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Post by MartinT on Aug 6, 2014 20:06:45 GMT
The Dynavector DV507-II Pickup Arm
The Dynavector DV507-II pickup arm is a pivoted, high effective mass arm with some unique design features. The design dates back to the mid-1970s as the DV-501 where the bi-axis concept first saw the light of day. Now in 507 Mk. II form, it is claimed to be much easier to install and set up as it is a single pillar design with cable entry at the bottom of the pillar and shorter overall length, making for wider turntable compatibility.
The vertical pivot is around the rear pillar, as with all conventional pivoted arms. However, the horizontal pivot is way up front, creating a short stub-arm and giving it the ‘bi-axis’ moniker. The main arm is a rectangular section beam of immense strength, giving it a rather industrial look. This beam is balanced on its ball race by the large rear counterweight. However, this counterweight only balances the arm, including the weight of the headshell and cartridge, on its bearing and plays no part in tracking force! The beam loads the bearing evenly and is consequently very free to move except for the application of damping via eddy current using two magnets and a curved damping plate running between them. An elegant solution avoiding all the problems associated with the use of damping fluid. Bias is spring-loaded and set with a dial.
The ‘real’ pickup arm, if you like, is the stub arm at the end of the main beam moving about its horizontal bearing, balancing the headshell/cartridge with a rear decoupled counterweight and applying tracking force via a spring. The sum effect is that this arm has very high inertia (effective mass) in the horizontal plane and very low effective mass in the vertical plane. The only other type of pickup arm to exhibit such different horizontal and vertical inertias are parallel tracking arms. The cartridge rides up and down warps with great ease yet can only ride the inward groove journey slowly since it feels tremendous horizontal resistance to any fast movement, translating all of the groove modulation into signal. Since the main beam does not move up and down, a cute solution to cueing involves a rod running down the length of the beam, connecting the cueing lever with the stub arm to providing accurate damped cueing. VTA can be adjusted live while playing a record and allows very fine control over height. Since the stub arm is so short, achieving correct VTA is more critical than with a longer arm.
Cable connection is through a standard 5-pin arm connector, allowing use of different cables according to preference. I found the provided silver cable very good indeed compared with a Neglex cable and left it in service. The headshell is mounted via a standard SME-type connector, allowing for quick cartridge swapping and the use of complete shell/cartridge solutions like the Ortofon SPU. A selection of counterweights provides for balancing of headshell/cartridges up to 35g in weight. The whole arm weighs 1.4kg, an important consideration if mounting on a suspended turntable although clearly the Dynavector is more suited to solid turntable mounts.
You will have to have a special mounting plate cut for your turntable as it is very unlikely that there will be one to suit. Luckily it’s just a single hole so it’s not too difficult to have one commissioned. Installation is straightforward and the instructions are reasonably comprehensive. Everything is a tight fit in the Technics SL-1210 due to the arm plate and platter being mounted so low in the plinth. Use of the standard platter is definitely out as there is insufficient scope for the arm to go low enough with a standard cartridge. In any case, the DV is worthy of better performance than the standard platter can bring. I use a Mike New ETP, bringing the platter up in height to allow for effective VTA control.
The overall feel and handling of the arm is excellent, with a nice magnetic ‘catch’ inside the arm rest, accurate cueing, heavy and solid headshell, fine control of tracking weight, bias and VTA and that industrial look mentioned earlier. Appearance and finish are up to SME standards although sadly the documentation is not in the same class.
My first impression when listening was how very secure tracking appeared with a variety of music, never once sounding strained or on the limit. It even made the best stab at the Telarc ‘torture track’ 1812 Overture cannons that I’ve yet heard, not jumping from the wild grooves throughout the performance. The effect is one of incredible dynamics and the ability to start and stop on a sixpence. I have never heard such security in the groove, even putting to shame an SME IV / AT OC9 pairing that I used to own.
The second thing to startle, compared with most pickup arms, was the depth and quality of the bass. The arm achieves its objective of providing a rigid platform for the cartridge, and this is most easily heard in the phenomenally dynamic and wonderfully textured and tuneful deep bass, plumbing a real strength of the Technics and giving music a very structural foundation. This bass quality remains tight and does not descend into the sort of tubbiness that many suspended decks & arms substitute for real bass. This is closely followed by a remarkable suppression of surface noise, very welcome as I tend to listen at quite high volumes and never find the noise intrusive.
The Dynavector handles warped records with great aplomb as its stub arm rides up and down with the minimum of inertia. I have a very warped copy of Genesis - Wind and Wuthering and the DV rode the warps without leaving the groove at any time.
Further listening revealed a wide and deep soundstage, fine detail resolution and microdynamics, tonal neutrality and the seeming ability to get the best from any cartridge mounted to it. On one memorable evening I had an Ortofon SPU head mounted and very roughly balanced for the 3g tracking weight required. The sound was remarkable, fluid and vivid with a soundstage that went to the very corners of the recording, midrange detail that placed everything naturally and treble quality that totally belied the use of a spherical stylus. The midrange microdynamics had to be heard to be believed. This arm could have been designed for the SPU.
There is a sense of invulnerability to the way this arm reproduces music, removing the worry often associated with the playing of records and leaving the listener to simply envelope themselves in the music, quickly forgetful of the mechanics of replay. My overall impression of the Dynavector DV507-II is of an arm that has been designed from the ground up to answer questions of rigidity, damping and a stable cartridge platform by utilising novel ideas and superb engineering. It has been refined over the course of 35 years to the current model where it is compatible with more turntables than ever before. I feel that the Dynavector marketing machine has been non-existent for most of those years and the arm itself seems to be the object of legend rather than much real experience. Some indifferent reviews have not helped by matching the DV with inappropriate turntables or not striving to harness its strengths. It is undoubtedly an expensive component and is made to order from Tokyo rather than held in stock, making the chances of a demonstration very slim. However, the DV507-II is the result of years of study and honing to create a design of incredible focus and purpose, capable of superb sound quality and providing the lucky few with unique pride of ownership.
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Post by danielquinn on Aug 7, 2014 9:47:20 GMT
I can not comment on the arm and i note the bloke on TNT audio liked it so much he bought it .
however , it cannot have been designed to answer the question of rigidity . It has a detachable headshell ! This may or may not matter vis-a-vis sound quality but it must surely be a fact a detachable headshell is not as rigid as an integrated one and if i remember correctly AK has measured this .
Indeed a simple test would prove it , if i was to bend it at the join , i would wager it would take less force than it would to bend the arm of single piece of the same material .
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Post by MartinT on Aug 7, 2014 18:05:25 GMT
Listening to it, it doesn't appear to suffer from having a joint at the headshell. It forms a very tight coupling and there is no play when it's fully tightened.
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Post by pinkie on Aug 7, 2014 18:51:00 GMT
No question it's an original and distinctive design, and by a manufacturer who does good stuff with cartridges. It would be interesting to hear (although not on my PT which it would squash). It seems to produce polarised reactions. Those who have spent money on it love it. Other reviewers I have found less keen. But however much one might subjectively enjoy it, surely it does not defy the laws of physics. It has fairly ghastly tube resonances on the plots I saw, and an impossible effective mass cocktail no cartridge can possibly match. I am in a rare moment of flaky broadband atm, and can't easily check facts but from memory the vertical effective mass is about 6gm and the horizontal was off the chart for measurements but exceeded 50gm. How do you find a cartridge with board stiff horizontal compliance, and vertical compliance like a soggy bed?
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Post by MartinT on Aug 7, 2014 19:12:27 GMT
There is no tube, it's a beam. The Shelter works very well in it. The horizontal mass is damped with the eddy current brake, so it's not as wild a load as you might think.
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Post by Deleted on Aug 7, 2014 20:02:33 GMT
I'd take the rigidity of a short stub arm with detachable headshell over a 9" or longer armtube with a fixed headshell any day but then what do I know, I'm not the cleverist person I know The Dynavector was not the first of its type. The first high quality implementation of the concept was undertken by GE in the 50's with their A1-501 (see link). A1-501 Tonearm
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Post by MartinT on Aug 8, 2014 6:28:57 GMT
Now that IS interesting! Thanks for the link, Andy.
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Post by pinkie on Aug 9, 2014 17:12:01 GMT
Whether it is a tube or a beam is not really relevant to resonances, as I suspect you are aware. It is relevant to rigidity and effective mass. A beam represents an excellent solution due to its rigidity, but suffers with being too heavy. The benefit of a tube is to provide some rigidity with lower mass (and you can shove the cables up the middle)
But primarily tubes are used in modern pickup arms for reasons of mass. This was AK's rational for combining the two using a cross beam reinforced tube to gain rigidity without adding significant mass.
However, we digress. Tube or beam, if it resonates at some frequencies more than others it will pick up that colouration. The generators in the cartridge detect movement of the stylus relative to the cartridge body- they do not distinguish whether that movement is of the stylus relative to a (effectively) static cartridge body,or whether it is a cartridge body wobbling on a resonating platform relative to an (effectively) still cartridge.
Beam or tube, it is desirable to avoid large resonances. It is however possible that the charts published were flawed. They would be a composite of the resonances in the 2 beams. However, the main beam is so massive it would be far less affected by resonances than a conventional mass arm structure. Maybe that is why its sound is less affected than the pure resonance plots would imply.
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Marco
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Post by Marco on Aug 10, 2014 10:17:48 GMT
Listening to it, it doesn't appear to suffer from having a joint at the headshell. It forms a very tight coupling and there is no play when it's fully tightened. Indeed - and I can confirm that, having used the arm on your deck many times. The same also applies with my Ortofon. Those who focus too much on the 'lack of rigidity', with detachable headshell arms, are clearly missing the point, as other areas of tonearm design exist of far more importance than whether the headshell is fixed or detachable. Marco.
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Post by Deleted on Aug 10, 2014 14:35:49 GMT
Whether it is a tube or a beam is not really relevant to resonances, as I suspect you are aware. It is relevant to rigidity and effective mass. A beam represents an excellent solution due to its rigidity, but suffers with being too heavy. The benefit of a tube is to provide some rigidity with lower mass (and you can shove the cables up the middle) But primarily tubes are used in modern pickup arms for reasons of mass. This was AK's rational for combining the two using a cross beam reinforced tube to gain rigidity without adding significant mass. However, we digress. Tube or beam, if it resonates at some frequencies more than others it will pick up that colouration. The generators in the cartridge detect movement of the stylus relative to the cartridge body- they do not distinguish whether that movement is of the stylus relative to a (effectively) static cartridge body,or whether it is a cartridge body wobbling on a resonating platform relative to an (effectively) still cartridge. Beam or tube, it is desirable to avoid large resonances. It is however possible that the charts published were flawed. They would be a composite of the resonances in the 2 beams. However, the main beam is so massive it would be far less affected by resonances than a conventional mass arm structure. Maybe that is why its sound is less affected than the pure resonance plots would imply. What is relevant is that the working principles of the tonearm are fundamentally different from the norm just as there are for a linear tracker.
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Post by MartinT on Aug 10, 2014 17:12:24 GMT
Beam or tube, it is desirable to avoid large resonances. It is however possible that the charts published were flawed. They would be a composite of the resonances in the 2 beams. However, the main beam is so massive it would be far less affected by resonances than a conventional mass arm structure. Maybe that is why its sound is less affected than the pure resonance plots would imply. I can only say that it sounds less dry and more 'free' of tonal and dynamic limitations than my previous SME IV, Michell TecnoArm and Jelco SA-250ST arms.
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Post by pinkie on Aug 10, 2014 19:44:34 GMT
Andy A linear tracker is only different due to its geometry. It avoids tracking distortion, and it avoids bias (skate) but otherwise it is an arm. Anything the cartridge is connected to which vibrates (resonates) will produce an electric signal and consequent sound out of a cartridge. The issue is that a cartridge is an electric generator which produces a voltage when the stylus moves relative to the cartridge body. It doesnt matter whether it is the body moving or the stylus moving, they both create a voltage. Linear trackers and Dynavectors are no different in that respect
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Post by Deleted on Aug 10, 2014 21:55:07 GMT
There is an explanation here as to how a bi radial tonarm behaves differently to a normal type of tonearm. Link
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Post by MartinT on Aug 10, 2014 22:02:24 GMT
That's for the DV505, but it's pretty much the same design.
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Post by danielquinn on Aug 11, 2014 7:11:48 GMT
That be marketing that be.
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Post by MartinT on Aug 11, 2014 7:13:09 GMT
It's effectively a manufacturer's white paper. Not quite marketing, as it would at least be subject to peer review, but not unbiased either.
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Post by danielquinn on Aug 11, 2014 7:25:27 GMT
As it been subject to peer review. I doubt it. Indeed how would you peer review it. Listen to it What objective agreed criteria are there to substantiate a casual correlation between the design features and the way it sounds. It is entirely possible the arm sound the way it deos for different reasons than those postulated by the manufacturer.
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Post by pinkie on Aug 11, 2014 17:36:44 GMT
The arm - Dynavector biradial, has been reviewed in Hifi choice. I have the reviews at home somewhere, but I can't remember which models were reviewed. The resonance plots were not pretty, and the subjective evaluation by HFC was lukewarm to be kind. The mass of the main beam is heavy enough to screw up the horizontal compliance of a cartridge, but not heavy enough to eliminate resonances (we had an idea for that, and it was truly massive). I could probably get AK to rough out the sums for that when I'm back As for "Like a parallel tracker" that "inside force canceller" (read anti skate weight) is needed precisely because it is NOT like one But none of that means it can't sound lovely in Martins system. It just means it is subject to the laws of physics and arm geometry
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Post by Deleted on Aug 11, 2014 19:02:40 GMT
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Post by MartinT on Aug 11, 2014 21:05:27 GMT
Thanks, Andy.
Here's a translation of that final review. It's a little 'interesting' to read.
I found myself nodding at the first two reviews' findings, in that they match mine very closely. Now, that Grand Prix turntable is mighty interesting.
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