My guess was the designer did screw the regulators to the board because they were running cool. That only concerns the longevity of the regulator, and it seems to fine then.
But the other matters deal with the regulator working with as little noise as possible and with the lowest impedance output that 3-pin regulator can allow. For that you should need the mods I intend to do.
But the other matters deal with the regulator working with as little noise as possible and with the lowest impedance output that 3-pin regulator can allow. For that you should need the mods I intend to do.
Have a look at the regulators articles on TNT-Audio.
Also read this topic here:
http://www.diyaudio.com/forums/power-supplies/28978-improving-lm3x7-regulator-circuit.html
Also read this topic here:
http://www.diyaudio.com/forums/power-supplies/28978-improving-lm3x7-regulator-circuit.html
Hi Carlos,
"OTOS, the output capacitors (1000uF) has already been recommended on this Forum to be a similar value (220uF) BUT... preferably not being a low-esr type. If you are going to use one, you should add a 0R5 resistor in series with cap. "
What you were saying is the output cap of 1000uF should be 220uF, if going to use a low ESR type then I should add a 0R5 in series with the 220uF?
"OTOS, the output capacitors (1000uF) has already been recommended on this Forum to be a similar value (220uF) BUT... preferably not being a low-esr type. If you are going to use one, you should add a 0R5 resistor in series with cap. "
What you were saying is the output cap of 1000uF should be 220uF, if going to use a low ESR type then I should add a 0R5 in series with the 220uF?
Are you speaking of perhaps using the Salas Shunt Regulator (SSR) circuit as the external supply? This keeps coming up over and over again here on diyAudio so I figured I need to investigate. If sounds like (no pun intended) that this circuit has been designed where low-voltage and a super quiet PSU are needed for sensitive circuit situations. If that's the case, the Salas sounds like it should be the PSU of choice for these types of circuits? Or, without a high-end system, or high-quality headphones, is it overkill? At a minimum, if I'm going to put together more of these type PCB circuits, maybe I should have a supply of SSR kits on hand and consider using when necessary. Are they available in full kit form somewhere? From an SSR digram I downloaded and printed yesterday it appears it is very versatile and supports a wide range of input voltages.
I'd also be interested in what you find in the digital x-former area for the S/PDIF circuit too.
http://www.diyaudio.com/forums/group-buys/188974-gb-thread-salas-ssr1-1-bib-shunt-reg.html
Tea-bag will have group buy once a while.
Yes, the output capacitor should be smaller, like 220uF, and shouldn't be low-ESR. If it is you should add a small resistor in series with it. With the capacitor, not with the output.
And the adj capacitor should be increased to 220uF: that is essential. On the datasheet National recommends increasing that capacitor value to improve noise and impedance, instead of the output capacitor.
Salas supply follows one "family" of supplies: shunt types. The one I will be trying here (and on the AK4396 DAC) is the Sulzer/Jung type, which is another family. The latter relies on lots of feedback to lower impedance.
It's quite likely I will be performing comparison tests between shunt and Sulzer/Jung supplies.
AFAIK, and I may be wrong, Salas supplies are not as quiet as Sulzer/Jung types. But what I'm most interested in here is the very low impedance of Sulzer/Jung types, which I think is much lower than any shunt type.
Of course I will share that info when I get it.
I think I need to do more research on this SSR. While it certainly may have benefits as part of the PSU used in a DAC, I'd be curious as to the quantification of those benefits. It may seem like I'm beating a dead horse here, but what are the 'real' audible improvements as a result of using the SSR circuit? Anyone know of a good 'SSR for Dummies' tutorial?
You're right. After a certain point in achieving a certain audio quality, what begins is the law of diminishing returns.
Even more, many of those returns are considered doubtful by many, because they are considered subjective, non-measurable by standard techniques. So for those following the "objective view" those changes are non-existent, imagined by the listener.
Many discussions were carried out over these matters, and probably will continue to do so.
Most of the people on this forum are more eclectic, so you may find valuable comments over their findings.
PSUs, cables and passive components are among the most fertile fields for discussions of this type.
On the power supplies question, the argument against series/massive feedback designs that use that to lower impedance, noise, etc. is the same as that over large feedback used to lower distortion on power amplifiers.
Shunt supplies follow a different principle and have lower feedback. So for that school they "sound" better.
In the end you will have to make your pick.
Even more, many of those returns are considered doubtful by many, because they are considered subjective, non-measurable by standard techniques. So for those following the "objective view" those changes are non-existent, imagined by the listener.
Many discussions were carried out over these matters, and probably will continue to do so.
Most of the people on this forum are more eclectic, so you may find valuable comments over their findings.
PSUs, cables and passive components are among the most fertile fields for discussions of this type.
On the power supplies question, the argument against series/massive feedback designs that use that to lower impedance, noise, etc. is the same as that over large feedback used to lower distortion on power amplifiers.
Shunt supplies follow a different principle and have lower feedback. So for that school they "sound" better.
In the end you will have to make your pick.
I would say I'm in the objective view camp. I like to be able to see - or in the case of audio - hear the difference. Sometimes it's hard to separate the objective from the subjective -especially when the benefit is often not stated. I love to build and put things together, but there's a practical side of me too. I don't want to get too wrapped up in mods that have an infinitesimal degree of improvement. I'm just not there - yet.
No, if you just listen to things you're on the subjective group.
Being subjective does not mean that you won't be objective on what you listen to, trying to discern where your ear (or your brain) is playing you a trick.
And I'm pretty sure you will listen repeatedly to things that you verify are there, little subtleties, which a hard-core objectivist will tell you do not exist, because they do not show on the measurements. Objectivist and measurements are synonymous on that area, and if it's not on the figures, it's your imagination.
Of course that is not so. A person can be fooled up to a certain point, but if you can arrange a way where you do listen to a certain thing and it doesn't show on the figures, then the figures are to be questioned. The ear is also an instrument, so you have to devise new ways that may get that.
On the supplies, apparently, the impedance has a lot to do with the interrelation with what is powered, and it seems to show on the audio quality.
But then comes in something which is important too, which is what people like, what they prefer, how they like or think the audio has to be. And it's there where things are messed up, IMHO.
That's why a good thing to keep you on your toes is listen often to music played with non-amplified instruments in good music rooms.
Being subjective does not mean that you won't be objective on what you listen to, trying to discern where your ear (or your brain) is playing you a trick.
And I'm pretty sure you will listen repeatedly to things that you verify are there, little subtleties, which a hard-core objectivist will tell you do not exist, because they do not show on the measurements. Objectivist and measurements are synonymous on that area, and if it's not on the figures, it's your imagination.
Of course that is not so. A person can be fooled up to a certain point, but if you can arrange a way where you do listen to a certain thing and it doesn't show on the figures, then the figures are to be questioned. The ear is also an instrument, so you have to devise new ways that may get that.
On the supplies, apparently, the impedance has a lot to do with the interrelation with what is powered, and it seems to show on the audio quality.
But then comes in something which is important too, which is what people like, what they prefer, how they like or think the audio has to be. And it's there where things are messed up, IMHO.
That's why a good thing to keep you on your toes is listen often to music played with non-amplified instruments in good music rooms.
Without belaboring this part of our discussion too much, I guess all I do with audio is listen.
I have a somewhat underdeveloped musical side, but play no musical instruments. However, I know what I like and know what sounds good - to me anyway. That may sound like a contradiction. IMO, specifications of gear are the objective measurement of the equipment and 'somewhat' predict how it should sound. I've been told that different people will hear the same thing differently. To me, that's the subjectiveness of the nuances of the audio coming into play - if all other factors in the audio playback chain remain unchanged. The equipment is still playing the same thing electrically, over and over and over. It doesn't change 'electrically' depending upon the listener. Perception of what different people hear does though. Am I making any sense? That's why I believe you can only push the electronics so far, before their ultimate affect on the audio is so small - even the subjective perception of what we hear is not noticeable. Now, if we want to believe in our head that we do hear a difference, that's where I start to question the motivation of the listener.
To each his own though.I know this topic has been discussed ad nauseam on several other forums, so we need not continue it hear, although it has been enjoyable.
BTW, I've got some different op amps on the way to try. I bought some AD827s and a couple LM4562s (CAN). I'm hopeful the audible differences will be noticeable and sound better - to my ears anyway.
If it does, I will have to believe the changes introduced by the new op amp affected the sound characteristics - first electrically, and then acoustically. Or, am I sounding nuts at this point? BTW, I do love live music - especially in small venues. Just don't get to partake as much of it as I'd like.
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Hi,
Your build looks good skylab - good job. How does it sound compared to other dac chips ?
The schematic seems to show the output as dc coupled - is there any dc offset on the output ? Your pcb, however, looks like it uses two Tonerex caps w/bypasses to block the dc - is this correct ? Is the schematic wrong ?
Thanks,
Tom
Your build looks good skylab - good job. How does it sound compared to other dac chips ?
The schematic seems to show the output as dc coupled - is there any dc offset on the output ? Your pcb, however, looks like it uses two Tonerex caps w/bypasses to block the dc - is this correct ? Is the schematic wrong ?
Thanks,
Tom
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