LM3875 vs. LM3886 ??

Dxvideo · 26th April 2007, 10:31 AM

Hi all,

I made a new clone today just because I have two spare LM3875.. I am trying it now.
I made the same circuit as in data sheet. Just added an input load resistor (27K) and output zobel (2R7-100n) and the gain is 27/1K.
Before I made LM3886 and LM4780 amps. But the 3886 has a bass boosted NFB circuit (linkwitz transform) and the 4780 has a preamp. But this is pure Gain Clone no preamp no bass boosting.
However I feel no difference on sound between the old ones and that except bass performance.
Has anybody tried all that three National chips together? And feel any sound difference?
I asked that because as I remember somebody mentioned that the LM3875 has better sound characteristics (I dont remember who).

Best regards,

! · 26th April 2007, 05:50 PM

If you hear no difference, then isn't it possible the LM3875 DOES have better sound, since you don't have the preamp on it this time? Better question is whether the pre added anything to the other amp or if it also, sounded same either way.

These three are very very similar chips though, given the rest of the amp is the same they should sound very similar. LM4780 is just two LM3886 die in the same package, it only gives up a slight bit of thermal disadvantage with both die heat sources in close proximity, and a tigher, lower impedance path between shared power rails.

LM3875, looking at the schematic it's the same topology internally minus the mute feature, though presumably different integral transistor output pairs and a little less aggressive biasing.

Essentially, if you had a deliberate goal to use 3 different chips to arrive at amps that sound the same, these 3 are what you would choose to use, so having it happen in reality isn't so surprising.

Here's a nice page to look at,
http://home.pacific.net.au/~gnb/audio/lmcomp.html

Dxvideo · 27th April 2007, 07:01 AM

Hmm very detailed comparision. They look same and of course its normal to have the same results.
But I remember one of member insisted on LM3875 has better sound.
Anyway this is not important. So I have another gainclone. But this time its pure gain clone. And it works very very fine.

26th April 2007, 10:31 AM	#1
Dxvideo diyAudio Member Join Date: Nov 2003 Location: Turkey	LM3875 vs. LM3886 ?? Hi all, I made a new clone today just because I have two spare LM3875.. I am trying it now. I made the same circuit as in data sheet. Just added an input load resistor (27K) and output zobel (2R7-100n) and the gain is 27/1K. Before I made LM3886 and LM4780 amps. But the 3886 has a bass boosted NFB circuit (linkwitz transform) and the 4780 has a preamp. But this is pure Gain Clone no preamp no bass boosting. However I feel no difference on sound between the old ones and that except bass performance. Has anybody tried all that three National chips together? And feel any sound difference? I asked that because as I remember somebody mentioned that the LM3875 has better sound characteristics (I dont remember who). Best regards, __________________ Best regards, Ozgur

27th April 2007, 07:01 AM	#3
Dxvideo diyAudio Member Join Date: Nov 2003 Location: Turkey	Hmm very detailed comparision. They look same and of course its normal to have the same results. But I remember one of member insisted on LM3875 has better sound. Anyway this is not important. So I have another gainclone. But this time its pure gain clone. And it works very very fine. __________________ Best regards, Ozgur

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26th April 2007, 05:50 PM	#2
! diyAudio Member Join Date: Jun 2005 Location: Midwest	If you hear no difference, then isn't it possible the LM3875 DOES have better sound, since you don't have the preamp on it this time? Better question is whether the pre added anything to the other amp or if it also, sounded same either way. These three are very very similar chips though, given the rest of the amp is the same they should sound very similar. LM4780 is just two LM3886 die in the same package, it only gives up a slight bit of thermal disadvantage with both die heat sources in close proximity, and a tigher, lower impedance path between shared power rails. LM3875, looking at the schematic it's the same topology internally minus the mute feature, though presumably different integral transistor output pairs and a little less aggressive biasing. Essentially, if you had a deliberate goal to use 3 different chips to arrive at amps that sound the same, these 3 are what you would choose to use, so having it happen in reality isn't so surprising. Here's a nice page to look at, http://home.pacific.net.au/~gnb/audio/lmcomp.html

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