curious about this LM3886TF / NE5532 combo board on ebay. any opinions?

[ijason]

good evening,

i know it's already a bad idea to try and link to anything on ebay... but i'll be darned if i can find this specific combination elsewhere. i'm looking at a combination board of a LM3886TF stereo amplifier and NE5532 volume control / preamp.

Hi Fi Stereo 68WX2 LM3886TF Audio Amplifier Board with NE5532 Audiophile Pre Amp | eBay

does anyone have personal experience with this particular board? good or bad?

i have to admit i don't know much about what makes one model superior to another. but i DO know that i am currently trying to figure out how to control the volume on a TK2050 over in this thread. and since i haven't bought any of the hardware, maybe i can make my life easier by starting with an integrated controller?

 

[Michael Bean]

Hi ijason,

You probably should have put this post in the chip amp forum. Moderators?
That link doesn't work here, is there any way you can post the schematic and PCB layout? For what it's worth, I have yet to see any of the various posting here from EPay offerings that looked like it was layed out optimally. I've also seen some pretty bad circut designs too.

Mike

 

[ijason]

good evening,

Hi ijason,

You probably should have put this post in the chip amp forum. Moderators?
That link doesn't work here, is there any way you can post the schematic and PCB layout? For what it's worth, I have yet to see any of the various posting here from EPay offerings that looked like it was layed out optimally. I've also seen some pretty bad circut designs too.

Mike

i have no idea whether to post in chip amp or digital amp forum? isn't a digital amp always a chip amp? please feel free to move my thread wherever most appropriate

here is an updated non-ebay link for the same card : Assembled LM3886+NE5532 BTL 68W*2 Audio Power Amplifier Board YJ030-in Consumer Electronics on Aliexpress.com

i have no idea about the different iterations of amp cards based on specific chips. the only information given about this product is the amplifier chip involved in the card...

if there is a similar card, from a known manufacturer, also with a combined NE5532 i would be very interested. there tends to be much better documentation from big producers, verses some guy in china.

thanks for your help

 

[Mooly]

Moved to chipamps

I tried fixing your ebay link but failed. What is the item number on ebay ?

 

[ijason]

good morning,

Moved to chipamps

I tried fixing your ebay link but failed. What is the item number on ebay ?

thank you for trying to fix the link. no need to worry about the ebay link, i've posted a new - and more stable - link to the same hardware.

in the future, should my questions about digital amps be posted in Chipamps or Digital Amps?

 

[Michael Bean]

Those chips, the Ne5532 and the Lm3886 are both analog chips, not digital.
The picture of the assembled PCB isn't real enlightening, but if they're only charging about $40, I'd be nervous about getting fake chips and/or marginal quality. But who knows, could be OK. Buying things like that is always a gamble.

Mike

 

[ijason]

good morning,

Those chips, the Ne5532 and the Lm3886 are both analog chips, not digital.
The picture of the assembled PCB isn't real enlightening, but if they're only charging about $40, I'd be nervous about getting fake chips and/or marginal quality. But who knows, could be OK. Buying things like that is always a gamble.

Mike

aaaaaaaah ha. that would explain why the Digital Amp forum was exactly the wrong place for my question

you mention the $40 price-tag being a red flag. there seem to be a large number of digital amp boards - from vendors such as SureElectronics and PartsExpress - that are well within the $30-$50 price range. are digital amp boards such a different animal that i should be less concerned about their low prices? or are those just as likely to be marginal quality?

there's such a huge range of prices for amp boards, is there a generally accepted "spend less than this and you're taking a chance" price-point?
thinking in the neighborhood of a 2x50watt amp.

thanks

 

[Michael Bean]

Upon further review, I'm not really liking a few things I see in the pics. The high frequency power supply bypass caps are too far from the chip pins. They advertize "200 watts", that's not going to happen, the "tf' version of the lm3886 is self insulated and can't dissipate enough heat for that use. And the output relay (I think) looks awfully small physically.

Mike

 

[ijason]

good morning,

Upon further review, I'm not really liking a few things I see in the pics. The high frequency power supply bypass caps are too far from the chip pins. They advertize "200 watts", that's not going to happen, the "tf' version of the lm3886 is self insulated and can't dissipate enough heat for that use. And the output relay (I think) looks awfully small physically.

Mike

thank you for a great opinion on the combo board. that is exactly the kind of review i was hoping to get, very helpful

as long as the NE5532 is the topic of discussion; do you have any strong feelings for/against this particular chip? i am still very much learning about building my own receiver, and have been trying to figure out gain control for limiting output of a d-amp. here's the thread.

i was considering using a SainSmart NE5532 card as a pre-amp for gain control, but have been informed that it the card i was looking at wouldn't be best for adjusting gain....

instead i was advised that a simple pair of nice potientiometers would be a better option.

 

[tomchr]

The component selection looks good; Panasonic polyester caps and metal film resistors. Plus Points for that. Sadly, the layout leaves a lot to be desired. As others have pointed out, the decoupling is way too far from the IC. As is the Zobel network. There's no Thiele network...

~Tom