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eBay mono LM1875 kit
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Old Yesterday, 02:49 AM   #231
rabbitz is offline rabbitz  Australia
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Yes, the P19 is LM3886. I also have a Neurochrome 3886DR.

I tried several TPA3116 and the only one I liked was the blue/black designed by Danzz (see pic). All the rest had issues such as hiss, noise or failed.

P72 is ESP Project 72. There are several dual PCBs on ebay like the one in the pic but not ideal.
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File Type: jpg RZ_LM1875_ebay_dual.jpg (86.4 KB, 31 views)
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Old Yesterday, 03:13 PM   #232
chermann is offline chermann  Austria
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Thanks rabbitz for that information.
i look forward to see FFs future plan with LM1875
i find that the bass is still"strange" or bloated...i will measure the frequency response.



chris
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Old Yesterday, 03:43 PM   #233
rabbitz is offline rabbitz  Australia
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I've ordered a Project 72 PCB from Rod Elliott (ESP) and see if that build is any different in sonics.
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Old Yesterday, 07:33 PM   #234
chermann is offline chermann  Austria
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Hi


the red 10 16V electrolytic cap is definitively junk! - this is maybe the reason of bloated/strange bass.
from 10 Hz up to 100 Hz i have a lower gain (look at the scope Voltage)and at 10Hz the signal is really strange. at the pdf file you can see the ESR + ESL measurements --> this cap is junk!!
generally i see at 10-400hz a phase shift which changed from14khz to 19 khz to the other direction.
a sane cap looks fine
last pic at 10hz


chris
Attached Images
File Type: png 10.png (63.0 KB, 9 views)
File Type: png 20.png (64.6 KB, 9 views)
File Type: png 40.png (59.6 KB, 9 views)
File Type: png 80.png (61.7 KB, 3 views)
File Type: png 19k.png (55.9 KB, 2 views)
File Type: png ok10.png (60.0 KB, 2 views)
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File Type: pdf strange red 10 cap_ESR_ESL.pdf (214.9 KB, 1 views)
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Old Yesterday, 08:23 PM   #235
FauxFrench is offline FauxFrench  France
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Quote:
Originally Posted by chermann View Post
Hi
the red 10 16V electrolytic cap is definitively junk! - this is maybe the reason of bloated/strange bass.
from 10 Hz up to 100 Hz i have a lower gain (look at the scope Voltage)and at 10Hz the signal is really strange. at the pdf file you can see the ESR + ESL measurements --> this cap is junk!!
generally i see at 10-400hz a phase shift which changed from14khz to 19 khz to the other direction.
a sane cap looks fine
last pic at 10hz
chris

Chris, I guess it is the capacitor in the string from the inverting input of the LM1875 and to signal ground? If so, would you have a bi-polar Nichicon or Elna capacitor to replace it with? This capacitor risks being reverse biased and that may disturb your low bass.

Last edited by FauxFrench; Yesterday at 08:26 PM.
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