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Breeze TPA3255 XLR Balanced Amplifier TearDown : DIP8 Op Amps.

v1adpetrov2

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I have prepared radio components, except for inductance, I will install them this weekend...
 

ICIETDIYEUR

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Ok ;)

1> You will try an indoctor like -> THIS <- or -> THIS <- ?

2> For the Schottky diode you will use the SS36 model ?

3> You didn't tell me my capacitors in photo could be suitable or did a choose another models ?

Regards.
 

v1adpetrov2

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Ok ;)

1> You will try an indoctor like -> THIS <- or -> THIS <- ?
2> For the Schottky diode you will use the SS36 model ?
3> You didn't tell me my capacitors in photo could be suitable or did a choose another models ?
1. I'll pick up some kind of inductance from used...
2. Yes, I bought SS36-E3/57T, Schottky diode 3A 60V
3. Any capacitors with a low ESR will do. Yours will also be perfect!
 

ICIETDIYEUR

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OK :)

Did you think that one of the inductor that i have indicated by link will be good ?

I also have these 3 links for diodes: which one would you recommend ->

LINK 1

LINK 2

LINK 3

Thank you in advance for your answers ;)

Regards.
 

v1adpetrov2

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OK :)

Did you think that one of the inductor that i have indicated by link will be good ?

I also have these 3 links for diodes: which one would you recommend ->
LINK 1
LINK 2
LINK 3
1. No inductance is suitable, because they pass through a very weak current of 30mA and 110 mA.
It is necessary inductance at least with a current of 500mA (0.5 A).
www.mouser.fr Search in the section: All Products -> Passive Components -> Inductors, Chokes & Coils -> Power Inductors - Leaded
For example:
inductance_2200uH_03.jpg

2. Diode fom LINK 1 will do.
 
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ICIETDIYEUR

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OK.

Thank you.

I had noticed that they were quite weak while running :(

I think I will make a tour of my needs for an order at MOUSER ;)

Regards.
 

ICIETDIYEUR

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@ v1adpetrov2

Hello :)

Here is my reflexion about the inductor value for the regulator LM275 HVS-12:

Based on datasheets ->

Inductor for LM2575HVS-12.jpg


I may have forgotten something or misinterpreted graphic... :rolleyes:

This would give that with the references from MOUSER ->

Régulateur LM2575 et ses composants (VDD - GVVD - AOPS 12Volts).jpg


What do you think ?

Regards ;)

PS:

Références de la 10K.jpg


What reference would you take at MOUSER ?

Bonus: for those who would be interested to know the voltage of the LED if they want to replace it to change its color for example ->

LED 1,8Volts et polarités.jpg
 
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v1adpetrov2

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@ v1adpetrov2

Hello :)

Here is my reflexion about the inductor value for the regulator LM275 HVS-12:

Based on datasheets ->

View attachment 242577

I may have forgotten something or misinterpreted graphic... :rolleyes:
This would give that with the references from MOUSER ->
What do you think ?
Your calculations are correct!
I just took a two-fold peak value of the current consumed and got a value of 0.17...0.2A.
But even with such a current, the inductance = 2200uH according to the graph.
 

ICIETDIYEUR

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Schematic.jpg

Did you make a voltage reading at the input of this 'modified assembly' with the power supply set to 42V amp on ?
 

v1adpetrov2

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Over the weekend, I changed the elements around the LM2575HVS chip.
Input voltage = 42V.
Before the replacement , the oscillogram of the output voltage of 12V looked like this (output ripple = 590mV):
1_out_from_LM2575HVS_before_mod_.png

After replacement output ripple = 130mV:
2_out_from_LM2575HVS_after_mod_.png

Then I replaced the +-5.65 V two power capacitors 220uF/16V on the "virtual earth" of the operational amplifiers.
With these capacitors, the voltage on the 22 kOhm divider resistors constantly floated from 11.0V to 11.3V.
Before the replacement , the oscillogram of the output voltage of 12V looked like this (output ripple = 60mV):
3_out_from_VirtualGround_before_mod_.png
After replacement output ripple = 10mV and the voltage remains stable 11.3V:
4_out_from_VirtualGround_after_mod_.png

LM2575HVS_mod__01.jpg LM2575HVS_mod__02.jpg LM2575HVS_mod__04b.jpg LM2575HVS_mod__03.jpg LM2575HVS_mod__05.jpg
 
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ICIETDIYEUR

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Hi v1adpetrov2 ;)

Great job ! :cool:

I am not at all surprised by the result compared to the origin (type and values of components used :eek:).

I have a few questions if you don't mind:

1> Why did you take a value of 47F for "Cin" and not 100μF ?

2> What equipment are you used to weld the diode ?

3> What are the technical characteristics of your self and is it important whether it is "air" ?
(You recommended another one at MOUSER: see above).

4> Why use 820μF for "Cout" ?
(I know it is used for both OPAMPS and TPA3255).

It's weird that there are some kind of "waves" in the "2_out_from_LM2575HVS_after_mod_.png" photo...

5> It seems to me that 560μF is a very high value for OPAMS condos: I think that 220μF correspond rather well (but to go to 25 Volts).
Is there a reason for this choice ?

6> Is your choice for these EPCOS preferable to PANASONIC (Low ESR from MOUSER) ?

7> You added an additional 0,1μF/63V decoupling condo on "Cout" (you didn't mention it but we see it in your photo): is there a reason ?

8> Did you diagram the power supplies and circuits around the OPAMPS ?
(importance of input impedance for the choice of OPAMPS).

I tried to realize it but I had trouble following the circuits in places and I do not master the software for the reproduction of circuits :mad:

I searched all over the net but it seems that no one has the diagram of this superb little amplifier... :(

Kind regards :D
 
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v1adpetrov2

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I will answer several points of your topic at once: I installed the radio components that were available in the store closest to me.
The diode was soldering with a blow dryer.
Any diode can be used: SMD or for mounting into holes.
The capacitors were chosen by Low-ESR, only 820uF and 560uF were available.
7. Yes, all three electrolytes should be shunted with 0.1uF film capacitors, which reduced RF interference.
8. I did not make up a wiring diagram for operational amplifiers, because a standard scheme of a non-inverting amplifier with a "virtual ground" and a gain = 3.2 is used.
 
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ICIETDIYEUR

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Thank you for all this information ;)

Well seen "the hair dryer technique" :D

1> For capacitors: what values would you have retained if all the values were available (OPAMPS and "Cout") ?

a>For OPAMPS, we can take into account, for two OPA1656, a maximum of 20mA under 12Volts in continuous mode without forgetting an evaluation in impulse regime: can we determine the value of each capacitor (positive and negative rail) ?

b>NOTE: Datasheet formula for "Cout" of the LM1575 HVS-12->

Calculate Cout.png


Résult ~= 12 µf (We have a problem "HOUSTON"...) o_O

But datasheet said too:

"The above formula yields capacitor values between 10 μF and 2000
μF that will satisfy the loop requirements for stable operation. But
to achieve an acceptable output ripple voltage, (approximately 1%
of the output voltage) and transient response, the output capacitor
may need to be several times larger than the above formula yields".

...not very clear :rolleyes:

And also:
"The lower capacitor values (220 μF–680 μF) will allow typically
50 mV to 150 mV of output ripple voltage, while larger value
capacitors will reduce the ripple to approximately 20 mV to
50 mV.
Output Ripple Voltage = (ΔI ind) (ESR of COUT)
To further reduce the output ripple voltage, several standard
electrolytic capacitors may be paralleled, or a higher-grade
capacitor may be used. Such capacitors are often called
“high-frequency,” “low-inductance,” or “low-ESR.” These will
reduce the output ripple to 10 mV or 20 mV. However, when
operating in the continuous mode, reducing the ESR below
0.05Ω can cause instability in the regulator".


2> Regarding decoupling capacitors: should we not prefer a "local decoupling", that is to say as close as possible to the component that receives the power for more efficiency ?

Like that (green and orange arrows) ->

1 - Décou. TPA.jpg


2 - Décou. AOP.jpg


C - DECOUPLING BASE.jpg


So ?
 
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v1adpetrov2

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1. The capacitor after chip LM2575HVS - from 470uF to 2000uF.
Two capacitors on the "virtual earth" - from 470uF to 1000uF.
I have the measured the equivalent series resistance (ESR) of the capacitors EPCOS 820uF and 560uF was about 0.07 Ohms.

2. Decoupling capacitors of the bipolar power supply (as in our case) of the operational amplifier must be installed between the positive (negative) pole of the power supply and the "ground".
And on your Chinese "miracle adapter", five capacitors are located immediately between the positive and negative poles of the power supply. The benefit from them can only be in circuits with unipolar power supply of the op-amp.
You can read more about opamp nutrition in this article: Avoid Common Problems When Designing Amplifier Circuits
More details: A Designer's Guide to Instrumentation Amplifiers, 3rd Edition
 

ICIETDIYEUR

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Hello v1adpetrov2 :)

I Thank you for the links ;)

You write: "...
Decoupling capacitors of the bipolar power supply (as in our case) of the operational amplifier must be installed between the positive (negative) pole of the power supply and the "ground".
And on your Chinese "miracle adapter", five capacitors are located immediately between the positive and negative poles of the power supply. The benefit from them can only be in circuits with unipolar power supply of the op-amp...".

You are wrong about the feeding of OPAMPS: I made a survey of part of the diagram that is ->

Part of schematic.jpg


The power supply of our OPAMPS is unipolar, which explains the presence of a single SMD capacitor of 10μF decoupling (on the positive necessarily :rolleyes:) just above the location of the OPAMPS.

I have mentioned in my partial diagram a kind of explanation of the choices for the values of capacities.
(I did not represent the Chinese "decoupling bases")

Your opinion ?
 

Doodski

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Your opinion ?
You need a proper eraser. A Staedtler Mars Plastic and a proper pencil and you could clean up your drafting skills immensely. :p :D Doing calculus and that sort of stuff is way easier with a nice pencil like this one. The numerals and symbols stay clear and defined and look real nice. Just saying because you are like almost 100% there in your handwritten drafting stuff. :D
0017437_staedtler-plastic-erasers.jpeg

zzzzz.jpg
 

ICIETDIYEUR

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Hi Doodski.

How should I take your intervention (useless and/or futile) ?

Kind regards.
 

ICIETDIYEUR

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If it was a joke it is missed because it is in bad taste but if it was written to say nothing: it is perfectly successful.
 
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