[Vintage-Audio] Cassette Audio Quirk?

[Steve Byan]

On Jun 1, 2009, at 6:22 PM, Duane Fischer, W8DBF wrote:

> I keep encountering a problem every time that I remaster the audio  
> on a
> cassette tape to a CD format.
>
> Yes, for those of you who may remember this, I have also recorded the
> cassette audio to my Sony DAT deck and converted the mono on the  
> cassette to
> stereo on the DAT.
>
> The Master DAT is perfect, at least to my finely tuned ears.  
> However, when I
> feed the DAT to the Sony CDRW deck to create a CD, things go a bit  
> crazy.
>
> The CDRW apparently hears a snap or a crackle or a pop or ...? When  
> it hears
> this noise, not audible to me, it causes distortion in the CD  
> recording.
>
> I have changed all input/output cables from the amplifier to the  
> DAT, from
> the DAT to the amplifier, from the CDRW to the amp etc. All are the  
> Gold
> plated heavy audio cables six feet in length.
>
> I have tripled checked the Yamaha cassette deck and all of the other
> hardware that is involved.
>
> I can not find anything wrong with anything.
>
> This only happens when I am trying to convert an audio cassette to  
> CD, makes
> no difference if the cassette is in mono or stereo or identical mono  
> on both
> stereo tracks.
>
> Have any of you encountered any issue like this one involving a  
> cassette
> tape?

I've no experience with that kind of gear, but from a theoretical  
perspective it's possible that the 48 KHz sample rate noise from the  
DAT deck is being aliased down to a 3.9 kHz tone by the 44.1 kHz  
sampling rate in the CDRW deck. There are anti-aliasing filters in  
both the DAT output and the CDRW input, but it's possible that enough  
signal is leaking through to screw things up. What happens if you just  
go from the cassette to the CDRW deck and omit the DAT deck?

Best regards,
-Steve

--
Steve Byan
stevebyan at comcast.net
Littleton, MA