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eBay mono LM1875 kit
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Old 20th October 2019, 06:13 PM   #241
chermann is offline chermann  Austria
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Quote:
Originally Posted by FauxFrench View Post
Sounds good. We are waiting impatiently for the results.
Bonne nuit!

Hello again..


so the first 20 hours are done. i am actually happy with this configuration. i know the caps from other project and i am once again very satisfied with the sound of these green monsters


here is a album (little bit strange..)where i found no bloated bass anymore with my sonus faber venere 1.5 (stand 1,3m before the back wall and 90 cm before the side wall) the control is now how i like it. i played this 6R speakers nearly between 10-25W now..


chris
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File Type: jpg playlist for testing_bloated bass_no.JPG (72.5 KB, 103 views)
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Old 21st October 2019, 03:19 AM   #242
Bare is offline Bare  Canada
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Originally Posted by chermann View Post
Hi


[B]the red 10 16V electrolytic cap is definitively junk!
last pic at 10hz


chris
Geee ! who woulda thought? Curious part is your actually using it.
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Old 21st October 2019, 07:28 AM   #243
FauxFrench is offline FauxFrench  France
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Location: The mountains, calm and quiet.
Quote:
Originally Posted by chermann View Post
Hello again..

so the first 20 hours are done. i am actually happy with this configuration. i know the caps from other project and i am once again very satisfied with the sound of these green monsters

here is a album (little bit strange..)where i found no bloated bass anymore with my sonus faber venere 1.5 (stand 1,3m before the back wall and 90 cm before the side wall) the control is now how i like it. i played this 6R speakers nearly between 10-25W now..

chris

Well done, Chris.
Both the green 10uF and 100uF capacitors are Nichicon bipolar types?
If no more bloated bass, how does the amplifier in general sound on your Sonus Faber?
Better or worse than TPA3250?
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Old 21st October 2019, 07:42 AM   #244
chermann is offline chermann  Austria
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Join Date: Jan 2017
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Quote:
Originally Posted by FauxFrench View Post
Well done, Chris.
Both the green 10uF and 100uF capacitors are Nichicon bipolar types?
If no more bloated bass, how does the amplifier in general sound on your Sonus Faber?
Better or worse than TPA3250?

hi FF


Yes the ES are bipolar caps. if you look at neurochrome - he use it too ....
i use them for my recovery at my 28years old Accuphase C200v and at my TPA3255 amps. i tried other bipolar e.g. the small blue from panasonic no chance - they are hard in sounding, normal polar elna silmic 2 are a save cap. i am sorry but foil caps i have nearly nothing at home...


i will do a compare between my TPA3250 and my "fake amp" after some extra hours running the ES caps.


chris
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Old 21st October 2019, 09:02 AM   #245
chermann is offline chermann  Austria
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Originally Posted by Bare View Post
Geee ! who woulda thought? Curious part is your actually using it.

Hi Bare


yes i know but i try a bit science
i measured some used junk caps from the kit and original used caps. capacity and ESR is the main difference - the ESL is nearly the same


chris
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File Type: pdf strange red 10 +NFB 47cap_ESR_ESL.pdf (422.9 KB, 13 views)
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Old 21st October 2019, 07:33 PM   #246
chermann is offline chermann  Austria
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Quote:
Originally Posted by FauxFrench View Post
Well done, Chris.
Both the green 10uF and 100uF capacitors are Nichicon bipolar types?
If no more bloated bass, how does the amplifier in general sound on your Sonus Faber?
Better or worse than TPA3250?

Good evening


As "requested" by FF i did a SQ compare between my actual 1875amp1_2 (green caps) and my modded TPA3255 (fake amp) and my mod FX502spro (TPA3250).


at my sonus faber venere 1,5 - this are in my aspect "sounded" because the bass has a hump about 6 db in low frequency.

well the Class D chips are very similar and sometimes i think the small one FX502spro is better but if i switched to the "big" amp (TPA3255) it shows the small one were the direction should go. the TPA3255 is in every aspect smart and dead quiet, the dynamic is 1 step ahead the small amp.


so what about the LM1875? the bass is not bloated anymore -its a fine strong and deeper bass- i mean the bass drums are a bit bigger but the skin is not so tight as the other amps - but with the venere maybe not the ideal partner.
the mid and high are excellent - i never hear today a bad , t, th, s, z from the LM1875... plus the male voice get and extra honey (e.g. Udo Schild / album Im still waiting).....very enjoyable if you thing what i have to invest at the class D amp to avoid this !!!

what i miss is the sound stage in width and deepness the attention to hear more about the rear area and deep left/right cost some "points". i am still not happy with the "noise" - i try to explain : if you breath slow through your nose - this sound is existing from the amp in the background -so this fog avoid the clearness from deep and width.
maybe a much better supply ripple will help - or the THD and the PSSR is the "main reason"???



so it is still a very fine amp...and I am not finished with this chip amp.
chris
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Old 21st October 2019, 10:19 PM   #247
FauxFrench is offline FauxFrench  France
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Join Date: Dec 2017
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Quote:
Originally Posted by chermann View Post
Good evening

As "requested" by FF i did a SQ compare between my actual 1875amp1_2 (green caps) and my modded TPA3255 (fake amp) and my mod FX502spro (TPA3250).

at my sonus faber venere 1,5 - this are in my aspect "sounded" because the bass has a hump about 6 db in low frequency.


well the Class D chips are very similar and sometimes i think the small one FX502spro is better but if i switched to the "big" amp (TPA3255) it shows the small one were the direction should go. the TPA3255 is in every aspect smart and dead quiet, the dynamic is 1 step ahead the small amp.

so what about the LM1875? the bass is not bloated anymore -its a fine strong and deeper bass- i mean the bass drums are a bit bigger but the skin is not so tight as the other amps - but with the venere maybe not the ideal partner.
the mid and high are excellent - i never hear today a bad , t, th, s, z from the LM1875... plus the male voice get and extra honey (e.g. Udo Schild / album Im still waiting).....very enjoyable if you thing what i have to invest at the class D amp to avoid this !!!

what i miss is the sound stage in width and deepness the attention to hear more about the rear area and deep left/right cost some "points". i am still not happy with the "noise" - i try to explain : if you breath slow through your nose - this sound is existing from the amp in the background -so this fog avoid the clearness from deep and width.
maybe a much better supply ripple will help - or the THD and the PSSR is the "main reason"???

so it is still a very fine amp...and I am not finished with this chip amp.
chris

Hi Chris,

Many thanks for the detailed comparison analysis. For the LM1875, no more bloated bass but high quality mid and treble.

LM1875 became very popular among more conservative users appreciating jazz, chamber music and other classical music, folk music, acoustic music etc. where the reproduction of acoustic instruments and vocals is important. That fits well with your findings. LM1875 should also be suited for the satellite speakers in a 2.1 system.

With moderate power, LM1875 is less obvious for the type of modern music in which bass is a crucial element. I noticed that your taste in music is quite varied, probably with a preference for analytic recordings.

You describe some fine details in the LM1875 sound you find are not the best. Exactly which technical parameter that may be linked to such sound characteristics, I do not know. One characteristic of class AB is that the sound of the amplifier changes more with the operating circumstances than for class D. Such operating circumstances are in particular supply voltage level and amplifier gain.
If I recall right, you have a nice double and variable power supply. I will propose you to try that power supply with the LM1875. The regulated supply voltage will have very little ripple and the sound characteristics may change with the supply voltage level. Also the gain (min. 20dB) may change the sound characteristics.

From your results, I have now ordered Nichicon Muse capacitors as well.
I got the cheap IRS2092 mono-board for just below 14 Eur. I bought only one as I will use it for test and eventually a sub-channel.

Last edited by FauxFrench; 21st October 2019 at 10:32 PM.
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Old 22nd October 2019, 07:01 AM   #248
chermann is offline chermann  Austria
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Join Date: Jan 2017
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Hi FF

yes the LM1875 is a very fine sounding amp.
if you mentioned my lab power supply-yes this should be less ripple but the fans are really loud and its not for listening.
yes i like analytical and very important - good sound stages . this gives me the "live" feeling at home ...and once again: with music like Blank&Jones album "relax edition 4" = electronic this amp sounds very good and the power is really enough for at home to shake the house
testing with other speakers - my kef Q100, open baffle 12/5

i am still hoping to get better sound out of the 1875 -
- PSU - less ripple as possible
- check all original kit components
- set the gain down - what should i do?
- PSRR is at the neg.supply worse - frequency depending (figure 7 ) is here something to "help" the chip ?

to be honest - yes if you look at the data sheet you see what that chip can compared to the others.(attachment) i know that its partly nonsense to buy a kit about 2 add some components (+6) and expected a fantastic sound but that for me the target to squeeze that out -thats my personal mind setting.

chris
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File Type: pdf chip compare.pdf (594.1 KB, 6 views)
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Old 22nd October 2019, 07:07 AM   #249
chermann is offline chermann  Austria
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Location: Vienna
@IRS2092 amp


please write your findings to the IRS2092 thread.
200W IRS2092 Amp for $20


here are some links to read:
Tips and suggestions on IRS2092 implementation?
My design L20D IRS2092+IRFI4020H 200W8R


chris
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Old 22nd October 2019, 07:33 AM   #250
Vix is offline Vix  France
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Location: Grenoble, France
Hello guys,

Sorry for off-topic, but I see no other option other than to post here: I tried to send a Private message to a member FauxFrench, but I couldn't, saying that his inbox is full and cannot accept more messages. So, FauxFrench, if you are reading this, please let me know, as I'd like to contact you. Thanks

And now my 2 cents on topic: of all "LM-Gainlone" iterations I have tried, the most pleasing to me was the tube buffered one, with inverting input, big EI transformer and small capacitors (1000 uF per rail).
Class D, I have tried tpa3116 but it sounded a bit thin and harsh on my ears...

Regards,
Vix
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