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Description
Basic information about
turntables and records.
What should I listen for when evaluating a turntable or CD player?
For tape decks and turntables, beware first of speed variations (wow and
flutter). A good check for this is Richard Strauss' "Also Sprach Zarathustra"
(aka: The Theme From 2001), which has a long, low, sustained organ note that
comes in well before the main theme starts, and is held through the first
movement. Concentrate on that. Make sure it doesn't wobble or warble. There's
also a good bit at the beginning of Pink Floyd's "The Wall", but it doesn't go
on as long, so you've got less time to think about it. Tape decks are prone to
losing high-frequency notes, so pick something you like which has lots of
treble, and make sure it is clear.
The sound of a turntable is largely bound up in the kind of cartridge mounted
on it. Make sure to listen to a table with a cartridge similar to what you're
buying, and not one in a different price bracket. If possible, audition the
turntable with the same arm and cartridge, so that you will experience potential
cartridge/arm interactions, too. Most cartridges work better with one arm than
another. Treat the tonearm/cartridge pair as a system, rather than independent
parts.
For CD players, try some piano music. See if the high notes sound tinny.
Also, try something which has some soft parts, not the same as turning the
volume down. Distortion for CD players (as for other devices) is measured at a
high output, but in fact in CD players (unlike others) it's likely to be worse
in soft passages of music. Most classical recordings contain a suitable soft
passage. Most rock music won't.
Distortion in CD players, if you want to call it that, is a function of the
granulation noise, or time-delay pre-echo that can come out of the filtering. To
listen for this, use material that is rich in high-order harmonics, such as
brass music. Unfortunately, you can't reliably predict how a CD player will
sound by looking at specifications, features, or the technology it uses. If you
want to know how a player will sound, you MUST listen to it.
Are CDs better than LPs?
Some excellent recordings are mastered digitally, and sound great on LPs.
This suggests that there is nothing inherently bad about digital.
Some find that LPs sound better than CDs. Advocates of LPs claim that the
digital to analog (D/A) converter in home CD players isn't up to the quality of
the information on the disc. They also claim that the analog electronics in a
home CD player can be poor.
Some believe that CDs do not sound like LPs because the CD does not have the
frequency response errors, the distortion, or the stereo separation problems of
LPs.
In general, though, there are good and bad CD players, just as there are good
and bad turntables, cartridges, and tone arms. Any ultimate comparison would
require ultimate equipment, which is unaffordable. In moderately priced systems,
there will be some signal damage from the turntable system and some signal
damage from the CD player.
LP lovers often learn the nuances of cartridge selection, record care, and
even turntable and tonearm adjustment. They have found that the turntable will
sound different if the arm height is adjusted, if the cartridge angles are
changed, and if the tonearm wire is moved. CDs do not offer as many avenues for
the home experimenter.
However, Audio Amateur Magazine has published modification projects for CD
players; particularly for Magnavox 560 and similar European players. Audio
Magazine has also published such articles.
What turntable should I buy?
Despite improvements in motor technology, most great turntables use belt
drive. Rubber roller (idler) drive sounds the worst.
Select a turntable with a very heavy platter for the least wow and flutter.
Give the platter a rap with your knuckle. It should not "ring" like a cymbal. It
should feel and sound dead.
Also look for a turntable that has good isolation from base to stylus. With
the amp on and the turntable selected, but with the turntable motor off, put an
old record on the turntable, lower the stylus onto the record, and then tap the
edge of the base. Not too hard, you don't want to send the arm flying. At worst,
you will hear a quick 'thump' followed by silence through the speakers; if
you're lucky, you'll hear nothing at all. If the sound continues beyond a quick
'thump', the mechanical isolation is not great, and you should look at some
other make. When you perform this test, be sure to unplug the turntable power
cord.
If the turntable has a tonearm, try to evaluate the arm, too. A good arm
should be adjustable in height. A good arm should allow cartridge adjustments. A
good arm will be very rigid and have no bearing play. A good arm should
accommodate a wide range of cartridges. Despite this, some arms work better with
high compliance cartridges, while others are at their best with low compliance.
Ask.
Turntables by Denon, Dual, Linn, Michell, Oracle, Pro-Ject, Rega, Sota,
Thorens, and VPI are recommended. If you want a turntable on a budget, consider
the NAD 5120 at approx. $160.
Will phono cartridges still be around ten years from now?
Most likely, there will still be cartridges available, but not in the variety
available ten years ago. They will become "Special Order" in some stores and
unheard of in others.
"Pro" or "DJ" cartridges will stay available in good supply, "Audiophile"
cartridges will stay available and very expensive, "Mid-line" cartridges will
become very scarce, and a few "Budget" cartridges will remain available in
copious supply. At the same time, some makers will drop their cartridge lines
completely.
Will LPs still be around ten years from now?
There is a strong movement of collectors and purists who will keep their
collections and buy good used discs. Count on these people to keep the used disc
market hot for 25 years longer.
As for new music, less is being pressed today than 20 years ago. Many popular
artists are being released on LP in parts of Europe, but availability is
dependent on country. One person said that many new LPs are available in Spain.
LP sales have increased recently in Japan and in the UK. Polydor is now
re-releasing older recordings on vinyl, and will continue to press them as long
as it is profitable. Likewise, there are several re-releasing projects in Japan.
Some are for Jazz collectors and others are for pure analog as well as classical
music lovers. They are selling the LPs by subscription, with shipments every 2
or 3 months. Each release includes about 20 titles. Japan has released over 100
LPs this way last year.
How can I clean LPs?
There are expensive machines for this purpose which work very well. One
popular model goes by the name Nitty Gritty. These machines spray cleaner onto
the record, work it into the grooves, and then vacuum the cleaner and dirt out.
If you are serious about records and have lots of them, it may be a good
investment for you.
If you have a more reasonable collection, you might be happy with a good hand
washing every now and then. To give your records a good hand washing, start by
preparing this wash:
1 gallon distilled water 1 gram Alconox (a laboratory detergent)
Also, get a natural bristle brush and trim it to the correct
stiffness/bristle length so that the bristles can get into the grooves but
aren't stiff enough to scratch the record. Some record-cleaning recipies
recommend alcohol. However, alcohol will leach plasticizer from vinyl, and
eventually degrade LPs. Alcohol will also disolve the shellac of 78s, so should
never touch a 78.
Lay the LP flat and pour a thin coat of the above fluid on it. Brush the wash
into the grooves with the bristle brush. Brush in the direction of the grooves,
going through all grooves. Flush the wash and dirt off with cool, running tap
water. Rinse the record with distilled water and pat it dry with a soft, clean
cotton cloth.
Also consider using a carbon fiber brush every time you play the LP. It picks
up some surface dirt and removes static.
How do you set the stylus pressure correctly?
Stylus tracking force is typically adjusted at the back of the tonearm with a
knob that is calibrated in grams at the stylus tip. With the control set to
zero, the stylus should sort-of float above the record surface. The control is
then increased to the number recommended by the cartridge manufacturer.
Do not, under any circumstances, use a lower than recommended force, as the
cartridge may lose the ability to maintain contact with the groove wall on
passages of large amplitude. This WILL result in RECORD DAMAGE.
If you want the best possible tracking and sound quality, you will want to
fine-tune the tracking force. Use a test record and listen very carefully, or
get the help of a good dealer with a battery of instruments.
How do you set the anti-skating on a tonearm?
If you have a recommendation or suggestion from the tonearm manufacturer,
follow their advice first. They will give you the best starting point.
Some tonearms come with calibrated anti-skate. The manufacturer of these
tonearms has tried to calibrate the anti-skate control so that if you match the
setting of the anti-skate to the setting of the stylus pressure, you will have
nearly perfect anti-skate. Read the manufacturer's recommendations to see if
this applies to your tonearm.
You can see gross errors in anti-skate by looking at the stylus. If you shine
a light on the front of the tonearm while playing a record, you will be able to
see whether the stylus is centered in the stylus holder. If the stylus is biased
to one side or another while playing a record, then the anti-skate is way off.
More subtle adjustments can be made by listening for mistracking. If you can,
obtain a record with equal left right modulation at high frequency with
ascending modulation magnitude (volume), such as the Shure ERA-III, IV, or V
test record. They have five bands of "greensleeves" played on flute, and you
fiddle until the audible breakup is equal in both channels, and adjust tracking
weight until it occurs in the highest band. This is, like other cartridge and
tonearm adjustments, easier for the experienced hand than the beginner.
Some high-end dealers have electronic instruments which allow them to
accurately adjust anti-skate and other cartridge and tonearm parameters. If you
can get this service, consider yourself fortunate.
How else do you adjust a tonearm/cartridge/stylus?
There are a few other critical adjustments. Again, a good high-end dealer may
be your best resource. Your ear may also be your best test instrument.
You need a level turntable. Use a quality carpenter's level. Some people like
the Shure stylus force gage for setting stylus pressure accurately. Other tools
which are well recommended are the Geo-disk, a good protractor, and above all,
the Cart-Align, which uses a very precise etched plastic mirror for cantilever
alignment.
You'll also want to set the tracking angle. It CAN be done by eyeball, but is
best done with test instrumentation and a record. There is also the cartridge
angle, tonearm height, etc. Read the instructions which came with your tonearm
for the best specific advice for that tonearm.
Tonearm cable is more critical than any cable anywhere else in the signal
chain. Cable capacitance directly sets the high frequency characteristics of the
cartridge. In addition, the correct grounding of the shield is essential to
minimize hum. It may be necessary to change preamp input capacitors so that the
cable/preamp combination loads the cartridge with the right overall capacitance.
Replacing tonearm cable will have a similar effect, but may be harder to change
tonearm cable than to change preamp input capacitors. Consult the cartridge,
tonearm, and preamp manuals for specific advice. Also refer to 16.6 for more
information on tonearm cable.
What are input and output levels and impedances for signal sources, preamps,
amps, etc?
We have been unable to find any formal standard on this topic. However, there
is an EIA Bulletin: EIA Consumer Products Engineering Bulletin No 6-A (CPEB6-A)
1974, titled "Preferred Voltage and Impedance Values for the Interconnection of
Audio Products". The key word in the title is 'Preferred'.
EIA CPEB6-A recommends 3mV at 47k ohms for magnetic phono cartridges, 250mV
at less than 10k ohms for tape and preamp outputs, and 100k ohm minimum for
tape, tuner, and amp aux inputs. The bulletin also has information on
microphones, and headphones. You can order a copy through a technical library or
directly from the EIA.
Why are turntable speeds 78 RPM, 45 RPM, etc?
The speeds were chosen because that is the speed that resulted when you used
standard parts. Electric motors rotate at 1800 rpm, most shafts are 1/4". Those
combinations with the proper gears and idlers came out to 78 rpm. In reality
it's 78.26 rpm. Tape recorder speeds evolved the same way.
The 78.26 was standardized after electric recording/playback occured. Prior
to that, speeds were "in the neighborhood of" 78 rpm. Some lower and some
higher. 80 rpm was used in many recordings. (Courtesy of Bill Vermillion)
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