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Old 3rd March 2008, 09:30 AM   #41
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Quote:
Originally posted by ezkcdude

The press release for the Sabre DAC said it is $29 in lots of 1000. Can you imagine how expensive it would be in single/small quantities? And to achieve the 134 dB spec (which is for mono), you would need two chips. Otherwise the DNR goes down to 128 dB. Not only that but it's 64LQFP. Most people shy away from SSOP. Even if the Sabre DAC isn't vaporware, I don't see it having any impact on the DIY market.
Elsewhere, somebody said you could get small quantities (5) at $49 per chip. Both you and I are in the UK, so that's about 125 at current exchange rate, which I consider reasonable for the performance on offer. Certainly a DIY unit of 200-500 pounds that competes with multiple thousand designs is still worth pursuing? Besides, I am sure that eventually somebody somewhere will sell the chips in single units. I usually get my chips from Farnell who do not have any from ESS at present. Besides, I have a wedding to pay for, and a DAC project based on dual mono PCM1794 to do first.

There are threads on here for DIYers using surface mount components. There are a few ways you can deal with this. Personally I find them all a pain except the expensive routes. I find the best thing is to invest in a (T)SSOP to DIP adapter which gives you a chip-pin footprint similar to that of the TDA1541 which gives you plenty of room - and no soldering woes. The same sort of adapters are available for 64LQFP - they are marketed specifically for prototyping and facilitate chip swapping on pin compatible designs like when a manufacturer makes a part obsolete and replaces it with the latest model, which enables you to look at the datasheet to see if there are any issues, and if not, unplug the old chip and plug in the new one and see what difference it makes. Anyway, once your prototype is working and you wish to keep it and stick it in a unit, I think getting the PCB made and SM components put in by a company who will do that is worth the outlay. I know it means that for us brits, our good looking finished products tend to end up being more costly, but it beats retail. I should know... before DIY I spent 25k on a single stereo hifi system.

As I replied to somebody else on here, 6dB is a doubling or halving of performance depending on which direction the dB difference is in because it's a logarithmic scale as I bet you already know. A few dB can make a lot of difference. Just because 128 and 134dB do not look far apart numerically does not mean a thing. One is nearly twice as good as the other.
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Old 3rd March 2008, 10:02 AM   #42
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Quote:
Originally posted by InfiniteGain


Only 3dB?...That 3dB is on a logarithmic scale! Are we really realizing how much 3db is? A 6dB volume change is DOUBLING the volume, the 3dB in paralleling DAC chips in mono is a 50% improvement in whatever aspect the dB measurement is in (SNR, DNR, THD or anything else measured in dB) so 3dB is a significant difference.

It comes down to whether you can hear it, and that always comes down to how good the next bit of your sound reproduction system is (amp and speakers).

I made the point about the 3dB gain as someone else had suggested the figure was 6dB, I wasn't commenting on whether the figure itself was significant. Having said that, I have doubts that any improvement past say 120dB is audible.

As for SM soldering, http://www.tirnaelectronics.co.uk/ will help, and are very good.
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Old 3rd March 2008, 11:18 AM   #43
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Quote:
Originally posted by InfiniteGain


Both you and I are in the UK, so that's about 125 at current exchange rate, which I consider reasonable for the performance on offer.
Last I checked, I was still living in the USA. Although, I certainly wouldn't be opposed to living over there!
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Old 3rd March 2008, 01:01 PM   #44
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Quote:
Originally posted by Spartacus



I made the point about the 3dB gain as someone else had suggested the figure was 6dB, I wasn't commenting on whether the figure itself was significant. Having said that, I have doubts that any improvement past say 120dB is audible.

As for SM soldering, http://www.tirnaelectronics.co.uk/ will help, and are very good.

Quote:
Originally posted by ezkcdude


Last I checked, I was still living in the USA. Although, I certainly wouldn't be opposed to living over there!
Sorry, confused you with Spartacus!
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Old 3rd March 2008, 01:31 PM   #45
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When you consider the ESS part includes S/PDIF interface, sample rate converter and four stereo DACs, 25 isn't such bad value.
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Old 3rd March 2008, 01:35 PM   #46
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Quote:
Originally posted by InfiniteGain





Sorry, confused you with Spartacus!

I AM NOT SPARTACUS!
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Old 3rd March 2008, 01:41 PM   #47
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Quote:
Originally posted by Spartacus
When you consider the ESS part includes S/PDIF interface, sample rate converter and four stereo DACs, �25 isn't such bad value.

Precisely, and an ASRC which should be much better than anything else currently available. The price will likely come down to when they get production into full swing. At least I keep telling myself this (hope springs eternal).

Even at its current cost, its a good deal if it delivers the goods. I have no reason to think it won't based on feedback about the eval board.
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Old 3rd March 2008, 01:44 PM   #48
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I wonder what the output voltage of this DAC wil be. I'm guessing it will be fairly large compared to a "normal" DAC. In consequence, you'd probably need an amplifier with a fairly small gain to make the combination work best.
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Old 3rd March 2008, 01:47 PM   #49
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Quote:
Originally posted by 4real
I wonder what the output voltage of this DAC wil be. I'm guessing it will be fairly large compared to a "normal" DAC. In consequence, you'd probably need an amplifier with a fairly small gain to make the combination work best.

The output depends on the analog supply. It appears to pretty much swing the rails.

It would be pretty simple to get the I/V stage or filter stage to output 2VMRS.
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Old 3rd March 2008, 02:18 PM   #50
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Ok found it, page 16 on the datasheet. It does seemto be rail to rail.
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