tba820\tda2030 amp Help

[jonny4580]

Hi there,
I want to build a simple amplifier to go inside a subwoofer and i was wondering if anyone had a diagram of a circuit that uses minimal parst and can be built on strip board, this will be my first build so i don't really want anything too complicated but i am not afraid of soldering and testing things,I just want a nice simple amplifier based on the TDA2030 or an RCA4558 or TBA820, any advice appreciated
many thanks
Jonny

[johnr66]

Hi, The TBA820 is a low power (2 watt) chip and needs a lot of parts to make work. I don't know what an RCA4558 is (some old obsolete chip amp, I guess). I'd use the TDA2050 as an easy first project with few parts and good output.

How big is your sub? Will the signal feeding the amp contain only low frequencies for the subwoofer or does it require filtering to remove the high frequency signals (sounds)?

[jonny4580]

Originally Posted by johnr66

Hi, The TBA820 is a low power (2 watt) chip and needs a lot of parts to make work. I don't know what an RCA4558 is (some old obsolete chip amp, I guess). I'd use the TDA2050 as an easy first project with few parts and good output.

How big is your sub? Will the signal feeding the amp contain only low frequencies for the subwoofer or does it require filtering to remove the high frequency signals (sounds)?

my sub is only a 6" speaker but the enclosure is excellent, the input is just the low frequencies so it wont need filtering no, in an ideal world i would like to be able to adjust the gain\volume of the sub but this is not essensial
Thanks for the reply pal
jonny

[Mooly]

The 4558 is a low power dual opamp that would drive headphones at best

This may not sound much help but the chips you mention can be very problematic in a DIY set up. They need extreme care in physical layout and wiring so as to be fully stable. They seem like the easy option... often they are not.

Best bet is to base one on a proper available PCB or kit.

[jemraid]

Hi Jonny,

If you bought LM3875 or 6 and used the data sheet diagrams: http://www.national.com/ds/LM/LM3875.pdf

You wouldn't even need any strip board, just point to point like this;



Add a Zobel across the speaker terminals [as in the single supply diagram] and a 10k pot as a volume control.

Jim

[jonny4580]

Originally Posted by jemraid

Hi Jonny,

If you bought LM3875 or 6 and used the data sheet diagrams: http://www.national.com/ds/LM/LM3875.pdf

You wouldn't even need any strip board, just point to point like this;



Add a Zobel across the speaker terminals [as in the single supply diagram] and a 10k pot as a volume control.

Jim

Cgeers pal forgive my ignorance but whats a zoble andgerer would the volume pot go ...on the input or the output?

[jemraid]

Hi Jonny,

If you go to Fig 2 in the data sheet, you will see Rin 10K this is the volume potentiometer or variable resistor, then find Rsn and Csn 2.7 Ohm and 0.1 uf these two items form the Zobel network.

Cheers - Jim

[aethelbert]

Hi,

I have a little stereo amp that I made using two TBA820m chips. I used the datasheet schematic with a dual 10k volume pot on the front end. I have it in the front room with a sony walkman or an ipod and it drives a vintage pair of morduant short floorstanders.
Hardly an "audiophile" setup and granted it's a different application than yours but guess what? I love it. It makes me smile, it costs peanuts and you can build an amp the size of a matchbox that'll make enough noise to upset the neighbours.
Give it a go.