Fun with vinyl measurements

[stereoplay]

Hello,

as I posted before, I tried a new approach to measure Wow&Flutter and failed.

I used a optical encoder disc with 2000cpr:

Setup on a real turntable:

But the encoder is not precise enough to obtain noise-free measurements.

So in the next step I will try it with a gyroscope, very similiar to that Shaknspin gadget.

 

[stereoplay]

As said before I built my own "Shaknspin" device. I fixed all components on a 12" disc with hotmelt glue...

Data transfer is done via WLAN with a high 3,33KHz sampling rate.

I transfered the measurement results in my software and I really must say: The results are much better than with a test record.

I attached four turntables:

• Hitachi HT-51
• Mitsubishi LT-10
• Denon DP-30L
• Grundig PS4500

 

[stereoplay]

I improved the measurement technique and canceled out the noise who is specified in the gyroscope specs (0,0038dps/sqrtHz).

 

[JP]

Can you do just 2-4 revolutions on the polar and use a different color for each rev? It’s very difficult to interpret as-is.

 

[stereoplay]

I will check this out.

 

[stereoplay]

I also measured on these 3 turntables the rumble applying different weighting standards. Measurements are done with a "Rumpelmesskoppler".
Spectra are shown left, right, lateral and vertical. Reference is 315Hz/5,4cm.

Maybe this is also interesting.

 

[stereoplay]

I did some improvements in presenting the measurements as suggested. The polar plot was also not scaled correct.

I'm really impressed by the performance of my good old Denon DP-30L.
Next few days I will post also a Grundig PS-4500, Pioneer PL-1000, JVC QL-55Y and Micro Seiki RX-2000...

 

[JP]

Much easier to read.

 

[stereoplay]

Here are the results for a Pioneer PL-1000, JVC QL-55Y and Micro Seiki RX-2000...

The Seiki is driven by a string, so it is no wonder that we see more low frequent wow than usual as a direct driven platter.

 

[Balle Clorin]

Fantastic, You should consider selling the hardware and software. If the software accepts CSV data it could even be used with the Shaknspin

I overlaid my Gyro SE, data from Shaknspin, quite similar performance( I used 20Hz low pass filter on the Shakenspin data, assuming your plot had the dame filter) as the Hitachi HT-51. Noise that the Shaknspin gyrosensor is quite noisy

 

[Balle Clorin]

Checking RIAA with and without Step up trafo, no difference in frequency response

 

[dlaloum]

Checking RIAA with and without Step up trafo, no difference in frequency response
View attachment 186070

Cantilever resonance at circa 12kHz?

 

[Balle Clorin]

The typical resonance that all MC carts have.
Fits my old ears nicely…
added AT measurement too in post above

 

[dlaloum]

It need not be so....

Look at the Dynavector Karat:

DV KARAT 17DX | MC Phono Cartridge | Dynavector International Site

The main change to the new Dynavector 17D3 is an improvement in the design of the front yoke. This appears, on the surface, to be a small difference yet contributes to a greatly improved overall performance justifying a model number change. The new yoke improves focus in the magnetic circuit and...

www.dynavector.com

Exempary totaly neutral performance from an MC - quite rare!

It is achieved by getting the cantilever mass down very very low - pushing the cantilever resonance up very high (can't recall exactly, but in the back of my mind a figure like 50khz is saying something...)

This is achieved by the cantilever length being all of 1.7mm ( as opposed to the normal 6mm) - it is also a diamond rod .... but IMO it could have been an old fashioned aluminium tube, and it would still be excellent... the main gain is from shortness!

 

[sergeauckland]

It need not be so....

Look at the Dynavector Karat:

DV KARAT 17DX | MC Phono Cartridge | Dynavector International Site

The main change to the new Dynavector 17D3 is an improvement in the design of the front yoke. This appears, on the surface, to be a small difference yet contributes to a greatly improved overall performance justifying a model number change. The new yoke improves focus in the magnetic circuit and...

www.dynavector.com

Exempary totaly neutral performance from an MC - quite rare!

It is achieved by getting the cantilever mass down very very low - pushing the cantilever resonance up very high (can't recall exactly, but in the back of my mind a figure like 50khz is saying something...)

This is achieved by the cantilever length being all of 1.7mm ( as opposed to the normal 6mm) - it is also a diamond rod .... but IMO it could have been an old fashioned aluminium tube, and it would still be excellent... the main gain is from shortness!

Indeed, the frequency response is commendably flat, but the distortion in the vertical direction, i.e. in the L-R, is higher than other cartridges due to the increased tracking angle error as the short cantilever moves up and down.
Similar error with the cantilever-less Decca cartridges where in addition there's a stylus rotation, so with vinyl, there doesn't seem to be a way of getting 'perfection', it's just a choice of which imperfection to minimise at the expense of another.

S

 

[dlaloum]

Yes, it is always a balance between competing variables... the joy of vinyl!

Getting the best from an ultra short cantilever solution requires an excellently engineered arm, with good (and judiciously applied) damping - but then that applies to all setups.

In any case the actual measured distortion when tested on the Karat have been markedly lower than alternative MC designs! - a benefit of NOT having the cantilever resonance in the audible range (typically the cantilever resonance will add 2%+ THD - so moving it to 40Khz+ is a very good thing!)

Do you have some measurements that reflect the vertical direction distortion?

Here are a bunch of period reviews of the Karat (earlier model with "long" cantilever - 2.3mm !)

Dynavector Karat Diamond

Dynavector Karat Read more about cartridge, diamond, dynavector, karat, cantilever and ruby.

www.yumpu.com

 

[Hayabusa]

As said before I built my own "Shaknspin" device. I fixed all components on a 12" disc with hotmelt glue...

Data transfer is done via WLAN with a high 3,33KHz sampling rate.

View attachment 166906

I transfered the measurement results in my software and I really must say: The results are much better than with a test record.

I attached four turntables:

• Hitachi HT-51
• Mitsubishi LT-10
• Denon DP-30L
• Grundig PS4500

Nice!, so what does it do? This is a high speed sampling 3 axis acceleration sensor?

 

[sergeauckland]

Yes, it is always a balance between competing variables... the joy of vinyl!

Getting the best from an ultra short cantilever solution requires an excellently engineered arm, with good (and judiciously applied) damping - but then that applies to all setups.

In any case the actual measured distortion when tested on the Karat have been markedly lower than alternative MC designs! - a benefit of NOT having the cantilever resonance in the audible range (typically the cantilever resonance will add 2%+ THD - so moving it to 40Khz+ is a very good thing!)

Do you have some measurements that reflect the vertical direction distortion?

Here are a bunch of period reviews of the Karat (earlier model with "long" cantilever - 2.3mm !)

Dynavector Karat Diamond

Dynavector Karat Read more about cartridge, diamond, dynavector, karat, cantilever and ruby.

www.yumpu.com

The measurements I've seen come from the 1982 HiFi Choice book of Cartridges and headphones, by Martin Colloms. The Dynavector Karat Diamond DV17D with a 1.7mm cantilever showed VTA of 27° which resulted in 2.9% vertical distortion even at 300Hz, at only +6dB above 5cm/sec, but only 0.9% horizontal distortion at +9dB, also at 300Hz.
The comment was
"Distortion was higher than usual for the price, and the high levels on vertical, single or IM tone signals betrayed a serious weakness in vertical linearity".


S

 

[dlaloum]

If you do a search through users experiences with the Karat - discussions about sensitivity to arm setup, VTF and VTA are commonplace.

Quite a few discuss having the arm adjusted to a slight negative angle (ie: base lower than head) to get the VTA optimal for the Karat.

I personally had to mess with it quite a bit, it is not in current rotation, and I do not recall the outcome ...

But yes - it requires unusual attention to VTA - and the default "level" setting of the arm, is not the optimal setting for this cartridge. - I don't believe that is a result of the short cantilever, but may be a result of the manufacturing methods and limitations - such as fixed needle angle on cantilever with cantilevers supplied with needles already mounted from the cantilever manufacturer, while the cartridge design was originally intended for a needle angle several degrees off the current production... (but I am guessing)

 

[RayKay]

It need not be so....

Look at the Dynavector Karat:

DV KARAT 17DX | MC Phono Cartridge | Dynavector International Site

The main change to the new Dynavector 17D3 is an improvement in the design of the front yoke. This appears, on the surface, to be a small difference yet contributes to a greatly improved overall performance justifying a model number change. The new yoke improves focus in the magnetic circuit and...

www.dynavector.com

Exempary totaly neutral performance from an MC - quite rare!

It is achieved by getting the cantilever mass down very very low - pushing the cantilever resonance up very high (can't recall exactly, but in the back of my mind a figure like 50khz is saying something...)

This is achieved by the cantilever length being all of 1.7mm ( as opposed to the normal 6mm) - it is also a diamond rod .... but IMO it could have been an old fashioned aluminium tube, and it would still be excellent... the main gain is from shortness!

Yes, Dynavector uses a very short 1.7mm diamond rod:

But the Bang & Olufsen MMC 6000 uses a comparatively long (x? mm) beryllium cantilever (I can’t find many good photos of this and, unfortunately, the diamond tip is missing on this specimen):

And a calibration plot for a typical production unit shows exemplary response to 40K:

Once again, success comes from the synergy of the complete system rather than the advanced strength of an individual design feature.