[Jambo]

Ok guys, I'm going to let this into the wild....

Some points to note:

-Please read the whole of this thread so that you know what is, and what isn't included in the kit (eg a power supply IS NOT included).
-Please make sure that your soldering is up to it
-The HID functionality doesn't seem to work on my PC so please take this as untested and not guaranteed.
-Same goes for deemphasis - the hardware is there but I haven't done the firmware. I also may not ever do it but I'll gladly send you my ideas on how to do it.
-Kits cost £85 plus postage. Import duty will be your problem (if applicable). Microprocessor is available programmed and soldered for no extra charge.
-I will provide as much support as I can between now and September, but on September 1st I start work in Baku and I can't guarantee to help as much as I would like.
-A user manual will be available as soon as kits are shipped out. It is nearly finished and it will be constantly updated.

Now... There are 19 of these available in this batch. The PCBs are sitting on my desk, as are a lot of the ICs. As soon as I have received payment for 19, I will order the remaining parts - they will arrive next day and I will make up the kits and post them out within a week of receipt.

If all 19 aren't sold within a reasonable time (2 weeks?), then a refund will be available and/or we can discuss an alternative way forward.

Postage Costs:
Kits will be posted by Royal Mail and delivered by your local mail company. I will get a service which requires a signature IF it is available in your country. I'm a believer in easy numbers so here are my proposed postage charges:
UK: £4
Europe: £7
Rest of World £10

Partial Kits/Assembled Kits
I do not intend to supply partial kits/bare PCBs at this stage. This is because I have a lot of costs to cover and all budgeting has been around 20 kits and the associated bulk discounts. If this is a success then I will order further batches of PCBs and bare boards will be available. Assembled/partially assembled kits available by negotiation.

Please contact me by PM for payment details. If you have any issues with my integrity, please see my feedback on ebay, jambo0885.

I have tried to post a mall-fi but haven't heard back from the mods yet.

Any further questions, feel free to PM or reply to the thread.

Cheers,

Jamie

 

[TSi]

damn... tat looks really really clean! is it possible to get a few more pictures on it?

 

[pistolpete111]

I had posted the guts of this in a PM to Jambo, but I guess it's relevant to everyone.

What do people plan to do about a power supply for their Jambo DACs?

I recall someone on this thread mentioned using a PC PSU, but they are normally not recommended for hifi stuff I think. I'm no expert, so I'm a bit unsure about how I should go about the power supply - are voltage regulators the only difference between a good and bad PSU? I guess there is more to it than this?

Could the power supply kit that the guys at twisted pear sell for the Opus be modified for this DAC? I guess that their power supply is pretty good...

Any opinions/advice would be great,

Thanks

 

[Beefy]

Quote:

Originally Posted by pistolpete111 /img/forum/go_quote.gif Could the power supply kit that the guys at twisted pear sell for the Opus be modified for this DAC? I guess that their power supply is pretty good...

I think that they would be the best option IMHO.
Use Low Current Dual Power Supply (LCDPS) - A Dual Regulated CLRC Supply for 3.3V and 5V.
Use Low Current Bipolar Power Supply (LCBPS) - A Regulated CLRC Supply for ±12V.
...... assuming the LM317 regs can go as low as 3.3V.....?

If I thought that I could manage that SMD soldering, I'd be over this project in a heartbeat. But anything smaller than a SOIC OPAMP would probably cause me problems

 

[akione]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif ...... assuming the LM317 regs can go as low as 3.3V.....? If I thought that I could manage that SMD soldering, I'd be over this project in a heartbeat. But anything smaller than a SOIC OPAMP would probably cause me problems

Yes, they do. 1.2V min.

Should be easy to knock up a suitable supply on perfboard.
Or maybe build a SuperReg if you want the best.

[My problem with SMD is the little 0805 resistors .... they shoot off when I
pick them up in my tweezers and I can never find them again.

]

 

[pistolpete111]

The SuperReg kits don't seem to be available from VSE at the moment - the "buy" link just gives an error.

The Twisted Pear route sounds like a good one - everyone has only good things to say about them. The only disadvantage is that the two twisted pear kits needed (LCDPS, LCBPS) and the cost of a transformer will work out on the dear side - well over half the price of the DAC itself.

The third option, I think Jambo mentioned it before was to use a wall wart with a DC converter for the 12V. I see the advantage of it being that the transformer is housed far away from the DAC, but I assume that if the wall wart was a good solution the Twisted Pear guys would just use it and not have gone through all the work invovled in designing their power supply units.

Did any of you ever play about with using different power sources for a DAC? How would a wall wart with good regulators compare to the Twisted Pear power supplies?

Thanks again,

 

[Beefy]

Quote:

Originally Posted by pistolpete111 /img/forum/go_quote.gif The Twisted Pear route sounds like a good one - everyone has only good things to say about them. The only disadvantage is that the two twisted pear kits needed (LCDPS, LCBPS) and the cost of a transformer will work out on the dear side - well over half the price of the DAC itself.

TREAD perhaps? You'll need 4 though! Tangent Regulator, Adjustable, plus Diode bridge

Quote:

The third option, I think Jambo mentioned it before was to use a wall wart with a DC converter for the 12V.

The DIY darlings TREAD, STEPS, LCDPS/LCBPS σ11/22 etc are good for audio because of their incredibly high performance. You won't get nearly as good performance from a wallwart, and you will probably compromise the DAC performance as a result.

 

[error401]

If you're okay with a switcher, a wall-wart is fine, since you'll be regulating its output for the critical supplies anyway. I'd then use a TREAD for the DVDD and a JSR-03 for AVDD (or another TREAD). Use the switcher to generate -12V. Should be pretty cheap. Another option for the switcher IC is the TI DCP02 series, like the DCP021212D. These are isolated 2W supplies, so you give it 12V (or 5V or whatever) and you get two 12V outputs that can be connected in series to get +/-12V and ground. They're pretty noisy and expensive and have poor load regulation - but they come in DIP and don't require any external components really. I've found them useful for powering things from the USB power supply, since you don't need to use a virtual ground with them. If you wanted, you could even post regulate them.

Unless you home-grow it on a protoboard, I think you're looking at a fairly expensive PSU. The cheapest way I can think to do it without using any switchers, and using easy to get boards is to get the LCBPS and transformer from Twisted Pear (probably cheaper if you buy parts yourself, but not sure). Add a pair of TREAD kits from tangent and you're set.

The farthest I would go as far as 'niceness' would be the σ22 (or something similar like LCBPS), followed by a pair of JSR-03 or similar super regulators from peranders.

 

[pabbi1]

You can also go cheap linear on eBay or here - casing is the challenge. Just search for 'linear power supply' - sometimes you can get what you need.

 

[pistolpete111]

Thanks everyone for the replies.

I've looked into it a bit more myself, and the Twisted Pear route seems to be the best alright. Think I might add a few extra kit's of theirs into my order as well

 

[Jambo]

In agreement with all that has been said really!

As ever, it's a trade off - As I've said before, I have acheived nice results with a wall wart powering a pair of LM317s for AVDD and DVDD and an NMA1212SC switcher for +/-12V. This is easy to put on veroboard, only the regs and some caps needed and some resistors if you go for adjustable regs. In fact, I haven't been able/felt the need to try my DAC with anything better as yet.

Also to emphasise again that AVDD (+5V) is BY FAR the most crucial supply, the WM8740 is very sensitive to ripple on its analogue supplies, ripple on DVDD and +/-12V has thousands of times less effect!

I think the Twisted Pear supply would work great and would definitely look nicer, but it is more expensive.

Quote:

Originally Posted by akione /img/forum/go_quote.gif [My problem with SMD is the little 0805 resistors .... they shoot off when I pick them up in my tweezers and I can never find them again. ]

What you probably need is a better set of tweezers - changed my (soldering) life when I got a decent set! I like the crossed over kind, the ones you squeeze to let go of things and when you let go of them, they still hold onto whatever you picked up.

You'd be surprised how easy it is to solder SSOPs if you have the right gear (that's a chisel tipped iron, lots of flux, leaded solder and braid for me) - but this DAC is potentially an expensive way of learning.

TSi - I'll get some more pics up, afraid photography isn't a strongpoint of mine though and I am limited to the camera on my phone!

 

[akione]

Quote:

Originally Posted by Jambo /img/forum/go_quote.gif .....What you probably need is a better set of tweezers - changed my (soldering) life when I got a decent set! I like the crossed over kind, the ones you squeeze to let go of things and when you let go of them, they still hold onto whatever you picked up.

.... Funny you should say that ........ that's exactly what I've done.

Haven't built anything else with SMD, yet, but it should be a lot better now.

[Actually, the problem's more likely to be because of the Arthritis I have in my hands.

]

 

[Jambo]

As promised, some new pics:

 

[pistolpete111]

The pics look great

Can't wait to get my hands on this now. I really like the way it has a good few inputs, all lined up on a single side - will fit neatly into the enclosure I have for it.

Just out of curiosity, I see a "SPDIF Config" section on the board. What can it be used for?

 

[decayed.cell]

Hm I find those two caps at the end a bit tall, is there enough room to mount them on their side, say one over one under?