The Talking Machine Forum — For All Antique Phonographs & Recordings

I am digitizing records today, and I came across something strange in a copy of "There's a Rainbow 'Round My Shoulder' by the Harmonians on the Velvet-Tone label, which according to 78discography.com, is pressed from Harmony masters.

So what I found is a very loud, very mechanical rumble in the background. It sounds as if Harmony's record lathe was spring driven (and in need of service). Was this common practice? I thought that most studios used gravity lathes.

That sounds like your pickup dragging on the surface of the record. Not likely present as part of that acoustical recording.

The cartridge does hang a bit low, but I have not had that in any digitization before or since.

Sounds indeed like a cartridge body touching the record. What is your set up (TT, preamp, cart, stylus, input)?

Did you use a combined mono signal or just one channel? In case of one channel only, this would be pretty easy to explain as the cartridge would pick up both lateral and vertical signals, with the usual rumble of a laminated disc being present.

I also hear some strong pumping artifacts, like it is caused by heavy noise reduction that is eating up great parts of the recording.

If you don't already know, Velvet Tone / Harmony / Diva/ and other related labels were all recorded and pressed by Columbia, who I doubt would have had anything out of order. These labels were cheaply priced, and produced to recoup Columbia's late investment in Acoustic equipment, but they didn't drop their standard even for dime store clients.

Okay, I fixed it. It was just what y'all said, with the cartridge scraping on the record (odd that ths was the only disc that happened too, but whatever) and that has now been fixed.

The "pumping" sound, if we're thinking of the same thing, is present even before noise removal.

Finally, I am using a Dual 1212 turntable (from 1969 or 1970, I believe hooked up to a Marantz receiver (idk the model number offhand). Nothing else is present. Cartridge is an Audio-Technica ATN3600-78.

Glad to hear you were able to fix it. I just checked the effective tonearm mass of the 1212 (ca. 9g), so the overall resonance should be okay with the ATN-3600.

That pumping sound could be caused by the preamp. Some phono-preamps support both MM and MC pickups, but have to be set by a switch to the correct cartridge type. I vaguely recall to have heard such strange tonal behavior on a preamp that was set to MC input while an MM cart was running. You could try a simple external preamp and use the auxiliary input on your amp. Just an idea, as this is certainly not how it should sound.

I don't know exactly what is meant by "pumping noise", but it seems as if the playback volume is constantly increasing and decreasing.

bart1927 wrote:I don't know exactly what is meant by "pumping noise", but it seems as if the playback volume is constantly increasing and decreasing.

Sometimes that happens with digitizations with a lot of noise, as the program cuts out some audio in its hunt for noise. I really don't know for sure how to clean audio up, and by no means am I striving for archival quality, I do these just to listen in the car. So my low skill level definitely has an impact (that said, on a clean record I can all but eliminate the noise while keeping nearly all of the signal).