Yamaha just recently introduced the new PSR-S770 and PSR-S970 arranger workstations. As usual, I’m always anxious to dive into the service manual and see what’s up.
First, I’d like to thank Uli and capriz68 on the PSR Tutorial Forum for their help. Uli made a very nice table from my ramblings, so be sure to check it out there.
Without further introduction, here is a table comparing previous generation models (PSR-S750 and PSR-S950) against the new models.
PSR-S750 PSR-S950 PSR-S770 PSR-S970 -------- --------- -------- --------- Main CPU SWX08 SH7731 SH7731 SH7731 Clock rate (MHz) 135.4752 256 320 320 Tone generator SWP51L SWP51L SWP70 SWP70 Ext clock (MHz) 11.2896 11.2896 22.5792 22.5792 DSP SDRAM (MBytes) 8 8 8 8 DSP RCLK (MHz) 45.1584 45.1584 95.9616 95.9616 Mic ADC AK5381 PCM1803 AK5357 AUX IN ADC AK5357 AK5381 AK5357 AK5381 DAC AK4396 AK4396 AK4396 AK4396 Digital amp YDA164C 2*YDA164C YDA164C 2*YDA164C Wave ROM (MBytes) 256 256 512 2048 Wave SDRAM N/A N/A 32MBytes 32MBytes SSP2 chip No Yes No No
The main CPU remains a Renasas SH4AL-DSP CPU. The clock speed is increased from 256MHz to the 320MHz, which is just shy of the rated maximum for the SH7731.
Wave memory is increased from 256MBytes (S950) to 512MBytes (S770) and 2GBytes (S970). Part of the S770 and S970 wave memory is reserved for expansion pack voices: 160 MBytes (S770) and 512 MBytes (S950). How Yamaha uses the rest of the memory is up to Yamaha. However, we are now in an era when we cannot compare products solely on the basis of physical wave memory size. Our ears and performance experience are more important than mere byte counts!
The S970 has two NAND flash memory devices labelled “audio style.” The devices are:
4Gbit NAND flash = 512MBytes 2GBit NAND flash = 256MBytes --------- Total audio style 768MBytes
Yamaha specifies memory size in bits, so one must be careful to convert during analysis. The PSR-S950 has a NAND flash device labelled “Program ROM,” which presumably served the same purpose as well as holding the operating system image that is loaded at boot time. The S950 device capacity is 512MBytes (4Gbits). The S970 reserves 128MBytes for audio style expansion.
The upper mid-range model, i.e., the S970, is biamplified with two digital power amps. The older S950 is also biamplified. Not much change here.
The big news is that Yamaha have a new tone generator integrated circuit (IC), the SWP70. The SWP70 uses the serialized wave memory interface that I described in an earlier post. The SWP70 appears to operate at twice the speed of the older SWP51L. The SWP70 has implications for other future products, so I will analyze it in a separate post.
With respect to the PSR-S970, however, there is another evolutionary step. With the appearance of the new SWP70, there is also the disappearance of the SSP2 IC. The introduction of the SSP2 IC coincided with the introduction of Vocal Harmony 2 in both the Tyros line and the PSR-S950. It is reasonable to infer, then, that vocal harmony is implemented on board SSP2. With the PSR-S970, there are two possibilites.
- Vocal harmony is assigned to the now faster main CPU, or
- SSP2 functionality is integrated into the new SWP70.
The SWP70 is beefed up in other ways including a new wave working memory.
The future looks interesting as always!
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