Vintage Denon Direct Drive Turntable

I have been interested in experimenting with a direct drive TT for some time just to see what all the fuss is about. I would be comparing it to my belt drive TERES.

Does anyone have any experience with a Denon DK 2300 TT with the DP 80 Servo controlled direct drive motor? These came out in the '80s, I believe. The base allowed for two arms as well.

Is this TT worth the time and effort?
I can't believe I'm writing this, but I am old enough to have actually owned a "vintage" Denon direct drive turntable when it was a current model! If my 'vintage' memory serves, it was a very good turntable but I think the current Teres would more than give it a run for the money.

Good luck!
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.
A rare thing indeed when a direct drive table will sound even with a belt drive. I and a friend both owned "Big Dog" Denon tables in the 80s. We were encouraged to take home a flimsy $300 NAD belt table just for grins. Within 10 seconds of listening, we both looked at each other and simultaneously let out a profanity. Sold our tables and purchased new ARs with Sumiko arms and Talisman carts. End of story there.
To be more clear, I am considering buying this TT to recondition and experiment with it, and have no previous experience with Denon nor direct drive. The simplicity of a DD TT is appealing compared to a belt or even an idler wheel and if the speed and torque are well controlled and the motor is quiet, it might be quite a good solution.

Lewm, I have not seen the TT yet but what you describe sounds like they are the same. The arm is a DA 401 with unknown cartridge. If I liked the TT, I would consider remounting the DP80 as well, and would enjoy seeing how you are proceding.

Celtic, your experience is appreciated. Isn't it great when a comparison is absolutely obvious and there is no regret? Are you still using a belt drive?

Still, this forum is filled with those who are rethinking their drive technology.
Granted it will probably be a much more expensive experement, but the Teres Verus motor would let you experience the best of both worlds.
I have a Denon DP37F direct drive 'table with Sumiko Blue Point on it. It has reached 25 years (with 2 new drive motors), and works very well. I can't say enough good things about it. My big issue was with TT isolation, which I solved. It is also a very simple 'table to setup, and to use.
Just yesterday I got my DP55k table back from Denon. I had it in for service. The only problem I've had with it since purchasing it new (the DP55K table, DA307 arm, DL103-D cart. and AU320 transformer) close to 30 years ago. A testament to Denon for still supporting its products after so many years. In my experience, the big divide in opinions regarding the quality of sound from this genre of table comes down to what it is placed on. It took me a while to figure it out, but I could only get good sound when it was on a very high mass, well damped base, the likes of an old, heavy, wooden antique chest of drawers with the drawers filled. I remember the dealer who handled these tables at the time had sand filled pedestals for them. A typical component rack won't cut it. I think Lewm is on the right track with his suggestions for plinth improvements. The importance of isolating this type of table was addressed by VPI back in the day with their "VPI Base". I've never heard one on a VPI base, they come up for sale once in a blue moon. In short, no table is going to perform at its best unless it is properly set up, and that includes what is used as a base / support. Zargon, Lewm - I'd like to hear of your results /experiences. Best wishes.
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.
Nrenter, the Teres may get the gift of a Verus independent of the Denon project... (:-) I don't expect the Denon to replace it, but provide an alternative for either my office system or a table for evaluating and grading used LPs.

Licoricepizza, your comment about having to replace two motors is a bit of a concern. Can you elaborate? Was it the motor or the electronics?
I have own a Denon DP80 with a DK2300 plinth since 1980 and it has performed perfectly without any fault. It is heavy, over sixty pounds in weight.

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.
I had a DP75 which was similar with the two piece platter. It was a less expensive version of the 80 for some reason,can't remember what the difference was. About a year old the speed became unregulated and it took off like a helicopter!Interesting arrangement, a tape recorder head that read a magnetic strip on the inside of the platter.Sent it back to Denon who could not fix it and therefore exchanged it with a "B" stock unit. 307 is a terrible arm design with mushy rubber seperating the arm tube from the pivot point.No rigidity and extreme loss of information. I would be nervous about one of these today,the rubber would probably be dried out making the arm useless.401 is a better arm,but needs a low mass high compliance cartridge.
Dear Donshoemaker: As a fact the 75 has better specs than the 80.

Regards and enjoy the music.
So far, I have not done any maintaince on its bearing. I believe Denon motor units very much resemble to my other JVC turntable motors which are also sealed and do not need any oil change at all. My DP80 has, no doubt, proved to be a testament to its great reliability - a tribute to Denon.
Steve_g, I appreciate your advice on the need for the proper base. I assume the DP80 is not spring or shock mounted in any way in the base? Stay tuned.

Lewm, the comparison to the SP10 MKII is quite a statement. This could get interesting. Thanks for the information on the electronics, as I would not have anticipated ICs in this unit. Does anyone else believe the DP80 and the SP10 could be on a par?

Kcc123, I can't get to your link. Can you try again?
Hi Zargon,

Here are two more photos-



The ic's are in the motor controller circuit. I had a split platter Denon at one time; can't remember the model number, but the motor control cicuitry was in a separate box that connected to the table via an umbilical cord. Is that like your DP80? My DP55K has the electronics built into the underside of the plinth. Curiously, my table was back at Denon for repairs and needed a couple of ic's replaced. If anyone is interested I can provide the part numbers from the repair slip. Let me know.

The DA307 arm was indeed capable of excellent performance. If my memory serves, it was part of a whole vibration control concept that extended from the tables platter mat to the development of the 103 series cartridges. It worked great with the 103D, and when they were not available, I found the Adcom XC-MRII worked very well. Your concerns about longevity are well founded. I ultimately wore mine out. An SME 309 now works in its place.
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.
Kcc123, thanks for the pictures. The DP 80 is a very advanced looking design for 1980, and must have created a market stir amoung other TT builders.
Hi Lewm,
I think the massive DK2300 plinth provides an excellent platform for many tonearms, low mass and high mass. I have partnered it with SAEC 308L, Audiocraft AC3000 Silver Signature, Grace 747, Signet XK50, Rega 300 ……., all with very good results and especially the Micro Seiki MA505S which is beautifully matched with the Denon.
Thanks everyone for your responses and information. This Denon still interests me and I'll report on the project.
FWIW, the 75 (which came with plinth), and the 80 (which was sold plinthless, but with at least three choices of plinth) are not that far off in terms of specs. The DP-75M was JPY 180,000 (with plinth and arm), and the DP-80 was JPY 95,000 by itself, the DK-2300 plinth retailed for JPY 70,000, and arm was separate. The S/N ratio and self-reported WOW/Flutter numbers are better on the 75, but the Japan Institute of Standards put the WOW of both at the same level (and both slightly higher than the self-reported numbers). The spin-up of the 80 is supposed to be slightly faster, and the DP-80+DK-2300 is about 10% heavier than the DP-75M (including arm). Either one should be serious contenders as those were the prices of most firms' 'one-down-from-the-top' offerings around 1980 (the top-priced offerings were things like the DP-100M, Technics SL-1000, Yamaha PX-1, Sony PS-X9, Exclusive P-3a, etc).

I would love to try one a Denon but I have too many 'projects' lying in wait...
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.
S/N Ratio: DP-80 S is 77; DP-75M is 80dB
Wow/Flutter: DP-80 is <0.015%; DP-75M is < 0.008%w.rms
The JIS measure shows both below 0.02%.
I don't know how rumble is measured.

Wow and flutter (originally separate measurements, now put together) measure the level of frequency instability below and above 4Hz of wobble. I read once a long time ago that the weighting system of measurement tends to be inaccurate at high wobble frequencies, making it effectively meaningless. I have thought that this is one reason why high mass platters are supposed to sound better on almost every kind of drive system - they effectively reduce the possibility of high levels of high frequency flutter.

As for levels vs the competition, it was quite good (there weren't many tables made which spec-ed better) but several tables were similarly below 0.015% or 0.1%.
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.
T_bone, I found an old Denon add for the DP 80 which list the Wow/Flutter at 0.008 wrms and the SNR at 80 db. I assume your data was from independent testing? The Denon numbers are better but may have been influenced by the marketing/sales staff.
Dunno. Can't account for the difference. I was quoting from notes I made last year (I looked it up last year when I was doing research on Japanese DD TTs from the 70s and 80s) but just now checked over at the Vinyl Engine website and found an English-language brochure for the DP-80 giving the same numbers I previously noted. Perhaps things were improved in the latter years of production and that is where your ad comes from. FWIW, the brochure provides a great deal of info on how the thing was designed and built - very instructive in its own way.
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.
Be very wary of the Denons. There is a magnetic strip on the inside of the table with a pickup head to read the magnetic pulses. If the strip is scratched, or otherwise not in pristine shape, do not get the table.
As I understand it, the 80 was issued after the 75 and weighs more and has better speed stability. Since I am planning to build a plinth, that would seem to be the table to acquire.

T_bone or Lewm, can you give me a link to the brochure?

I was unaware of the magnetic stip concerns, and would assume these are no longer made? Hence the sensitivity?
That magnetic strip is unrepairable, but necessary to the operation of the table
The 75 improved on the 80 in some ways, and was made afterwards, I bet to a slightly lower price point when sold separately to assuage fans of the DP-80 (Denon themselves were trying to bring the DP-80 to the masses based on the DP-80's critical success and Japan's economic development in the meantime). The Vinyl Engine is a fantastic resource for fans of non-current analog equipment. The library for Denon is here.
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.
Dear Zargon: +++++ " Is this TT worth the time and effort? " +++++

yes, the reward is a beautiful one.

I own both units 80/75 and is very hard to say which one is more neutral due that both are similar and almost the same.
Differences are that the 80 has a pitch control that the 75 has not and that the mat are different: the one on the 80 seems more " dense ", anyway I don't use those mats.

Like in the SP-10 the Denon original plinths are not the best way to go so is here where you have to work to achieve a top quality performance.

I use two similar but different material build on these Denons: one is made from real marble ( a beautiful green one ) and the other from Onyx, I think that each plinth weight s around 60-70 lbs that as a fact function like " arm board " because the TTs " seats " on three ( small )polymer/plastic blend tip toe like a top the stone plinths and the plinths goes over AT pneumatic footers.

+++++ " I would be comparing it to my belt drive TERES. " +++++

you will be surprised how good are those Denons.
IMHO it is a good " move " to have two totally different TTs ( Teres/Denon ) .

Are at the same level that the Sp-10?, well IMHO they are aand are better looking " boys " due that the Denons were designed for people like you or me and not to radio-studio like the Technics ones where the " cosmetics " was not so important but even the DP-100 ( studo version ) is way better " looking " than the Technics MK2/3.

IMHO Denon has nothing to " envy " not only to Technics but to any other unit out there.

Regards and enjoy the music.
I am far from an expert on these, but i have done some reading on them. My speculation on the 75, and this comes from comparing original pricing, brochures, sales method, specs, embedded technology, etc, is that after 5+ years of making the DP-80 and seeing it become something of a hit, they had come up with some slight technological improvements in platter and chassis to reduce rumble a bit more, and as Japan was entering a disposable income boom and doodadegadgetry was king, it was a great thing to add to the line-up. Voila! The younger brother to the DP-80 coming of age. Unit costs were much lower mostly because fixed costs had been amortized already, but based on a suspicious lack of info about the DP-75 motor, and the few specs I see, I suspect the DP-75 motor had a fair bit less torque than the DP-80, and while I do not know for sure, I think the DP-75 had fewer manual override possibilities than the DP-80. This table appealed both to the crowd who had not already replaced their DP-3000 and DP-6000 with the DP-80 over the previous 6yrs (it was too expensive, etc) and to the people who wanted to hit a certain price point vs income. With the DP-75, one got almost the same thing, and better specs to boot, for about 30% less (table only), so just like the top top end of digital cameras these days when technological obsolescence happens much faster, manufacturers keep just a bit back on model numbers offered with a lower price point, just to stay sane. Only after the deceased has been respectably buried do they offer better-in-all-ways technology for less money.

I own neither, and offhand, if I really wanted to choose one of those two only, I would buy both and try them in the same plinth, keep one and sell the other. I have no further basis to go on than that for deciding which one I would prefer. I can say that the DP-80 is iconic, because it was the first of the 3-phase motor split-platter construction Denons made to dramatically reduce acoustic feedback-induced resonances, and while icons are not always better performers than their descendants, they are icons, and that has some value to some people.
Thanks Raul, for chiming in and filling in the blanks. The lack of manual pitch control was the one I thought was the case (does it have screws underneath to control that way like some of its contemporaries which had pitch control underneath as well?)
Dear T bone: No, the pitch control is on top in the right side of metal ring, as a fact are two knob/button: one to swith from automatic/manual and the button to change ( +,- ) the pitch.

The other difference between the 75/80 is that the 80 torque is bigger/strong.

Regards and enjoy the music.
Thanks for your insightful contribution and your encouragement for going forward with the DP 80 project. Any way you could share a picture of these TTs and plinths?

Your research seems to have clearly resolved the who came first discussion. While it is an interesting experiment, I probably won't acquire both, but will use that money on a DIY plinth.

I appreciate the information and cautions of others in terms of what possible problems to avoid when buying.
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.
Hi Lewm,
I think you can fabricate an alloy plinth something similar to mine for my JVC motor unit. Those legs are used as tonearm mounting pillars and can be adjusted for height. They are also fitted with Audio Technica insulators at the bottom.


Dear Lewm: I own the DK300 and is a little better than the one that comes with the 75 but IMHO these plinths are the weak link on the quality Denon performance.

Regards and enjoy the music.
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.
Hi lewm,
It looks like the Micro Seiki because that was the inspiration come from. I didn’t have the ability to do it but someone else did. One could simply take one’s design and ask a metal fabricator to accomplish the project, at a cost. By the way, I shouldn’t have called it a plinth but a support or base, may be a supporting base would be more appropriate. It is my perception that a plinth of any material will anyhow contribute a sort of sonic signature, if not distortion, to the sound. So a plinth-less design was a way to overcome and reduce the amount of sonic coloration that would be introduced, I could be wrong.
Here are some more photos of the base:-



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.
Lewm, can you provide a link(s) to the pro/con discussion of a plinth for DD tables? My quick look can not seem to find it. Thanks.
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.
As regarding to my plinth-less support, I am thinking to add a lining of sorbothane and sandwich between the skeleton base and motor unit to further improve the isolation and resistance to shocks and vibrations from other sources.
I have done another approach to my other turntable "the SP 15" with reasonable success by using acrylic for the plinth material which was not difficult to cut and drill. Also it was aesthetic appealing and was my main concern at the first place. I did think about using slate but it would be prohibitive costly, if feasible for those with deeper pockets. Actually if I were choosing a plinth for my DP80, I would choose slate as my priority though.

My three armed SP15:-


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.)

I have owned my DP80/dk300 for 6 weeks now along with a Koetsu SA1100 special edition tonearm. I am running a re-tipped and nuded Denon 103, this rig is my last stand at analogue nirvana and I'm deeply impressed so far.

I am looking at developing a new plinth, for reasons that are discussed above, also as the footers on the dk300 are nothing more than threaded alu blocks encased in plastic with felt attached to the bottom. I'm really interested in a substantial slate plinth, but as kcc123 says, it's cost prohibitive. I'm off to some reclamation yards this weekend to try and source some slabs.

My second option is to go for a massive layered plywood jobbie, with maybe a sheet of SDS isophonon as the top layer, although I feel the slightly textured finish of the sheet may be a concern for coupling to the underside of the chassis. My previous deck was a KAB modified SL1210 and for that I built a solid wood plinth surround (box) that contained an inch of silver sand and granite slab for the deck to sit on, this is also an option, but I really want to go all out for the slate solution, however, getting 4 inches depth along with cutouts, coupling holes and finishing is no mean feat.

I have also sourced some butyl rubber speaker damping compound to apply under the 'skirt' of the chassis.

Look forward to any theories you guys may have for suitable solid or cld plinths.
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.