Details of how Ben, the designer of the Soncoz SGD1 with dual ES9038Q2M's resolved the ESS Hump in linearity vs amplitude.
How to Fix ESS Hump on SGD1 and LA-QXD1 | Audio Science Review (ASR) Forum
John
How to Fix ESS Hump on SGD1 and LA-QXD1 | Audio Science Review (ASR) Forum
John
John can you show us the innards of the SGD1 and what mods have been done.
Always interesting to see what is possible.
Hi all,
I did try low noise +/-9v to op but no improvment to sound, put my 12 v back.
In post #3003 it uses a ltc6655. Is it a 5v in 3.3v out regulator? can that be change to something else? Can’t find it at local store.
BR// Daniel
I did try low noise +/-9v to op but no improvment to sound, put my 12 v back.
In post #3003 it uses a ltc6655. Is it a 5v in 3.3v out regulator? can that be change to something else? Can’t find it at local store.
BR// Daniel
Hi Daniel,
The question of an alternate low noise 3.3v reference seems to be coming up more recently. In the past we have suggested use of something like LT3042 or LT3045 as a reference rather than as a regulator. They could be used either way and are easy to set to the correct voltage with one resistor.
A pretty complete off the shelf device could be: New LT3042 Ultra Low Noise Linear Regulator Power Supply for Amanero XMOS DAC G1 012|Replacement Parts & Accessories| - AliExpress ...although you have to talk to the seller to make sure they send you a 3.3v output version. Otherwise you might have to change a resistor yourself.
A cheaper option but that needs some setup configuration for your use might be: LT3042 PSRR RF Linear Regulator Power Module 20V 200mA Ultra low Noise Ultra high Board Reverse Battery Current Protection|Demo Board Accessories| - AliExpress ...I think we could help you figure out how to hook it up.
Although its not my favorite, TL431 seems to be everywhere. With extra filtering it might be made to work, but I haven't tried it in this application and am reluctant to recommend it.
Another thought people have suggested is GLED431 which is very low noise, but does not directly produce the voltage we want. Also, a complete 3.3v version such as we might use should be tested with a scope to make sure it doesn't oscillate. Makes it perhaps not ideal for beginners. https://refsnregs.waltjung.org/GLED...D Reference Cell _Walt's Blog 2014_092418.pdf
The thing about AVCC is that it has a big effect on the sound of the dac. IME, sound quality suffers if its not really good.
The question of an alternate low noise 3.3v reference seems to be coming up more recently. In the past we have suggested use of something like LT3042 or LT3045 as a reference rather than as a regulator. They could be used either way and are easy to set to the correct voltage with one resistor.
A pretty complete off the shelf device could be: New LT3042 Ultra Low Noise Linear Regulator Power Supply for Amanero XMOS DAC G1 012|Replacement Parts & Accessories| - AliExpress ...although you have to talk to the seller to make sure they send you a 3.3v output version. Otherwise you might have to change a resistor yourself.
A cheaper option but that needs some setup configuration for your use might be: LT3042 PSRR RF Linear Regulator Power Module 20V 200mA Ultra low Noise Ultra high Board Reverse Battery Current Protection|Demo Board Accessories| - AliExpress ...I think we could help you figure out how to hook it up.
Although its not my favorite, TL431 seems to be everywhere. With extra filtering it might be made to work, but I haven't tried it in this application and am reluctant to recommend it.
Another thought people have suggested is GLED431 which is very low noise, but does not directly produce the voltage we want. Also, a complete 3.3v version such as we might use should be tested with a scope to make sure it doesn't oscillate. Makes it perhaps not ideal for beginners. https://refsnregs.waltjung.org/GLED...D Reference Cell _Walt's Blog 2014_092418.pdf
The thing about AVCC is that it has a big effect on the sound of the dac. IME, sound quality suffers if its not really good.
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Thanks,
As you say Mark, TL431 is avalible.
If i remember correctly it can be calculated online if you know how much mA is used?
BR// Daniel
As you say Mark, TL431 is avalible.
If i remember correctly it can be calculated online if you know how much mA is used?
BR// Daniel
The TL431 datasheet explains how to apply it in Section 10, starting at page 22: https://www.ti.com/lit/ds/symlink/tl431.pdf?ts=1597764179856&ref_url=https%3A%2F%2Fwww.google.com%2F
Best to study the whole datasheet, though. Not just one section.
Something to keep in mind that gave one user a problem: Strange oscillations with TL431 voltage reference - Electrical Engineering Stack Exchange
Possibly interesting TL431 blog: Reverse-engineering the TL431: the most common chip you've never heard of
Best to study the whole datasheet, though. Not just one section.
Something to keep in mind that gave one user a problem: Strange oscillations with TL431 voltage reference - Electrical Engineering Stack Exchange
Possibly interesting TL431 blog: Reverse-engineering the TL431: the most common chip you've never heard of
That's sheer design incompetence. Set aside the range of output capacitors is clearly specified in the data sheet, every qualified designer knows that low ESR (film or ceramic) capacitors at a voltage regulator output will make the regulator sing, unless specifically designed to support such (which is always clearly specified in the data sheet).
Some of the people who want to use alternate circuits are not EEs. Just a heads up for those that don't even own a scope (of which there are quite a few). I don't see any reason to resort to name-calling or other derisive language, you were a beginner at some point too.
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Not all EEs are designers and not all designers are EEs. About those that don't even have a scope, they should probably look for another hobby.
If you spotted any name calling and derisive language above, please quote. When I was a beginner I was looking forward to learning from proven qualified people. And I purchased a scope to start with, that was lesson zero.
I would agree that finding a way to get an adequate scope is very important. IMHO, just as important as having an adequate DVM. That and learning how to use both. I say that for the beginners reading the thread who might want a 2nd, 3rd, or whatever opinion on the subject.
And some of those fall into the camp that think datasheets are no more than a serving suggestion and are sure they know better.
WRT scope, 100% agree. The amount of time that gets wasted here trying
to help people only to find they haven't got a scope can be frustrating. When
I was young they were expensive, these days you can pick up a 50MHz for
very cheap, there's no excuse, especially for digital audio projects.
Without one you are flying blind and have no clue what is going on.
TCD
Hi Daniel,
Hopefully, all the recent talk about the usefulness of having a scope have not dissuaded you from continuing to try to find a way to work on a dac. Some people have successfully performed extensive mods to Chinese dac boards without having a scope.
Its true that the price of pretty good scopes has come down drastically from what they once cost, but they still aren't necessarily something everyone in the world is able to afford right now.
Hello,
I took the advice and picked up a used small lcd scoop.
I know that is it cheap model from China, But it seems to work anyway.
I haven’t had the time do any diy on the Dac, more then to test the scoop om the digital and signals and test it on a 1000Hz sinus out from the Dac.
BR// Daniel
I took the advice and picked up a used small lcd scoop.
I know that is it cheap model from China, But it seems to work anyway.
I haven’t had the time do any diy on the Dac, more then to test the scoop om the digital and signals and test it on a 1000Hz sinus out from the Dac.
BR// Daniel
Hi Daniel,
Which scope did you get? Do you have a pic or a link to one so we can see what it looks like?
Which scope did you get? Do you have a pic or a link to one so we can see what it looks like?
Hello,
Sorry for late reply, i was out of town..
It is a cheap one, got it for free from a friend.. so used and abused but seems to work to "see" the digital signals and a analoge sinus at output when sending a 1000hz digital in at dac.
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BR // Daniel
Sorry for late reply, i was out of town..
It is a cheap one, got it for free from a friend.. so used and abused but seems to work to "see" the digital signals and a analoge sinus at output when sending a 1000hz digital in at dac.
BR // Daniel
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Hi Daniel,
Can't tell from the pic if it has 1 or 2 input channels, nor what the rated bandwidth is. Maybe you can tell us if it has one or two input connectors? Also, looks like the display says 100MHz. If its really a 100MHz scope that's may be a nice gift someone gave you.
Can't tell from the pic if it has 1 or 2 input channels, nor what the rated bandwidth is. Maybe you can tell us if it has one or two input connectors? Also, looks like the display says 100MHz. If its really a 100MHz scope that's may be a nice gift someone gave you.
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Hi,
Just one input and max 40Mhz.
Anyway, i have ordered parts to build 3.3v to AVCC with a Lme47920.
And will separate some 3.3v with my small regulators over from another Dac.
I also did a cheap PCB for the output stage. Will arravie during next week I hope. Quick and dirty, so won’t preforme as textbook but but..
BR // Daniel
Just one input and max 40Mhz.
Anyway, i have ordered parts to build 3.3v to AVCC with a Lme47920.
And will separate some 3.3v with my small regulators over from another Dac.
I also did a cheap PCB for the output stage. Will arravie during next week I hope. Quick and dirty, so won’t preforme as textbook but but..
BR // Daniel
Pcb uses schematic from Mr.Slim in post #3003.
Can be some errors and like I saý alot of designerrors like groundplane, supplylines etc.. And due to some problems to collect parts from local supplyer the choice of components can look a bit strange…
BR //Daniel
Can be some errors and like I saý alot of designerrors like groundplane, supplylines etc.. And due to some problems to collect parts from local supplyer the choice of components can look a bit strange…
BR //Daniel