LM1875 from Silicon Chip Your Impressions

[Angel-Baby]

Hello Just after peoples impressions on the LM1875 design from silicon chip personally I think it could be a lot smaller in design than it is, but they say it works ok the reason I am asking for your impressions is I wish to make a few of these LM1875 amps and just stumbled across the Silicon chip design and thought I would post here for feedback.

Thankyou any help much appreciated
Cheers
AB
P.S. here is the link for the amp

http://www.siliconchip.com.au/cms/A_103236/article.html

[Nuuk]

I guess the name gives you a clue. 'Schoolies Amp' is probably aimed at students and by making it not too compact, it's easier to build and see where everything goes.

[paulmac]

I made a few 1875 modules to power my main amp a few years ago, and basically followed the data sheet. I built mine (5 channels) on individual bits of veroboard with no hassles.

In my opinion (which has been influenced by ears that are not golden....) they sound great.
The volume control doesn't go past half way.

I've also built an LM3886 amp that also sounds just fine, also on veroboard. It's in use as a "loud" amp when my wife has a singing session.

I've never put the two head to head to try to compare the sound of them, because (a)I couldn't be bothered, and (b)because I've been suitably amazed with both of them for their simplicity, their ease of use, and their lack of noise.

If you want simple, and it's only for the lounge room, go for the LM1875. With only five pins, it's hard to stuff it up. Just make sure you have a nice power supply reserve behind it, something like CarlosFM's "snubberised" setup, and you'll be fine.

Having said all that, I'm going to re-do my amp with some 3886s one day. That will be after I make the 200w "louder" amp with 6x 3886s for PA use....

Too many projects, not enough time...

Paul.

[AnthonyPT]

Rod Elliott's ESP site does a 1875 circuit

board and it is more compact and has

two amps on it. That is if you want a readily

available 1875 low hassle option and are

not going for a hardwire attempt.

http://sound.westhost.com/project72.ht

Regards

AnthonyPT

[NITRO]

Hi
I've designed 1875 PCB that size is almost half of the silicon chip design (96 x 26 mm. including bridge rectifier, two 4700uF caps and remaining components and still got a empty space ). If you are interested i can send PCB drawing to you.
Regards.


Türker

[Angel-Baby]

Hello everyone thanks for all your replys much appreciated I got given 10 of these lm1875 chips from a friend at a electronics shop that has now closed thought I would put them to good use and yes NITRO I would love to have a look at your lm1875 design if thats ok please e-mail when you get a chance
Thanks again everyone for your feedback
Regards
AB

[carlosfm]

Originally posted by paulmac
If you want simple, and it's only for the lounge room, go for the LM1875. With only five pins, it's hard to stuff it up. Just make sure you have a nice power supply reserve behind it, something like CarlosFM's "snubberised" setup, and you'll be fine.

I always liked the LM1875 very much.
That's what I use on my bench, always listening to it.
LM1875 + snubberized PSU.

I have tested this amp on my main system, with my difficult Epos ES11 speakers and I could not believe... it drives them quite well.
Also, it's small, I can take it everywhere.
It made quite a success on this year's new year's day party, with an old Philips portable multibit CDP (tweaked) and a pair of (tweaked) Boston speakers I have.

Who wants to make a small, simple amp should try these chips.
Beware, you can end up with a (low power) high-end amp.

[NITRO]

Hi Angel-Baby,
Here's my PCB layout for lm1875,i hope you'll like it.By the way there's one important point on layout.There's one hard to see SMD resistor between IC pins 4 and 2 as a feedback/gain resistor that directly soldered to pins.But if you don't have any SMD you can use conventional resistor in the same place because there is a enough space in that area.

[Angel-Baby]

Hello again and thanks for all your replys much appreciated and thankyou nitro for your layout I am going to sit down today some time and start building some of these
Thanks again everyone
Regards
AB

[michal]

I always liked the LM1875 very much.
That's what I use on my bench, always listening to it.
LM1875 + snubberized PSU.

Carlos, what schematic is your LM1875 amp based on?
I am building an amp with LM1875s and I'd like to get the best sound quality possible. I've made one some time ago using the data sheet's schematic, but I guess there's a better way.

Regards,
Michal.