Technical Information about DCC (Digital Compact Cassette)
This directory contains datasheets for a number of DCC-related chips by Philips. These were all found on the Internet.
For an overview of which recorders use which chips, download this Excel spreadsheet.
Various documentation about DCC from reliable sources such as Philips, mention that there were three generations of DCC recorders and chipsets. The only generation of chips that was really well documented (and for which datasheets are available online) is the third generation. The DCC-951 Circuit Description gives a good overview of how these IC’s work together.
To play a DCC tape, the player needs to:
When recording, the DCC recorder needs to:
If you’re new to the world of DCC, you will probably want to start by reading the datasheet for the SAA2023 or SAA3323 Drive Processor (DRP). They are essentially the same, except for the supply voltage (5V vs. 3.3V). DRPs were used in the last recorders that were produced by Philips, and combine a lot of functionality that was previously done by multiple chips. If you understand the functions of the DRP’s, it’s not too hard to understand the schematics of recorders of all generations, even though earlier recorders use older chips for which there is no datasheet.
The Read Amplifier amplifies and filters the signals from the magneto-resistive DCC playback heads, and multiplexes the analog signals for further processing. It needs external signals to control the multiplexing. The TDA1317 and TDA1318 are intended for use with 9-track head assemblies and the TDA1380 is for 18-track heads. Stationary recorders with pivoting heads used the TDA1317 or TDA1318; portable recorders with fixed heads could use two 9-track chips (e.g. the DCC-130 uses two TDA1318) or a single 18-track chip. The TDA1317 has non-multiplexed analog outputs as well as a multiplexed output.
The DEQ was used only in the DCC-130 to process the analog multiplexed input signal from the read amplifier. It worked together with the SAA2022 TFE. We have no information about the SAA2051 which was used in first and second generation recorders.
The ERCO chip was in charge of detecting and correcting errors from the incoming signal from the tape during playback, and formatted the signals that went to the tape during recording. We have no information about it.
The DDSP controls the capstan motor based on the incoming data during playback, or runs it at a fixed speed for recording and analog cassette playback. We have no information about it.
The TFE is used in the DCC-130 only, to combine the functionality of the ERCO (Error Correction) and DDSP (Digital Drive Signal Processor) chips in the first and second generation recorders. It needs to work together with the SAA2032 De-Equalizer (DEQ) chip.
The DRP integrates the functionality of the DEQ (De-Equalizer), ERCO (Error Correction) and DDSP (Digital Drive Signal Processor) from the first and second generation recorders into a single chip. It takes care of all the conversion from multiplexed head signals to PASC and back, and generates timing signals for the capstan motor and the surrounding chips. The SAA2023 is used in the stationary 3rd generation recorders and the SAA3323 is used in the Marantz portables (DCC134, DCC170, DCC175). The only difference between the two chips appears to be that the SAA2023 uses a 5V power supply, whereas the SAA3323 uses a 3.3V power supply.
The SBC converts PCM to PASC (MPEG) subband data. It was used in first and second generation recorders. We have no information about this chip.
The SBF is used to synthesize PCM data from a PASC data stream. One of these was needed for each stereo channel. It was used in first and second generation recorders. We have no information about this chip.
The SFC combines the functionality of the Subband Codec and Subband Filter in earlier recorders. It converts PCM baseband audio into PASC (MPEG) subband data, and vice versa. What it can’t do is the lossy compression part of PASC, so during recording it needs help from an Adaptive Allocator and Scaler. The SAA2002 was used only in the DCC-130, whereas the SAA2003 was used in all the 3rd generation recorders.
The AAS is used during recording to apply the psycho-acoustic model of PASC to the subband data stream from the SFC, to determine how many bits should be allocated to each subband, and what the multiplication factor (scale) of each subband should be. The SAA2013 was used in all third generation recorders (together with the SAA2003 SFC), whereas the SAA2012, even though it appears to be more advanced, wasn’t used in any recorders at all. There is no information about the SAA2011 which was used in the first and second generation recorders.
The DAC converts a PCM signal at 48kHz, 44.1kHz or 32kHz to analog. The SAA7350 can also provide timing signals to a TDA1547. It was used in many digital audio devices, not just DCC recorders. The TDA1313 was used in the DCC134. The TDA1305 is 18 bits and was used for the stationary 3rd generation recorders. The UPD63200 (18 bits) was used in the DCC130; unfortunately there’s only a Japanese datasheet online for it as far as we could tell. We have no information about SAA7321 and SAA7323 which were used in second generation recorders.
The SM5840 is an 8-times oversampling digital filter for digital audio, that works together with the SAA7350. We have no information about the SM5881 which was used in the DCC130 and DCC134.
The SAA7366T is an 18 analog to digital converter used in 3rd generation recorders. We have no information about the AK5326 which was used in first and second generation recorders.
The TDA1309H was an 18-bit analog-to-digital and digital-to-analog converter that was used in the Marantz portable recorders (DCC170/DCC175).
The DAI or DAIO converts the IEC958 (S/PDIF) signal from a coax or optical input to I2S (Inter-IC Sound) bit stream, and back. It also encodes and decodes SCMS bits in the IEC958 stream. The M51581 was used in first and second generation recorders. The TDA1315 supports 18 bit audio and was used in 3rd generation recorders.
The write amplifier is connected to the DCC recording heads. It demultiplexes the formatted digital stream with modulated data and uses it to control the current through the recording coils in the head. The TDA1319 support 9 heads, whereas the TDA1381 supports 18 heads. We have no information about the TDA1316 which was used in the first and second generation recorders.