I have a Technics turntable —> Pro-Ject phono box —> Play:5 (2nd Gen) which is part of a stereo pair of 5s. When I enable line-in and turn up the volume, I hear a faint whine coming out of both 5s and, more irritatingly, a really fast tapping sound coming out of the left 5 only. It’s super fast - 6 or 8 taps a second. It’s not the buzz that you hear when the preamp is ungrounded; I’ve messed with the ground connection and it doesn’t stop the whine or the left-side tapping. But I still suspect it might be ground related, because when I bring my hand to the back of the preamp to check connections, the tapping on the left stops. When I pull my hand away, it resumes. (The whine is persistent throughout.)
These artifacts aren’t terribly noticeable at lower volumes, but if I crank it up, I hear them both in between tracks or during quiet parts of songs.
I searched for “clicking,” “tapping,” “popping” - no existing articles seemed to describe the exact same sound I’m hearing with line-in. Any suggestions on what the root of it might be? The fact that the tapping is only on the left, and stops when I bring my hand near, seems especially bizarre.
Best answer by chriscook
Kyle, I figured out the tapping sound.
The preamp is the Pro-Ject Phono Box II MC/MM. I had it set to MC. I’m using a Grado Prestige Red cartridge, which is actually neither moving coil nor moving magnet - it’s moving iron (MI) but functionally most similar to MM as far as signal level. When I changed the setting to MM, the tapping went away.
I still hear the whine, especially at higher volumes, but at normal listening volumes it’s not noticeable. I’ll tackle that some other day :)