M2tech – M2TECH Joplin User Manual

Page 27

JOPLIN
384

/32bit ANALOG-TO-DIGITAL CONVERTER

REVISION P

B – SEPTEMBER 2012

M2Tech

www.m2tech.biz

8.3.5. Equalization curve

The Joplin has been conceived to be used with a wide variety of different sources: tuners,
recorders, turntables. Some of these sources require an equalization to enjoy their sound.
The Joplin is provided with a wealth of equalization curves to satisfy even the most
requiring vinyl collector or reel-to-reel tapes enthusiast. Of course, equalization can be
disabled when the source doesn’t require it. This is obtained by choosing the “FLAT” value
for this parameter.

16 different curves for microgroove LP’s, 7 curves for 78rpm, 4 curves for reel-to-reel
tapes are available. Please see Section 9 for more details on equalization.

8.3.6. Display dimming

The Joplin display intensity can be set on 5 different levels. In addition, an automatic dim
mode allows for keeping the display off every time it’s not necessary to read it. When the
automatic mode (value “A”) is chosen, the display activates at the highest intensity every
time a control is accessed, then it remains active for 5 seconds after the last control is
accessed, finally turning off.

8.3.7. High pass (anti-rumble) filter

When acquiring a noisy source, it is sometimes desirable to cut some low frequencies. For
example, warped records or the output of a mike preamp or a mixer when recording live in
a windy setup. Two high-pass cut-off frequencies are available: 16Hz (for microgroove
LP’s and also for modern era stereo LP recorded with RIAA curve when the extra 16Hz
high pass is known to be used for the LP making) and 50Hz (for most 78rpm records
which have generally poor music contents below 50Hz). See Figure 20 for more details on
high-pass filter effect on frequency response.

8.3.8. Low pass (anti-hiss) filter

When acquiring a noisy source, it is sometimes desirable to cut some high frequencies.
For example, many 78rpm records have poor music contents above 5kHz and a strong
surface noise. Using a low-pass filter allows for a more intelligible sound. Two low-pass
cut-off frequencies are available: 5kHz and 10kHz. See Figure 20 for more details on low-
pass filter effect on frequency response.