sjc@mordor.UUCP (05/07/84)
Two recent postings have asked about a mysterious flutter or dropout that occasionally occurs when recording vinyl disks, but which correlates with the music, rather than with the position on the tape. A friend who owns a BX model tells me he had similar troubles, complained to his dealer, and was sold a Nakamichi high-pass filter which solved the problem. Supposedly the Nakamichi electronics handles very low frequencies so flawlessly that vinyl disk defects and warps saturate the heads and/or tape. Allegedly the meters don't pay attention to such low frequencies. I hesitate to suggest this, because I would expect disk defects and warps to be periodic rather than occasional, and because many receivers and preamps are not DC-coupled between the phono input and the tape deck output, and therefore provide high-pass filtering for free. But you might arrange to borrow a preamp with a rumble filter, or one of the Nakamichi high-pass filters, or a pair of capacitors of the appropriate size, and see whether the problem goes away.--Steve (S-1 Project, Lawrence Livermore National Laboratory) MILNET: sjc@s1-c UUCP: ...!decvax!decwrl!mordor!sjc (mailheader return address may not work)
dmmartindale@watcgl.UUCP (Dave Martindale) (05/10/84)
It is true that most electronics is either capacitively coupled, giving a DC gain of zero, or uses some method to reduce the DC gain to 1. But the signal caused by a warp is usually somewhere in the 5-20Hz range, and most electronics will amplify that just as well as a 30Hz musical note. If you want music to be passed while warp signals are attenuated, you need a filter designed for that, with a fairly sharp cutoff.