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Old 30th January 2013, 04:59 PM   #241
glt is offline glt  United States
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The AKM looks interesting: share PCM pins with DSD, S/W volume control, Dual mono for 60 bucks, Hmmm :-)
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Old 30th January 2013, 05:02 PM   #242
glt is offline glt  United States
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either are at least several hundred times lower noise than the tps, we are talking noise and impedance measured in nV, not V and nR or R not mR (the impedance of the LDO will be dominated by the caps
Are you talking noise density or RMS noise?
If using noise density, I remember some AN measuring noise floor around 1-2 nV/SQRT(Hz) and the TPS measures 14 nV/SQRT(Hz)
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Old 30th January 2013, 07:32 PM   #243
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the new DSD korg dac use CS4398, that like iron a lot
the same dac in the MR1000 and MR2000 DxD recorder

Pure Super Audio: KORG to release an ultra-high resolution 5.6MHz DSD DAC with affordable price tag
http://www.head-fi.org/t/632686/korg...-1-bit-dsd-dac
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Last edited by nicoch58; 30th January 2013 at 07:39 PM.
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Old 30th January 2013, 08:06 PM   #244
qusp is offline qusp  Australia
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does it matter? in both ways the Sala shunt, jung shunt and for example Ackos flea variant turn out to be significantly less than 1V RMS, meaning they are measured in nVRMS and the impedance in both cases are yet another order of magnitude different. but yes RMS, I havent bothered to work out the v/ sqrt Hz for the tps for your pass band/s (which I guess you pulled from Ian;s numbers. its a good reg, its still handily beaten in all areas of performance except price by these others

Last edited by qusp; 30th January 2013 at 08:16 PM.
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Old 30th January 2013, 08:20 PM   #245
qusp is offline qusp  Australia
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these posts by marce are quite relevant and back up some the points ive been trying to get across.

2 posts on

page 3

and one very scary, but very topical one on page 4
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Old 30th January 2013, 08:39 PM   #246
glt is offline glt  United States
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Originally Posted by qusp View Post
does it matter? in both ways the Sala shunt, jung shunt and for example Ackos flea variant turn out to be significantly less than 1V RMS, meaning they are measured in nVRMS and the impedance in both cases are yet another order of magnitude different. but yes RMS, I havent bothered to work out the v/ sqrt Hz for the tps for your pass band/s (which I guess you pulled from Ian;s numbers. its a good reg, its still handily beaten in all areas of performance except price by these others
Well, 99% sure I wont "hear" those numbers, but if a regulator measures 1 uV RMS 10-100K, then the noise density is 3 nV which is near noise floor. Do you have links to noise density charts for the shunts?
The pass band is from the manufacturers. Everyone reports RMS numbers typically 10-100K. The noise density is approximated as a square box according to a tutorial from Analog Devices (The RMS is the square box area of the density)
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Last edited by glt; 30th January 2013 at 08:43 PM.
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Old 31st January 2013, 12:26 AM   #247
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The place you'll really hear low noise is the psu for the oscillator, but in fact, dropping noise levels everywhere is the best way to get more definition and stereo imaging.

If the load is pretty constant, like most digital lines are, then you can use an emitter-follower to drop noise down to the noise floor of the transistor, so then it becomes about how well you can make it and your choice of transistor (low noise, high gain bandwidth, low input capacitance). The only downside for this is the lack of load regulation and the output impedance is quite high ~1 to 2R. But these downsides don't matter for digital-constant-load.

I've done this many times and heard the difference. It's easy, simple, and cheap and has real sonic benefits.

If you saw what i did with the humble LT1084, which I learned about from others work on the 317, you can see I have two RC filters - this very effectively blocks high freq noise, which the regs can't do well, and the lt1084 takes care of the low freq ripple. Killing the 1~2Hz noise is still a challenge and that can mess up a clock too. I have quite a lot of source impedance because of the RC filters, but this is not significant for the application = pre-reg for digital

The ADP7104 is available in 9V @ 15uV noise. You can use some rc filters on its output to feed the base of the emitter-follower and create a nV noise 3.3V supply for digital-constant-load.

But the above is no good for analogue - that needs very good load regulation and low output impedance.

That link to Marce says, "For clocks I would recomend some very small COG caps(pFs) with 0.1uF X7R's as intermediate reservoir caps, then some 10uF X7R then a few larger elecs or tants."

Funny, I seem to remember making something like this and getting flamed for it.

I think I have to quit Diyaudio. There's a very vocal someone here who likes to be right too much, even when it is destructive and perverse.

Last edited by KlipschKid; 31st January 2013 at 12:46 AM.
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Old 31st January 2013, 01:03 AM   #248
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The AKM looks interesting: share PCM pins with DSD, S/W volume control, Dual mono for 60 bucks, Hmmm :-)
Indeed. I've been interested in it for a while, and now there is a low-price diy board....

How easy do you think it is to write code to control volume etc ? It is 32 bit so the volume control should be decent I hope.

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Old 31st January 2013, 02:58 AM   #249
qusp is offline qusp  Australia
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KK, funny, marce models and measures everything he does, the software hes using will pretty much model it all as he makes the PCB design. there is nothing wrong with the parallel thing if its done correctly, you obviously started to react before actually reading what was written.

the problem is and he mentions this too, that you can set up resonances with the trace and part inductance, which can cause ringing and randomly choosing (same as just using the same values for everything) values to use on a completely un-characterized PCB is a good way to get them. I also dont see you using 0402 parts and there is nowhere on the PCB close enough for a useful low value bypass... your process seemed to be just choosing a mixture of caps and putting them where they will fit, with no measurement; can you explain the similarity?

that is what I critiqued, not the use of the parallel parts. the technique is good, but 'risky' to do blind.

Last edited by qusp; 31st January 2013 at 03:07 AM.
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Old 31st January 2013, 03:18 AM   #250
qusp is offline qusp  Australia
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Well, 99% sure I wont "hear" those numbers, but if a regulator measures 1 uV RMS 10-100K, then the noise density is 3 nV which is near noise floor. Do you have links to noise density charts for the shunts?
The pass band is from the manufacturers. Everyone reports RMS numbers typically 10-100K. The noise density is approximated as a square box according to a tutorial from Analog Devices (The RMS is the square box area of the density)
you may not hear them, but they are at a level that will meaningfully impact on the SNR/DNR/THD of the ESS analogue stages. yes I know the calc, but dont have the time, or desire to do it to illustrate a point for you.

I looked to see if I could find the stuff on the forum about regulator noise with no luck, but its from an in depth article on regulator noise in linear audio, which is a hard copy magazine/manual. its in Volume 4, the latest one; lots of other great stuff in there.
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