I was reading older forums and I recall a member saying that the Nak OMS-5 has the best transport of any player. I couldn't find any threads of exactly how to do a digital mod with this with this model. Do any you guys have a schematic on how to build a digital coax out and where to connect this on the nak?I have a OMS 5 service manual(paper) and a OMS5 that has the factory modifications to read off spec discs in excellent working condition. Any ideas would be appreciated.
It does not lend itself easily to adding a digital output. It has no biphase-mark output that can used with the addition of a connector and a few passive components and the data format is unsuitable for current SPDIF transmitters.
It does not lend itself easily to adding a digital output. It has no biphase-mark out
Bummer I was really hoping to get new life out of this. Thanks for the reply.
Bummer I was really hoping to get new life out of this. Thanks for the reply.
Hi gto127,
You may be quoting me on this.
I'm thinking the easiest way to do this would be to run the RF pattern into another, more modern CD player board. One "stupid" enough to simply process the data without worrying about controlling the transport. You would have to echo the "tray in" and "play" commands so the TOC could be read in.
This would be a great project to only use the DSP and related circuitry on a mod PCB. Then it could be added to any CD player without a digital out.
I lack the skill and time to figure this out by myself.
-Chris
You may be quoting me on this.
I'm thinking the easiest way to do this would be to run the RF pattern into another, more modern CD player board. One "stupid" enough to simply process the data without worrying about controlling the transport. You would have to echo the "tray in" and "play" commands so the TOC could be read in.
This would be a great project to only use the DSP and related circuitry on a mod PCB. Then it could be added to any CD player without a digital out.
I lack the skill and time to figure this out by myself.
-Chris
run the RF pattern into another, more modern CD player board. One "stupid" enough to
Thanks anand-Does anyone know of a inexpensive cd player that would meet this description and how to do this?
Thanks anand-Does anyone know of a inexpensive cd player that would meet this description and how to do this?
RFBRW-what is MK? I'm a relative newbie to this forum. Also do you think a nak cdplayer 4 board would work? I have one that needs a laser and I have a schematic for the unit.
Hi rfbrw,
Actually, one only needs a cheap CD mech (likely to play without being told). You only require the demod and digital out signals to function. I'm not sure that quality will have any bearing on the result.
I am in favour of a DSP board approach. Just use an available DSP chip with the RF amp built in and a mute input. Feed your RF signal into the RF input on the DSP chip after correcting the level and provide a toslink and RCA type output. This shouldn't be a large board. You could then adapt this to any CD player, or even use it as a sub section for a home brew model. The tough part about building a CD would be to tune the servo gains and filters.
I'm wondering if one or more of our members experienced in this area would take the project on?
-Chris
Actually, one only needs a cheap CD mech (likely to play without being told). You only require the demod and digital out signals to function. I'm not sure that quality will have any bearing on the result.
I am in favour of a DSP board approach. Just use an available DSP chip with the RF amp built in and a mute input. Feed your RF signal into the RF input on the DSP chip after correcting the level and provide a toslink and RCA type output. This shouldn't be a large board. You could then adapt this to any CD player, or even use it as a sub section for a home brew model. The tough part about building a CD would be to tune the servo gains and filters.
I'm wondering if one or more of our members experienced in this area would take the project on?
-Chris
Hi rfbrw, gto127,
You don't want to use one of these. They expect all the signals to be there. Drawer, everything (ie. they are too smart for this). That and one of these is too nice to chop up for this project.
gto127,
-Chris
You don't want to use one of these. They expect all the signals to be there. Drawer, everything (ie. they are too smart for this). That and one of these is too nice to chop up for this project.
gto127,
It's like a major revision change in a model number. In this case an OMS-5 MKII only bears a resemblance to the original OMS-5 in the case appearance. Everything else is totally different, including the laser and transport. With other makes, a MKII may only be the addition of a remote or minor cosmetic change.
-Chris
anatech said:
But it is a servo'ed system. Even the simplest of mechanisms still has to have some idea of the lasers position. I would thought if you have the mechanism you have to have the controls. A frontend chip like those of the CXD2500 series extract the audio and perform control duties as do the Philips SAA732X devices. Even the ancient CD104 cries foul when the HF is removed.
Hi rfbrw,
However, since the RF pattern is being fed in, and another servo system is controlling the head and everything else, the errors should remain within normal ranges. Don't forget that we are feeding in an RF signal only. This bypasses the focus and tracking servos completely (and laser power control). The only other things that will be active are drop out detection and error correction. You still need the RAM unless it's on chip.
-Chris
They sure are.
However, since the RF pattern is being fed in, and another servo system is controlling the head and everything else, the errors should remain within normal ranges. Don't forget that we are feeding in an RF signal only. This bypasses the focus and tracking servos completely (and laser power control). The only other things that will be active are drop out detection and error correction. You still need the RAM unless it's on chip.
-Chris
Hi rfbrw,
Think about providing all the normal signals for an in-box D/A on a header at the very least.
-Chris
Heck, anything! Smt or through hole doesn't matter as long as the parts are available (cheap is always good). Smt version boards would be best purchased as a group buy or a commercial item. I'd love to build one of these up!
Think about providing all the normal signals for an in-box D/A on a header at the very least.
-Chris
anatech, rfbrw count me in if you guys come up with something and want to do a group purchase. I appreciate you putting this much thought into this project. I used to think transports didn't matter until I heard a very good one and another transport through the same DA converter. There was a definate difference in sound quality.
Hey gto127,
Whoa! Hold on there a minute!
I don't have the proper knowledge to set this up, or I would have done so already. We need someone in the digital forum who will become interested and try this out. I might even be barking up the wrong tree here.
-Chris
Whoa! Hold on there a minute!
I don't have the proper knowledge to set this up, or I would have done so already. We need someone in the digital forum who will become interested and try this out. I might even be barking up the wrong tree here.
-Chris
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