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my power amp ic of my amp always blowing

PostPosted: 10 Jan 2019, 08:44
by ballfire
hello everybody..


anybody give me some advice.. my solid amp power amp IC Keep blowing when I install new one..after a minutes of playing maybe 15 minutes with my amp the power amp ic goes on tiny little humming sound inside then 'pliccck"" it made a crack on the ic itself and smells sucks and the output sound gone..then I change it to a new one ..and clicks and broke again...

what would be the problem of this??can anybody help??

Re: my power amp ic of my amp always blowing

PostPosted: 10 Jan 2019, 09:06
by phatt
If it's buzzing before it blows it could be hi freq runaway feedback.
although you can't hear that high it is pushing full power.
Without more detail and maybe a schematic of the circuit it's really hard to help. Is it a DIY amp or factory build? What is the model number on the Chip?
A lot of these chip amps need a Zobel network right at the output pins to be stable at hi frequency,, if not yes they can self destruct.

Before you burn another chip build yourself a *Lamp Limiter* which limits the current and stops the chip blowing while you work out what is wrong.

Not sure if we have this topic on FSB but good info on how it works here;
https://www.ssguitar.com/index.php?topic=2093.0.
Phil.

Re: my power amp ic of my amp always blowing

PostPosted: 10 Jan 2019, 16:32
by thetragichero
what amp?
what chip?
could it be heat-related? marshall mg100 has a heat sink AND a fan on the output chip, and i've read that the fan dying is the cause of many chips dying

more info, please!

Re: my power amp ic of my amp always blowing

PostPosted: 11 Jan 2019, 01:16
by ballfire
phatt wrote:If it's buzzing before it blows it could be hi freq runaway feedback.
although you can't hear that high it is pushing full power.
Without more detail and maybe a schematic of the circuit it's really hard to help. Is it a DIY amp or factory build? What is the model number on the Chip?
A lot of these chip amps need a Zobel network right at the output pins to be stable at hi frequency,, if not yes they can self destruct.

Before you burn another chip build yourself a *Lamp Limiter* which limits the current and stops the chip blowing while you work out what is wrong.

Not sure if we have this topic on FSB but good info on how it works here;
https://www.ssguitar.com/index.php?topic=2093.0.
Phil.


thanks phil..

i found out the current recieving by the power amp is higher.my amp is using a tda 2040 chip..
my secondary dcv of my transformer is 22.0 dcv volts.. but why is it after the diode bridge it became 28.0 dcv volts which higher to the power amp tda2040 current limit??

its okey to remove the diode bridge in order to recieve directly a 22.0 dcvolts to the power amp chip??

what should i do in order to low the 28.0 dc voltage to 22.0 only after the diode bridge?

thanks..

Re: my power amp ic of my amp always blowing

PostPosted: 11 Jan 2019, 02:44
by phatt
the max voltage for tda2040 is 40VDC.
So you are way over the limit. [smilie=new_microwave.gif]

You need to do home work on rectification. Google rectification :secret:

The secondary output of of a transformer is ACV NOT DCV!!!
The Rectifier converts it to DCV.
Depending on the type of rectifier design the DCV output is often much higher.
In the case of full wave bridge the DCV is 1.4 times the ACV.
So Set your meter to ACV and read the taps on the transformer secondary. then multiply it x 1.4

To stay in the safe zone you need a transformer that reads no more than 14-0-14 VAC. then after rectification x 1.4 will give you 19.6VDC.

Any more than 20-0-20VDC then say goodbye to the chip.
That transformer voltage is far too high for that chip.
Phil.

Re: my power amp ic of my amp always blowing

PostPosted: 11 Jan 2019, 02:52
by ballfire
phatt wrote:the max voltage for tda2040 is 40VDC.
So you are way over the limit. [smilie=new_microwave.gif]

You need to do home work on rectification. Google rectification :secret:

The secondary output of of a transformer is ACV NOT DCV!!!
The Rectifier converts it to DCV.
Depending on the type of rectifier design the DCV output is often much higher.
In the case of full wave bridge the DCV is 1.4 times the ACV.
So Set your meter to ACV and read the taps on the transformer secondary. then multiply it x 1.4

To stay in the safe zone you need a transformer that reads no more than 14-0-14 VAC. then after rectification x 1.4 will give you 19.6VDC.

Any more than 20-0-20VDC then say goodbye to the chip.
That transformer voltage is far too high for that chip.
Phil.



oh i understand do you mean its okey to the tda2040 using a dcv 28.0??

maybe i put a larger aluminum heatsink?

by the way i have a 18volts 3 amperes power transformer can i use this? using with a 2 ampere diode bridge???

Re: my power amp ic of my amp always blowing

PostPosted: 11 Jan 2019, 09:06
by phatt
You need to read the data sheet.
Max voltage is 40Volts DC.
so if TDA2040 runs a single supply then 40VDC is MAX
If you are running a split supply/Dual rail then it's +20/-20VDC MAX
Which adds up to the total of 40VDC.
I'd say around +18/-18VDC would be safe.

You need to clarify if your chip is running a single supply or dual supply?
Phil.

Re: my power amp ic of my amp always blowing

PostPosted: 11 Jan 2019, 13:32
by ppluis0
Hi folks,

There also exist the option to replace the power IC with a TDA2050 as the pinouts and associated components appears to be the same in their respective datasheets.

This integrated amplifier works up to 50 Vdc of supply voltage.

Cheers,
Jose

Re: my power amp ic of my amp always blowing

PostPosted: 11 Jan 2019, 13:44
by phatt
ppluis0 wrote:Hi folks,

There also exist the option to replace the power IC with a TDA2050 as the pinouts and associated components appears to be the same in their respective datasheets.

This integrated amplifier works up to 50 Vdc of supply voltage.

Cheers,
Jose


Good point, :thumbsup
Phil.

Re: my power amp ic of my amp always blowing

PostPosted: 12 Jan 2019, 01:27
by ballfire
phatt wrote:You need to read the data sheet.
Max voltage is 40Volts DC.
so if TDA2040 runs a single supply then 40VDC is MAX
If you are running a split supply/Dual rail then it's +20/-20VDC MAX
Which adds up to the total of 40VDC.
I'd say around +18/-18VDC would be safe.

You need to clarify if your chip is running a single supply or dual supply?
Phil.



whoaa its really put me into real clarification now i know ...thank you very much phatt..and others

thank you very much people on the other side of the globe dealing with these topics ..
im very thankful to know these people here talking about amps.

i hope im leaving in america so that i dont have any problems on my amp they really fix it..they know really about it..

ok my amp is running in split supply so i need a 18 vcd power supply..my reading each supply rail both runs on 28 dcv so its really bad thats why the previous chip broke off..its really burden me fixing this thing..

i have now a 18vcd tansformer 3 ampere, can i use a 2 ampere single phase diode bridge after that 18vcd secondary??

anything??

Re: my power amp ic of my amp always blowing

PostPosted: 12 Jan 2019, 02:10
by phatt
Glad to help as the psu is actually quite a tricky thing to understand. :scratch:
You need to learn about what is AC and what is DC in your power supply.
A transformer can only pass AC Voltage. there is no DCV in/ out/ through a transformer.
So when you say you have an 18VDC transformer,, we have no idea what voltage is really present.

The Transformer delivers ACV then the Rectifier converts the AC into DC.
Depending what type of rectifier you use will define the DC voltage that is produced. Google Rectification.
I found this in 10sec;
http://electricalengrz.blogspot.com/201 ... ation.html

A full wave bridge is likely the most common form but there are many other ways to obtain DC from AC.
Attaching a pic of other forms of rectification. Note how each design produces quite different outcomes.
The currents and voltages are very different.
Full wave is the most effective way hence it's very common.

As said before; Switch your meter to ACvolts then read the voltage at the transformer,,, post that **AC** voltage here.
then post a schematic or at least a pic of your psu, rectifier setup,,Then we can help.
Phil.

Re: my power amp ic of my amp always blowing

PostPosted: 12 Jan 2019, 03:08
by ppluis0
ballfire wrote:thank you very much people on the other side of the globe dealing with these topics ..
im very thankful to know these people here talking about amps.


In the south hemisphere of our planet the amplifiers also blown from time to time... :lol:

Re: my power amp ic of my amp always blowing

PostPosted: 12 Jan 2019, 05:44
by ballfire
phatt wrote:As said before; Switch your meter to ACvolts then read the voltage at the transformer,,, post that **AC** voltage here.
then post a schematic or at least a pic of your psu, rectifier setup,,Then we can help.
Phil.



hello everybody this is my psu inside my amp

any corrections or fix suggestions??

Re: my power amp ic of my amp always blowing

PostPosted: 12 Jan 2019, 08:11
by phatt
Well if the transformer output is 21-0-21Volts *AC* Then the DC Voltage is correct.
Which leaves you with 2 options;
Replace the transformer with one that has 12-0-12VAC taps.
That will give you around 17-0-17VDC rails for power chip, well within the limits of that chip.

Or find a chip that can handle higher supply voltages. Up to you [smilie=a_whyme.gif]

BTW you have drawn the negative filter caps upside down, the curve is the neg side in drawings,, but you at least put the positive sign in the right place. No big deal but can get confusing.

Re: my power amp ic of my amp always blowing

PostPosted: 12 Jan 2019, 08:41
by ballfire
phatt wrote:Well if the transformer output is 21-0-21Volts *AC* Then the DC Voltage is correct.
Which leaves you with 2 options;
Replace the transformer with one that has 12-0-12VAC taps.
That will give you around 17-0-17VDC rails for power chip, well within the limits of that chip.

Or find a chip that can handle higher supply voltages. Up to you [smilie=a_whyme.gif]

BTW you have drawn the negative filter caps upside down, the curve is the neg side in drawings,, but you at least put the positive sign in the right place. No big deal but can get confusing.


thanks phatt..

im thinking before maybe i should put there a 12-0-12 transformer.yeah youre right there it should be a safe margin..

the caps i just drawn it fastly with photoshop app but i know the orientation of it ...

Re: my power amp ic of my amp always blowing

PostPosted: 12 Jan 2019, 17:41
by Ice-9
Have you checked the voltage at the actual pins of the TDA2040 chip instead of the voltage at the rectifier side. the circuit may have some voltage dropping resistors to get the +/- 28 V down a little to the max +/- 20v . It would help a lot if you said what the amp make and model is as a schematic may be available to help. If you already mentioned this I may have missed it.

Re: my power amp ic of my amp always blowing

PostPosted: 13 Jan 2019, 11:38
by deltafred
Content removed, it's too early to do fault diagnosis and I haven't had enough coffee yet!

Note self - read the bloody circuit diagram.

Re: my power amp ic of my amp always blowing

PostPosted: 14 Jan 2019, 01:24
by ballfire
Ice-9 wrote:Have you checked the voltage at the actual pins of the TDA2040 chip instead of the voltage at the rectifier side. the circuit may have some voltage dropping resistors to get the +/- 28 V down a little to the max +/- 20v . It would help a lot if you said what the amp make and model is as a schematic may be available to help. If you already mentioned this I may have missed it.



good morning everybody..and the people who replies in this topic..

ive been busy trying to fix it ..sunday im busy repairing it..by the way i bought a 12-0-12 volt power transformer and install it rightly and it power on ..

the power amp chip dont blew anymore..i think in that situation the amp work stable..but theres a little problem..theres a little distorted with output in clean channel..

how can i remove it?? and make it just pure clean output??

Re: my power amp ic of my amp always blowing

PostPosted: 14 Jan 2019, 04:40
by phatt
Maybe turn down the gain in the clean preamp might help.
It depends just where in the signal path the distortion is coming from.
Without a schematic we are all flying blind so it could be many things.
Phil.

Re: my power amp ic of my amp always blowing

PostPosted: 14 Jan 2019, 05:24
by ballfire
phatt wrote:Maybe turn down the gain in the clean preamp might help.
It depends just where in the signal path the distortion is coming from.
Without a schematic we are all flying blind so it could be many things.
Phil.


good day..
thats a good suggestion..lessen down the gain pot on clean actually it has one...

my amp has 5 Op amp inside plus the power ic..it has also reverb section..i cant trace it instantly it will took me too long to do it..so maybe i will check the op amps first and check the resistance of the parts one by one by multimeter maybe theres something failing parts..

if i cant find the part causing the distorted thing on the output ..i guess im gonna trace it down but it will take me too long..


but anyways i felt succesfull on it because i fix it ..and the power amp dont blew again...and i can play my guitar on it again..

thank you for the advices..lets see what will happend next..