Using a lm4780 instead of 2x lm3886?

nicku1302 · 5th November 2007, 07:34 PM

I'm interested in building a stereo amplifier. I came across a lm3886 which would require me to use two satisfy my stereo requirements. Next i found the lm4780 which essentially has 2 lm3886 in it. Are there any advantages of using 2x lm3886 over the single lm4780?

AndrewT · 6th November 2007, 09:23 AM

Hi,
the two channel version is probably made to reduce assembly costs on a production line.
I think the 3886 with separate power and ground lines for each channel will perform better since the currents are halved and the crosstalk will be reduced if laid out correctly.
Two competely separate monoblocks will perform better than a stereo amplifier and each can be located right beside the speaker terminals bringing the very big advantage of extremely short speaker cables.

jackinnj · 6th November 2007, 09:56 AM

but remember that if using 2 devices you need 2 sets of bypass caps on Vcc/Vee -- not a huge expense, however.

you can use 2 LM4780's in parallel mode for a steroidially enhanced amplifier.

sangram · 6th November 2007, 02:37 PM

It may be due to implementation and power supply differences, but my simple stereo LM3886 has much better sound quality than my LM4780 BPA. They are as different as chalk and cheese in their layout and the power supplies have no resemblance to each other, though.

Another advantage of 3886 is heat dissipation and the availability of an insulated package (both sort of work against each other, though). that makes for larger allowable package dissipation or easier construction.

mbates14 · 6th November 2007, 05:03 PM

the only advantage i see to the 4780 is cost efficiant, more simple in production runs, cheaper.

and the thing that i like most: building compact stereo amplifiers.

i built a full power stereo amplifier that used this IC, and it fits in the palm of my hand.

and used a couple of small higher current boost converters. one thats a boost inverter. that way i eliminated the size of complexity of a flyback supply.

nicku1302 · 6th November 2007, 05:38 PM

Ok thanks for the responses, I'm aiming for a compact design, the lm4780 seems to be the best approach for me at this point.

Does anyone have any suggestions on a better chip amp along the same lines of the lm4780

Nuuk · 6th November 2007, 06:13 PM

When it comes to chip amps, the amp part usually takes much less space than the PSU and the connectors, so I really don't think one using LM4870 will be any more compact than one using two LM3886's!

In addition (and you don't say how you are going to build this amp) the pins on the LM4870 are closer together than those on the LM3886. If you are hard-wiring the amp, the LM3866 will be a lot easier! If not you will need a PCB.

Quote:

Does anyone have any suggestions on a better chip amp along the same lines of the lm4780

Well, you don't tell us which amp you are going to build, so I don't think we can suggest a "better" one!

nicku1302 · 6th November 2007, 06:30 PM

Quote:

Originally posted by Nuuk

In addition (and you don't say how you are going to build this amp) the pins on the LM4870 are closer together than those on the LM3886. If you are hard-wiring the amp, the LM3866 will be a lot easier! If not you will need a PCB.

Well, you don't tell us which amp you are going to build, so I don't think we can suggest a "better" one!

I am planning on building a 50 Watt stereo amplifier. Also, i will be using a PCB

AndrewT · 7th November 2007, 07:03 AM

Quote:

Originally posted by nicku1302
Does anyone have any suggestions on a better chip amp along the same lines of the lm4780

building a pair of monoblocks will improve performance.

lanchile07 · 7th November 2007, 02:06 PM

Hello nicku1302.did you ever though about a LM3875 chip?
I just got one build(integrated amp)and it is very good,simple and it does not get hot at all.I am very happy with the result.

5th November 2007, 07:34 PM	#1
nicku1302 diyAudio Member Join Date: Nov 2005 Location: us	Using a lm4780 instead of 2x lm3886? I'm interested in building a stereo amplifier. I came across a lm3886 which would require me to use two satisfy my stereo requirements. Next i found the lm4780 which essentially has 2 lm3886 in it. Are there any advantages of using 2x lm3886 over the single lm4780?

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6th November 2007, 09:23 AM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, the two channel version is probably made to reduce assembly costs on a production line. I think the 3886 with separate power and ground lines for each channel will perform better since the currents are halved and the crosstalk will be reduced if laid out correctly. Two competely separate monoblocks will perform better than a stereo amplifier and each can be located right beside the speaker terminals bringing the very big advantage of extremely short speaker cables.

6th November 2007, 09:56 AM	#3
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	but remember that if using 2 devices you need 2 sets of bypass caps on Vcc/Vee -- not a huge expense, however. you can use 2 LM4780's in parallel mode for a steroidially enhanced amplifier.

6th November 2007, 02:37 PM	#4
sangram diyAudio Member Join Date: Sep 2002 Location: India	It may be due to implementation and power supply differences, but my simple stereo LM3886 has much better sound quality than my LM4780 BPA. They are as different as chalk and cheese in their layout and the power supplies have no resemblance to each other, though. Another advantage of 3886 is heat dissipation and the availability of an insulated package (both sort of work against each other, though). that makes for larger allowable package dissipation or easier construction.

6th November 2007, 05:03 PM	#5
mbates14 diyAudio Member Join Date: Jun 2002 Location: non	the only advantage i see to the 4780 is cost efficiant, more simple in production runs, cheaper. and the thing that i like most: building compact stereo amplifiers. i built a full power stereo amplifier that used this IC, and it fits in the palm of my hand. and used a couple of small higher current boost converters. one thats a boost inverter. that way i eliminated the size of complexity of a flyback supply.

6th November 2007, 05:38 PM	#6
nicku1302 diyAudio Member Join Date: Nov 2005 Location: us	Ok thanks for the responses, I'm aiming for a compact design, the lm4780 seems to be the best approach for me at this point. Does anyone have any suggestions on a better chip amp along the same lines of the lm4780

7th November 2007, 02:06 PM	#10
lanchile07 diyAudio Member Join Date: Oct 2007	Hello nicku1302.did you ever though about a LM3875 chip? I just got one build(integrated amp)and it is very good,simple and it does not get hot at all.I am very happy with the result.