A Guide to Turntables

[Big Daddy]

Richteer,

If you don't mind, I can add this important information to Post #1. It is also a good idea to change the name of the thread to A Guide to Turntables. I can do that for you.

http://www.epanorama.net/circuits/phono.html

Many amplifiers have phono inputs for connecting record players to the amplifier. Phono input is designed to take up to few millivolt signal from phono pickup and amplify it. The amplifier stage does also some equalization based on standardized RIAA curve. The RIAA reproduction curve:

Source: Wikipedia

That RIAA equalization is used in the playback to reduce the high pitch noise and maximize bass dynamics in the phono playback. The audio material which is rocorded to the record has been pre-equalized so that the frequency response of the whole chain from the mixing desk to your speaker will give flat frequency response.

General information on phono input

When choosing a cartridge for a given phono section, it is the "gain" or output that have to match.

• Typically almost all receivers, and most integrateds have standard 'low-gain' phono preamplifying sections (30dB to 38dB of gain typically). These require the use of either moving magnet cartridges (typically in the 2.0 to 5.0mv range) or high output moving coil types (generally 1.5 to 2.0mV output).
• The better preamplifiers (and the odd integrated or receiver) accept low-output moving coil cartridges - which have outputs of .2 to .9mV. These high gain phono sections will typically have approx 55dB to 75dB of gain.
• Very old tube amplifiers (50 years old) have had CERAMIC cartridge input which is very high input and accepts around 100mV signal level.

Different cartridge types:

• MM (Moving Magnet) cartridges are designed to play into 47k ohms or higher input impedance. MM's will typically be loaded with capacitive loading in the pF range. Moving magnet phono cartridges have a typical output of ~3mv at 47K Ohm load. Movin gmagnet cartriges are the ones most commonly used.
• MC (Moving Coil) cartridges are typically designed to be loaded anywhere from 10 ohms to 1000 ohms.
• Ceramic catridges are high impedance signal sources. Their are not used nowadays because they were not "hifi quality".

http://www.enhancedaudio.com/eqcurve.htm

In order to create records in the first place, adjustments had to be made to compensate for the lack of surface space on a record. Because records rely on grooves, in order to accurately relay Bass passages on a record, the grooves would need to be so far apart that in many cases it would be impossible to fit a full song on a 78 or more than one or two on an LP. In order to compensate, records were designed minus a great deal of the Bass and manufacturers depended on the equipment that they were played on to add that bass back into the file during the listening process.

An EQ Curve is simply a preset equalizer that says, "I know you're going to be missing these frequencies...I'll just put them back in automatically."

The RIAA curve was designed for LPs and 45s. Almost all modern preamps or stereo systems add this RIAA curve in one respect or another on playback. In the heyday of turntables and stereo systems, many folks would shop for hours until they found the stereo system that sounded best. Because all stereos sounded differently, this can let you know just how well this RIAA curve was followed. Each company interpreted these EQ settings with their own style. While this was good for listening, it may not be the best for today's technology. If you are mainly transferring LPs and 45s to the computer, you may want to read about the CTP1000 Flat Phono Preamp Series. Just Click Here.

78 records were designed differently and require a different set of equalizer settings in order to play them accurately.

http://en.wikipedia.org/wiki/RIAA_equalization

RIAA equalization is a specification for the correct playback of gramophone records, established by the Recording Industry Association of America (RIAA). The purpose of the equalization is to permit greater playback times, improve sound quality, and to limit the vinyl damages that would otherwise arise from recording analog records without such equalization.

The RIAA equalization curve has operated as a de facto global industry standard for the recording and playback of vinyl records since 1954. Before then, especially from 1940, each record company applied its own equalization; there were over 100 combinations of turnover and rolloff frequencies in use, the main ones being Columbia-78, Decca-U.S., European (various), Victor-78 (various), Associated, BBC, NAB, Orthacoustic, World, Columbia LP, FFRR-78 and microgroove, and AES.