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Old 16th September 2008, 03:38 AM   #11
lineup is offline lineup  Sweden
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How about using 4 x LM1875
2 + 2 paralleled in bridge. Has anybody done this?
-------------------------

The problem with LM3875 / LM3886 /LM4780 is the

1. Too high slewrate + high bandwidth
... which makes a noisier sound and not as musical

2. SPiKe protection electronics = garbage in Output Stage.
Which 'cuts' the peaks in music.
Like in a badly processed CD disc
.. with compressed sound & not perfectly dynamic sound waves.
--------------------------

I remember one older article, where was explained why LM1875 is the better.
It has been commented here in www.diyaudio.com forum

Was showing why LM1875 is the better = more musical chip.
Compared to the new and powerful and high speed 3875-3886-4780

My thinking:
Higher speed & higher Open Loop Gain, in those later chips
= MORE Global Negative feedback in signal
= MORE Compensation capacitance in signal
== MORE Bad Sound


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Old 16th September 2008, 02:06 PM   #12
dynabok is offline dynabok  Hong Kong
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Seems everyone have their own preference, I am going to show my current 1875.
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Old 16th September 2008, 02:06 PM   #13
dynabok is offline dynabok  Hong Kong
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I don't know how attached another image in the same post, this is the inside look of my 1875
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Old 16th September 2008, 05:32 PM   #14
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+1 for the 1875.....
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Old 16th September 2008, 07:42 PM   #15
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I did not try the 1875 because I was looking for more power, but I compared the 3886 with the 3875. I used same powersupply, same resistors and caps. The 3875 is now my favorite it has a cleaner more direct sound.
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Old 17th September 2008, 12:17 AM   #16
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Quote:
Originally posted by Tranceformer
I did not try the 1875 because I was looking for more power, but I compared the 3886 with the 3875. I used same powersupply, same resistors and caps. The 3875 is now my favorite it has a cleaner more direct sound.
differences:
In my opinion, most of the audio variances between the different model chips can be negated via the power supply or power circuit choices; however, LM1875 and LM3875 alike, are still less powerful than LM3886 by 3 to 4 decibels output. The optimized power circuits, for these to produce high fidelity audio, are all probably quite different. To me, the quote above looks like one of the National Semiconductor chip amps has facilited the use of a favorite power circuit.
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Old 17th September 2008, 04:22 AM   #17
dynabok is offline dynabok  Hong Kong
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oh,,,,,seems everyone like national semiconductor LM series, is there any different from TDA series? how about TDA series, I never tried TDA series before, is it also good? can anyone share their DIY experience on TDA series? I want to build TDA for my next chip AMP.
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Old 17th September 2008, 07:46 AM   #18
lineup is offline lineup  Sweden
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Besides Class D amplifier chips and Digital Audio amps
SGS-Thomson
has many Class AB Audio Power Amplifier chips.

http://www.st.com/stonline/products/...amplifiers.htm
Quote:
Audio Power Amplifiers Families
Bash Product Selector
Class AB <5V Product Selector
Class AB >5V Product Selector
Class D <5V Product Selector
Class D >5V Product Selector
Digital Audio Amplifiers Product Selector
Digital Audio Drivers Product Selector
Microphone Preamplifiers Product Selector
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Old 17th September 2008, 02:45 PM   #19
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Quote:
Originally posted by dynabok
oh,,,,,seems everyone like national semiconductor LM series, is there any different from TDA series? how about TDA series, I never tried TDA series before, is it also good? can anyone share their DIY experience on TDA series? I want to build TDA for my next chip AMP.
I do enjoy the TDA7294 because its quite powerful and its treble isn't as much challenge as LM3886. Maybe its not right for me to enjoy something because its less of a challenge? Well, the midbass vs power circuit does provide some hours of entertaining puzzle.
A good friend sent me this link: http://www.elecfree.com/electronic/tag/tda2030/ It looks mighty tempting.
And, that reminds me that most of the ST Thompson that I have liked best, were applied bridged or symmetry(ish). One of my first chip amps was TDA2003 bridged and with a 15vdc laptop power supply. That thing is lovely pushing a big 4 ohm aluminum cone driver.

Without further ado, here's my second favorite:
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Old 17th September 2008, 03:39 PM   #20
lineup is offline lineup  Sweden
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Quote:
Originally posted by danielwritesbac

I do enjoy the TDA7294 because its quite powerful and its treble isn't as much challenge as LM3886. Maybe its not right for me to enjoy something because its less of a challenge? Well, the midbass vs power circuit does provide some hours of entertaining puzzle.
A good friend sent me this link: http://www.elecfree.com/electronic/tag/tda2030/ It looks mighty tempting.
TDA7293 100 Watt, max +-50 Volt supply, 4ohm
TDA7294 100 Watt, max +-40 Volt supply, 8ohm
TDA7295 080 Watt, max +-40 Volt supply, 8ohm
TDA7296 060 Watt, max +-35 Volt supply, 8ohm

4ohm or 8ohm is the recommended minimum load
But of course you can use 4/8 for any of these,
if you play within the safe limits of the chip ratings

Bit lower power are TDA2052, TDA2050, 60 Watt vs. 32 Watt Hifi.
Max Supply Voltage: +-25 Volt DC.
And for many normal diy applications, these 2 chips are really quite good.
And very easy to use. Of course.
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