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Chip Amps Amplifiers based on integrated circuits

Looking for the Circuit drawing of this LM4780 Board
Looking for the Circuit drawing of this LM4780 Board
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Old 23rd April 2019, 12:28 AM   #31
PRR is offline PRR  United States
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Quote:
Originally Posted by avtech23 View Post
...If I were to make this board parallel (connect the jumper between 'R OUT' and 'L OUT')....
Don't do that without thinking!!!!

Say you have a 1% difference between amplifiers. At some moment, one is at 20V, the other at 20.2V. This is a 0.2V difference across the jumper. The amplifiers' output resistance may be less than 0.01 Ohms. Say the jumper is similar. 20V across the 8 Ohm load is 2.5 Amps to load, but 0.2V across 0.03 Ohms jumpering is 6.6 Amps of waste current and heat in the chip!
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Old 23rd April 2019, 06:05 AM   #32
avtech23 is offline avtech23  Australia
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Looking for the Circuit drawing of this LM4780 Board
Thanks for the warning PRR.

The schematic says to 'short out the jumper' and the PCB is designed with a shorting link..

But looking at the datasheet, it suggests 2x 0.1 ohm 3W resistors in series with the output in the centre.

I take it that this would work as it would reduce the 6.6A/1.3W to 2A 400mW?

edit: the audio sector boards appear to use 0.15R 3w power resistors (output).
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File Type: jpg parallel.jpg (98.6 KB, 75 views)
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Last edited by avtech23; 23rd April 2019 at 06:08 AM.
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Old 23rd April 2019, 06:41 AM   #33
Mark Whitney is online now Mark Whitney  Netherlands
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Are they not the large green resistors with R10 printed on them? R10 and R19 printed on the board.
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Last edited by Mark Whitney; 23rd April 2019 at 06:44 AM.
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Old 23rd April 2019, 07:01 AM   #34
avtech23 is offline avtech23  Australia
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Looking for the Circuit drawing of this LM4780 Board
The boards I am going to be using have a series inductor at the output.

Click the image to open in full size.
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The ever growing project list.. :NAP140 Clone, NAD 3020i & 3225PE, JLH1969, TDA2050, Fender 5F2A Princeton, NE5532 Pre, SHPA, B1 Korg. : VSQC Phunk Style, Retro 50W, Filmosound 601. : Apex AX-14, TGM-10, TDA7265, LM4780 (Last in line)...maybe
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Old 24th April 2019, 03:35 AM   #35
Killersupra is offline Killersupra
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Hello everybody,

I just stumbled across this thread for the same reason as OP, as it turns out, audiomodule.eu is down and I never received the PCB schematic and BOM via email, but I did get them printed out with my purchase.

After a long search I managed to find them, hope this does the trick.

Best regards.
Attached Images
File Type: jpg LM4780 Schematic.jpg (101.3 KB, 76 views)
File Type: jpg LM4780 BOM.jpg (154.8 KB, 77 views)

Last edited by Killersupra; 24th April 2019 at 04:02 AM. Reason: Text formatting
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Old 24th April 2019, 05:58 AM   #36
pitbul is offline pitbul
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LM4780 I am using in parallel output with one important thing, resistors which defines amplification should be 0,1% accuracy, after that amp is working without issues which PRR mentioned.
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Old 24th April 2019, 07:45 AM   #37
zoky2 is offline zoky2  Slovenia
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Killersupra,

thank you very much for the schematic and BOM,now I can put together the board .


Regards
zoky2
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Old 28th April 2019, 05:29 PM   #38
Salar is online now Salar  Germany
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Hi to all, thanks a lot indeed! It is also very nice that some basics were discussed again,
really appreciate it.
All the best,
Salar
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Old 23rd May 2019, 03:01 PM   #39
Salar is online now Salar  Germany
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What volume pot to use with this board? Is it dependent on R11&R18? Sources are
strictly line level DACs. Is 10k the value to go?
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