Thule Audio CD-250-B Brochure
New Upgrade board for DVD250B and CD150B with
192 kHz sample rate converter
- Gives new life to your CD collection
We know this is a bit of a cliché in the audio business , but we really
think it’s a fitting description for our newest product. And with the
SACD and DVD Audio formats still struggling to convince the
consumer of their relevance, due to the format war and lack of music
material, Thule Audio now offers an unique solution to significantly
improve the sound from CD disc’s.
A little history: In 1997 Thule Audio introduced the Digit board, for
the balanced version of our CD player. It was designed from our
many years of experience working with balanced products, using the
best available components at the time. The converter from Burr
Brown, PCM 1702K (K for specifically selected high performance),
gave our CD players a performance unsurpassed. In te sts all around
the world it has matched much more expensive players from some
of the most well known brands in the business.
Last year we were unfortunately forced to stop the production of this board, due to availability problems of some
special parts for this product.
We have for quite some time felt that something was missing in our product range, and it is therefore with great
pride, that we present DIGIT II, a 192KHz/24bit upsampling board. From the beginning we have wanted to make
an upgrade board that could be used in as many of our applications as possible, so because of the built-in
intelligence in this board, it actually chooses the correc t clock signals depending on what type of product you
put it in. Therefore it is possible to mount this board in our DVD250B as well as the new CD150B with Sony
loader.
The design of this board enables it from the factory to fit directly into both the CD150B as well as the DVD250B,
without any kind of modifications. This means that you only have to stock one type, you can sell to both CD and
DVD customers. The board will be delivered in a nice box, off course including instructions and specifications.
On the technical side there are quite a few interesting things to mention. First of all the board is equipped with
the absolutely newest technology available on the market today. The heart in this upsampling board is the new
state of the art AD1896, 192kHz/24bit asynchronous sample rate converter, combined with the new Burr Brown
PCM 1738 high end D/A converters, coupled in double differential mode. The crisp and true sound produced in
them are really something worth listening to. Of other components, we have chosen hig h sta bility oscilator s with
ultra low jitter, precision resistors and the best available capacitors in the market.
The asynchronous sample rate converter converts the 44kHz/16bit CD signal into a very high frequency
bitstream based on an intelligent interpolation from the last 64 input samples.
The high frequency stream is then filtered and resampled at the output rate of 192kHz with 24bit resolution.
Thule Audio reserve the right to alter design and specifications without notice.
With this advanced digital processing we have obtained following advantages:
With this advanced digital processing we have obtained following advantages:
With this advanced digital processing we have obtained following advantages:With this advanced digital processing we have obtained following advantages:
1. Significantly improved dynamic range for a 16bit CD signal.
1. Significantly improved dynamic range for a 16bit CD signal.
1. Significantly improved dynamic range for a 16bit CD signal.1. Significantly improved dynamic range for a 16bit CD signal.
What really matters to obtain the best musical performance is not the full level distortion (0dB), but the low level
distortion: Even the poorest D/A converters has 0.004-0.005% distortion at 0dB, but at normal music levels -30
dB to -60dB, the distortion raises to several percent.
The low level distortion is called dynamic range, and is normally measured at -60dB.
The theoretical maximum dynamic range for a 16bit signal is 96dB. The best D/A converters can achieve a
performance of about 95dB.
With the intelligent high frequency interpolation a significant 5dB improvement to totally 100dB of dynamic
range is obtained.
2. Effective suppression of clock jitter.
2. Effective suppression of clock jitter.
2. Effective suppression of clock jitter.2. Effective suppression of clock jitter.
Jitter is due to variations in the clock rate from e.g. pulse di spersion , and will g enerate side loopes to the original
tone in the D/A conversion process. These sideloopes diminishes the clearness and brightness in the sound
stage.
Due to the asynchronous rate conversion, the input and output rate is completely independent, thus the jitter in
the original signal is completely suppressed. The 192kHz output rate feed to the D/A converters is generated
locally from a high precision crystal oscillator.
3. Out of band noise attenuation.
3. Out of band noise attenuation.
3. Out of band noise attenuation.3. Out of band noise attenuation.
Normally the D/A converter will generate several mV of high frequency noise just above the audio frequencies
(20kHz) from the delta-sigma process. This noise must be removed by analog filtering or it can disturb the
stability of the audio-amplifier. However, this analog filtering means other disadvantages as phase shift in the
audio band.
With the 192kHz sample rate conversion, the delta sigma noise is moved up over 192kHz and only a very
moderate analog filter is necessary.
4. D/A Converters.
4. D/A Converters.
4. D/A Converters.4. D/A Converters.
The Burr-Brown D/A converters PCM1738 are a new revolutionary type called Advanced Segment DAC@, which
combine the dynamic sound from a multi bit D/A converter and low level precision from a Delta-sigma DAC:
The most significant 6 bit are converted in multi bit DAC and the 18 least sig nificant bit are converted in a Delta
Sigma DAC.
With the new DIGIT II upgrade board we are convinced that the sound from your CD’s will be much closer to the
quality of a DVD-audio and SACD disc. In fact, we are sure that the quality of the recording on your CD’s in most
cases will be the bottle neck for better quality.
Play your CD collection again with DIGIT II and you will discover new details, you
Play your CD collection again with DIGIT II and you will discover new details, you
Play your CD collection again with DIGIT II and you will discover new details, youPlay your CD collection again with DIGIT II and you will discover new details, you
have never heard before.
have never heard before.
have never heard before.have never heard before.
Thule Audio reserve the right to alter design and specifications without notice.
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