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eBay mono LM1875 kit
eBay mono LM1875 kit
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Old 29th November 2020, 05:19 AM   #801
rabbitz is offline rabbitz  Australia
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The shutdown pop on the LM1875 is only small and not annoying (3000uF to 4700uF per rail). It's odd that it doesn't happen with the fake chips supplied with the kit.
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Old 29th November 2020, 08:17 AM   #802
kokoriantz is offline kokoriantz  Lebanon
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Has someone seen a better quality distortion spectrum measured of this kit somewhere? Or know what ratio 2nd to 3rd harmonic for 0.02%.
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File Type: jpg lm1875 spectrum.JPG (55.5 KB, 155 views)
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Old 29th November 2020, 09:14 AM   #803
chermann is offline chermann  Austria
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hi


no. no new measurements from this kit.
AFAIK this picture shows john audio techīs method to measure:
1khz main tone and the 3khz or 4kHz pilot tone which is 1% of the 1khz tone.

so you can better look at the the pilot signal especially at pushing more power...


chris
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Old 29th November 2020, 10:00 AM   #804
kokoriantz is offline kokoriantz  Lebanon
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In fact, I see the 2nd harmonic dominant with 60mv rms for 18.4 fundemantal. This gives 0.32% at 40w.
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Old 2nd December 2020, 01:32 AM   #805
kokoriantz is offline kokoriantz  Lebanon
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Default This how to recognize the original LM1875

I am shopping for the IC, and I couldn't find any directives on this site to get for sure original ones. So I share my investigation.
An excellent website is LM1875 manual with 100% guaranteed detection of a fake chip.
UTC manufactures also genuine ones under D1875 old versions and LM1875L new. Both have also fake ones. TI has old version with big letters in the center, forget it, and the new version with small letters on the top.
Looking on pictures, I noticed that the original new one, not the old has non-uniform upper tab Tab.JPG and the back is wide and rectangular. On Aliexpress I found only one proposition for 18$/10pcs, to know that TI sells 1190$/1000pcs.
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Old 2nd December 2020, 04:43 AM   #806
Sadface is online now Sadface  New Zealand
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Farnell, Digikey, Mouser and RS Components have genuine stock.


LM1875T/NOPB | LM1875T/NOPB Texas Instruments, Audio Amplifier 5.5MHz, 5-Pin TO-220 | RS Components
https://nz.element14.com/texas-instr...856?ost=lm1875
Search results for: LM1875 – Mouser New Zealand
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Old 2nd December 2020, 06:13 AM   #807
kokoriantz is offline kokoriantz  Lebanon
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Very high shipment cost. mouser for my region is 20$ bellow 60$ order. The 18$/10pcs is free shipment. You can buy directly from TI for more than 6$ shipment.
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Old 2nd December 2020, 07:01 AM   #808
Sadface is online now Sadface  New Zealand
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I just pad out mouser/digikey orders with other parts I know I will use to get it over the threshold for free shipping.

Mouser has an extensive range of Vishnu/dale cmf/rn series resistors which is about all I use except for high power
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Old 2nd December 2020, 07:44 AM   #809
asuslover is offline asuslover  Romania
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Mouser does not offer free shipping in USA , Newark wants 150$ spent in order to get free shipping , plz don’t buy your chips from AliExpress !!!!
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Old 2nd December 2020, 07:46 AM   #810
Sadface is online now Sadface  New Zealand
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Quote:
Originally Posted by asuslover View Post
Mouser does not offer free shipping in USA , Newark wants 150$ spent in order to get free shipping , plz donít buy your chips from AliExpress !!!!

That seems ridiculous, free shipping all the way across the pacific to little old New Zealand but no free shipping domestically? That strikes me as the opposite of normal....
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