Micro-Acoustics QDC-1 phono cartridge

Stereo Phono Cartridge. It will make any well recorded L.P. sound exactly like its master tape.

People in the record business have known for a long time that a well recorded stereo disc is potentially every bit as good as its master tape. Our founder and president. Arnold Schwartz, created the Series 300 Micro-Point Recording Stylus - an ultra precision cutting tool used to master the world's finest recordingd. (Over two-hundred million records a year are manufactured from masters cut with our Series 300 Micro Point Styli.) And it has been our experience that there's no problem in getting the music onto the record the problem has been in retrieving it.

The cartridge is the culprit.

Until the advent of the QDC-1, there really wasn't a cartridge on the market that could make a stereo record sound as good as its master tape. So cartridge manufactures didn't have to deal with an absolute standard of measurement for their product. They sold their cartridges very much like loudspeakers , using subjective criteria. In the end, the customer had to choose between the "sound" of one cartridge or another. The fact is that a cartridge shouldn't have any sound of its own. Ideally it should just be a direct link between the record groove and the preamp input. That's precisely what the new QDC-1 is - an ultra precision component that neither adds  nor detracts from the music you hear. And because it does what it does so well, it will change the way all cartridges are judged. Now a cartridge's performance can be measured against a completely reliable abjective standard.

Stated simply; "Does a cartridge make a well recorded disc sound identical to its master tape? Or doesn't it?" our does. Here's why.

[1] The  QDC-1 Series 300 playback styli (QDC-1e, 1s, 1q) are shaped and polished with the same ultra precision as our world famous Micro-Point recording styli. These styli follow the complexities of the record groove with greater tracing accuracy than heretofore obtainable.

[2] The QDC-1 stylus bar is directly attached to its transducer, eliminating the losses inherent in standard flux field coupling. This unique method of lossless coupling provides a faster response time than any other known system.

[3] The QDC-1 stylus is balanced by two elastic bearings positioned to provide precise 45°-45° signal resolution. This symmetrical configuration precisely controls stylus excursion from minimum to maximum groove amplitude, without the floppy overshoot of conventional single bearing designs.

[4] The QDC-1 electret transducer puts out a perfectly linear signal from 5 Hz to 50 kHz, without the phase shift normally associated with inductive transducers. Its reproduction of complex wave forms is equal to the best direct coupled amplifiers.

Specifications

Stylus Configuration (User Replaceable):

QDC-1e :  .0002 x .0007 elliptical solid nude diamond

QDC-1s  :  .0005 spherical soild nude diamond

QDC-1q  :  Quadra-Point/CD-4 solid nude diamond

Frequency Response: 

QDC-1e  :  5 Hz to 20 kHz ±2 dB

QDC-1s  :  5 Hz to 20 kHz ±2 dB

QDC-1q  :  5 Hz - 50 kHz ±3 dB

Tracking Force Range:

QDC-1e :  0,75 to 1,5 grams

QDC-1s  :  0,9 to 1,5 grams

QDC-1q  :  0,9 to 2,0 grams

Channel Separation: 

QDC-1e :  Nominally 30 dB at 1 kHz (nominally 20 dB at 10 kHz)

QDC-1s  :  Nominally 30 dB at 1 kHz (nominally 20 dB at 10 kHz)

QDC-1q  :  Nominally 30 dB at 1 kHz (nominally 15 dB at 20 kHz)

Output Voltage:  3,5 mV each channel at 5 cm/sec peak recorded velocity

Load Impedance:  47 k Ω