How long before your cartridge warms up?

Hi Audiofun, all:

The fundamental cause is that cartridge suspensions (particularly the elastomer dampers) change in mechanical characteristics as a function of operating temperature, and these characteristics also change with humidity. The temperature dependency is why you will see references to "temperature-stable" suspension and damping systems in cartridge literature from Denon, Highphonic and others.

The 11th figure on the following page compares the temperature dependency of Denon's DL-1000A with other cartridges (presumably also Denon-made).

https://www.denon.jp/jp/museum/products/dl1000a.html

Although "temperature-stable" suspensions are less temperature dependent than other suspensions, they are not completely temperature independent. Some effect of temperature on cartridge performance still remains (and you can see this in the same Denon figure).

In my own experience, silicon rubber does combine acceptable damping performance with temperature stability, but it tends to not sound very good, so you probably won't find many cartridge designers using it.

The manufacturer of your cartridge may specify a preferred operating temperature and relative humidity. Chances are that you will be able to reduce the warm-up time and get better sound overall if you heed those recommendations.

FWIW, the frequency response of phono cartridges also changes depending on the LP groove radius - the deeper the cartridge goes in towards the label area, the more the top frequencies will be attenuated (by enough to be clearly measurable).

kind regards, jonathan

Hi Doug: your experience with altered VTF for different operating temperature is worthwhile, but with one caveat.

Increasing the VTF will make tracking more secure and bring the SRA back to where it should be, but it will not compensate for temperature-driven deviations in measured frequency response. To correct that, I don't believe that there is any alternative to setting the room temperature to whatever the cartridge manufacturer recommends.

OTOH, since the measured frequency response at the outer bands of the LP will almost certainly be different from the frequency response at the inner bands, perhaps it is not such an important thing to quibble over.

(I have been re-reading a white paper that the Entre company published for their EC-25 cartridge series, which includes graphs showing the differences between outer-groove response and inner-groove response. The outer-inner difference that Entre reported was between 6-7dB for a Japanese-made test record, and it looks to be about 13dB for a test record made in either the US or Europe.)

kind regards, jonathan

PS. Recommendation for Lyra owners - our preferred operating range calls for temperatures of 22-23 degrees centigrade, and a relative humidity of 58-60%.