lm1875 fizzing away probelm - Page 21 - diyAudio
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View Poll Results: Was a good idea to use two lm1875 or a big stk chip
Use stk 8 27.59%
use lm1875 21 72.41%
Voters: 29. You may not vote on this poll

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Old 5th February 2013, 07:19 PM   #201
PetruV is offline PetruV  Romania
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Quote:
Originally Posted by PetruV View Post
i think il stay with the tda 8560q, but i want something like 4x50w that cn be bridged in 2x50w +100w
Change of plans,more like return to the old plan, in my my main amp that im going to build now. i want 6 tda7294 for satelites and two of them for center chanel and a transitor amp for subwoofer 500w or so.
This is going to be very cheap to build until we get to the transformer part,where im going to wind my own(primary aleardy made) using a welder transformer since they are cheap, or maybe a smps since thats even chepear.

Excuse me being a cheap @#$@ but im only 13 and legal working age is 16 so 3 more years to way until you will see me have losts of awesome stuff
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Old 6th February 2013, 06:13 PM   #202
PetruV is offline PetruV  Romania
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Just tried the dataheet schematic on the lm1875t and one of the speakers just goes up quite a lot and makes a 50hz buzz,can you tell me what it is,maybe its because the fedback circuit on that one is near to the transformer at a couple of milimiters,tried moving it to 5cm away and the same happens,will som aluminium foild arond the trafo help
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Old 7th February 2013, 08:12 AM   #203
PetruV is offline PetruV  Romania
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I FOUND THIS schematic on the web What can i use to get it up and working,and what mistakes are there,i want 300-500w at 4r
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File Type: gif 20117134028808.gif (191.1 KB, 84 views)
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Old 7th February 2013, 09:16 AM   #204
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How long can you go ?

When you catch the fact that an amplifier is composed by the supply feeding
the various stages...you'll see that indeed it's just a bunch of devices attached
to the transformer, which purpose is to ISOLATE from the mains and to provide the suitable potentials to make everything work. In audio it's not like other fields or applications ( I'm not talking about Supreme joke ) because all
the processing determines the sound.
Now take a deep breath and read the V supply of that power output stage.
One of those transistors( VT5-12) is 4 times more powerful than a single LM 1875, just by looking at the max current that may flow trough the device, and they are 8, needing a biiiig heatsink, and a big transformer ( and a big 25A bridge rectifier! and two big caps!)

Last edited by picowallspeaker; 7th February 2013 at 09:20 AM.
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Old 7th February 2013, 04:27 PM   #205
PetruV is offline PetruV  Romania
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Quote:
Originally Posted by picowallspeaker View Post
How long can you go ?

When you catch the fact that an amplifier is composed by the supply feeding
the various stages...you'll see that indeed it's just a bunch of devices attached
to the transformer, which purpose is to ISOLATE from the mains and to provide the suitable potentials to make everything work. In audio it's not like other fields or applications ( I'm not talking about Supreme joke ) because all
the processing determines the sound.
Now take a deep breath and read the V supply of that power output stage.
One of those transistors( VT5-12) is 4 times more powerful than a single LM 1875, just by looking at the max current that may flow trough the device, and they are 8, needing a biiiig heatsink, and a big transformer ( and a big 25A bridge rectifier! and two big caps!)
Lol i used 40a bridge in lm amplifier,the lm1875t is weak @#$% ,i made it since it was cheap and aleardy had the trafo,and case.
I saw the voltage and yes i know need a big trafo,im not dumb,i wwill wind my own but with primary aleardy made
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Old 7th February 2013, 04:36 PM   #206
PetruV is offline PetruV  Romania
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googled 2sc 1006 ans its very weak probably not enough to drive 2n3055 or 2sc5200 or 2n3773 or 2n3771 or tip35c or some other over 100w transitors to yeld 300 500w for a subwoofer
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Old 8th February 2013, 07:40 AM   #207
PetruV is offline PetruV  Romania
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More more,what about that lm12,or some other high power op amps,will the be good for audio
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File Type: jpg 450W amplifier schematics.jpg (183.7 KB, 71 views)
File Type: jpg LM12-150w-high-power-amplifier.jpg (24.8 KB, 67 views)
File Type: jpg 2icacuw.jpg (193.6 KB, 68 views)
File Type: jpg 96lxrs.jpg (180.5 KB, 67 views)
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Old 8th February 2013, 03:57 PM   #208
PetruV is offline PetruV  Romania
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Anyways is that chinese schematic ready for usage,but WE need to choose the transistors

Last edited by PetruV; 8th February 2013 at 04:23 PM.
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Old 9th February 2013, 11:23 AM   #209
PetruV is offline PetruV  Romania
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I bought 4 tda 2003 since theyre good n cheap but only one is a tda 2003, 2 others tda2003av and the othe wich looks different on the back is an utc2003 is there any diference
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Old 9th February 2013, 12:38 PM   #210
JMFahey is offline JMFahey  Argentina
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I think by now everybody noticed petruv is a troll who loves pulling our legs.
People like him "burn" real noobs who ask legitimate questions.



@ ezavalla: no le des pelota a este pendejo pelotudo que nos está cargando a todos.
Dice que quiere armar un amplificador con fuente +/-95Volts, pero un TDA2003 le oscila y distorsiona.

Fijate el nivel de su tecnología:
diyAudio

Además envuelve el trafo en papel de aluminio, dice que "no mide porque el tester no tiene pilas", que no necesita disipador porque "prueba 2 segundos", etc.
No pierdas el tiempo con esta gilada.
Un abrazo.

Last edited by JMFahey; 9th February 2013 at 12:45 PM.
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