MC Phono Stage with Large Capacitance Load

（中文在後）Most MC phono stages do not offer variable capacitance loads. Even when they do, like my Tom Evans Groove+ SRX2, only offer values in the pF range. This phono stage from Chord is quite unique in providing an option to add 2.2uF to any impedance value. And such a large capacitance load indeed helps smooth the high frequency response of a typical MC cartridge, which was not observed before with pF-range values.

絕大多數MC唱放不提供調整電容負載，即使有，像我的Tom Evans唱放，可調值最大才到幾百pF。雖聽得出差別，但測量頻響時看不出差異。這台Chord唱放竟然可以在任何阻抗值，選擇加或不加2.2uF的大電容值。而在實際測量時真的看到，加了之後可以將MC唱頭高頻常見的上揚現象予以抑制。

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The effects of getting the natural resonance point of a cartridge/arm combo within the optimal 8 to 12Hz range, are demonstrated here not only just to avoid tracking issues with warped records, etc., but also clearly lowers the IMD distortion. Human ears are very sensitive to IMDs and such an obvious change will definitely alter the sound quality significantly.

控制唱頭/唱臂的低頻共振點，不只是要避免唱片不平或低頻音染的問題。在這唱臂測試過的唱頭都顯示，加質量（這裡用黏土）將共振點降到10Hz的最理想值，可以將IMD失真顯著地改善。人耳對IMD極敏感，如此大的數值差，一定會造成明顯的聽感差異。

Relationship between Cartridge Alignment and Channel Separation

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Chart#1 shows the azimuth adjustment process of a cartridge mounted with stylus at about 2mm off the optimal alignment position. Chart#2 is with precise alignment to the Loefgren B IEC formula. One can see the overall channel separation resulting in more than 3dB of differential.

有知名音響網紅曾說裝唱頭時，因為可用的切線很多種，隨便裝也沒關係。這裡的實驗顯示，調整精確與否，明顯影響到唱頭的分離度。圖1是針尖與最佳狀態的點差了約2mm時，調整azimuth的過程。圖2是精確地對準Loefgren B IEC 的點且針桿平行於線。可以看到整體分離度有3dB以上的差別。

AC noise from elevator

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AC noise generated from the building's elevator moving, is quite visible from Chart#2 compared to the baseline Chart#1. The so called "EMI Meter" from Green Wave also reports up to 1000mV of noise compared to the baseline's 46mv. Unfortunately, no AC filter including the one from Green Wave, or even an ISO transformer can block such noise.

建物裡的電梯動作時產生的電源污染，可以從比較兩個附圖裡看出。那個號稱測EMI的錶，也顯示超過數百甚至上1000的數值，比平靜時46高出很多。而且所有的濾波裝置，甚至隔離變壓器，對這種頻段的雜訊似乎都沒什麼效果。

Tracking Ability of an Old Decca Cartridge

（中文在後）The Decca family of cartridges are often said to have poor tracking ability. In fact, with proper anti-skate force, at least in standard tests they track better than many MC cartridges. But when they mis-track, the distortions are more offensive to ears. Here in the first spectrum chart taken when running a typical tracking test, the old SC4E shows the typical Decca-family behavior of having higher 3rd harmonic distortion which is less pleasant than the 2nd. This is just the opposite of most other cartridges. In the second chart, the SC4E is put through the maximum signal strength of +18dB and it still manages to play through the whole track with manageable distortion levels, better than many MC cartridges.

許多人說 Decca系列唱頭循軌不好。其實如果抗滑設定對，至少在標準循軌測試，會比許多MC唱頭的循軌表現好。主要問題是，它們的三次諧波失真比二次高，這與大多數唱頭相反。耳朵會比較容易聽到奇次失真，所以容易察覺它微小的循軌問題。第1個頻譜圖是正常強度的測試，顯示這典型Decca唱頭的失真行為。第2個圖是用最強的+18dB訊號測試，顯示這個老唱頭還可以相當穩定的唱完，而且整體失真還不差，不像一些MC唱頭會出現很不堪的波型。

AC Noise from Home Lighting

（中文在後）Among various lighting options for the listening room, LED bulbs (right) are probably better than the compact fluorescent type (left). As shown in the first AC spectrum chart, the fluorescent bulb creates visible noise spikes in the near 50kHz region as well as higher order harmonics. The 2nd chart is the baseline with no light turned on, and there's no visible difference when the LED type is used.

如果聆聽室的照明燈光有選擇的話，LED燈泡（右）應該會比小型日光燈泡（左）好。頻譜圖1顯示日光燈泡會產生50kHz附近的雜訊，而且還有更高的諧波。圖2是未開燈的數據，與用LED燈泡時幾乎無差異。

One reason why Decca-family cartridges are difficult

（中文在後）One reason why the Decca-family cartridges are difficult to tune optimally is the sizable gap between the lateral and vertical compliance numbers (Fig. 1). With most tonearms, the lateral resonance tend to be lower than the 8--12Hz ideal range (Fig. 2) while the vertical too high (Fig. 3). Adding/subtracting mass will aggravate the situation in either of the directions.

Decca系列唱頭很難調整好的其中一個原因是橫向與縱向的順服度差異大，如圖1。在多數唱臂，會造成橫向的共振頻率低於8到12Hz的理想值，而縱向會太高。而加/減質量都會造成其中一個方向惡化。