Need a recommendation for an IC amp.

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lazzer408

lazzer408

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Joined 2010
I'm looking for a good quality single or two channel IC (single channel IC may be better suited) that can run on a +/-25 to +/-30v supply. Minimal external components would be ideal.

I'd be fine with a pre-built ebay board if someone knows a good one.

I have a nice toroid transformer to use on a project and need a small amp for my computer to power some bookshelf speakers.

TDA2050? LM3886? others?
 
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Oliphant

Member
Joined 2009
you shouldn't use an LM1875 or TDA2050 at +/-25V rails if your speakers average impedance is rated at 6ohms - as the speakers actual impedance can drop to 4ohms. This would draw much more current than each of these little chips can deliver at this voltage.

I would recommend you use an LM3886 or LM3875. These chips will happily drive your speakers at the voltages you quoted.
 
Bob Richards

Bob Richards

Member
Joined 2011
opalcreekaudio.com
The mute function on the 3886 means there's no turn-on transient. I like that a lot. Also, a chipamp will have tighter coupling between the output devices and the temp sensing circuit, so reliability and minimization of crossover distortion is likely better than with a discrete design. I'm not saying chipamps are necessarily better than any discrete design, just that I wouldn't rule them out.
 
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Oliphant

Member
Joined 2009
Bob Richards said:
The mute function on the 3886 means there's no turn-on transient. I like that a lot. Also, a chipamp will have tighter coupling between the output devices and the temp sensing circuit, so reliability and minimization of crossover distortion is likely better than with a discrete design. I'm not saying chipamps are necessarily better than any discrete design, just that I wouldn't rule them out.
Click to expand...

The TDA7294 also has a mute function, it appears that you can use it in a similar way to the LM3886 mute pin.

lazzer408 will you be buying a kit or designing your own circuit?
 
lazzer408

lazzer408

Member
Joined 2010
Oliphant said:
The TDA7294 also has a mute function, it appears that you can use it in a similar way to the LM3886 mute pin.

lazzer408 will you be buying a kit or designing your own circuit?
Click to expand...

Ok long story short...

I'm going to (eventually) be building a 6BQ5 4ch amplifier for my car. I'm in the testing stage trying various PI designs on a home chassis and a friend ordered some Edcor 4-ohm UL OPTs to try as well. In the mean time, I need an amp that's quick and easy and started looking into the chip amps. I had a few chip-amp boards laying around, that were pulled from various computer speakers, and one of them was used in a subwoofer and had a dual-rail supply. I gutted the low-pass section from it and gave it a listen. I was quite pleased with how it sounded. It blew away (in quality) this Technics receiver I use often for testing. Not that that's saying much. The chip amp sounded more like my tube amp then some of these other discrete output receivers I have.

So... I ordered a stereo chip amp off Ebay that uses a pair of TDA7294 for each channel. I let the power rating get to me again. If anything I'll get 4 chips off it.

Seems like there's a lot of people who like the LM3886. Is it really good compared to other ICs?
 
A

AndrewT

R.I.P.
Joined 2004
a 3886 won't work in a car.
The car battery and it's charging system give a voltage that varies from ~11.5V to 13.8Vdc

The 3886 will not work with less than 20Vdc.

The maximum output from any amplifier is ~ 1/3rd of the DC supply voltage.
@ 13.8Vdc the maximum output is ~4.6Vac
This gives ~5W into a 4ohm speaker.
 
lazzer408

lazzer408

Member
Joined 2010
TI really needs to pull their heads out of their butts and stick with a rating system that's consistent.

What's the difference between the LM3876 and LM3886?

According to them...

LM3876 "56w into 8ohm 0.1% THD" (voltages unclear. +/-35v?)
LM3886 "50w into 8ohm" (THD unstated) (+/- 35v?) -or- "68w into 8ohm 0.1% THD" (voltage not stated) -also says- "extremely low THD+N of 0.03% at the rated output" -also says- "38w into 8ohm 0.1 THD"

What are the real specs of these things?
 
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GringoAudio

Member
Joined 2007
Jeff Rowlands, 47 Labs:
These manufacturers use chipamp design and charge thousands. AndrewT are you not a True Believer? :cool: I made an inverted LM3875 Gainclone about 8 years ago. It sounds better than anything I have ever bought factory made.
Chipamps are more than 'good enough'.
 
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GringoAudio

Member
Joined 2007
-I don't understand the question. - AndrewT

I would have thought my capitalization of the words True Believer would have at the very least piqued your curiosity as to what it meant. Link below. I thought this term was pretty much part of the common lexicon, guess not. It implies 'cult' which the gainclone amp movement almost is. I admit it. My audiophile friends ALSO find fault with my GC chip amp. Their loss as far as I am concerned. If you are a skeptic then why are you on this forum? This is for cult members only. ;)
The True Believer - Wikipedia, the free encyclopedia
 
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