Re: Re: Re: Re: Re: Lead sheets on transport
That will be true of older servos running at 1x speed where the disc spins about 400 rpm. The implies that the supplies will be modulated by this frequency and at harmonics of this frequency (400Hz, 800 Hz, 1200 Hz, etc). Some of the CD-ROM mechanisms playback CD-DA at 24x to minimize "rip" time...these servos will need correct to a 24x higher bandwidth or about 10 Khz. So as the consumer and PC products converge more and more, we should see servo bandwidths increase.
This modulation by the servos on power supplies might be something that can be played with to find out which spin rate sounds optimum. Necessary in these type of designs is a RAM buffer that will take the data and reconstruct the original data stream from multiple overlapping reads.
I have an 52x LG CD-ROM that I'm experimenting with at the moment. It is light, plasticky, and cheap and has been responsive to changes in
Guido Tent said:
That will be true of older servos running at 1x speed where the disc spins about 400 rpm. The implies that the supplies will be modulated by this frequency and at harmonics of this frequency (400Hz, 800 Hz, 1200 Hz, etc). Some of the CD-ROM mechanisms playback CD-DA at 24x to minimize "rip" time...these servos will need correct to a 24x higher bandwidth or about 10 Khz. So as the consumer and PC products converge more and more, we should see servo bandwidths increase.
This modulation by the servos on power supplies might be something that can be played with to find out which spin rate sounds optimum. Necessary in these type of designs is a RAM buffer that will take the data and reconstruct the original data stream from multiple overlapping reads.
I have an 52x LG CD-ROM that I'm experimenting with at the moment. It is light, plasticky, and cheap and has been responsive to changes in
- removing the tray(worse)
- adding coaxial RCA jack wire with CAT5(better)
- damping with blutak (better)
- bypassing 5V/12V supplies with small Panny HF caps(better)
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The LSI chips and design for manufacuturability(ease of assembly) have resulted in a clean mechanical design. The small value surface mount electrolytics and lack of local bypassing(motors and servos) could be areas that can easily be corrected. The one thing that would be neat would be a button to toggle the spin rate when playing back audio (ie. 1x, 2x, 3x, 4x....24x) to see which sounds best.
LG 52x CD-ROM mods
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