[orpheus]

I was able to audition the Chime in the Chime across america, and I sorely miss the quality of it's sound.  I don't have the money to build a whole Chime right now, but I could build the HagDac into an enclosure , and then build a Chime later on.  

Can I use the power supply for the Bugle?  I already have one built.  I know you speced the HagDac at accepting up to +15/-15, but is there enough current in the Bugle supply?  Would SLA batteries be a good option if the Bugle supply isn't appropriate?

How would I support the board inside the enclosure?   I didn't see any holes for standoffs on the board.  I am sorry if this has an obvious answer, as I am not an expert builder.  

Is there an enclosure you would recommend?

Thank you for your time-
Aaron.

[hagtech]

The bugle power supply will work fine.  I use one setup for +/-12V for testing.  The +/-15V will be ok too, although you might want to replace the 15V regs with 12V ones.  Reduces a little heat on the HAGDAC (which re-regulates).

As for support, I tried real hard to put in a mounting hole, just couldn't find room for it.  The layout is really packed.  I would suggest something simple, like a big glob of silicone glue.  One dollop performs the tasks of mount, shock obsorber, and insulator.  And you can peel off board later.  I sell the HAGDACs with the connector pins installed, so you can use 0.1"  wire headers to connect.

You can also temporarily use a HAGUSB if you need such an input.  I did this with my JIMDAC in a box.



jh

[orpheus]

I just got the HagDac today, and I'd like to clarify some things about the standalone implementation to make sure that I don't make a mistake.  Most of my questions are about grounding.

I've got a few 12 volt SLA batteries that I'm using for some other projects, and I thought that one of them might make a great supply for the HagDac.  What I'm not sure about is grounding.  I have a + and - on the battery, but there is no ground connection on the battery.  What should I use?

I'm also not sure about general grounding with the stand alone hagdac wiring diagram.  Should there be a chassis ground connected to the RCA's ground for input/output, or to any of the pins marked "ground" on the board?  

What do all of the little boxes on the wiring diagram (like the one connected to pin 1 on the input gnd) represent?  If you could post a diagram or tell me exactly how the grounding is done, I would really appreciate it.

You have labeled pins 19 and 20 to be connected together.  The manual says that this implements steep rolloff.  If I don't wire the pins together, what do I have?  Slow rolloff?  I am interested in trying the slow rolloff option if it's available.

Could I attach LED's to the RLK and PLK pins to add indicators?  How would I implement a polarity switch?

I have an extra plastic hammond case, could I use that, or should I use a metal case?  

Thank you for taking the time to read my post.  
-Aaron.

[hagtech]

few 12 volt SLA batteries

You need two batteries.  One for positive supply, one for negative.  For positive, connect the "+" to VCC and "-" to GND.  Negative, connect "+" to GND and "-" to VEE.

chassis ground connected to the RCA's ground for input/output

Chassis should connect to earth ground.  You can float the rest of the audio circuitry or connect it to chassis (depends on rest of audio system).  I would try connecting it first.  This is probably best done at the S/PDIF input, isolate the audio outputs.  Once the RCA shield is mounted to chassis, the rest of HAGDAC board is referenced to this point.  

little boxes on the wiring diagram

Those are just no connects.

pins 19 and 20 to be connected together

Yes, this implements fast rolloff.  Leave unconnected for slow rolloff.  Many people wanted this option.  We found the detail and sonics to be better in fast mode, which really suprised me.  I expected otherwise.

attach LED's to the RLK and PLK pins

Yes.  Look at the CHIME schematic for ideas.  It is not the only way to do it.  These are open collector logic levels, so they are pretty easy to interface with.  The simplest being an LED from pin (say PLK) to ground.  The pullup will drive LED - but you'll need more current, so add another pullup in parallel.  

One note of caution, with PLK, it also is used to MUTE the audio for non-44.1k inputs.  The LED voltage might be too low to signal a high logic level.  Without muting, at 48k word rate, the output screeches loudly.  Using a blue LED would be ok.  Here's one way to do it with 12V batteries

How would I implement a polarity switch?

It is just a switch to ground.  See CHIME schematic.

Metal cases are generally better for audio, but in this case I think you can get away with plastic.  

jh

[sjmikeb]

Orpheus,

I have been contemplating doing something very similar to what you are doing.  Please post your impressions of the standalone unit vs. the Chime.

Thanks and regards,
Mike

[orpheus]

I finally have some time to put together my standalone hagdac, but I'm having trouble sourcing the appropriate wire headers.  Couldn't find anything at Radio Shack that would work, and searching digikey hasn't given me a slam dunk result.  Would you be willing to give me a part number?

I want to make sure that I understand your explination of the grounding scheme.  I think I've got it, but I want to make sure.  If I am attaching the RCA shield at the digital input to the chassis, but floating the RCA shields on the output, I am referencing the grounds on the board to the ground on the digital input.  How does this work if I use a plastic case?  Should I star ground to the digital input ground, or just abandon the idea of a plastic case and use a metal one (which seems like the way to go)?


I apologize for having to ask such basic questions, I just want to make sure that I get it right and don't ruin the board.

Thank you for taking the time to read my questions.
-Aaron.

[hagtech]

With plastic case, the it is just a matter of tying the Earth ground to something.  You can leave it floating, too, if the following linestage provides a reference.  Tying Earth to S/PDIF input shield is fine.

You won't mess up the HAGDAC.  Only issue is one of hum or buzz.  System level stuff that all depends on your other gears and cables.

jh

[orpheus]

Thanks for taking the time to respond.  Do you have any thoughts on where I could source the wire headers?  Thanks for your help.
-Aaron.

[hagtech]

You can get from Mouser or DigiKey.  What I would do it to remove the pin headers and solder wires directly to board.  But only do this if you're good at soldering.

The trick is to use a snippers and cut the black plastic shroud holding the pins together.  This lets you remove one at a time.  Or use a razor.  Then heat the solder on top and pull pin through out the bottom using a pliers.  Only once the pin is out, you remove the solder using a vacuum pump or braid.  Or for you, just heat it up again (add a little new solder to get flux) and stick the new wire in.  You really don't even need to desolder the holes.

jh

[orpheus]

I just got it up and running.  I tried a few different connection methods.  I had hoped that I could build something that I could just plug it into and out of so that when I build the full Chime I wouldn't have to resolder any pins, so I bought the sockets that are on the parts list for the Chime board from Digikey.  The pins on those sockets aren't very sturdy, and I wound up breaking too many of them, so I decided to solder wires to the pins themselves.  

I just hooked it up with two 12 volt SLA batteries and listened briefly through some headphones and was pleased to hear that it was working.  From the little I've heard the sound is very promising.  I'm looking forward to doing some listening and comparing later on to see how it stands up to my Phillips 963.  The Chime was much better in all areas, so I have high hopes for the hagdac.

-Aaron.