The Korf Blog

The inside story: our research, development and opinions

1 October 2019
Is This the Best Headshell in the World?
We've ended our last post with a question:

"Is it possible to build a headshell that'll be twice as good as the already excellent Orsonic AV-101b?"


Of course it's possible, given an unlimited budget. There are lots of exotic materials and fabrication techniques that aren't used in consumer devices purely because of their cost. A single aerospace-grade part can easily cost $25000 to manufacture, and that is before the profit margin!

But if we stay within the typical price range of a quality headshell, can we significantly improve on Orsonic's measured performance? Or is it still the state of the art?

There's a mystery headshell on my lab desk that I can't show you yet. But I have done all its measurements and will share them today. You decide whether it really is good enough to be world's best, but among those that we've measured it is without peers.
Measurements
Sorry for having to disguise the headshell, but it must remain hidden for the time being. It weighs 9.5 grams without the wires and fingerlift.

We're using a Denon DL-103 cartridge as it is a bit more challenging, and its vibration profile highlights the problems better.

All other testing conditions remain the same:

  • GrooveMaster II tonearm
  • TechDAS AF 3 turntable
  • Playing back the vertically modulated 20 Hz to 20 kHz sweep from a test LP
  • 2 accelerometers are recording the vertical acceleration: one at the headshell, and one on the armtube.

The first chart shows the measurements taken at headshells.

(please ignore the 150 Hz peak, it's the 3rd harmonic of 50 Hz on a noisy DAQ channel)
You can see the broad similarity of resonant picture with the Orsonic and our mystery headshell. But the extent of those resonances differs by the factor of two. The high frequency resonance doesn't have the data labels as the accelerometer's own frequency makes the comparisons highly non-linear.

The second chart shows the accelerometer readings at the arm tube.
Same story as at the headshell. The mystery headshell does almost everything Orsonic does, only a lot better.

We have also done IET measurements of the mystery headshell. First, here's the oscilloscope trace of its ringing after being hit by a calibrated weight (and Orsonic's trace for comparison):
Mystery
Orsonic AV-101b
Here's the spectrogram of the mystery headshell. Drag the white vertical line to compare it to Orsonic's.
While the main resonance looks more or less the same, lack of high frequency excitation is noticeable.

The waterfall chart holds no surprises. Everything's nice and smooth and over by 110 milliseconds.
Here's what happens if we attach a Technics EPC-U24 cartridge:
There's just one lonely 3 kHz peak. The picture of resonances is noticeably clearer with the mystery headshell.
The mystery headshell offers twice the measured performance of Orsonic during playback

To sum the measurements up, our mystery headshell

  • does offer twice the measured performance of Orsonic AV-101b when taken at the tonearm during actual playback
  • more than matches its performance in the IET tests

So what is this mystery headshell?
It was designed and built by Korf Audio as a demonstrator of what is possible when the classic analogue reproduction technology meets today's advanced design tools, materials and manufacturing techniques.

In the coming series of posts, you'll be able to see some steps of its design process, from material selection to the use of 3D printing in prototyping. I can't promise to show you everything, but I will try to make this little excursion into the Korf Audio lab interesting.

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