J33™ Development

Ever since the first audio recordings, there has been a constant push to improve the recording quality. This began with simple magnetic wire which evolved to magnetic tape, the turntable and today digital. This has yielded an abundance of recorded material, much of which has yet to be transferred to today's digital standards. This, in fact, was the impetus for us to develop the Radial J33 turntable preamp.

The RIAA Equalization Curve
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 been the de facto global industry standard for the recording and playback of vinyl records since the 1950's.

RIAA equalization is a form of preemphasis on recording, and deemphasis on playback. A record is cut on a disc cutting lathe with the low frequencies reduced and the high frequencies boosted. On playback the opposite occurs. The result is a flat frequency response, but with noise such as hiss and clicks arising from the surface attenuated. The other main benefit of the system is that low frequencies, which would otherwise cause the cutter to make large excursions when cutting a groove, are much reduced, so grooves are smaller and more can fit into a given surface area, yielding longer playback times.

A potential drawback of the system is that rumble from the playback turntable's drive mechanism is greatly amplified, which means that players have to be carefully designed to avoid this. The J33 is equipped with a specially designed high pass filter that eliminates turntable rumble. This is particularly effective when using the J33 in high sound pressure level environments such as night clubs or performance concerts.

RIAA equalization is not a simple low-pass filter. It carefully defines transition points in three places: 75 µs, 318 µs and 3180 µs, which correspond to 2122 Hz, 500 Hz and 50 Hz. Implementing this characteristic is not especially difficult, but more involved than a simple amplifier.

RIAA CURVE

Phono preamps for stereo playback
Due to the reduced demand of vinyl records, most Hi-Fi amplifiers today are no longer equipped with a built-in phono preamplifier. The J33 provides an easy interface that permits one to connect the turntable output and ground wire to the J33 which then produces a -10dB consumer level output that is perfectly suited to connect to an auxiliary or CD input on a standard HiFi receiver.


Turntable to J33 to computer

Transferring Records to Digital
With well over 50 years of historic recording, there has never been a greater need for archiving. And with today's computer technology, it is now possible to transfer a scratchy recording and eliminate much of the background noise without sacrificing much or any of the original content. The J33 makes the process easy! Simply connect the J33 to your recording system using either the -10dB RCA outputs or by sending the signal from the balanced XLR outs to a pair of mic preamps.


Turntable to J33 to Mixer to Computer

Creative sampling process
Old records are not only used for archiving, but today, samples are often recorded, manipulated and then reworked to create drum loops and sound effects. The J33 is once again used as the interface between the turntable and the recording system.


Turntable to J33 to Mixer to Digital Sampler

Using the J33 Live
With the advent of hip-hop, rap and house, it is now common to see DJs perform live with the same limelight as rock-star personas. Scratching has become an art form. Although turntables are often connected via a DJ mixer, there are situations where connecting the turntable to a live mixing console is needed. The J33's mic level outputs make it easy to connect a turntable on stage and send it through the mic splitter and snake to the FOH mixer.


Turntable to J33 to Mixer to PA System

With the recent revival of the long-play record, it seems that the J33's arrival on the scene could not be more timely.