Craig,
I think that he meant to use a dual ganged pot and use one to act as an "encoder" to sense where the pot is on its rotation. It would divide the regulator voltage.
I think the bent audio solution is still better, but its not as good as the APOX 🙂
The Bent audio system uses a DACT stepped attenuator and attaches a motor pulley to it. They can also move a switch for a tranformer based system.
Some pots don't sound too bad. I am not sure there is a high quality "inexpensive" motorized pot.
Remember, these are only my opinions. Still, not a bad dea and we were going to use the pot idea instead of the encoders, but the encoders seemed more elegant.
I think that he meant to use a dual ganged pot and use one to act as an "encoder" to sense where the pot is on its rotation. It would divide the regulator voltage.
I think the bent audio solution is still better, but its not as good as the APOX 🙂
The Bent audio system uses a DACT stepped attenuator and attaches a motor pulley to it. They can also move a switch for a tranformer based system.
Some pots don't sound too bad. I am not sure there is a high quality "inexpensive" motorized pot.
Remember, these are only my opinions. Still, not a bad dea and we were going to use the pot idea instead of the encoders, but the encoders seemed more elegant.
Another New Product Idea: CD-ROM interface
Hi Dale and Craig,
I know this is also a little off topic, but I was wondering if
you guys would consider making an APOX interface with
a CD-ROM drive, such as this:
http://www.teac.com/DSPD/52XCDROM.htm
This drive is about $30, and I know someone who is using it
with a DAC and is getting great results. This CD-ROM
supposedly outputs SPDIF. The interface design would
use an LCD to simply display the track, and maybe playing time, etc. The most important feature would be the remote control capability.
Now, this is kind of re-inventing the wheel because anyone can
go out and buy a cheap cd player with a digital out for $99. But,
if a high-quality CD-ROM drive is used, it may make a better
transport with lower jitter, better error correction and disc
readability, smoother operation, faster loading, etc.
The other advantage is one can pick their own power supply,
and can opt for something better than the cheap switchers that
are used in many cheap dvd/cd players. The power supply won't need to power things like audio and video boards and other
things that are not needed if one is going to use their own
high-quality external DAC.
I guess the overall goal is a nice remote controlled interface for a
decent CD-ROM transport, and the results would be a higher quality digital output signal, quieter playback mechanism, better error correction and disc readability, etc.
I think something like this came up a month or two back about a
CD-PRO interface. I was hoping to use a less expensive drive that
still is high quality.
What do you guys think of this? Feel free to be honest and blunt, I can take it
-Vinnie
Hi Dale and Craig,
I know this is also a little off topic, but I was wondering if
you guys would consider making an APOX interface with
a CD-ROM drive, such as this:
http://www.teac.com/DSPD/52XCDROM.htm
This drive is about $30, and I know someone who is using it
with a DAC and is getting great results. This CD-ROM
supposedly outputs SPDIF. The interface design would
use an LCD to simply display the track, and maybe playing time, etc. The most important feature would be the remote control capability.
Now, this is kind of re-inventing the wheel because anyone can
go out and buy a cheap cd player with a digital out for $99. But,
if a high-quality CD-ROM drive is used, it may make a better
transport with lower jitter, better error correction and disc
readability, smoother operation, faster loading, etc.
The other advantage is one can pick their own power supply,
and can opt for something better than the cheap switchers that
are used in many cheap dvd/cd players. The power supply won't need to power things like audio and video boards and other
things that are not needed if one is going to use their own
high-quality external DAC.
I guess the overall goal is a nice remote controlled interface for a
decent CD-ROM transport, and the results would be a higher quality digital output signal, quieter playback mechanism, better error correction and disc readability, etc.
I think something like this came up a month or two back about a
CD-PRO interface. I was hoping to use a less expensive drive that
still is high quality.
What do you guys think of this? Feel free to be honest and blunt, I can take it
-Vinnie
I got my new front and rear panels for my apox kit today. I rearranged the back to make better. I have decided to make a 4" x 5" pcb for the chassis, which will do the input selection, volume control via the pga2310, along with regulation for the +/- 15 and +5 power supplies. It will operate similar to the apox 3, but for input selection, I was thinking about using the analog devices SSM2404 quad CMOS switch for input switching.
--
Brian
--
Brian
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Member
Joined 2002
damit you now owe me a new keyboard from all my druel dripping out of my mouth. DAM YOU!! : O )
Here is a shot of the board mounted to the front panel. If you are confused as to why the encoders are mounted backwards, it is because Dale was kind enough to provide me with the older revision boards, which had the encoders wired the opposite way. This is my friend's chassis and board setup. I used the latest revision for mine, and spaced them another inch apart, using cables to connect the whole thing together. I made another chassis 14" wide, and will be using the encoders full width apart for it.
As for the Analog Devices switches, SSM2404, here is the product link:
http://www.analog.com/Analog_Root/productPage/productHome/0,2121,SSM2404,00.html
As to the audio quality of having a pga2310, microcontroller and gainclone in a small 12"x10"x3" box... I am going to make it work the best that I can in the limited space, but in the end, this project is for my girlfriend, and she isn't very picky.
The goal of this project is to look minimal and fully functional. She didn't want 3 chassis for one unit, as I first planned.
--
Brian
As for the Analog Devices switches, SSM2404, here is the product link:
http://www.analog.com/Analog_Root/productPage/productHome/0,2121,SSM2404,00.html
As to the audio quality of having a pga2310, microcontroller and gainclone in a small 12"x10"x3" box... I am going to make it work the best that I can in the limited space, but in the end, this project is for my girlfriend, and she isn't very picky.
The goal of this project is to look minimal and fully functional. She didn't want 3 chassis for one unit, as I first planned.
--
Brian
Attachments
Re: Another New Product Idea: CD-ROM interface
I don't know if it's the same drive, but Ayre is using Teac CD ROM drive in their 3,000 GBP player. I read review in hi fi + and it was very positive. Something definitely worth consideration and cheaper than CD-Pro😉
Vinnie R. said:
I don't know if it's the same drive, but Ayre is using Teac CD ROM drive in their 3,000 GBP player. I read review in hi fi + and it was very positive. Something definitely worth consideration and cheaper than CD-Pro😉
Attachments
Member
Joined 2002
hey i was just about to scann that with my new scanner and post some stuff. Humm should we start a new thread about this. Would it be worth it.?
Questions.
What kinda drive to use.?
Who would start the schematic for the dac?
We want Balanced?
Questions.
What kinda drive to use.?
Who would start the schematic for the dac?
We want Balanced?
If it is good enough for Ayre, and others, Teac must be the one! I can't read the model of the drive in the photo, can anyone?
The control codes for all CD drives must be similar- after all, you just stick 'em into your computer, right? So maybe if the APOX folks add the CD drive control functionality (and daughter board?), it would work with any drive. This is a GREAT idea!!! and cheap!!
Why don't the mods create a thread: APOX CD controller or some such. The APOX guys have no choice! We want this product!
Clearly this is a better idea than the pro CD drive control for most of us. The DAC can be various options, but the APOX members seem to have a knack (and the chops) of being able to produce products that satisfy almost everyone, so they might be able to make a design based on all our input. Balanced-but of course!!!
Or, can't we use any of the DAC designs floating around?
The control codes for all CD drives must be similar- after all, you just stick 'em into your computer, right? So maybe if the APOX folks add the CD drive control functionality (and daughter board?), it would work with any drive. This is a GREAT idea!!! and cheap!!
Why don't the mods create a thread: APOX CD controller or some such. The APOX guys have no choice! We want this product!
Clearly this is a better idea than the pro CD drive control for most of us. The DAC can be various options, but the APOX members seem to have a knack (and the chops) of being able to produce products that satisfy almost everyone, so they might be able to make a design based on all our input. Balanced-but of course!!!
Or, can't we use any of the DAC designs floating around?
here's a DAC thread that seems to sum up a lot:
http://www.diyaudio.com/forums/showthread.php?s=&postid=184009#post184009
http://www.diyaudio.com/forums/showthread.php?s=&postid=184009#post184009
Member
Joined 2002
Jason, Variac etc.
If you decide to go that route, you really ought to consider changing the firmware so that you can lock the unit down to lower rotational speed.
I think that at this moment in time, it is not "optimal" to make a standalone CD player. What I am planning is a computer based play-back system (PC) with external DAC. Windows Media 9 series supports lossless compression and you will get about 450-600 CD's with lossless compression on a 250MB hard-drive.
Then you can of course play back anything you want, and perhaps spend your time even better in software optimization such as up-samplers, digital crossovers, room correction etc. You will of course automagically take part in the effort that Microsoft and others are putting into software development (mixer etc.)
Your mileage may vary.
Petter
If you decide to go that route, you really ought to consider changing the firmware so that you can lock the unit down to lower rotational speed.
I think that at this moment in time, it is not "optimal" to make a standalone CD player. What I am planning is a computer based play-back system (PC) with external DAC. Windows Media 9 series supports lossless compression and you will get about 450-600 CD's with lossless compression on a 250MB hard-drive.
Then you can of course play back anything you want, and perhaps spend your time even better in software optimization such as up-samplers, digital crossovers, room correction etc. You will of course automagically take part in the effort that Microsoft and others are putting into software development (mixer etc.)
Your mileage may vary.
Petter
Re: Re: Another New Product Idea: CD-ROM interface
that's one expensive repackaging!
Any reason why any old 50c cdrom would sound just as good?
Peter Daniel said:
that's one expensive repackaging!
Any reason why any old 50c cdrom would sound just as good?
Here's a better pic of the drive. The Ayre model number is CX-7.
Petter, as to the computer based play-back system (PC) with external DAC, some of us want to stay away from computers if possible. I still prefer to take a CD out of a jewel box, browse through the cover, instead of just picking and item from a list on a computer screen. 😉 But I agree that this is a way things will be done in a future.
Petter, as to the computer based play-back system (PC) with external DAC, some of us want to stay away from computers if possible. I still prefer to take a CD out of a jewel box, browse through the cover, instead of just picking and item from a list on a computer screen. 😉 But I agree that this is a way things will be done in a future.
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Craig and harvardian (just down the road from me!),
harvardian is right about how I envisioned the use of the pot to "encode" position. This would be fairly simple, I think.
Regarding the bent audio solution: I suppose a motor could drive any shaft so that a non-motorized pot could be used. A stepped-motor would allow the PIC to not need the resistance feedback, so long as the PIC remembers its location even if unplugged (not too hard). The pot would, of course, allow much finer volume resolution than a 24 stepped attenuator, or even an 8 bit relay setup. I had never thought of it controlling a rotary input select switch, though that is certainly possible as well.
I guess I figured a single pot would be less noisy (especially if calibrated) and more precise than a series of resistors and relays.
This is probably another area of voodoo audio, and I'm afraid to even ask it, but are discrete resistors (via stepped attenuators or relays) considered better than a high-quality pot?
harvardian is right about how I envisioned the use of the pot to "encode" position. This would be fairly simple, I think.
Regarding the bent audio solution: I suppose a motor could drive any shaft so that a non-motorized pot could be used. A stepped-motor would allow the PIC to not need the resistance feedback, so long as the PIC remembers its location even if unplugged (not too hard). The pot would, of course, allow much finer volume resolution than a 24 stepped attenuator, or even an 8 bit relay setup. I had never thought of it controlling a rotary input select switch, though that is certainly possible as well.
I guess I figured a single pot would be less noisy (especially if calibrated) and more precise than a series of resistors and relays.
This is probably another area of voodoo audio, and I'm afraid to even ask it, but are discrete resistors (via stepped attenuators or relays) considered better than a high-quality pot?
BrianGT,
Lucky girlfriend!
There's nothing really wrong with the SSM2404, but I'm curious about why not use the relays? Is it a simple economy issue?
Your cases are fantastic.
-Dave
Lucky girlfriend!
There's nothing really wrong with the SSM2404, but I'm curious about why not use the relays? Is it a simple economy issue?
Your cases are fantastic.
-Dave
CD player controller
VinnieR,
Well after you mentioned $30 for a CD player.
I just became very intrigued.
I was all little hesitant with the CDPRO-2 due to the price.
Its truly amazing that they can offer the CD player at $30
unfortunately, I have never interfaced to an IDE/ATAPI
bus. (Maybe Dale has?)
I'm assuming to get the high speed data, you would need an
FPGA or some dedicated IDE/ATAPI interface chip.
Anybody have any experience with that?
Maybe thats the reason the CD-PRO2 is more expensive.
the only CPU interface is the serial bus?
That would be a pretty cool project
-Craig
VinnieR,
Well after you mentioned $30 for a CD player.
I just became very intrigued.
I was all little hesitant with the CDPRO-2 due to the price.
Its truly amazing that they can offer the CD player at $30
unfortunately, I have never interfaced to an IDE/ATAPI
bus. (Maybe Dale has?)
I'm assuming to get the high speed data, you would need an
FPGA or some dedicated IDE/ATAPI interface chip.
Anybody have any experience with that?
Maybe thats the reason the CD-PRO2 is more expensive.
the only CPU interface is the serial bus?
That would be a pretty cool project
-Craig
Re: CD player controller
Hi Craig,
Yeah, decent CD-ROMs that you would put in a PC are in the $30 range, not much more than $60 I don't think. I know of a Sony CDU5211 that has play, stop, next track, and eject on the front, along with a headphone jack and volume control. One of our products at my job uses this CD-ROM 🙂
On the back of the Sony is a 40-Pin ATAPI interface, and also a digital audio out (SPDIF?). Like I said, the user would choose their own DAC (as there are lots out there), and it would be
DipChip that would design a board that will allow the CD-ROM
to be controlled via remote, and maybe a display 😉
As for features, I personally wouldn't want too many, but others might. I just want a basic but high quality transport that can be controlled via remote.
The Sony uses a 5V 1A input and a 12V 1.5A input. A custom designed linear regulated power supply would give the best performace over inferior switcher power supplies that a lot of
dvd/cd players have, which people use to send SPDIF out to a DAC. The whole idea is that one can choose their own DAC, Chassis, and power supply (or DipChip can design one too
)
Since a lot of CD-ROM devices for computers have basically the same interface, more than one type can be used. The goal is
to find one for a good price that has really good error correction,
low jitter, super-quiet operation, and can read disks very well. The low jitter part may require some tweaking to the clock circuitry (PLL).
So, is there enough interest to start a new DipChip thread on this discussion board? I don't want this to thread-jack the APOX kits.
What do you guys think?
-Vinnie
dipchip said:VinnieR,
Well after you mentioned $30 for a CD player.
I just became very intrigued.
I was all little hesitant with the CDPRO-2 due to the price.
Its truly amazing that they can offer the CD player at $30
unfortunately, I have never interfaced to an IDE/ATAPI
bus. (Maybe Dale has?)
I'm assuming to get the high speed data, you would need an
FPGA or some dedicated IDE/ATAPI interface chip.
Anybody have any experience with that?
Maybe thats the reason the CD-PRO2 is more expensive.
the only CPU interface is the serial bus?
That would be a pretty cool project
-Craig
Hi Craig,
Yeah, decent CD-ROMs that you would put in a PC are in the $30 range, not much more than $60 I don't think. I know of a Sony CDU5211 that has play, stop, next track, and eject on the front, along with a headphone jack and volume control. One of our products at my job uses this CD-ROM 🙂
On the back of the Sony is a 40-Pin ATAPI interface, and also a digital audio out (SPDIF?). Like I said, the user would choose their own DAC (as there are lots out there), and it would be
DipChip that would design a board that will allow the CD-ROM
to be controlled via remote, and maybe a display 😉
As for features, I personally wouldn't want too many, but others might. I just want a basic but high quality transport that can be controlled via remote.
The Sony uses a 5V 1A input and a 12V 1.5A input. A custom designed linear regulated power supply would give the best performace over inferior switcher power supplies that a lot of
dvd/cd players have, which people use to send SPDIF out to a DAC. The whole idea is that one can choose their own DAC, Chassis, and power supply (or DipChip can design one too
)Since a lot of CD-ROM devices for computers have basically the same interface, more than one type can be used. The goal is
to find one for a good price that has really good error correction,
low jitter, super-quiet operation, and can read disks very well. The low jitter part may require some tweaking to the clock circuitry (PLL).
So, is there enough interest to start a new DipChip thread on this discussion board? I don't want this to thread-jack the APOX kits.
What do you guys think?
-Vinnie
Scraggles,
Thanks for the link.
After looking over the guys project. I now think the project is easier than I thought. He only uses a small microcontroller with 2K ROM to interface to the CD-ROM's IDE bus.
And since the code is only 2K at most, how hard can it be?
And if Vinnie found a CD player with SPDIF out. someone around here must have made a DAC?
Cool! 😎
-Craig
Thanks for the link.
After looking over the guys project. I now think the project is easier than I thought. He only uses a small microcontroller with 2K ROM to interface to the CD-ROM's IDE bus.
And since the code is only 2K at most, how hard can it be?
And if Vinnie found a CD player with SPDIF out. someone around here must have made a DAC?
Cool! 😎
-Craig
New board the APOX-IS2
Hi guys,
I started re-designing the APOX-IS1 board to fix the XLR connectors. but then Dale suggested something.
He wanted me to remove the XLR connectors from the board, and just have wires soldered to the panel mount connectors.
Also he suggested that I split the ground wires, so that instead of handling 4 single ended inputs, the board could handle 8 single ended inputs (L and R switched in by pairs)
I posted the schematic here for some feedback!
APOX-IS2
What do people think of these changes?
Thanks,
Craig Beiferman
Hi guys,
I started re-designing the APOX-IS1 board to fix the XLR connectors. but then Dale suggested something.
He wanted me to remove the XLR connectors from the board, and just have wires soldered to the panel mount connectors.
Also he suggested that I split the ground wires, so that instead of handling 4 single ended inputs, the board could handle 8 single ended inputs (L and R switched in by pairs)
I posted the schematic here for some feedback!
APOX-IS2
What do people think of these changes?
Thanks,
Craig Beiferman
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