A/D Phono Box S
A/D Phono Box S
store your records and tapes collection in computer and protect it against
time and enviromental effects in the easiest way.
Why to do that, and how to do that ?
Our aim was to design product which will be very flexible and will allow to our clients
converting of their precious records or analogue tapes to computer. This allows them
to create undestroyable back up of valuable and beloved collection. For most of our
clients is also very important, that archiving their collection in computer allows them
to play their favourite music from computer and to extend lifetime of rarity records.
This is very important also from point of view of maintanance of cultural heritage.
Beside it, storing of music in computer is the way which offers possibility of further
processing of the records in computer. Removing clicks, eliminating noise from old and
wearing records, and all other creative audio processes. Data from computer can be
burned on CD and also can be used in car, for certain users also very important
feature, because there is existing a lot of music which was never issued on CDs or
issued CD s was remastered in "modern way" with very limited dynamic range.
Music from computer can be also transfered into mobile device as smartphones,
tablets, iPods, iPads and so on.
But A/D Phono Box S has also other significant advantage : it allows to connect
turntable or tape deck (or other source of signal) to device which has no line input.
Today some AVRs has only digital inputs and connecting of the turntable or tape deck
seems to be insoluble problem. The answer is A/D Phono Box S which allows
connecting of two sources of signal, via its SPDIF optical output.
Block diagram and description
A/D Phono Box S - consists of :
1 - MM/MC phono stage
2 - Linear input stage
3 – Record level adjustment
4 - Input selector and Record level adjustment
5 - ADC (analogue to digital convertor) with SPDIF and USB output.
USB output
Input selector and
Record level adjust
AD convertor
Line input stage
Analogue output
SPDIF output
1 - Phono stage :
MM/MC input is on cicnch connector. With switch you can select MM input, where is
gain of 40dB, input impedance 47kohms and capacity 120pF. MC stage has gain 60dB,
input impedance is 100 ohms, capacity is for MC irrelevant value. Phono stage is using
acti-damp technology co-invented by Dr. Sykora
2 - Linear input stage :
is on jack 3,5 mm, using isolating amplifier and impedance converter in order to avoid
excessive loading of connected source of signal.
3 - Input selector :
allows to select desired input Phono or Line. Signal from selected input is present on
Analogue output. This function allows to connect A/D Phono Box permanently in HiFi
system, use it as standard phono preamplifier and in case of need you can convert
your records into digital data stored in your computer
4 - Record level adjustment :
Sources of signal can significantly vary in level of their output voltage. Old tuners can
deliver only 50mV, tape decks or reel to reel decks has very often 350mV and some
sources can deliver also 2V. The same situation we have at turntables. There are MM
cartridges which deliver 2mV, and others can deliver also 6mV. If we count with gain
40dB which means 100 x it result in output voltage 200mV or 600mV. Such big
differencies in voltage level can easily overload input of AD converter which you will
hear as distortion in music. On the other side when AD converter is not feed with
proper level of the signal, we will loose resolution. That is why level of the signal on
ADC input must be carefully adjusted.
5 - A/D converter :
is based on Texas Instruments chip PCM2906. The PCM2906 is Texas Instruments
single-chip USB stereo audio codec with USB-compliant full-speed protocol controller
and S/PDIF output. The USB protocol controller works with no software code. This
means that no additional software is required. A/D Phono Box S is recognized by your
computer and is automatically installed as new recording software. The
PCM2904/2906 employs SpAct™ architecture, unique system that recovers the audio
clock from USB packet data. On-chip analog PLLs with SpAct enable playback and
record with low clock jitter and with independent playback and record sampling rates.
Analogue to digital conversion is supporting depth of 16 bit and sampling frequency
up to 48kHz. This is the same resolution which offers DVD-A and it is even slightly
higher than resolution offered by standard CD. You can convince yourself, that your
recording from turntable via A/D Phono Box S can be of higher resolution and better
quality than your CDs.
USB Recording :
Recording into computer requires Recording Software. On Internet can be found a lot
of recording software. Very good results we have with "Audacity". This is freeware
and can be downloaded from http://audacity.sourceforge.net/. For sure this is not
limited by Audacity, can be used also with other software. For Mac based computer
can be used for example "Garage Band".
Tape deck
A/D Phono Box S
Analogue or optical
Here we can see A/D Phono Box S connected to the turntable and also to additional
line source. Output of A/D Phono Box S is connected to computer by USB cable.
Optical or analogue output is connected to Second output of A/D Phono Box S is
connected to amplifier. This is the most complex and in the same time the most
effective use of A/D Phono Box S. It allows to use all the possible features.
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