Joe modifies DACs for a living. Surely he can lay his hands on two suitable ones. And he gets them back for resale. I've disclosed my financial interest, which is the same regardless of the results (and will just cover shipping) .
OK. Would the twisted pair buffalo 2 be a suitable board for experimentation? They are currently on close out for $199. Now what makes them potentially interesting is the lack of an I/V stage so we can build whatever is acceptable for testing.
I would be willing to fund one board.
I would be willing to fund one board.
Or, even cheaper but maybe a little more work, I have one Buff 32S I'd contribute if anybody has another. Joe or one of his fans here in the US could do the mod. Free, from the peanut gallery. (My third offer of assistance, and last.)
The un-affordable ones are, ironically rubidium clocks are VCXO's locked to the spectral lines of a couple of rubidium isotopes (anyone can look up the details) and they are still considered secondary standards. I would ask Joe how he filtered his PS at 1e-6 Hz considering .001 Ohm and 1F is 160Hz, but I must have misinterpreted something.
Or the servo amp that has no 1/f noise, or how long it took to verify noise at 1 cycle per 10 days or so.
Almost forgot settling time of the servo loop?
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Scott. I will see if I can get one of my old ESS boards up and working enough to send to you. I'd love to see what you make of it.
Just thinking aloud again. The buffalo32 on offer I believe is also 'add I/V' is the IVY http://www.twistedpearaudio.com/docs/linestages/ivy3_schematic_1_0.pdf suitable for this experiment. If so, then at least for measurements only one DAC is needed and you can swap I/V boards. DBLT may be a little trickier with this.
The 32S is TP's only all-in-one offering, with DAC chip, I/V, and output all on one board. As luck would have it, I also have the earlier, first, Buff DAC (24?) which is sans I/V and might be more suitable. Also free (!) to the right experimenter.
They will come, other complications of a personal nature means patience is required. I am accused of being an anti-measurement guy, not true, but I know how it will be interpreted. Sigh.
But yesterday I was accused TWICE of greed, then an outright appeal to shut the thread down by "tubesguy", today of being a charlatan, practicing witchcraft and a mere parts tweaker and seller (which you know I am not).
Do I need to remind some of the other things that were said about me before AJT took action last time?
These ARE personal attacks and they WILL shut down the thread if left unchecked. This is clearly the subtext here.
You say have a technical discussion? They are not presenting any. When I voice what I believe my genuine reason to doubt DBT, there is no technical discussion at all. Just "best to stick what we know best" is hardly engaging in a technical discussion.
You know, the only one here who has tried to get a technical discussion going is me, but at every attempt it gets shuts down. You can't have a technical discussion when the real intent on one side is simply debunking? I mean, clearly some minds have been closed a long time ago.
So I am starting to wonder, why bother. But... I will go ahead with those measurements, always were, and do things at my own pace and do what I always do, look for results. And gosh, SY now finds it disdainful that I have the same soundcard as him? And you can't wonder why that puts me off? But it just arrived in the post.
I will get to those measurements, but they are about pleasing ME before anybody else.
I need to make the tests repeatable or else... think about if not... or else?
Did you say "we can try" - that is wonderful. I would love others to replicate what I have done, that's been the idea all along. Confirm for themselves, not just be a mere spectator.
But to answer your question, yes, as soon as I reasonably can. There are other issues here right now that are more pressing - the next month is crucial in every respect. If things go wrong, it will cause me a major loss of freedom.
Round One Measurements:
Once I get down to the nitty gritty, then I can see myself posting a lot of material and little comment other than strictly necessary. I will start with a DAC and gradually increase the capacitance up to 1uF by which the response will be down near -2dB @ 20KHz. These will be based on 18.5KHz and 19.5KHz tones.
As this is the DAC I have here, that I can do this to, please note, it not exactly same as this, but very common:
Here the same capacitor value can be adjusted and compared. Anybody here who has access to this type of DAC and virtual ground I/V (many) will be able to do the same, using the same value capacitance, this should make it easy to replicate, 0.22uF, 0.39uF, 0.47uF, 0.56uF, 0.68uF, 0.82uF and finally 1uF. The 'knee' that we are looking for, where there should be an obvious change hopefully in the measurement, should happen between 0.39uF (there is no noticeable change) to 0.82uF (very noticeable). So that series of IM's might show something up. We shall see.
The truth may well be that nothing turns up. Then so be it.
Round Two Measurements:
Then we go on to the second round, this will use Steve Bolser's 1bit impulse files - Steve has said that should produce a lot of data. Again, if OK with Steve, I can release those files for others to use. The aim here is to find a measurement, or rather a stimulus that can trigger the event and be captured. I mean, think about it, would I go to this trouble if I didn't hope to find something? And who would want more than anybody else to capture and measure it than me? The one who has been called a charlatan? Chris, does that make sense to you that I would go to all this trouble if that was true? Hardly.
Keep in mind, while I want to do this, there is no reason that others can't beat me to it, especially the above 'Round One' of IM measurements, there are plenty here who can also do them, but as the are spectators looking for somebody to poke fun at, I have my doubts. But the truth is that they can easily find a DAC or player with the above post-DAC circuitry and do it too.
Chris, based on what we have seen so far, if indeed that 1st Round shows up something significant, if I cannot make it repeatable, then considering the character assassinations (and they are undeniable) being leveled at me, what stops them from just calling me a liar? After all, is that not what many have been doing?
They have to be repeatable - they have given me no choice. But that's OK as it was always the idea.
But, in the end, somewhere they have to cease being mere spectators.
They can still do it now themselves and beat me to it - and no problem from me.
OK If tubesguy can confirm his non-IV buffalo will interface with the IVY III I'll get ordering.
Can someone well versed in the art take a gander at the IVY schematic and confirm its good for what we want to do? To me it looks eminently suitable, but what do i know, I only have 2 soldering irons 🙂
Can someone well versed in the art take a gander at the IVY schematic and confirm its good for what we want to do? To me it looks eminently suitable, but what do i know, I only have 2 soldering irons 🙂
and so wth the lost post of Joe, thread is closed for now, contact any of the mods when you are ready with your testing and results.....you can work behind the scene, right? if this thread were in the vendor's forums, no mods will intervene, but being in the technical forums, it's anybody's ballgame..- Status
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