9 May 2013
I Use your granddads'
electronics, it sounds incredible!
I love thrift
shops or second hand shops. I love digging around in other peoples' old stuff.
Especially electronics. The reason is that I can often buy gear that when it was
new would have cost thousands of rands for a fraction of the price. Some really
high end stuff can be found for next to nothing. One recent find is a Pioneer
PD-S501 CD Player with the so called "stable platter mechanism". Partnered with
my Yamaha AX-350 amplifier it makes for a pretty high-end little system. Both
items were bought from a pawn shop for next to nothing. Score!
The Pioneer PD-S501 has a Pulseflow DAC which is Pioneers' name
for a 1-bit or bitstream DAC. Their implementation is the best I've heard so
far. It's incredibly detailed allowing me to hear background detail in many
recordings I never noticed before. Beware though, I do find it very bright on
certain CDs and it can be tiring to listen to. It depends on how the disc was
mastered.

14 April 2012
MY RIG
I do most of my listening using the Monica DAC along with the tube headphone
amplifier. Audio is fed via TOSLINK interface from the PC running iTunes. I used
to compress CDs using AAC at 256kbps, but switched to Apple lossless format
recently.


This is the famous
Monica non-oversampling DAC. I modified it for TOSLINK optical input. Replace
C22 and C14 with 0.01uF capacitors as per the CS8414 datasheet. The TORX177
produces TTL output levels. Remove R16.
|
|
|
Main Circuit Board
Place the +5V/GND for the the TORX177 module into the holes for C3 |
|
|
|
TORX177 Module
optical module showing +5V/GND (black and red) and signal wire (yellow) |
|
|
|
December 2011
How to tell if a CD was mastered using Video
Tape
I was excited to get a
1982 copy of ABBA: The Visitors on ebay
recently. It is now the oldest CD in my collection. The Visitors is special
because it was one of the very first albums to be released
on CD in 1982. What is more
special is that
The Visitors was digitally recorded (a few tracks are analog) using the new
3M
Digital Audio Mastering System at
Polar Studios.

I recently (12/30/2018) ripped the audio tracks on ABBA: The
Visitors to .wav files so that I can look at them in Audacity. I made an
interesting discovery. When I viewed the tracks in spectrogram view I noticed an
unusual anomaly. There was a tone at about 15-16kHz going through all the tracks
on the disc.

When all is said and done. (click for larger
view)

Head Over Heels.
(click for larger view)
Each track on the disc display this anomaly. A
high frequency tone or noise in the background of the music. The level is quite
low so it is not audible, but it can be clearly seen. Consider that this is a
view of the actual PCM samples on the disc. At no time did I pass any of these
signals through an additional stage of ADC before viewing them in Audacity.
There is a simple explanation for the presence of this noise
or tone. Way back in the early 1980s the only way to master a CD was to write
the digital data as a pseudo video signal to U-Matic video tape. Before the
audio data could be written to the video tape it had to be processed by a PCM
Processor. It converted the digital audio into a video signal the video recorder
could record. It would appear the audio was played into the ADC units of this
PCM processor (typically a Sony PCM-1630) and in the process the horizontal scan
frequency of the video signal leaked in. The horizontal scan frequency is 15.750
or 15.625kHz depending on whether NTSC or PAL video timing is used during
mastering. When you look at the spectrogram view you will see the noise/tone at
that location.
It is very likely that many other early CDs display this
interesting anomaly.
19 June 2011
Yamaha CDX-530
I took some photos of the innards of my Yamaha CDX-530. I now
have a service manual for it too. I love this player. It never screams at you.