Vintage Denon Direct Drive Turntable

What then is a DK2300? Is it Denon terminology for a DP80 installed in a DK300 plinth with a Denon tonearm supplied? If so, what tonearm do you have? After all, the sound of the unit is going to depend more on the tonearm/cartridge synergy than it will on the deck per se, assuming the deck is not defective. If I'm correct, and if you have a Denon DA307 tonearm, then I own the very same unit. I am re-mounting the DP80 in a slate or high mass wood plinth, and I will use either a Triplanar or RS-A1 tonearm with it. However, the DK300 plinth is actually pretty nice. I think the combo of DK300 and DP80 could be improved by better coupling of the plinth to the DP80 chassis. They used flimsy wood screws at only three points on the inner rim of the tt chassis. You might try using really long wood screws that go much farther into the wood OR drill it out and use long, strong bolts. A further act of courage would be to drill additional holes in the tt chassis so to use more fasteners between tt and plinth. I haven't got the guts. I also dampened the decorative ring around the outside of the tt assembly by inverting it and filling it with beeswax (or whatever melt-able potting material was used in old KLH9 ESL power supplies). That thing is dead quiet now.

Zargon, the DP80 per se is one of the best of the Denons, and in my view and according to one person who owned both in recent years and used them with modern tonearms and cartridges, may be just as good as a Technics SP10 MkII. At typical prices, the DP80 is a real bargain. If the tt has any problems, I was able to obtain some spare ICs for the electronics. There is one IC that is necessary to run the whole shebang; if it's not working correctly in any of its many functions, you've got a dud. I have two spares if you need that part. Other than that, I replaced all the discrete transistors and all electrolytic caps in mine. Replacing the transistors is not really necessary, but replacing the lytics is a good idea just on the general principle that they are all more than 20 years old. (Lytics have a limited lifespan.) Having said that, I don't think any of the original parts in my unit had gone bad, except for a slight malfunction of the aforementioned IC.

Kcc123, Aha! I see that the DK2300 plinth is a two-armboard version of the DK300 that I own with my DP80. Thanks for the photo. Since you have owned your tt for 30 years, can you tell us if you've ever done ANY maintenance on the tt bearing? This is a subject that is not even mentioned in any Denon literature, including the DP80 Service Manual. Denon does not even reveal what kind of bearing is used in the DP80 (or any other of its tables of that era, as far as I know). I have come to believe that it is a sealed bearing that requires no periodic oil change, but I have to guess that Denon was not thinking about 30 years of use when they built the thing. Any insight would be appreciated.

Donshoemaker, I don't know the difference between a DP80 and a DP75. I've already sold the DA307 that came with my DP80, and I did notice the rubber bushing that comes BEFORE the pivot point, which looked like a bad idea in principle, but lets remember that Denon engineers were not stupid. Therefore I withhold judgement on the tonearm; it might be excellent, but I did not need it.

Raul, I noticed that too, that the DP75 has a lower stated rumble or S/N ratio compared to the DP80, but in those days the standards for those measurements were very flexible. IOW, very different numbers could be gotten depending on what one used as a reference in measuring noise. Denon may have used two different standards for the two tables. The DP80 was more expensive and was ahead of the DP75 in the product line, so I don't know what those numbers mean or whether they are relevant to performance.

Kcc123, it looks like you've got a Micro Seiki MA505 on your Denon. How do you like it? I have one too and am thinking of mating it with the DP80.

Steve-g, the DP80 and others in that line-up have all electronics on-board, built into the chassis.

T bone, thanks for your insights. I am wondering about wow and flutter in a turntable, which would be reflection of speed irregularity rather than noise, I think. In the brochure for the DP80, Denon claims unprecedented speed stability, so whatever the measured numbers were, I would assume they were low compared to the competition. What were the numbers, do you know? I think we were talking about signal to noise or rumble specs before.

I am having some slate cubes made using the piece of slate that dropped out of the slab when the hole for the Denon was cut. It was easily large enough to give birth to a dozen cubes, each 2X2X2 inches. But I am also thinking about feet that provide better isolation or decoupling from the shelf. I like Herbie's Audio feet, but they are not high enough, as I would like at least 2" of clearance. Rollerblocks are another option.

Thanks, T bone. I had seen those numbers for S/N in Denon literature. I look forward to the DP80 listening experience, if I can ever find the time to make or have made a plinth for it.

I've got the same brochure that Tbone is talking about, from the Vinyl Engine. The one for the DP80 does quote a 77db S/N ratio, as he says. Both 77db and 80db are well below the S/N ratio of any LP playback system, so noise per se is not going to be the issue with either the DP75 or the DP80. The question is how do these two tables sound, in general, with a high quality tonearm and cartridge in a well conceived plinth. I perceived two issues with the DP80 cum DK300 plinth: (1) The chassis is fastened to the deck with only three short wood screws, i.e., the coupling is suboptimal. (I think I mentioned this elsewhere in this thread; sorry. This can be ameliorated with better fasteners and/or more fasteners.), and (2) The DP80, like all Denon DD tts that I have seen, has a hollow cosmetic ring around its circumference, which would seem to be a source of resonance or possible coloration of the signal if energized. (Again, I mentioned this before; I "cured" the problem by inverting the chassis and filling the hollow inside of the ring with potting material I rescued from an old KLH 9 power supply.) But this is all twaddle until I get a chance to listen to it.

T_bone, that sort of an idea for an armboard went thru my mind also. But how are you going to support the rectangular slate armboard, once it's been cut out of the main slate slab? It could be done, but nothing I thought of seemed satisfactory, given that I believe it's a good idea to have solid coupling of the tonearm to the bearing. If you like to de-couple the tonearm, which some people do, it is more do-able. The best compromise would be to use two slabs of slate, one on top of the other. Then the armboard could be created by cutting out a corner of the topmost slab, with a commensurate hole in the bottom slab to permit passage of the tonearm shaft and wiring.

Stringreen, The magnetic strip issue has been done to death. If the table holds speed, you don't have a problem. If it does not hold speed, you MAY have a problem with the magnetic strip, but there are many other possible and cureable causes of speed instability. Also, Denons are by far not the only DD tables that used the magnetic strip/tapehead as a way of monitoring platter speed. I have seen it myself on hi-end Sony tables of the same era, and I would bet there are others.

Tbone, you seem to know a lot about the history of these tts. Besides the measurements we discussed, do you know in what ways the DP75 was an "improvement" on the DP80, e.g., platter design or weight, electronics, etc? I had my DP80 electronically restored by a local pro who owns an SP10 MkII himself. He was very impressed with the DP80s innards and felt it was advanced vs the MkII, in terms of the circuitry. (This of course has nothing to do with sonics; I am not claiming that he said it would sound better.) Like Zargon, I was heretofore under the impression that the DP80 lived above the DP75 in the Denon model line, but I take your word for it that this was not the case. Or maybe the DP75 came along after they discontinued the DP80, in response to a perceived demand. Or maybe the DP75 was marketed more internationally vs the DP80, which was only made in 100V version (i.e., for Japan), as far as I know.

Tbone et al, In the DP80, when you use the adjustable speed control you are bypassing the quartz crystal oscillator. That's the only way you can get the electronics to agree to change the platter speed, I guess. If the electronics are all copacetic, the platter will turn at exactly 33.33 with the quartz oscillator engaged, but the speed is not adjustable in this mode. This mode is much like the SP10 MkII. Presumably, it's preferable in terms of speed stability to have the quartz oscillator in play.

Raul, Upwards in this thread we discussed the Denon plinths a bit. Kcc123 has a DK2300 plinth, which is a two-arm job and looks like it has nice high mass. Today I hefted my DK300 plinth. It's a laminate of possibly some good quality plywood or hardwood and very heavy; I imagine the DK2300 is even heavier, because it is bigger in order to accomodate two arms. So I am thinking that these plinths might not be so bad. What needs to be improved is the coupling between the tt chassis and the plinth, and I intend to try to achieve that by using much thicker and longer wood screws. Or long bolts that go clear thru the plinth to the bottom side. This small mod plus the dampening of the hollow ring around the platter (see my post above) may be quite effective upgrades, without resorting to a home-made plinth. I do have a piece of slate for the DP80, if that strategy fails.

Kcc123, That is very cool. Shades of the Micro Seiki DDX1000. I would call that an UN-plinth, not to say that it would not sound great. However, there's no way I could make something like that. Did you do it yourself? Can you show side or bottom views, if that is not too much trouble?

Raul, I take your word for it, on the DK300, but it's worth an experiment, since I own one and since all I need are some gigantic wood screws to see if I like the improvement. I would also fabricate some new arm boards.

That looks like a nice design that would really get a firm grip on the JVC. The pros and cons of a plinth for a DD table have been much discussed elsewhere. There is no question in my mind that a massive and properly constructed plinth does wonders for an idler drive table. There are two camps as regards DDs; you seem to be in the less is more camp, as opposed to the more is more camp. A really dense plinth of slate, for example, or layered wood, for another, should not contribute negatively in terms of sonics. Beyond that, I have no basis for an opinion, except thoughts.

Does this forum have a search engine? If so, try searching on the word "plinth". If not, go to Vinyl Asylum and do a similar search. Also, scroll down the list of threads on this Analog section and look for threads about Garrard, Lenco, Technics SP10, Denon, direct drive, idler drive, etc. Hope this helps. There was at least one thread here that was directly addressed to your question, recently.

Kcc123, It's quite possible that the sorbothane liner will work out well, but I have never been fond of sorbothane "feet". One thing to consider is the factors that govern energy transfer between dissimilar materials. At the interface energy will be either reflected back into the energized material or transmitted to the contact material. In both materials, energy is dissipated as heat as it bounces around. There are websites that give constants for different materials and show how to predict the outcome of interfacing one with another. If you want the energy of the motor to be drawn away from the chassis and platter, it seems to me it would be a good idea to choose materials that interface well with the metal of the chassis. That is, you might be best off with what you have now, with the JVC metal ring plinth. Moreover, it might be a good idea to have something heavy and metallic in direct contact with the motor per se, a la Albert Porter's SP10 plinth. (Go to the Soundfountain website to see photos and drawings.)

Raul, I would like you to listen to a state-of-the-art restored idler tt, e.g., a Garrard 301/401 or a Lenco L75 in a proper plinth, using one of your own tonearms and cartridges. Your opinion of how these tts compare to BDs and DDs in your experience would interest me. But it's very important to be sure the idler is properly restored and in a proper plinth before any judgment.

You can buy a slab of two-inch thick PA slate from any of several sources and have it shipped to you anywhere in the US for a total cost of less than $500, maybe much less than $500 if you don't have to pay shipping. After that you need to find someone local to you with a CNC milling machine that can cut the hole for the Denon to fit. Since the Denon requires a not-too-complex hole that consists of a series of concentric circles, you don't really need the services of a water-jetter to get it done. I am assuming the milling would cost ~$200 additional. I own a proper size slate slab, and I am going to visit a guy who can cut it during the coming week. You can come up with a pattern for the needed cut by tracing the hole in your DK300 plinth, which is what I have done.

Treehugga, I don't know what the "world's finest slate" is. I did see many months ago a long drawn out argument between Jonathan Weiss of OMA and the Slate Deck guy in the UK, over whose slate was "finer". OMA use Pennsylvania slate; I am told by Vermont slate guys that VT slate is actually "harder" and more dense than PA slate, but I selected PA slate, because others have had great success with it. After all, the real question is what slate is best for a plinth. IMO, the best slate is NOT likely to be the hardest, densest, type. I will leave it at that.

I am/was planning to fasten the DP80 into the slate using the same three screw-holes provided for fastening it to the DK300. How to do this is very crucial to the outcome, because good coupling between the chassis and plinth is essential. If I work up the courage, I may drill additional holes in the DP80 chassis to allow use of more than 3 fasteners. The other potential problem is that those holes are perilously close to the edge of the cut-out needed for the chassis to fit. I fear that the slate will crumble or crack during drilling. I am going to try to get a consultation on that problem from an experienced slate worker, before doing any hole-drilling.

If you know that the Denon DP80 bearing is sapphire, then you know more than I was ever able to find on the subject, or anyone else here. Thanks. I am going to try to get to visit a slate cutter on Friday. (He has a CNC machine and is just getting into the business of cutting slate.) I've had one local water-jet guy back out of the job, because he was afraid of damaging my slab.

Based on the literature supplied by the respective companies, I would expect that the SP10MKII motor has more torque than does the DP80 motor. In their blurb, Denon imply that there is an ideal amount of torque, in their opinion, i.e., too much can be a problem, but they don't elaborate on the subject. Their given numbers are lower than are those of Technics.

I agree with most of what you say. How did you or do you rank the best idler tt you've heard vs the best DD, and what do you think are the qualitative differences? In any case, I am having a lot of fun with vintage TTs these days. That in itself is ample justification for pursuing their perfection.

Good answer. I don't really believe there is any one "best" drive system either. Perhaps one may be more cost-effective than another, but that's about it. (Up to say $3000, I think you can beat out most BDs with any of several DDs or idler set-ups. Of course, one reason for that is that I am comparing a brand new BD to tts that one can buy used for quite a discount off their long-ago cost.) I think we are lucky to have different "flavors" of vinyl reproduction with all these different modes for making the platter rotate.

Treehugga, The weight of all that slate so dwarfs the weight of the DP80 chassis that the latter is irrelevant. The big thing is how to couple the DP80 to all that mass, so it can do some good. Are you going to drill all the way through both layers of slate, so that three very long bolts can couple the DP80 to both layers? Are you going to use any adhesive between the two layers of slate or only the force of gravity, which is considerable in this case? How will you mount a tonearm? (I ask these questions, because I am thinking along the same lines.)

(1) I have done the thought experiment as regards threading the slate. I don't think it would work. I am not going to try. I think the only choice with slate is to just drill a hole thru and then use a nut and bolt. There IS some appeal to the idea of threading the slate, because it would make for better coupling in theory. But I think the slate would just crumble if you tried to tighten down the screw. You might experiment with a scrap piece of slate, though.
(2) If you have the slate slabs honed, the sides would be plane parallel to each other and there would be a close fit between the two pieces. Most mills can hone the slabs, at least here in the US. (I had it done in Vermont and in Pennsylvania, by two different companies.) I don't think you need adhesive, but I do think that sorbothane is a bad idea. It would essentially de-couple the two pieces of slate, when what you want is good coupling. Just my 2 cents.

T_bone, Raul used a minimalist plinth like that with both an SP10 and a DP80 and liked the results. It would be interesting to use your first effort as a reference, if and when you try to build a heavier/denser plinth for the DP80. I think the DP80 and other top line Denons are under-appreciated in the recent upsurge of interest in DD tables of yore.

Treehugga, I've done the same thing in my Denon slate plinth, which is not quite so massive as yours (50mm thick vs 100mm). I use a Triplanar, so all that's required is to locate and drill the three bolt holes for its base. It's easy to drill slate with a masonry bit as long as the hole is relatively small in diameter. I have identified several very fine tonearms that can be surface-mounted, like the TP. These include the RS-A1 (which needs no drilling at all), the Terminator 2, and the Dynavector 505. I'm sure there are more that I don't know about. I reckon my plinth weighs 60-70 lbs AFTER cutting out the hole for the Denon, so yours is a true monster in terms of mass. Stay tuned.

Treehugga and T_bone, As I now understand the operation of a waterjet, it cannot make router-like cuts and patterns; it can only cut the material all the way thru. This obviously imposes some limitations for plinth designs. I would have liked to have been able to create a recess into which one could insert a tonearm mounting platform. T_bone, I am not sure I understand your idea, but I think it cannot be executed with a waterjet. You'd be able to do it with separate layers of slate. Treehugga, at my suggestion, the CAD guy designed the program so that the three holes for mounting the Denon were cut FIRST, before the major central cut-out was done. This worked out fine.

My post of 01-26-09 should be ignored. I later learned that using a CNC milling machine to cut the hole for the Denon would be very very expensive vs using a water jet and probably less precise.

Treehugga, I've just gotten around to assembling my DP80 in its slate plinth. My slate slab is only 52mm thick but it appears to be a little larger in dimension compared to yours. I am sealing the slate right now (today) with a concoction of turpentine and certain additives. I am going to mount either a Dynavector DV505 or my Triplanar, or both. (The slab has room for two arms.) I will post a photo as soon as the seal dries, in a few days. I have been listening to my Technics SP20 Mk2A in a similar slate plinth with an RS-A1 tonearm for about a month. It sounds so good that I had forgotten all about the DP80, until now. Your slab must have weighed nearly 200 lbs before you cut out the hole for the DP80; I am impressed. (One sq ft of Pennsylvania slate, one inch thick, weighs 15 lbs.)

Thanks, Tree. I should have written "SP10" instead of "SP20", but I guess that was an obvious typo. I admire your guts in drilling those three holes for the Denon; I had the guy who made the CAD file incorporate them into the program, then the waterjet cut them FIRST, before making the huge cut-out for the Denon chassis. That way there was no chance of the slate crumbling during drilling of the mount holes. Your waterjetter had the additional challenge of going thru 100mm of slate. That alone must have been a bit scary and requires skill with the machine. Next up will be my Lenco L75 in slate with the PTP top-plate (see Lenco Heaven for description). The slate is cut perfectly; I am now having the platter and the PTP painted satin black to match the plinth. But this is about direct-drive, not idler-.

You could probably get a Pennsylvania slate slab shipped to you in SoCal from my supplier. If you're interested contact me off-line. They are in Pen Argyll, PA. And yes, I do like the slate shelf under the slate plinth for the SP10. I only bought one of them so am using the stock Adona granite/MDF shelf under the Denon. Can I hear any difference related to the shelves? Nah; I don't know the difference between the two tts yet. Listening to Art Pepper + Eleven last night. The Denon/Triplanar/Koetsu had me tapping my feet.

Forgot to reiterate that I think it is a good idea to dampen the resonance of that cosmetic ring that surrounds the platter on all Denon dd tables. If you're going to the trouble and expense of making a slate plinth, it behooves you not to overlook this detail. As I think I wrote way back at the beginning of this thread, I inverted my DP80 chassis (sans platter) on some blocks of wood for support, so as not to put weight on the spindle, and I filled the ring with some melted beeswax (or whatever was used as potting material in a KLH9 electrostatic speaker power supply). This worked very well; with the hardened beeswax filling, the ring does not "ring" any longer.

T_bone, I made sure that the beeswax stopped flowing just short of the part of the ring that houses the controls. It solidifies rather rapidly as you pour it, due the fact that it is cooling at the same time, so there was no problem controlling its dispersion. No wax in the electronics. I am sure Treehugga was able to do the same, since his damping compound probably was never very liquid.

Treehugga, That's loverly. You might try a different tonearm some time, just for kicks.

I've just finished my second evening of listening to my DP80 mounted in a 70-lb slate plinth with Triplanar tonearm bolted directly to and thru the plinth (no discrete armboard) and a Koetsu Urushi. I am ecstatic, as you might guess from the fact that it is past 1 AM here on the East coast US, and I have not yet gone to bed. This thing is sweeeeeet. I just got done with Chick Corea, Return to Forever, on ECM, a recording I bought new in the 70s. I re-experienced everything but the chemical high of those days. It has a BIG sound (certainly in part due to the Urushi/Triplanar) but also incredible drive and rhythmic presence. I will post photos in my system, as soon as I get a new camera, in a couple of days. Awesome is a cliche', but so be it.

I think a large dollop of the goodness of this set-up is bolting the Triplanar very firmly to the slate. In theory, any energy put into the tonearm by the Koetsu is going to be traveling down the tonearm and into 70-lbs of slate, where it would easily be dissipated. I can't easily mount the Triplanar on either the SP10 Mk2A slate plinth or the forthcoming Lenco/PTP in slate, because the respective chassis' simply do not allow the tonearm to get close enough to the spindle, so I probably won't be making comparisons among the 3 tables using this tonearm. (It could be done with the SP10, but I would need to raise up the Triplanar on an additional small piece of slate, about 3/4" thick.) I may be able to do a tt comparison with the RS-A1 or the Dynavector DV505. But what I am most surprised about with regard to the Denon is how completely open and rhythmic it is, virtues usually ascribed to sprung belt drives and idlers. Whereas, traditionally I think of the Denon dd's as being a bit on the dark side. There is no trace at all of that quality using slate. None at all. I briefly tried the SAEC ss300 platter mat in place of the Denon rubber mat. I am not sure this is a good idea, because the ss300 is heavier, and one wants to stay close to the mass of the stock mat. (In the owners manual, Denon specifically warns against using anything but the stock mat. This is because any tt servo mechanism is designed specifically to run a certain platter mass.) Anyway, I think the sonics may be even slightly better, cleaner with better bass definition, using the ss300. BTW, my slate is about 19"X23" and 2 inches thick. This calculates to about 90 lbs, before making the large cut-out for the Denon.

Photos of my Denon DP80 in 2" slate slab w/Triplanar and Koetsu Urushi, plus a photo of my SP10 Mk2A in a similar slab with RS-A1 and Ortofon MC7500. Are now posted on my system site, since I don't know how to post them right here.

Thanks, Raul. It is as simple as simple gets, just slate, turntable chassis, and tonearm. No armboards, no fancy suspension. Right now I am using 2x2x2 inch slate cubes for "feet", but I would like to introduce something with a little compliance. The Denon is sitting on a damped granite slab, as per Adona, on an Adona equipment rack, with which I am pleased. Adona damps the granite by adhering it to what appears to be a slab of high density MDF. This takes the ringing out of the granite. The Technics is sitting on a 1" thick slate shelf. I may have more slate shelves made; it works well on the Adona rack. I plan to mount the Dyna DV505 on the Technics slab. Eventually, I will have the Lenco in slate up and running.