Hi George,
At a first glance it looks quite sophisticated, but as mentioned before, there is not one size that fits all and that's what you see here.
What makes it still look rather good is the fact that the vertical scale is not logarithmic but linear. Not corresponding to the way we perceive sound.
I simulated their findings, and came with comparable results for a counterweight tuned at 6.4Hz.
The results, but now on a logarithmic scale are visible at the image below.
With their Arm/Cart combo's having a very high Fres peak of ca 15 dB, the damping is in no case more than ca. 3 dB.
With a better damped Cart, damping result would be even (far) less.
Hans
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Here is another interesting read about turntable speed. Make sure to read the comments from Mat Weisfeld and Ortofan.
Exclusive: One Week With Technics' New SL-1000R Direct Drive Turntable | Analog Planet
Exclusive: One Week With Technics' New SL-1000R Direct Drive Turntable | Analog Planet
And just to show the difference, this is how it would have been after fine tuning the spring rate and the damping within the counterweight, which of course is not within the possibilities of the real thing.
Damping has now more than doubled in dB's.
With damping I mean the height of the original peak at Fres versus the highest point in the damped curve.
Damping has now more than doubled in dB's.
With damping I mean the height of the original peak at Fres versus the highest point in the damped curve.
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Job well done as usual Hans !
Keep in mind, we are working on paper, they were working on a real product (specs, reliability, longevity) and a need to cover a whole range of cartridge compliance.
For a narrow range of cartridge compliance, the leaf spring and the elastomer damper can be twicked/optimised.
George
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Do you remember the humble NAD 5120? (actually a Tesla NC470)
https://worldwide.espacenet.com/pub...&FT=D&date=&CC=GB&NR=2110866A&KC=A&popup=true
George
https://worldwide.espacenet.com/pub...&FT=D&date=&CC=GB&NR=2110866A&KC=A&popup=true
George
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It's hard to believe that 30 years ago you could buy such an ingenious piece of engineering, protected by a patent, even including a turntable for 129,- GBP.
Hans
Regarding the low price of the NAD (it was 95 to 100 GBP) we can assume it was due to the benign influence of the priorities of Jiri Zanda.
The publishing/promotional establishment didn’t move an eyelid, the crowd wasn’t impressed, so we can safely assume that in the big arena, technological ingenuity is a waste of both time and effort when steered toward solving vinyl playback problems
(“I don’t see a problem”, or “don’t touch it, you’ll destroy that magical sound”)
George
The publishing/promotional establishment didn’t move an eyelid, the crowd wasn’t impressed, so we can safely assume that in the big arena, technological ingenuity is a waste of both time and effort when steered toward solving vinyl playback problems
(“I don’t see a problem”, or “don’t touch it, you’ll destroy that magical sound”)
George
Does anyone remember if this is the arm that Martin Colloms (?) measured with an accelerometer and found a 300Hz flexural mode?
This must be it Scott, as it was the only flexible arm then.
NAD offered the 5120 with two versions of tone arms: either with the flexible wand or with a typical alum tubular wand but kept the fluid damper and suspended mass on both. The arm assembly was plug-able. You could have one arm set for one cartridge.
The tubular arm was identical with the arm of the Lenco L-800.
One day I will get a friend’s 5120 with the flexible arm for some bench tests.
George
NAD offered the 5120 with two versions of tone arms: either with the flexible wand or with a typical alum tubular wand but kept the fluid damper and suspended mass on both. The arm assembly was plug-able. You could have one arm set for one cartridge.
The tubular arm was identical with the arm of the Lenco L-800.
One day I will get a friend’s 5120 with the flexible arm for some bench tests.
George
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And some more about "The ugly duckling" from 1984 (sorry it was reviewed in the Hungarian audio magazine, but some online translation service might be able to translate the text to English):
Introducing
Introducing
Thank you Laszlo.
Unfortunatelly the Google translate needs some more work for to produce meaningful results.
Can you please describe only what is under the heading "Méréseinkhez" (measurements) ?
And here is what Audio magazine had to say about this TT (pages 34-40)
http://www.americanradiohistory.com/Archive-Audio/80s/Audio-1984-02.pdf
George
Unfortunatelly the Google translate needs some more work for to produce meaningful results.
Can you please describe only what is under the heading "Méréseinkhez" (measurements) ?
And here is what Audio magazine had to say about this TT (pages 34-40)
http://www.americanradiohistory.com/Archive-Audio/80s/Audio-1984-02.pdf
George
What to think of this image from the Hungarian test, resp. a Panasonic, a Pioneer and the NAD 5120 TT ?
No time scale (55 Hz square wave ?) and no amplitude, but the NAD does seem to be the worst damped of the three, resonating with a seemingly high frequency (1 Khz ?)
A translation could help to better understanding .
Hans
No time scale (55 Hz square wave ?) and no amplitude, but the NAD does seem to be the worst damped of the three, resonating with a seemingly high frequency (1 Khz ?)
A translation could help to better understanding .
Hans
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Quick translation:
The measured data of the turntable are nothing special. The speed is accurate, the wow is higher than what today's modern machines produce, but still better than the rather modest factory specs. The noise is average. Interestingly the acoustic feedback curve is not nice either, we expected better from this machine. Not that the unwanted signal is too high, but it occurs in a rather broad band (20-55 Hz), and it even shows up beyond 10 kHz again.
We do not want to comment the frequency plot: we had a Tesla VM2102 pickup in our test sample, and we know that from the NC450 turntable test. The current curves are quite similar to those of the past.
The effect of the damping device can be measured very well. In order to demonstrate it, we gave 5 graphs instead of a single one on fig.12. On the flat arm first we set the damping to Q=2, then we started changing the resonance frequency. We got the upper graph at 7, the lower at 14 Hz. On the top graph hardly any peak — well known from the vast majority of turntables — can be seen. On the bottom curve the system is detuned, the shape of resonance resembles to what we know, apart from the dip at 7.5 Hz. Next we kept the frequency constant (around 9-10 Hz), and varied the damping: first disabled it (upper graph), that set it high (Q=2), resulting more even graph with less resonances. The last graph was taken from the tubular arm (resonance freq = 10 Hz, Q=2). The resonance remained moderate again. As we can see, the DVA system is really effective.
Graph 9 and 10: frequency plot and crosstalk, L and R
Graph 11: Acoustic feedback
Graph 12: left upper: Q=2, f=7Hz, left lower: Q=2, f=14Hz; middle upper: Q=0, f=10Hz, middle lower: Q=2, f=10Hz; right lower: tubular arm Q=2, f=10Hz
Square waves are at 1kHz
My comment is that the flexible flat arm (made of PCB
) is not the best idea. I prefer a lightweight but rigid arm.
The measured data of the turntable are nothing special. The speed is accurate, the wow is higher than what today's modern machines produce, but still better than the rather modest factory specs. The noise is average. Interestingly the acoustic feedback curve is not nice either, we expected better from this machine. Not that the unwanted signal is too high, but it occurs in a rather broad band (20-55 Hz), and it even shows up beyond 10 kHz again.
We do not want to comment the frequency plot: we had a Tesla VM2102 pickup in our test sample, and we know that from the NC450 turntable test. The current curves are quite similar to those of the past.
The effect of the damping device can be measured very well. In order to demonstrate it, we gave 5 graphs instead of a single one on fig.12. On the flat arm first we set the damping to Q=2, then we started changing the resonance frequency. We got the upper graph at 7, the lower at 14 Hz. On the top graph hardly any peak — well known from the vast majority of turntables — can be seen. On the bottom curve the system is detuned, the shape of resonance resembles to what we know, apart from the dip at 7.5 Hz. Next we kept the frequency constant (around 9-10 Hz), and varied the damping: first disabled it (upper graph), that set it high (Q=2), resulting more even graph with less resonances. The last graph was taken from the tubular arm (resonance freq = 10 Hz, Q=2). The resonance remained moderate again. As we can see, the DVA system is really effective.
Graph 9 and 10: frequency plot and crosstalk, L and R
Graph 11: Acoustic feedback
Graph 12: left upper: Q=2, f=7Hz, left lower: Q=2, f=14Hz; middle upper: Q=0, f=10Hz, middle lower: Q=2, f=10Hz; right lower: tubular arm Q=2, f=10Hz
Square waves are at 1kHz
My comment is that the flexible flat arm (made of PCB
) is not the best idea. I prefer a lightweight but rigid arm.
Last edited:
Thanks Hans for explanation. And others for great links and information.
-x-x-x-
The NAD and Dual tonearms are wonderful. Specially Dual. NAD tonearm Patent link it says on page 9 (?) due to flat strip of tonearm the horizontal yield of resonance is very virtually zero. If vibration/resonance energy can only be transferred how come horizontal resonance/vibration yields to zero ?
How about using Rochelle Salt as damping material ? We can drain the energy by using this material by bulb, resistor or other load.
Regards.
-x-x-x-
The NAD and Dual tonearms are wonderful. Specially Dual. NAD tonearm Patent link it says on page 9 (?) due to flat strip of tonearm the horizontal yield of resonance is very virtually zero. If vibration/resonance energy can only be transferred how come horizontal resonance/vibration yields to zero ?
How about using Rochelle Salt as damping material ? We can drain the energy by using this material by bulb, resistor or other load.
Regards.
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