Denon VL12 tonearm geometry design concept unclear

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Canaris
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Denon VL12 tonearm geometry design concept unclear

Post by Canaris » 19 Nov 2019 17:52

I wonder what theory stood behind Denon VL12 tonearm geometry design in order to obtain optimal two null points cartridge (stylus and cantilever) alignment? If we are to follow the published specifications the result is more than disappointing, leading to tracking errors of about 11 degrees, which may be a serious design flaw.

The only way of achieving optimal two null points alignment seems to be as follows:

- increase the offset angle by twisting the cartridge about 4.5 degrees, which is quite a lot, in order to obtain an offset angle of 25 degrees.
- adjust the overhang to about 20 mm in order to shorten the tonearm effective length

The assumptions made in here are as follows:

- effective length: 238.76 mm (according to the official published specifications)
- overhang: 25.4 mm (according to the official published specifications)
- mounting point (spindle to pivot point length): 213.36 mm (deduced value by subtracting the overhang from the effective length)
- tonearm offset angle: 20.5 degrees

If the official published specifications are wrong and someone has the correct specifications, please, feel free to post them.

Japi Roelofs
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Re: Denon VL12 tonearm geometry design concept unclear

Post by Japi Roelofs » 19 Nov 2019 22:20

Hi and welcome to the forum

It looks like the specifications provided by Denon are wrong. Entering these numbers in the Tonearm Alignment Calculator produces an alignment scheme that is completely off the charts.

Your best bet is to measure the spindle to pivot distance yourself.

Canaris
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Re: Denon VL12 tonearm geometry design concept unclear

Post by Canaris » 20 Nov 2019 06:09

I don't own the VL12 yet, so I can't perform measurements on the unit myself. I try to compare the possible performance of different alignments for two tonearm geometries, before I decide to buy one of them. Because I mix music, I need two turntables, so, I can't spend close to 1000 euros on two units, only to find later that I am not satisfied with the tonearm geometry.
That's why I reach out for you help, in the hope that someone who already owns the VL12 might be able to provide the correct measurements.

Canaris
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Re: Denon VL12 tonearm geometry design concept unclear

Post by Canaris » 20 Nov 2019 08:52

After studying some pictures of VL12 from the official Denon DJ website, I tried to make some aproximate measurements from pictures and the results are as follows:
- tonearm mounting point (pivot to spindle distance): 228 mm
- offset angle: 20.5 degrees
- effective length: 238 mm (cartridge mounting screws in the middle of headshell slots)
- overhang: 10 mm (cartridge mounting screws in the middle of headshell slots)
- headshell slots length: 10 mm
The tonearm geometry seems to allow only for a Stevenson cartridge alignment with the following settings:
- overhang: 15 mm (maximum mounting point in headshell slots)
- effective length: 243 mm
- offset angle: 21.5 degrees
- tracking angle error: max. 2.08 degrees
- tracking distortion: max. 0.7 %
- average distortion: 0.5 %

Japi Roelofs
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Re: Denon VL12 tonearm geometry design concept unclear

Post by Japi Roelofs » 20 Nov 2019 11:18

I wouldn't worry too much about alignment. Since these DJ turntables are basically Technics clones, the tonearm geometry will be more or less similar to the standard Technics geometry too.

If you look at the other popular turntables (Audio Technica and Pioneer), you'll find they use the 230 mm effective length and 15 mm overhang scheme. Although the Denon looks a bit different, this is mainly due to the tonearm sitting a bit more to the side...
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Canaris
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Re: Denon VL12 tonearm geometry design concept unclear

Post by Canaris » 20 Nov 2019 11:56

I'm not worried about the fact that Denon chose to fit a different geometry tonearm on the VL12. On the contrary, they are to be commended for trying to offer something different. The question I had was about the purpose of this chosen geometry and the missing details from the published specifications.
Before making a purchase you want to acquire as much information as possible about a product performance in certain scenarios and to be able to compare it with other products.
When you buy a turntable designed for mixing music, you need two and the amount of money spent adds up. That's why you want to make at least an educated guess about a certain product. When I use the turntables for mixing music, not scratching, I care both about it's tracking abilities and the sound quality, the later being very important, because it is what keep the people dancing.

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Re: Denon VL12 tonearm geometry design concept unclear

Post by Japi Roelofs » 20 Nov 2019 17:30

The (admittedly quick and rough) drawings I made show that the Denon tonearm geometry isn't all that different from the other turntables. I made one drawing for the Pioneer, then copied it onto the other two. There might be a small difference of a couple of millimeters or degrees. My point being that it will be possible to align a cartridge any way you want — well maybe not Lofgren B as that puts the cartridge way out front.

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Re: Denon VL12 tonearm geometry design concept unclear

Post by Canaris » 20 Nov 2019 18:24

The approximated measurements from VL12 photo, indicates that the headshell slots length is about 10 mm.
If we use the whole length of the headshell slots for Stevenson alignment, then we are about 2 mm short on slots length in order to achieve Lofgren A, and almost 3 mm short for Lofgren B, so the only optimal alignment is Stevenson.

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Re: Denon VL12 tonearm geometry design concept unclear

Post by Japi Roelofs » 20 Nov 2019 18:32

If you say optimal, do you mean the cartridge sits in the middle of the headshell, i.e. screw heads in the middle of the slots?

In general, if a tonearm is designed for Stevenson, Baerwald can be achieved in most cases, unless the distance between the mounting bolts and the stylus tip is too small. So it depends on the cartridge.

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Re: Denon VL12 tonearm geometry design concept unclear

Post by Canaris » 20 Nov 2019 18:40

I used the term "optimal" in reference to the only 2 null points alignment possible, which in this case is Stevenson, with screws to the maximum mounting point.

Japi Roelofs
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Re: Denon VL12 tonearm geometry design concept unclear

Post by Japi Roelofs » 20 Nov 2019 20:42

Well, alright. I guess I'm not the right person to answer your questions, as I don't have this turntable myself.

I think it's safe to say that the specifications on the Denon website are incorrect. The long overhang figure combined with the shallow offset angle make proper alignment impossible in any shape or form.

Measuring these parameters yourself from a picture on the website doesn't seem very accurate either.

What you could do is check this thread here: viewtopic.php?t=97400, where actual owners of the Denon VL12 discuss it. I noticed a comment of one poster saying he aligned his cartridge using a Baerwald protractor.
Perhaps you can ask the question there, and maybe someone might be willing to do actual measurements of the pivot to spindle distance and effective length.

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Re: Denon VL12 tonearm geometry design concept unclear

Post by PseudoShooter » 24 Nov 2019 13:09

I am running an Ortofon 2M blue cart and I originally had to twist it to line up. I wasn't happy with that and revisited my alignment a few days later. I was able to get it aligned properly by pushing the cart all the way to the rear of the head shell.
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Canaris
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Re: Denon VL12 tonearm geometry design concept unclear

Post by Canaris » 24 Nov 2019 13:45

PseudoShooter wrote:
24 Nov 2019 13:09
I am running an Ortofon 2M blue cart and I originally had to twist it to line up. I wasn't happy with that and revisited my alignment a few days later. I was able to get it aligned properly by pushing the cart all the way to the rear of the head shell.
From the picture you posted I assume you don't use the VL12 for mixing music. I am a DJ and I intend to buy a pair of VL12s in the near future, so, I would like to hear your feedback on some issues, if you please. For how long do you own the VL12? How do you find its bearings performance and the pitch fader operation? Do you have a "dead zone" around the zero position of the pitch fader?
Thank you kindly!

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Re: Denon VL12 tonearm geometry design concept unclear

Post by PseudoShooter » 24 Nov 2019 15:35

Hey! I've had the turntable for almost a year now.

I use it solely for home audio so I've never used the pitch fader function. The bearings seem very nice and it is rock solid on speed. The platter is extremely heavy but it starts and stops almost instantly.

The only issue I've had so far is a very low motor hum but it hasn't changed in pitch or volume so I assume it's normal operation.

There are a lot of DJ reviews on YouTube about this TT too.

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