eBay mono LM1875 kit - Page 81

rabbitz · 29th November 2020, 05:19 AM

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.

kokoriantz · 29th November 2020, 08:17 AM

Has someone seen a better quality distortion spectrum measured of this kit somewhere? Or know what ratio 2nd to 3rd harmonic for 0.02%.

chermann · 29th November 2020, 09:14 AM

hi

no. no new measurements from this kit.
AFAIK this picture shows john audio tech´s 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

kokoriantz · 29th November 2020, 10:00 AM

In fact, I see the 2nd harmonic dominant with 60mv rms for 18.4 fundemantal. This gives 0.32% at 40w.

kokoriantz · 2nd December 2020, 01:32 AM

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.

Sadface · 2nd December 2020, 04:43 AM

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
Blocked

kokoriantz · 2nd December 2020, 06:13 AM

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.

Sadface · 2nd December 2020, 07:01 AM

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

asuslover · 2nd December 2020, 07:44 AM

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 !!!!

Sadface · 2nd December 2020, 07:46 AM

Quote:

Originally Posted by asuslover

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 !!!!

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....

29th November 2020, 05:19 AM	#801
rabbitz diyAudio Member Join Date: Jul 2003 Location: Newcastle, Australia	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. __________________ If there are no dogs in Heaven, then when I die I want to go where they went - Will Rogers

2nd December 2020, 01:32 AM	#805
kokoriantz diyAudio Member Join Date: Dec 2015 Location: south east asia	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.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Chinese Mono LM1875 Board	Twil	Chip Amps	56	23rd September 2020 12:59 AM
LM1875 Ebay dual channel pcb question	nenad88	Chip Amps	11	30th August 2018 12:21 AM
ebay lm1875 pcb	asuslover	Chip Amps	7	27th August 2016 04:58 AM
Running two LM1875 mono amp from single psu	si82	Chip Amps	21	2nd June 2014 04:32 PM
Just fired up my new dual mono lm1875 Gainclone.	Shoog	Chip Amps	5	19th January 2004 07:09 PM

New To Site?	Need Help?
Register to Participate Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

29th November 2020, 09:14 AM	#803
chermann diyAudio Member Join Date: Jan 2017 Location: Vienna	hi no. no new measurements from this kit. AFAIK this picture shows john audio tech´s 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

29th November 2020, 10:00 AM	#804
kokoriantz diyAudio Member Join Date: Dec 2015 Location: south east asia	In fact, I see the 2nd harmonic dominant with 60mv rms for 18.4 fundemantal. This gives 0.32% at 40w.

2nd December 2020, 04:43 AM	#806
Sadface diyAudio Member Join Date: Jan 2012	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 Blocked

2nd December 2020, 06:13 AM	#807
kokoriantz diyAudio Member Join Date: Dec 2015 Location: south east asia	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.

2nd December 2020, 07:01 AM	#808
Sadface diyAudio Member Join Date: Jan 2012	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

2nd December 2020, 07:44 AM	#809
asuslover diyAudio Member Join Date: Aug 2016 Location: Chicagoland	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 !!!!