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Old 3rd October 2011, 04:15 PM   #41
Coris is offline Coris  Norway
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Quote:
Originally Posted by Bunpei View Post
Your idea made me try it! The result is wonderful.
I added 1000 microF/16V Sanyo OS-CON at the output side of AVCC shunt regulator of TPA Buffalo III. The caps bring more powerful bass without losing a high resolution in mid and treble. I'm much satisfied with the result.
Thank you very much for your initial idea!
I`m not exactly sure that an quite big OS-CON (16v) is the best idea to use it to decouple the DAC chip on AVCC. I`m not exactly sure that is a good idea to add this 1000µ directly on the output of the power supply... But you have anyway now an idea what about...

I will suggest you to use many 100µ/6v ceramic or tantalum SMD (no terminals, lowest ESR) soldered together in a pack (avoid wires to connect those capacitors), directly on the AVCC pins of the ES9018, or the closest as possible to these pins. Not on the main power supply, which is anyway quite far from the DAC chip. In some cases precautions have to be taken to prevent damages because large start up currents, which those large capacitors can cause.
One have to keep in mind using in this case capacitors that have lowest as possible both ESR and parasitic inductance. The best to use here are ceramics or tantalum SMD components.
It is a clue to use 2x1000µ on both sides of the ESS9018 chip (AVCC L/R) and dedicated power supplies/regulators for those pins), It is not by chance that the designer have specified those pins as AVCC L&R...

If you will use the same principle with large capacitors direct on the power pins of the I/V - output stage, specially if you use that TPA I/V stage with op-amps, you will have even more pleasant surprises...

Last edited by Coris; 3rd October 2011 at 04:22 PM.
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Old 3rd October 2011, 06:57 PM   #42
Coris is offline Coris  Norway
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In case of large decoupling capacities on power pins, I would like to use low noise dedicated voltage regulators which have current limiter protection... I can not see any problem to use after a shunt regulator, another voltage regulator with current limiter and large decoupling capacities... I can agree with the statement that is not a good idea to use large capacities on shunt regulators... But this can well be another discussion...

Last edited by Coris; 3rd October 2011 at 07:01 PM.
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Old 3rd October 2011, 07:15 PM   #43
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Quote:
I will suggest you to use many 100µ/6v ceramic or tantalum SMD (no terminals, lowest ESR) soldered together in a pack (avoid wires to connect those capacitors), directly on the AVCC pins of the ES9018, or the closest as possible to these pins.
I will suggest you don't on a Buffalo, unless you replace the local AVCC shunt regulators with something else.

Such blanket recommendations can be dangerous without consideration of the rest of the system involved.
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Last edited by BrianDonegan; 3rd October 2011 at 07:25 PM.
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Old 3rd October 2011, 09:23 PM   #44
Coris is offline Coris  Norway
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Originally Posted by BrianDonegan View Post
I will suggest you don't on a Buffalo, unless you replace the local AVCC shunt regulators with something else.

Such blanket recommendations can be dangerous without consideration of the rest of the system involved.
Yes, you right! One have to take in consideration the rest of the system when want to experiment something. I personally adapted the rest of the system I use for the moment, to my needs, and to use the way I wanted. It is not the right way to do it without previously thinking what about.

I feel the need to clarify here in conjunction with the last posts/comments from TPA:

- This thread is not intend to destroy or denigrate the TPA products. My self I appreciate and respect the professionals who designed Buffalo. In the same time, I can easily register a kind of opposition from TPA to everything that is not in theirs way to do it. This is OK enough, but only I want to mention that this thread is not a TPA commercial one. Right?

- I do not make recommendations about how to do it, or how one have to use Buffalo series of products. As the title of the thread show, this is about ESS9018 experiments. I come here only with some suggestions and discussions for peoples who can be interest in experiments with this DAC chip, for they who want to try something else than TPA have previously approved, for they who can do it, and who are enough thinking human been to know what they do.

- At least, experimenting is a risky activity. One can destroy something, and it take his own responsibility in this. This is a way to learn... I`ve destroyed components many times, and this can happen to everyone. This is very normal in this field of activity. I do think that this forum, and they who participate to this thread are enough mature thinking human been, who can take own decisions, without special guidance and close care form TPA specialists...

BTW, if one destroy his Buffalo, than can buy another one. So it still be a good business for TPA...
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Old 4th October 2011, 11:28 AM   #45
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I only commented because of this:

Quote:
I added 1000 microF/16V Sanyo OS-CON at the output side of AVCC shunt regulator of TPA Buffalo III.
That could cause big problems with the AVCC module, and possibly result in a dead ES9018 chip.

Generally speaking, shunt-regulated supplies do not like to see a large capacitance on the load side.
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Old 4th October 2011, 01:14 PM   #46
Coris is offline Coris  Norway
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Quote:
Originally Posted by BrianDonegan View Post
I only commented because of this:



That could cause big problems with the AVCC module, and possibly result in a dead ES9018 chip.

Generally speaking, shunt-regulated supplies do not like to see a large capacitance on the load side.
It could be nice if you are willing to explain little bit (on short but better understandable) what/why could be the problems you refer to. It will be very usefully for everybody to understand why TPA AVCC module (shunt regulator) do not "like to see" large capacity on output... So will be (in my opinion) a real contribution to this discussion...

I have in a circuit an TL431 regulator which have 800µ (SMD ceramic) on output. Everything function very well, the regulated device it feels in a very good condition, and "nobody" died yet... But is not about an ES9018...

Last edited by Coris; 4th October 2011 at 01:16 PM.
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Old 4th October 2011, 02:15 PM   #47
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Coris,

The reliability problem is in the fact the caps will be storing energy at turn off that the regulator has to dump after the error amp has lost it's power. So the error amp is no longer in control, and the shunting transistor could see far too much current at turn off. I am not saying it won't work, it probably would be fine for a while. But anyone who kills their AVCC module like that will not be getting a replacement.

You should also read up on shunt regulation. Using a big cap at the output of a shunt regulator actually makes it harder for the error amp to do its job. A small amount of capacitance right at the device pins (which Buff 3 has) helps to decouple very high freq, but capacitance that is too large at the output actually becomes counter productive for a shunt regulator. At the input you should use as large as practical.

Now if you want to use large capacitance at the AVCC pins the best idea would be to use a linear regulator there which is probably the case on the DAC you have.

Cheers!
Russ
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Old 4th October 2011, 02:16 PM   #48
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Default why?

Coris/Bunpei:

My understanding is that well designed shunt regulators provide low noise and very low output impedance-lower output impedance than any capacitor. Besides a subjective point of view of the "different" sound, why, technically, would one place large capacitance at the point of load, which raises the impedance the load sees (vs a local shunt regulator). Technically speaking, would not placing large capacitance here slow down the power supply?
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Old 4th October 2011, 03:05 PM   #49
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I really don't want to sound like I am raining on your parade. I don't want to come across as discouraging experimentation and DIYing. I think it's great that you want to experiment and try things out, and I fully support your efforts.

I just wanted to be sure folks don't damage their gear while experimenting.

It would be easy to try a different regulator with added capacitance (etc)... that's why they are not built into the main board.
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Old 4th October 2011, 04:06 PM   #50
Coris is offline Coris  Norway
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Originally Posted by Russ White View Post
Coris,

The reliability problem is in the fact the caps will be storing energy at turn off that the regulator has to dump after the error amp has lost it's power. So the error amp is no longer in control, and the shunting transistor could see far too much current at turn off. I am not saying it won't work, it probably would be fine for a while. But anyone who kills their AVCC module like that will not be getting a replacement.

You should also read up on shunt regulation. Using a big cap at the output of a shunt regulator actually makes it harder for the error amp to do its job. A small amount of capacitance right at the device pins (which Buff 3 has) helps to decouple very high freq, but capacitance that is too large at the output actually becomes counter productive for a shunt regulator. At the input you should use as large as practical.

Now if you want to use large capacitance at the AVCC pins the best idea would be to use a linear regulator there which is probably the case on the DAC you have.

Cheers!
Russ

Thanks for the explanations. Now they who want to try something else, have a little bit more infos to take in to consideration before proceed...

In my case, yes I do use linear regulation (voltage). But was an situation that i used an 431 regulator with large capacities on the device was powered with. As I précised earlier these regulators have a current limiter function, and that because nothing happen with large capacity on the DAC power pins. But anyway, one have to be carefully...
Large capacities have a clue if one analyse the circuit from AC point of view. I have to say again that here is about that capacitors with lowest as possible ESR and parasitic inductance. It is the case of these ceramics and special made tantalum SMD type.
Having enough energy on the power supply points of some circuits, is a benefit for their slew rate, for their capabilities to good/quick reaction when need it. I mean in the lower range of frequency spectre, and in the higher too. Dynamics increase is more than evident in such cases. The Bunpei post can easily demonstrate that improvements occur at once when using large capacities. It is of course about the rest of the system that one have to think about too. This is very true! But if the rest of the system permit, then large capacities leads to improvements.
I will suggest a simple experiment: take an appropriate op amp with a high slew rate. Let`s say 3000v/µs. Use that as final stage. Decouple it with some 10µ. Hear the result. Change the decoupling with an 1000µ. Hear the result. I let you have own conclusions about the final result. Do the same with an 20v/µs, and compare the results.
This is one thing about large decoupling capacities. They are many others (positive). Not to forget the filter capabilities in such decoupling... I mean DECOUPLING (power in - load) and not filtering the output of a power supply...
Personally I did not have ever a bad experience when using such decoupling in the right place (on the right system).

Back to the ES9018, I will say that "my rule" was confirmed again. A huge increase in dynamics and the wider output frequency specter, more details occur only by using/changing the large decoupling capacities. Just measure or try to hear the possible noise on final output when large decoupling are in place, and when the "normal" one are used. Compare the results and conclude your self...
You do not need to trust me. Just try yourself (with the necessary precautions to avoid catastrophic result). Take in to consideration the important currents that are involved, the start up and shut down sequences when such large capacities are used. And not at last, the type of power supply involved in the system.
All the benefits of this approach disappear if one use usual electrolytic`s and solder the long terminals somewhere in the power rails, and by chance on the GND... It can get worse very easy then...

Last edited by Coris; 4th October 2011 at 04:15 PM.
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