Small chip amp for satelite speakers.

[Dynsdale]

Hi All.
I'm toying with the idea of using small active satelite surround speakers for a 7.1 system.
I won't be needing alot of power for these and am asking if anyone can suggest a high quality amp chip that would suit this purpose.
The reason I'm considering active speakers is that I want to mount them on my cieling and run the wires through the roof space using balanced audio for noise reasons.
I have looked at a good few datasheets for the popular 'LM' and 'TDA' types.
Maybe someone with more expierience with chip amps than me can help.
Cheers!

[vijay_meyou]

Hi,

If you really looking for low power you can use TDA 2030 14-18 watts Rms small chip amp. simple construction only few componets.low operating voltage 12-18 v sufficient.

just search over DIY

vijay

[abraxalito]

So you're running mains into your roof space too? Might be wise to double check for safety (fire risk) if you take that approach. Myself, I'd run lowish voltage DC and balanced amps (meaning bridged) to avoid any grounding probs. Agree that TDA2030 is an excellent and affordable choice.

[Dynsdale]

Hi all. Cheers for that, I was favouring the 2030 on the investigations I have done prior to approaching this forum.
It did look good on paper, happy for a bit of confirmation.
I have only experimented with the balanced line RX/TX side of the project so far. I have not delved deeply into the realms of the chip amp.
As far as the mains through the roof goes, I have given the legalities a thought and am yet to approach the relevant authorities with my inquiries.
If that is not allowed I will have to change my strategy a little. I love cables that are hidden away!
Thanks for the info.
Cheers!

[gfiandy]

Unless you have a real desire to do this for interest reasons. I would just run speaker cable to the speakers and have wall boxes to plug an amplifier into. This way there are no leagal problems, if the amp goes wrong you can easily change it and there is much less chance of a fire in your roof space. With small speaker near the ceiling speakers and a reasonable quality speaker cable there is unlikley to be an significant difference in sound quality.

You can then experiment with your amplifer design without the need to get into the roof and upgrade if you want to.

Regards,
Andrew

[Dynsdale]

Hi Andrew. Yes it is for interest reasons and I was trying to ovoid long speaker cable runs.
As far as mains in the roof goes, its not a good idea after a bit of rational thought.
I am starting an experiment with balanced line driven active speakers and their feasability for surround sound. Purely objective, if it will be too much PT I'll happily scrap it and do something more conventional as you suggest.
Define "reasonable quality speaker cable". (Just kidding there, bit of mischief on my part :P)
Thanks for the info, it's good to get many angles on this subject.
Cheers!
Carl

[gfiandy]

Hi,

I shall stand a long way back from the what is reasonable quality cable question I believe that flame war has been raging for many years now.

If you are really interested in creating a good low to medium power active speaker solution. I would look at the LM1875 rather than the TDA2030 its specifications are slightly better but it actually sounds much better. To avoid the leagal problems you could run transformed power to the speakers at 24V AC or lower which I think is the highest voltage you can use without needing to use high voltage protection techniques.

However bear in mind if the amp goes unstable they can flame out, and 24 V AC is quite capable of heating a cable to flash point with enough current or causing sparking. If you are putting it in a roof space put it in a metal enclosure and consider any risks from the cable potentially sparking.

For an active solution, you can get a very significant improvement in sound quality by going to full active and using one amplifer for each drive unit. Use a low level crossover before the amplifers, this way it is easy to create a 4th order L-R crossover and any frequency response shaping you require with low cost small components.

Regards,
Andy

[Dynsdale]

Hi Andy, thanks for the heads up on the LM1875.
Running 24 Ac through the roof sounds good, it will have the added advantage of not having to contain the PSU transformer in the housing, thus keeping it small and elegant. My wife would not be keen on obtrusive speakers ruining the decor.
Cheers,
Carl