That infernal hum!

Cohasset / Hippisley
Sun May 25 23:46:03 EDT 2008

-----Original Message-----
> So I'm thinking of another strategy for recording records and tapes 
> into computer files:  Use my laptop.  trouble is, my laptop doesn't 
> have an auxiliary input jack, just a mike jack.  Anything that I play 
> into that jack comes out loud and distorted.  Is there any kind of 
> adapter that I can get that will make it possible to use the laptop 
> for this purpose?  Or do I have to get another laptop?  That's not 
> going to happen for awhile.

Assuming you have some stereo records and/or tapes, you *will* need to add
an outboard USB or PCMCIA (aka "PC Card") box to your laptop since, as
someone else has noted, the mic jack is monaural only and USB and PCMCIA
represent the easiest way to get digitized stereo audio streams into your
laptop.  But being forced to do this is not all bad, because most of the
built-in sound card functions on laptops have some objectionable limitations
for those interested in making clean full-frequency-range recordings.  For
instance, it is a rare laptop that has 24-bit audio built-in (MacBook Pro
does).  Most laptops are 16-bit audio, whereas 24-bit sound cards are pretty
common these days.

Secondly, taped audio typically comes off your tape recorder (reel to reel
or cassette) at line level; this will overload your mic input unless you
have an attenuator cable, as someone else has noted.  And of course, you
will lose any stereo effects.

My son, who keeps up on computer hardware, says the current "favorite" for
external USB sound cards is the Sound Blaster Audigy.  At one time (and
perhaps even now) Turtle Beach was also a highly rated brand.

Phonograph records add one more dimension to your challenge, because they
have been put down on the vinyl with so-called RIAA equalization which
boosts the highs (for increased high frequency signal-to-noise ratio) and
reduces the lows (to reduce the total real estate used by bass notes).
Also, phono outputs (unless they're the very, very cheap ones with high
level ceramic cartridges) are in the same range as microphone levels; that
is to say, perhaps 20 dB down on average from line level.  As far as I know,
the standard Sound Blaster Audigy does *not* provide separate RIAA phono
inputs -- just line level inputs (and perhaps "flat" mic inputs), so it
becomes your responsibility to find a way to get from phonograph player
output levels with RIAA equalization to line levels with no equalization. 

In my opinion, the simplest way to handle all this stuff is to acquire a
used stereo preamp or receiver that is old enough to still have a PHONO
input position on the front panel selector switch.  Feed your tape recorder
outputs into any of the line level inputs (AUX, CD, TAPE 1, TAPE 2, etc.)
and feed the outputs of your phonograph into the PHONO jacks.  Then run a
cable from the TAPE OUT (unaffected by settings of the main volume control)
jacks or the PREAMP OUT (affected by the main volume control setting) jacks
on the preamp or receiver to your USB sound card stereo LINE IN jack, which
is almost always going to be implemented on the USB card as a single
1/8-inch jack with two hot connections (Left & Right) and one ground

There are many decent software packages available for recording on your
laptop; Audacity comes to mind, but there are others -- some free (check
TUCOWS.COM) and some costing bucks.  Some include (basic or as an option)
"click & pop" filters for your old vinyl records.

I've assumed throughout this that you are trying to make *decent* digital
copies of your old records and tapes.

If the laptop happens to be a MacBook Pro, there is a stereo input jack but
as I recall it's at mic level, so you still need an attenuator cable to
record your tapes.  And regardless of the input level the MBP may have, you
will still need to add an RIAA box to record your vinyl. 

Bud Hippisley

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