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Old 7th February 2003, 03:52 PM   #1
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Default My LM3875 Poweramp

Hi,

Circuit base on the gaincone, but without the volume....

And the gain is lower than the suggestion circuit.

The Power supply cap using a pair of the 4700uf
working voltage at +/-35V

Using the 470uf for the by-bass

Resistance using with the RMG Japan...

Sound looks great, still running-in!

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Old 7th February 2003, 04:04 PM   #2
Ilianh is offline Ilianh  Canada
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Hi, Good work, they look great

I've always wondered, those amps have 2 channels, they are 30 watts on 8 ohm each i think, can you bridge them?
to make like 60 watts on 8 ohm? Because I have like 5 lm3875 and i wanted to do something out of them.
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Old 7th February 2003, 04:10 PM   #3
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Those are probably the smallest monoblocks I have seen.
I wonder, however, do those boxes really provide sufficient
cooling or are you running the chips on rather low supply voltage?
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Old 7th February 2003, 04:12 PM   #4
SlaitH is offline SlaitH  Sweden
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looks very nice

cool thing with the small boxes. There isn't any coolers it doesn't get to hot??

/Patrik
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Old 7th February 2003, 04:15 PM   #5
Ilianh is offline Ilianh  Canada
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Its true that these generate alot of heat, and I bet those monolocks get hot.. But I'm sure that unless excessive hours of listening at max volume its not dangerous for the LM's.
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Old 7th February 2003, 04:35 PM   #6
halojoy is offline halojoy  Sweden
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Thumbs up hatasa - real good DIY Audio!

hatasa,
this amplifier DOES NOT fit in,
in the "UGLY amplifier" thread.
I like your work very much.

I do not think there is any worrying for too much HEAT.
When listening to music in a normal way
not much cooling is needed.
And I am sure LM3875 can take a lot.

Of course Capacitors can suffer from heat.
That is why I never put them TOO CLOSE to big heatsinks.

/halo - wants to buy hatasa amps ...
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Old 7th February 2003, 04:51 PM   #7
Ilianh is offline Ilianh  Canada
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Quote:
Hi, Good work, they look great

I've always wondered, those amps have 2 channels, they are 30 watts on 8 ohm each i think, can you bridge them?
to make like 60 watts on 8 ohm? Because I have like 5 lm3875 and i wanted to do something out of them.
gosh... that was bad sorry, I got mixed up with some other amplifier with similar a name ... My bad..

lm3875 are 56w into 8 ohm.... with a 100w peak.

bah.....






(no, I'm not drunk)
I'm at school, working on lab, just tought I'd take a pause to see whats up on diyaudio..
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Old 7th February 2003, 04:58 PM   #8
halojoy is offline halojoy  Sweden
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Default Re: My LM3875 Poweramp

Quote:
Originally posted by hatasa
Hi,Circuit base on the gaincone, but without the volume....
And the gain is lower than the suggestion circuit.

The Power supply cap using a pair of the 4700uf
working voltage at +/-35V
Using the 470uf for the by-bass Resistance using with the RMG Japan...
The only thing I would change is the Black Gates.
In my Opinion just a waste of money.
And ordinary Resistors are absolutely good enough
for any circuit.

/halo - have a little less money, than others
and manage just as good anyway
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Old 7th February 2003, 05:03 PM   #9
saletel is offline saletel  United States
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ok call me an idiot, but i've been wanting to do a gainclone amp for a while (not the reason i'm an idiot ) i only say that because i havent been able to find any schematics, so here i am asking. i'll probably be using lm3886t chips. so post a schematic for my simple mind. thanks
-Eric
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Old 7th February 2003, 05:07 PM   #10
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http://home.student.utwente.nl/f.s.b.../thor-amp.html
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