XDA-1 (Add On Product ???)

[Chuck Elliot]

I got the chassis today and mounted the hardware. I guess I better get to work on the inside!

[Chuck Elliot]

I designed the relay PCB this weekend. I have never done one of these before, but found a place on the Internet expresspcb.com/ that has free software and will do a small 2-layer board for $51.

The circuit has changed in 2 ways and I'll post a schematic of the changes later.

1) The LEDs have been removed and a 12V regulator IC is used instead to drop the 15V supply for the relays.

2) On stuofsci02's suggestion, the mosfet that controls the relays now has 2 triggers. The first is the Power-Ok signal that comes from the power supply and the second is for the 12V trigger from the XDA-1. I also added a jumper block so either can be bypassed.

[CrazyBlue]

Cool.

I'd be interested in one of these for sure. I don't need all the features of the XSP-1, but would like a high/low pass crossover with the same output stage as the XDA-1. Don't want to use the USP-1 for bass management and defeat the point of using the XDA-1. Might as well use the DAC in my Musiland and Oppo at that point and save some money. I hope Emotiva builds one.

I'd pay the same $$ for it as the USP-1 to get bass management and keep that output stage, provided it's as awesome as Lonnie says it is.

I'll find out after Christmas, maybe before, considering all the preorders. Looking forward to hearing peoples' impressions/reviews.

[roadrunner]

Nov 5, 2010 10:46:48 GMT -5 CrazyBlue said:

Cool.

I'd be interested in one of these for sure. I don't need all the features of the XSP-1, but would like a high/low pass crossover with the same output stage as the XDA-1. Don't want to use the USP-1 for bass management and defeat the point of using the XDA-1. Might as well use the DAC in my Musiland and Oppo at that point and save some money. I hope Emotiva builds one.

I'd pay the same $$ for it as the USP-1 to get bass management and keep that output stage, provided it's as awesome as Lonnie says it is.

I'll find out after Christmas, maybe before, considering all the preorders. Looking forward to hearing peoples' impressions/reviews.

You lost me on this one. I don't see how using cfelliot's "bypass" switch would provide bass management for the XDA-1. You would need something like the USP-1 or the XSP-1; and, to maximize the sound quality from the XDA-1 you would want to get the XSP-1 for its differential output stage and its analog bass management system.

[Chuck Elliot]

Nov 5, 2010 11:33:30 GMT -5 roadrunner said:

You lost me on this one. I don't see how using cfelliot's "bypass" switch would provide bass management for the XDA-1. You would need something like the USP-1 or the XSP-1; and, to maximize the sound quality from the XDA-1 you would want to get the XSP-1 for its differential output stage and its analog bass management system.

See post #3 in this thread for a full block diagram.

This is more than a "bypass switch". The balanced input goes to an analog crossover that splits the signal into hi/low.

The crossover point is fixed in the construction by the values on the crossover.

The crossover board also has level controls to adjust the relative attenuation on hi and low if needed. I do because my mains are 99dB and my subs are 89dB,

Although this is a limitation, I know where I want these values and they don't change.

I do not have balanced power amps or I would have designed balanced outputs.

[roadrunner]

Nov 5, 2010 11:55:52 GMT -5 Chuck Elliot said:

Nov 5, 2010 11:33:30 GMT -5 roadrunner said:

You lost me on this one. I don't see how using cfelliot's "bypass" switch would provide bass management for the XDA-1. You would need something like the USP-1 or the XSP-1; and, to maximize the sound quality from the XDA-1 you would want to get the XSP-1 for its differential output stage and its analog bass management system.

See post #3 in this thread for a full block diagram.

This is more than a "bypass switch". The balanced input goes to an analog crossover that splits the signal into hi/low.

The crossover point is fixed in the construction by the values on the crossover.

The crossover board also has level controls to adjust the relative attenuation on hi and low if needed. I do because my mains are 99dB and my subs are 89dB,

Although this is a limitation, I know where I want these values and they don't change.

I do not have balanced power amps or I would have designed balanced outputs.

Sorry, I got lazy and referred to your "device" as a "bypass switch". I realized that you had incorporated a fixed cross over internally. Crazy4Blues has mentioned in several threads that he needed a good bass management system for use with the XDA-1 and that he did not want to limit the potential sound quality by using the unbalanced output stage of the USP-1. Knowing that these were key issues for Crazy... I saw that your device did not address his desire for a way to provide bass management on a differential signal path. No slight was intended.

As a matter of fact, I have been following your thread and agreed with Lonnie that you have come up with a simple but elegant solution. You could probably "kit" this design and have a viable market should you desire to.

[CrazyBlue]

I'm just saying that if Emotiva built something like this, or even a little more flexible, for users with digital sources that want the advantages the XDA-1 offers when used as a preamp, but still desire the ability to high-pass their mains and cross over to a subwoofer (which in itself should offer improved SQ out of both over sending them a full range signal), I would buy it.

Take the balanced input stage, analog bass management section, and dual differential/balanced output stage of the XSP-1 and put it in a box for folks who probably won't/can't pay the $900 for the XSP-1 because they don't need the rest of the features it offers. Charge something like $400-$500 for it.

People like me get to keep the sonic advantages the XDA-1 offers as a digital preamp and save $400-$500 over the XSP-1.

This was the idea behind cfelliot's original post, I believe; to see if anybody was interested in such a component and whether Lonnie and the gang would be interested in offering it as an in-between or add-on to the XDA-1.

I can't afford a $900 preamp right now and if I need to use the USP-1 to get bass management, I'll just buy that instead of the XDA-1. I'm waiting until after Christmas and to see what others have to say once the DAC is in their hands. Then I'll decide.

Or I may buy both (XDA-1 and USP-1) and A/B them in my home and see which I prefer, my sources into the XDA-1 run full range or the DAC's in my sources into the USP-1.

Just have to wait and read the customer reviews and see if I can swing the funds to try both and A/B them when the time comes.

Or win the lottery...

;D

[Chuck Elliot]

I got the AC wired today. Secondary checked out at 2x19V:



On to the DC PCB!

Finally got to see the switch illuminated. Hate it, but this is a low priority for now. What I wouldn't give for an Emotiva switch - hint hint!!!

[Chuck Elliot]

I built and installed the DC Power Supply in the chassis today.

Last of the parts should be here beginning of the week. With the notification of the XDA-1 shipping in 2 weeks, I've got to get a move on - damn leaves in the yard!!!!

[Topend]

Thanks for the update. I am really looking forward to seeing the final product and reading about how it performs.

Cheers,
Dave.

[ottaone]

I'm liking this thread. Don't understand much but I'll keep a link to this thread. I promised myself that I will start preparing for my next career as an electronics technician/electronics assembler after I finish my French training.

Btw, cfelliot, what software do you use for your schematics?

[Chuck Elliot]

Nov 14, 2010 13:16:08 GMT -5 ottaone said:

I'm liking this thread. Don't understand much but I'll keep a link to this thread. I promised myself that I will start preparing for my next career as an electronics technician/electronics assembler after I finish my French training.

Btw, cfelliot, what software do you use for your schematics?

I started out as an electronic-tech with Data General in 1976, but moved to software in 1980. Doing this project is like returning to my roots!

I use Visio for all my general drawings. I was even able to do the AutoCAD dxf file with it to send to the chassis manufacturer.

The schematic and PCB layout is done with the free software provided by ExpressPCB expresspcb.com/

Eagle, also free(limited version), is probably the package of choice, but the learning curve was just too much for now - I will learn it, it has a lot of features such as auto-routing that ExpressPCB doesn't !

www.cadsoftusa.com/

Chuck

PS Good luck with the French!

[dsnyder0cnn]

Howdy,

This is a great project. It's more ambitious than what I would take on myself, but it's been fun reading about your progress!

I made it to the top of the XDA-1 preorder list too, but I'm not quite sure what I'll do with it yet. I don't think there is an ASIO or kernel streaming driver for it, so high-rez bit-perfect playback from Windows is unlikely via the USB input. Although it has an excellent output stage and nice volume control, my McCormack DNA-1 has only a single pair of inputs, and those are already attached to a UMC-1, so my system won't benefit from those either.

You said that the cost for this project is approaching the cost for a USP-1, but in your case, it sounds like it will be worth it. My system does not require analog bass management for two channel listening, so I'm a little sad/mad that Emotiva didn't spend a few extra bucks to add an analog passthrough. It would have been nice to leave the UMC-1 powered off and just use the XDA-1 for two channel listening.

I guess I'll go the route of other two/multi-channel XDA-1 owners: purchase an m2tech hiFace adapter (for the kernel streaming driver and low jitter S/PDIF output) and then pre-order the XSP-1 when available for the HT passthrough button and an analog output stage that will not mask the benefits of the XDA-1. It feels like I'm rewarding bad behavior, but my only other option is to spend $1,900 on a Benchmark DAC1 HDR.

I'm normally a pretty big Emotiva fan, but the fact that you (and many of us) are going through all of this to integrate the XDA-1 into your system is compelling evidence that the XDA-1 is something of a misfit in the current Emotiva lineup. Cheers.

[Chuck Elliot]

Nov 15, 2010 15:29:42 GMT -5 dsnyder0cnn said:

Howdy,

This is a great project. It's more ambitious than what I would take on myself, but it's been fun reading about your progress!

I made it to the top of the XDA-1 preorder list too, but I'm not quite sure what I'll do with it yet. I don't think there is an ASIO or kernel streaming driver for it, so high-rez bit-perfect playback from Windows is unlikely via the USB input. Although it has an excellent output stage and nice volume control, my McCormack DNA-1 has only a single pair of inputs, and those are already attached to a UMC-1, so my system won't benefit from those either.

You said that the cost for this project is approaching the cost for a USP-1, but in your case, it sounds like it will be worth it. My system does not require analog bass management for two channel listening, so I'm a little sad/mad that Emotiva didn't spend a few extra bucks to add an analog passthrough. It would have been nice to leave the UMC-1 powered off and just use the XDA-1 for two channel listening.

I guess I'll go the route of other two/multi-channel XDA-1 owners: purchase an m2tech hiFace adapter (for the kernel streaming driver and low jitter S/PDIF output) and then pre-order the XSP-1 when available for the HT passthrough button and an analog output stage that will not mask the benefits of the XDA-1. It feels like I'm rewarding bad behavior, but my only other option is to spend $1,900 on a Benchmark DAC1 HDR.

I'm normally a pretty big Emotiva fan, but the fact that you (and many of us) are going through all of this to integrate the XDA-1 into your system is compelling evidence that the XDA-1 is something of a misfit in the current Emotiva lineup. Cheers.

IMO, the XDA-1 as it stands is perfect, if you want to build a pure digital system. All you need is the XDA-1 and a power amp!

I do think, as was my original premise, that this type of add-on would be a great complementary product for those attempting to integrate HQ digital into an existing system and don’t need all the other stuff that the USP-1 offers.

I am guessing that my total costs for this prototype will be about $400. I am sure that Emotiva could do this for less than $300 sale price.

In a production unit I would want adjustable crossovers and attenuation. The attenuation is something that is missing from even the USP-1 and is mandatory for matching efficiency differences between mains and subs where the subs are far less efficient than the mains and/or don’t have their own volume control.

[Chuck Elliot]

Here are pictures of the PCBs. On the left is the crossover board from Elliott Sound(no relation) and on the right is my relay board.

Note on the crossover board (left side) the inputs are balanced and will connect to the XDA-1 as so.

All the connectors on my relay board use Phoenix screw PCB mount terminals.

Below the picture is a link to a larger version of the picture.

I’m still waiting for parts!!!!!!!



s273856667.onlinehome.us/emotiva/pcbbig.jpg

[Topend]

I wonder how this build is coming along? Eager to read about the final product connected to the XDA-1.

Dave.

[Chuck Elliot]

I'm building the crossover circuit board this weekend. I had to re-order some of the caps from Mouser as the ones I got would not fit on the PCB.

I got pretty busy over the last 2 weeks: code deadlines for work and getting the rest of the kitchen painted.

My XDA-1 comes tomorrow. I will connect it directly to my UPA-5 for a test. Albeit without my subs, which the Heresy speakers really need!

[Chuck Elliot]

Looks like I may be on hold here! I may need to add a analog volume control with the XDA-1 gain issues.

[Topend]

Dec 4, 2010 9:33:09 GMT -5 Chuck Elliot said:

Looks like I may be on hold here! I may need to add a analog volume control with the XDA-1 gain issues.

There is mixed feedback on the volume. Some (minority?) are reporting it is ok in their system.

Dave.

[Chuck Elliot]

OK, now that the volume control issue is settled and I don't have to add one to this project I can move on.

I do find that not having tones controls at lower volume levels when running direct makes things pretty thin. Plus I don't have my subs until I finish this.

I am currently using 6 dB attenuators to get adjustability at the low volume end. That along with using my old 60W Bryston.

Adding tone controls changes my plans somewhat.

The crossover board has balanced inputs, but if I add a tone control I will need to use the unbalanced inputs on it and move the balanced input in front of the tone control.

So: DAC -> balanced input - tone control -> crossover -> relay

I'm keeping a list to post when I'm done.

Chuck