very rigid.

The second and probably most advantageous reason for using a bayonet mount relate to the simplest of compliance issues. The head shell that comes with the DV507 weighs in at a hefty 15 grams. This is perfect for your typical low compliance MC carts. In turn, if you have a high compliance cartridge that you want to use, just use a head shell that weighs less. There is no need to replace an entire arm tube at the cost of several hundred dollars (in most cases).

Next, lets talk a bit about some of the inertia and dynamic damping. As you can see from the pic, there are two puck like objects and a curved plate that appears to slide freely between them. Those pucks are actually neodymium magnets. The design concept at work here is, as the arm begins to resonate at an undamped low frequency, the curved steel plate (which is attached to the main arm) comes under the influence of the magnets. These magnets help bring the arm back to its steady, non-resonant state. Again, more solid engineering at work here, actually this one is pretty ingenious when you think about it.

If you've studied your vinyl, you know when you reach parts of a record where there are extremely loud passages, the grooves are spaced apart wider. In the case of the 1812 Overture, it almost looks like the run out in the dead wax area (see pic below). You can visibly see how the groove wiggles back and forth. With the DV507, this additional damping proved immeasurably superior to a conventional gimbaled arm in its ability to track these passages in their entirely.

New to the DV507 MkII is the anti-skate mechanism. Both of the earlier versions of this arm used the fishing line and counterweight concept of anti-skating. The DV507 now sports a more conventional dial and spring arrangement. The concept isn't new or innovative but its proven itself reliable in many arms and gets the job done well.

Next up is a bone of contention to many, vertical tracking adjustment or VTA. Without a doubt, the design of this arm allows the greatest VTA or SRA (stylus rake angle) adjustment of any arm out there. As you can see from the pic, this is an on-the-fly adjuster. This arm is so tracks so well in use that I have adjusted the VTA while the album was playing without sending the arm flying across the record.

The total vertical height adjustment provided by this adjuster is 7mm. Now, 7mm in and of itself may not seem like the greatest amount height adjustment out there, but when you consider the sub arms pivot point is all the way out at the end of the main arm, the resulting change in angle (SRA) has got to be nearing three or four times that of a typical gimbaled arm with a similar VTA adjuster.

I don't really want to go into the audibility of VTA (or more aptly called SRA), but it is audible. I personally don't think that minute adjustments (fractions of a degree in SRA) can be heard. I can say with absolute certainty, when you adjust the DV507 up or down by a couple of mm (which equates to several degrees in SRA), it is completely audible. All of this VTA/SRA audibility stuff is a conversation best held for another article.

The cable connection to the base of the arm is a standard four pin DIN. The cables are of nice construction with the usual gold plating on the RCA plugs. The arm lift lever is nice and long and gives you a little more feel of control when you are trying to accurately place the stylus in the groove. The DV507 comes with a very nice machined aluminum bayonet mount head shell.

Here is one last unique feature that is actually pretty cool. If you look at the picture at the top of the article, you'll notice that the main arm slides into its arm holder. Mounted on the side of the arm and also within the arm holder are two low strength magnets. Rather than the typical flip over clamp to lock the arm in place, Dynavector has engineered a pair of magnets into the design to hold the arm in place. Does it make the arm sound better? Doubtful, but its one of those cool little features you'd expect coming from hi-end manufacturer like Dynavector.

Tracking Error Recovery

This is something very worthy of discussing because it is an integral part of the DV507 design. A couple of the features noted above relate directly to this error recovery.

Your typical gimbaled arm has a long arm tube with a cart at one end and your vertical and horizontal bearings nestled at the other end. Let us not forget the counterweight that hangs off the backside of gimbaled arm. The vertical pivot point of the arm lays all the way back at the bearings. I use the term ‘all the way back' for a reason. One of the major points that Dynavector makes regarding this pivot point is as stated on their website. Let me quote directly from Dynavector;

"Bi-axis inertia separation" may sound complex but it simply refers to a tone arm having two arms, which operate independently in the horizontal and vertical planes. In contrast, a conventional tonearm has only one arm, which moves both horizontally and vertically. This is called a gimbaled type tonearm and the inertia for both planes is the same.

The DV507 bi-axis tone arm has a large inertia for horizontal movement and a very small inertia for vertical movement. We shall now explain the reasons why this is advantageous.

It is well known that a cartridge generates an audio signal by the differential motion between the cantilever and the cartridge body. Consequently, if the supporting point of the cartridge (the tonearm) vibrates, the tonearm motion affects the audio signal.

In these conditions, the signal that causes the tonearm to vibrate is of low frequency and large amplitude.

In the currently used 45-45 stereo record cutting procedures, low frequency signals are almost entirely recorded in a horizontal direction. This means that the low frequency signal, which can cause vibration in the tone arm, exists only as a horizontal force.

The tonearm therefore must have sufficient effective mass and rigidity in the horizontal plane in order to provide a stable platform for the cartridge.

On the other hand, for the mid to high frequencies, the effective mass of the tonearm should not be too large since the combined mass of the cartridge and the head shell need to be taken into account as well. In particular, where records have a warped surface, the vertical effective mass needs to be small enough to ensure a good tracking ability on such surfaces.

To summarize, the tone arm should have a large effective mass and enough damping in the horizontal plane and at the same time a small effective mass in the vertical plane.

These conditions are almost impossible to achieve with a tone arm of conventional design using a simple gimbaled pivoting system. To solve the problem, Dynavector designed a bi-axis, inertia controlled tonearm where the shorter and lightweight vertical sub arm is placed at the end of the horizontal main arm. This is the special feature of our design.

To illustrate how the system works in practice, the following measurements will be of interest:

Cartridge behavior with two different two different types of tone arm was analyzed when tracing warped discs. Fig. 1 is with a conventional tone arm and Fig. 2 with the DV507.

In these figures line A refers to the displacement of the record surface and line B the behavior of the cartridge body. With a conventional tonearm, the displacement of the cartridge is much larger than the actual warp on the disc. At times the cantilever does not touch the record surface.

However, the DV507 shows a much better tracking ability because of its low vertical inertia.

Now, that was all well and good. It reads like really good hype but it's physics, pure and simple. Shorten the arm tube length and provide a constant downward torsion (vis-à-vis the tracking force dial) and you are going to have a far quicker recovery from vertical irregularities and loud passages found on many, many records. That is exactly what figures one and two show.

To restate what I just typed, let me steal this analogy. Imagine two vehicles going over a speed bump (at the same speed). The first is a big ‘ole Lincoln Town Car. When the Lincoln hits the speed bump the suspension gives, the shocks compress and the tires leave the asphalt momentarily and bounce slightly on the trailing side. The resulting ripple effect in regards to the stability of the rest of the bouncing car, takes a fair amount of time to recover completely. Next, a Mini Cooper goes over the same speed bump. The Mini has a much stiffer suspension and in turn it recovers much quicker from the same bump. It just goes up, over and continues down the course without the ill effects of ripple.

Take this a step further. If you've ever sat and watched how your arm and cart react to either heavy bass tracks or really loud passages while the vinyl is spinning, you saw the entire arm ‘haunch' up until it was over. One track that comes to mind is the 1812 Overture on Telarc (mastered by Stan Ricker). This track can actually blow the cart right out of the groove with its 6Hz bass (even with a ‘good' arm). I'll cover this later in the listening portion of the article but let's just say when I used this torture track; the DV507 stuck the corners like Big Steve's Ferrari with new rubber.

Assembly and Set Up

The DV507 came in a well-packed container. The arm was well shielded from shipping mishaps via rigid Styrofoam. The assembly was fairly straightforward. Dynavector provided a small booklet with step-by-step instructions that was quite easy to follow.

Once I had my arm board drilled and tapped for the DV 507, installation was a snap. I mounted my Dynavector 20XH cartridge and dropped it on my scales so I know which sub weight to use. I used one of those cheap, digital food scales for the measuring duties (you would be surprised how accurate it is). For the proper stylus distance, Dynavector provides a nice metal template for set up.

Once weighed, I popped it into the arm, set the counterweights and started to work in the VTA. Again, this was very simple. Loosen the adjuster, slide it up to the level that seems right, then fine tune by ear. After the install was complete I gave my HiFi News test record a spin to make the final adjustments on alignment and anti-skating. A few weeks after setting up the arm and table, Mike Pranka of Toffco dropped by with his Wally Tools to fine tune things a bit. In watching, I noticed that I wasn't that far off with any of my settings. That made me feel good.

Listening

Well, since I mentioned it previously, lets start with Tchaikovsky's 1812 Overture performed by the Cincinnati Symphony Orchestra and issued on Telarc [DG-10041]. Stan Ricker mastered this particular release recorded the Fifth Virginia Regiment firing the cannons within the courtyard at Ballwin-Wallace College in Ohio and ten overdubbed them onto the recording.

The bass produced by the cannon firing dips all the way down to 6Hz. Rumor has it that when Telarc first released this piece of vinyl, there were so many returns that they pulled it from the shelves and re-released a ‘toned down' version of the cannon fire. The problem was that on the passages with the cannon fire, all but the very best arms and carts would physically leap out of the grooves of the vinyl. I own one of the original releases and I've tried disk this on all the tables I've owned and reviewed and not a single one would track the cannon fire... until now.

Granted, the bass that comes out of my single ended system (even with vintage 15 inch subs) doesn't get anywhere near 6Hz but its only the tracking ability of the DV507 that I am concerned with. When stylus met those grooves that have proved fateful to so many, the combination of the DV507 and DV20XH sailed through them much, much better than I expected. Granted, the combination wobbled a bit on some of the heaviest cannon fire but they never leaped out of the grooves like I've witnessed so many time before.

Another one of my absolute favorite tracks to use to test arms and tables is HRH (Her Royal Highness) Count Basie, Chairman of the Board, a Classic Records reissue [SR-52032]. About halfway through the song where the trumpets and trombones are doing a BE daap, BE daap, BE daap, the kick drum rolls in. The kick drum is recorded really hot. Nearly every arm and table combo I've played this on has trouble with it. The stylus wants to jump out of the groove. Probably the best I've heard HRH on so far was the ultra cool Teres turntable in Cocobolo with the Schroeder arm. The DV507 easily equaled that same performance.

Like all of you guys, I've got some less than flat records in my collection. Even some of the new audiophile releases are having issues with flatness. As we discussed previously, this is where the DV507 should really shine. Now, I didn't throw anything on the platter that was so warped, nothing could play it but I did grab a couple that were close to questionable. The first was an original copy of Folk Singer by Muddy Waters. Before I played it on one of my other tables where I have a standard gimbaled arm. Though I have no way of measuring the recovery time from the warp (as shown in the graph above), I can say that the DV507 sounded nearly as if there were no warp at all. It tracked the hump like a champ. On the other hand, the gimbaled arm, you could hear an audible disconnect when the stylus actually left the groove. That now makes another small portion of my collection listenable. It also widens my choices a bit when I'm out scrounging up used vinyl.

When it comes to the DV507 coloring the sound, I've got to say it is extremely neutral. After living with it in my system for some time, I began to try to rationalize why I feel this way. When you take a long, hard look at how this arm is engineered, you can only come to the same conclusion. The main arm has an extremely high mass compared to the other arms on the market. In turn, the high mass and its (structural) shape will be less susceptible to ringing as other arms. The DV 507 does far better job at horizontal tracking due to the innovative Dynamic Damping. No other arms that I am aware of even try to address this issue as Dynavector has. Next you have proper horizontal bearing loading. Though some might think that the slight two to three gram asymmetrical loading of the horizontal bearings on a standard gimbaled arm plays no effect, I personally believe that it does. The slightest imperfection on one of the wear bearings will begin to cause tracking errors. Top all that off with the extremely low vertical mass of the sub arm tube and the constant downward force of the VTF gauge. This makes vertical tracking recovery far faster than a conventional arm. All of these are bold claims but each and every one of them is backed up by solid engineering that address each of those items specifically.

One of the interesting things that I've found in listening to different arms is when an arm begins to resonate, it tends to make the image of whatever you are listening to, get larger and slightly fuzzy around the edges. With the shear mass and rigidity of the DV507 coupled with the creative arm design, keeps the musical image nice and tight.

Since I found the imaging so focused, I grabbed a couple of my favorite pieces of test vinyl to see if the soundstage was smaller. First up was Pink Floyd's Momentary Lapse of Reason, the first cut on side one, "Signs of Life." This is my favorite test for soundstaging. I use this to test everything, speakers, CD players, preamps, amps, anything that could have an effect on the soundstage. The song starts out with a recording of ambient sounds of a shoreline and a wooden dock. As the song progresses, the water lapping against the shoreline should be projected between three and four feet outside of the right speaker. The DV507 easily projected the lapping water to my benchmark. Interestingly, the image was more focused than I have previously experienced.

Moving on to my next reference piece for soundstaging, Muddy Waters Folk Singer, another Classic Records reissue [CHS-1483 ]. Forget that this album is the equivalent to Dark Side of the Moon in the Blues genre, the recording qualities of this Blues masterpiece are sonically stunning. Throughout the entire album, Muddy and Buddy Guy trade off solo duties on each song. Sometimes its on an acoustic, sometimes amplified. On several tracks, you can hear Buddy grinding out some juicy blues riffs that should come from about two feet outside of the right speaker. Same for the bass player Willie Dixon except he comes from between one and two feet outside of the left speaker. The DV507 performed in stellar fashion again especially on the Willie Dixon bass tracks. So many other pieces of gear don't seem to get Willies recorded bass right. They tend to place him coming directly from the left speaker. With the DV507, it accurately places him just slightly outside of the left speaker. Again, the image projected was extremely well focused.

With all of my talk about focus, I think I need to define that a little better. Some pieces of gear that don't project a focused image have the instrument or vocalist appear larger than life. I've used the analogy before that a piece of gear can make Karen Carpenter look like Mama Cass. When a piece of gear gets it right as the DV 507 does, everything comes across with realistic dimensions, providing it was recorded that way of course.

When it comes to the DV507s ability to deliver transients with speed, accuracy and finally decay, I found all of them outstanding. In particular the DV507's attack my have some thinking it is a bit subdued. Personally, I feel that other pieces of gear can falsely project aggressiveness on the leading edges of notes and heavy transients. After spending a few months with the DV507 and attending quite a few live acoustic events paying particular attention to the attack and decay of sound, I'm convinced that the DV507 is more natural sounding than any other arm I've heard.

Cartridge Compatibility

Although I don't have the cartridge stash of some other reviewers, I've tossed everything I own at this thing to see how it would fair. I've got a nice variety of affordable and expensive carts on hand. The major carts that I have in my stable are (in no particular order) the Shure V-15, the Rega Elys, the Rega Super Elys, the Audio Note IQ, the Dynavector 20XH and a Van den Hul modified Spectral MCR Signature. For giggles I even threw a couple of old Audio Technica's, Grado's, Ortophon's and lesser Shures at it for good measure.

There wasn't a cartridge in the mix that didn't mate extremely well with the DV 507. It was kinda fun going back and listening to some of those old carts I haven't heard in years. There is no doubt that this vinyl rig made them sound way better than they ever could have in their day. From the low(ish) compliance of the Spectral to the high compliance of the Shure, not a single one had tracking or resonance issues on the DV 507. That statement alone says something as to the pure versatility of the DV 507. Of course the best sounding of the lot was the Van den Hul modified Spectral, as it should be.

Complaints

The trouble is, as you reach this realm of the audio spectrum, there are fewer and fewer items you can pick at. It might be nice if the engineers at Dynavector could figure out some way to make the bayonet even more rigid. Although the connection is very stable as it is, there is some room for improvement. Since the bayonet relies on a single, small pin to lock the cartridge in place, the only way to make the connection more rigid would be to add one or two more pins (one at 6:00 or two at 4:00 and 8:00). This would require (one or two) more slots in the end of the bayonet and a slight re-engineering of the tightening mechanism.

I'd assume they could leave the standard top pin placement (at 12:00) so that you could use NOS head shells with this arm. In turn they could offer the new head shell with the two (or three) pins as an accessory. Dynavector could also offer varying weights so that you can play with overall compliance.

After that, there really isn't much to pick at on this arm.

Conclusions

Overall, I have found this arm extremely neutral. As I theorized earlier, the sharp center focus is likely due to the arms extremely high mass and rigidity (amongst other things). Since the arm (literally) doesn't contribute to the sound, the images stay sharp, clean and proportionally correct, something we don't normally experience with other arms. I confirmed this to myself with my imaging and soundstaging test tracks. If the soundstage had shrunk, I might have thought the arm was taking away from the sound. Since I heard things placed well outside of the speakers (as I normally do on these tracks), I feel the sharp focus is exactly what is recorded on the vinyl. Now, whether you like that type of focus and imaging is another matter completely. For me, I far prefer that type of accuracy of image. You may not.

It's blatantly obvious that the engineers at Dynavector took conventional tone arm design and tossed it out the window before they came up with this design. What they came up with many years ago was a truly unique design. It doesn't fit into any classifications of arms that are currently available. Dynavector has taken their engineering prowess and corrected many of the issues that have faced tone arm design. From an engineering standpoint, the Dynavector 507 MkII really is quite a piece of ingenuity. It corrects many of the problems associated with accurate vinyl playback. And to top that off, this arm sounds fabulous. Maybe I should restate that, this arm doesn't sound like anything, and in the end I think that's what we are looking for. We don't want a piece of gear to impart anything (sonically) to the music.

If you are looking for the ultimate, sonically inert tone arm (or as close as one can get), you may have just found it in the DV 507 MkII. It is about as uncolored an arm as you will find. It tracks like the champ that it is, both vertically and horizontally. Its easy to setup and even easier to use. Add the fact that if you have (or want to start) a cartridge collection, this is one of the very few arms on the market that let you switch carts where you can be up and running again in just over a minute without having to break out you tools and test records. While some of you might be thinking that the bayonet mount is less than desirable, I'm thinking I need more head shells and carts. I (personally) don't hear any sonic degradation because of it.

Oh, one last thing, if you are thinking about mounting this arm on a suspended table, it likely won't work. This arm weighs far too much at 1380 grams (or over 3 pounds) to be bolted to much other than a table with a solid plinth. When in doubt, check with Mike at Toffco here in the US or fine folks at Dynavector.

Finally, this arm is epitome of cool. It looks like something right out of a futuristic Arnold movie. After spending tons of time with this arm, I've convinced myself that it truly is the Terminator of Tone arms.

My Ratings

Specifications

Type: Bi-Axis inertia controlled Dynamic and Eddy Current Damping Dynamic Balance type tonearm

Overall Length - 306mm. With head shell: max 326 mm

Effective Length: 241mm (i.e. tonearm pivot point to cartridge stylus point)

Overhang: 15mm

Offset Angle: 21.5 degree

Height: 59mm lifts up to 92mm

Height Adjustment Range: 39mm-72mm at sub arm center

Depth: 36mm without connecting cable

Optimum Cartridge Weight: 15-35 grams, including headshell

Horizontal Tracking Angle Error: -1.1 degree to +2.2 degree , 0 degree at inner band of record, 2.2 degree at outside

Tracking Force Adjustment Range: 0-38 grams by 0.2 grams step

Sensitivity: Horizontal: less than 50 mgrams, Vertical: less than 40 mgrams

Net Weight: 1,380 grams

Output Connection: 5P connector

Headshell Connection: EIA standards 4 Pin connector

Accessories: low resistance (0.025 ohms/m, 50pF/m) high quality arm cord, milled aluminum headshell weight 15 grams, mounting template for the arm, mounting template for headshell

Price: $4,250

Company Information

Dynavector Systems Ltd.
2-16-15 Iwamoto-cho
Chiyoda-ku
Tokyo 101-0032
Japan

Voice: +81 (0) 3-3861-4341
Fax: +81 (0) 3-3862-1650
Website: www.dynavector.co.jp

United States Distributor
Toffco
020 Washington Ave, Unit 314
St. Louis, MO 63103

Voice: (314) 454-9966
Email: toffco-usa@yahoo.com