[Jambo]

PbFree, thank you for your opinion, but please do not state it as if it is fact.

Lordmozilla - sorry for the delay in getting back to you. You have 5V so that's fine, I reckon the output stage would be adequately powered by +/-9V though I'd have to double check. You could use an LDO to derive 3.3V from one of the 5V rails quite easily.

 

[FrederikS|TPU]

How much do you think a complete DAC based on your design would cost all parts included except chassis?

If it is a cost effective design then I am definitely interested.

 

[Jambo]

Well, I think the DAC kits will be coming in at around £70-80.

Then for a power supply, make a pair of TREADS for the 3.3V and 5V and power them from a wall wart, and put a NMA1212SC on the same board to generate +/- 12V, that wouldn't cost much. Also Frederick I guess you can do quite well out of the £'s current weakness against the Euro!

I will do my best to make a power supply for this, but I need to do some reading first. I also need to recoup some funds, a student budget doesn't really lend itself to this kind of R&D!

Quick update on the project... Parts are here for another build, and I'm told that two of the new prototype PCBs will ship out to me on Friday, so I'll have them early next week, whooop!

 

[Marzie]

This sounds interesting, I will be watching this thread. Please PM me if/when a group buy is going to happen or if you decide to offer kits. Also, an up to date bom would be nice, just to get an idea of the parts cost.

 

[jgonino]

This is the perfect DAC for me! Only one other question:

Would it be possible to have 2 or 3 switchable RCA-outs?

PM me when/if you are planning a group buy.

 

[Calroth]

I can't exactly see how your output circuit goes, but since it's a WM8740, I presume it can be tweaked (for a given level of "tweak") for balanced output?

 

[Jambo]

Quote:

Originally Posted by jgonino /img/forum/go_quote.gif This is the perfect DAC for me! Only one other question: Would it be possible to have 2 or 3 switchable RCA-outs? PM me when/if you are planning a group buy.

Thanks for the continued interest guys - will PM you all. BOM and schematics will follow soon!

I have no plans to have switchable RCAs I'm afraid.

Calroth - You could extract balanced output perhaps from some vias on the PCB but it was not designed with this in mind. I don't have any balanced equipment and I originally designed this for myself, so that is why! There also is no room on the PCB for XLRs.

 

[Calroth]

Quote:

Originally Posted by Jambo /img/forum/go_quote.gif Calroth - You could extract balanced output perhaps from some vias on the PCB but it was not designed with this in mind. I don't have any balanced equipment and I originally designed this for myself, so that is why! There also is no room on the PCB for XLRs.

Oh, 'twas just a passing fancy, sparked by the idea of building this bad boy. I guess it could be possible to re-wire the entire output stage from the DAC chips onward, just by hooking on to their tiny tiny legs. But, again, it's more of a fancy than anything grounded in reality, and I'm sure your design will be awesome either way

 

[Jambo]

I just finished building one of the newest boards, I put WM8740s on this one and OPA134s on the outputs and it still sounds great. I haven't AB'd it with the other one though. This has all of the improvements I was looking for though, micro now sits on the board etc. I have a LOAD of uni work to do over the next fortnight but after that I have a good few weeks which I can spend pretty much full time on kits so if anyone interested hasn't spoken out yet, get in touch. Here's a pic of the assembled board:

 

[fault151]

How much you charging for the dac?

 

[lordmozilla]

that looks lovely! Nice work,

How is the input switching done?

 

[Jambo]

Fault151 - I've indicated what I think it will cost a few times on the previous pages, I'm looking to finalise that pretty soon, but I need an indication of volumes as it makes a big difference.

Lordmozilla - thanks

See the set of 8 header pins near the bottom left? 4 of them are grounds, the other 4 tell the micro to switch to the relevant source when grounded. I've been touching a jumper across the pins for testing, but when you build it into a case, you would attach four momentary switches to do this nicely.

Then the eight holes half way up the left edge where I haven't soldered anything, they are for the LEDs to indicate the current input source. Below that are two more grounds and two more micro pins which as yet aren't used, but I have an idea for that

Oh, and there are two more holes to the right of the switch headers which are attached to the 3.3V supply and ground, I thought that would be useful for a power indicator or something.

Any more questions, just let me know.

 

[Marzie]

Any new info? I had a dream the other night that I went into a local electronics supply shop and found a kit right on the shelf for the Jambo DAC, parts, boards, everything... I think its a sign...

 

[sid_]

Quote:

Originally Posted by Marzie /img/forum/go_quote.gif Any new info? I had a dream the other night that I went into a local electronics supply shop and found a kit right on the shelf for the Jambo DAC, parts, boards, everything... I think its a sign...

Jambo has already said that he is going to put kits together but that he's busy with coursework for university for the next few weeks - so everyone will have to wait until then.

You should let him know that you'd like a kit when they're available - the more people that want one, the cheaper it should be.

 

[fault151]

Quote:

Originally Posted by lordmozilla /img/forum/go_quote.gif that looks lovely! Nice work, How is the input switching done?

I might order one if you were on about the group buy. Im also in the UK.