The Korf Blog

The inside story: our research, development and opinions

3 October 2017
We Measure a Rega RB300, Part I
We interrupt our regular broadcasting to bring you the measurements of probably the best known perfectionist tonearm in the world — the original Rega RB300. In Part I, we'll present the basic vibrational measurements. Part II would be dedicated to the spring downforce device and whether it influences the sound.

Our test subject is absolutely standard unmodified Rega RB300 with a factory counterweight. It was made in the early 2000's and is mounted on a Rega P3.

I've used the same Audio Technica AT7V cartridge to make the measurements comparable.

The first chart compares the RB300 data with that of SAEC WE-308L and the noname Chinese Rega clone.
As expected, the Rega really shines when it comes to the relative absense of main armtube resonances. It's also clear that Rega's counterweight design is good, the stub resonating at a high 2kHz. The bearings are also acceptable and, while not in the same league as SAEC's, ring a lot less than off-the-shelf ones in a Chinese copy of Rega.

What really surprised me are the headshell resonances. They are at least as bad as the noname copy, and worse than a cheap headshell I put on a SAEC. This chart cuts off earlier, but Rega's headshell also got very excited above the accelerometer's resonance frequency. The 17-18 kHz resonance drove a DAQ set to max out at 0.5G into clipping.
Here's the next comparison, with our own Prototype 5 (it's the closest to Rega in main arm tube resonances).
Yes, our design of counterweight stub looks unacceptable in comparison. But the Ortofon's bearings hold their own. And the headshell I've drawn in 30 minutes and haven't even simulated, measures twice as good as Rega's.

Based on the measurements, the most obvious way to improve a stock RB300 would be to chop off its headshell and replace it with a CNC design. Out of countless RB300 modders, how many offer this option? Exactly zero. No idea why.

Next week, Part II of the Rega RB300 measurements!
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