The Korf Blog

The inside story: our research, development and opinions

20 March 2019
Headshell Performance — Audio Technica AT-LH13
In this series of articles, we measure the performance of removeable tonearm headshells. Today, the subject is an Audio Technica AT-LH13.

The headshell is made of AT's proprietary "technihard" aluminium alloy and weighs 13 gram without wires or mounting screws. The fingerlift is stamped steel.

The headshell consists of 2 parts: the shell itself, that is bead-blasted and anodized, and the stub with the connectors. The stub is fixed in the shell with an adjustable collar. This allows for (very fiddly and imprecise) overhang and azimuth adjustment.
Lack of any through holes makes attaching an accelerometer a child's play. For this and subsequent headshells, we will not be removing the fingerlift for measurements.

Before we go into the spectrograms and waterfall charts, please have a look at the oscilloscope trace of the AT-LH13's IET measurement. I have included the ones from Nagaoka AL-703 and SME 3009 for comparison.
SME 3009
The difference is significant. Even the main resonant mode of AT-LH13 is immediately extinguished.

Here's the spectrogram, and you can drag the vertical white line to compare it to Nagaoka AL-703 we measured in the previous post.
There are just 2 pronounced modes, and both are high frequency: 7 and 15 kHz. The engineering efforts towards more rigidity paid off.

The right scale on the charts is different because I needed to normalize the IET measurements for equal peak-to-peak amplitude.
The waterfall plot is nice and flat, as expected. It's all over by 100 milliseconds:

Here are the results of the IET measurement with a Technics EPC-U24 cartridge attached. These must be taken with a grain of salt because I couldn't mount it tightly enough using AT-LH13's threaded holes.
Same resonances as with a Nagaoka, only with lower Q and dying much quicker.
There are significant measured performance differences even with broadly similar headshells
Based on today's results, I think we can say that there are significant measured performance differences even with headshells made of similar materials and of broadly similar design. The small things like slots and the type of bayonet SME/JIS connector used matter.

In the case of AT-LH13, we saw how a few relatively inexpensive engineering decisions raised the performance a lot higher than I expected. Well done, Audio Technica!
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