Vintage Denon Direct Drive Turntable

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.