Plinth ideas for DENON PD-80 DD turntable

Yes. It was first time too, with no manual, but it’s not hard, just common sense. I DID make mistakes reassembling — alignment and centering, as I mention above — but they were easy to correct. Example: I didn’t center the two-part platter correctly. But the fix was simple: equal-thickness paper shims (spacers) at 5 points around the gap — same way as I center a speaker’s voice-coil in the magnet’s gap.

Also, choosing the new foam was a bit of guesswork: no details were available. I had a few on hand to choose from. Width was easy: if it fits the spaces where the pads go, it’s ok. I then chose highish density (it’s not specified on the packaging) with what seemed sufficient thickness, so it would compress when I tightened the Allen bolts, but not compress too much, retaining the "give" it needs to absorb vibration. It seems to do the job.

Two other easy tips... The gap should be checked between the fixed tape read-head and the moving magnetic-strip on the platter (1000 signals per rev — that’s about 2000 per second: very accurate). My gap was WAY off when I got it.

It’s easy to set. I used a precision feeler gauge, but even the Service Manual (which I got later) says just to use a business card. After reading that, I went back and checked the gap I’d set "precisely" with a gauge, this time with a business card — and the card was spot-on.

Checks yours with a card. If it’s too wide or too narrow, there’s only one screw to loosen, you’ll see it — set gap with card — not too tight, just so you can remove the card without a struggle — then retighten screw. Easy.

BUT at all times be SUPER-CAREFUL of that magnetic-strip. I don’t even touch it (skin-oils etc).

One more: when the platter is removed, you’ll see a small electrical switch. It’s marked 50Hz or 60Hz. Set for your local system of course. BUT the switch is a bit misleading: it LOOKS like a slide-switch, and the labeling (50 vs 60) reinforces this false impression. But it’s really a push-switch — DOWN is 50Hz, UP is 60Hz. (I mention it because mine was set wrong when I got it.)

I assume you know it’s a 100V unit (unless yours is special) so a step-down transformer is VITAL, especially in 220-240V territory. It needn’t be a massive step-down: the current draw is minimal (mine has a 1-amp fuse, but it’s for US 117V). My step-down is small, easily hidden out of sight, and it’s worked fine for a decade.

Of course a pro would double-check everything with instruments, which I don’t have, but if the instruments detect a problem, it’s most likely with aging, out-of-spec components on the circuit boards, not the simple switch.

I hope this helps.

Thanks @bima I hope it will help our readers and users of DP-80

My unit was NOS, probably unused, i only did the correction of the spindle position by unscrewing 4 bolts from the bottom and tightening them again after checking the position of the platter by verifying the gap around the platter from the top side. My motor block with the spindle was a bit off-centered (probably in the shipping process), but it was very easy to fix.

The tape read-head is spot on and everything is just fine and rotation is nice and smooth (noise free).

I only think about the lubrication, i have the oil supplied for my ex Technis SP-10 mkII by KAB. I can definitely do that if it’s necessary. But how many drops of oil i have to add ? I remember for SP-10mkII the recommendation was just to use a few drops (maybe 6) ? @bpnaudio I wish to prevent leakage of the spindle oil all over the drive inside :))

Still not sure about the damping material inside the platter, they do not recommend (in the manual) to unscrew the platter. But if you did that yourself maybe i can do that too.

Direct link to the material we can buy for the platter would be nice.

Your all welcome

Clarification - the 50/60 Hz switch only function is to add capacitance to the motor capacitor nothing else.  And all units are 100V so a step-down transformer is required for long term reliability.  

Good Listening

Peter

Another useful trick was with 2 red screws (under the platter) to let the DP’s own transformer move down for an inch or so.

Of course, all my turntables (except 2) are 100 volt and i have 1000 watt step down transformer for japanese electronics, another 110 watt transformer for US made electronics. And the power socket produce 220/240 volt here :)

I am very well prepared for all voltage standards in the world. My step down transformers are heavy as two bricks each. They are, however, so called "auto transformers" and i’m thinking to upgrade one of them which connected to my First Watt 110v amp.

Local company just relesed the upgraded version of step down trans for audio, which is different from my classic auto-transtormer from that comany.

"Unlike the auto-transformer, the transformer provides galvanic isolation of the load circuit from the mains. The transformer acts as a filter for impulsive noise arising in the primary network."

Many local folks using Japanese Toyozumi transformers, but most of them are also auto-transformers.

My powerful stepdown transformers produce 50Hz, i’ve noticed the trick with DP-80 switch earlier when i received it and checked online, mine was set to 60Hz before.

Still not sure about the damping material inside the platter, they do not recommend (in the manual) to unscrew the platter. But if you did that yourself maybe i can do that too.

As I mentioned, I didn’t have the manual at the time. Denon no doubt preferred you take it to a trained Denon tech with all the parts and tools, but is that possible 40 years later? 

But removing those bolts/leaf-springs is the only way to renew the foam pads: you can't even see them otherwise (some owners don't know they're there). Even if your TT is NOS (lucky you!) I suspect they’re gone. Age and air destroy them, not years of use.

The thing is, the split-platter design really works! Before-and-After was a big difference, so I consider new pads essential. You can even "feel" the difference when you squeeze the two platters together.

Other split-platters (eg Linn, Thorens) only do it so the motor/pulley can be farther inboard, under the platter, allowing a smaller turntable. There’s no sonic benefit — though an easy mod can turn it into one.

There’s only one issue I’m aware of with the DP80: centering the platters when putting them back together. You know how to do that, and I described my method above.

There’s one other thing — retightening the bolts securing the leaf-springs. IIRC, they were torqued tight, and should be torqued tight when reassembled.

BUT I decided not to. I felt I understood the suspension principle after working on it, and chose a different tension for the leaf-springs.

But I won’t get into that: some people might jump on my head. If’s definitely a modification — whereas the pads are a simple replacement of failed old parts.