Many people think you just need enough gain and EQ for a phono preamp. They are wrong- there is more to it than that.Ticks and pops can be on the surface of the LP, but far more of them are caused by poorly designed phono equalizers that are unstable, resulting in a tick or pop that isn’t actually on the LP. About 95% of ticks and pops have this origin.I am sorry, but this is complete BS.
I was quite surprised when I discovered this to be the case about 30 years ago. Any engineer knows that you use something called ’stopping resistors’ to stabilize a circuit. Otherwise you can get oscillation. If the circuit is on the verge of oscillation, as you see in nearly all Japanese designs used in receivers and integrated amps from the 1960s-1990s (none of which have stopping resistors whether tube or solid state), ultrasonic defects in the surface can set off short term instabilities in the equalizer, resulting in little ticks. This is not a feedback or passive EQ phenomena, nor is it related to solid state or tube as we have seen a good number of solid state phono preamps that are also free of ticks and pops.
The other problem is overload margin, which can also induce ticks and pops. The reason this shows up is the cartridge is an inductor and the tone arm cable is a capacitance, together forming a tuned resonance which can be active at ultrasonic frequencies in the case of MM cartridges and RF frequencies in the case of LOMC cartridges. The resonant peak can be 30db higher than that of the signal in the case of the latter! If the preamp isn’t alright with that, ticks and pops occur.
Ralph, I don’t want to have this discussion. That’s why in my first post I said:Many do see it as a preference. I see it as an engineering problem and a direct conflict with how the ear hears vs how spec sheets are created.
The CD vs LP debate is about preference, not who’s right or wrong. I hope we can get past that old argument someday. Both formats are capable of very good and very bad sound.
The ear/brain has certain perceptual rules and that is what the debate around CD/LP and tubes/transistors is all about. If you are engaged with the Emperor’s New Clothes, you will think the spec sheet is real and that is what you want to hear. If you know about human physiology (IOW how the ear/brain system works) then you find the spec sheets troubling because its obvious that they are intended to look good on paper while ignoring how sound is perceived.
Here’s an example: all forms of distortion are perceived by the ear as a tonality. We all know about the ever-loving 2nd harmonic that makes tubes sound rich. But what is less well-known is that the ear uses higher ordered harmonics (5th and above) to gauge sound pressure. This is probably because sine waves are very rare in nature where our hearing was developed. BTW this is very easy to demonstrate with simple test equipment.
The industry likes to see very low THD numbers (looks nice on paper) so we use feedback to get rid of those pesky harmonic distortions. The problem is that feedback makes distortion of its own, and because its entirely higher orders, inharmonic types and IMD associated with the feedback node, we easily perceive it as hardness and brightness even though it might only be 0.005%. This is what I mean by the Emperor’s New Clothes.
Aliasing works the same way- the ear perceives it as harshness and brightness. Because this tonality is caused by distortion, turning down the treble to make it go away doesn’t work. My beef with digital is that this is built into the recording. It is very rare to find a digital recording that lacks this form of coloration.
In the analog world this form of distortion is called ’inharmonic distortion’ because it relates to harmonics surrounding a certain frequency. In a tape machine this can be caused by harmonics of the audio signal interacting with the record oscillator. In a digital system, these inharmonics are centered around the scan frequency, and essentially are an intermodulation. I don’t think most people realize how serious a problem this actually can be; intermodulations may not look like much when its only two frequencies, but when a number of them are involved it gets very complex very quickly! This is why intermodulation distortion is so audible and a recording system that has this as an inherent fault is bound to have controversy around it, so its no surprise that nearly 30 years on, these debates are still common.