Newbie: Surround Amp OZ

[rthorntn]

Hi All

I am new to chip-amps, all looks great though!

I want to build a bunch of amps I will be feeding them from a audigy2 soundcard, but want the best to allow for future expansion. The speakers are no name Dick Smith with the exception of the centre which is a wharfedale, I plan to upgrade all this gradually.

My original plan is for 5 single channel 50W amplifiers with separate power supplies and an 150W+ amplifier to drive a large passive subwoofer.

Problem is I have limited electronics knowledge, my soldering is OK but I wouldn't know where to start making a PCB, I have used breadboards though.

So I am just looking for advice, pre-etched PCBs I can buy, tips, tricks...I have searched the forums lots of good advice I have figured I need some National LMxxxx chips and Toroidal Transformers...

I am in Sydney, Australia so good sources of parts here would help. I can spend up to $500 Australian ($350USD).

Thanks in advance for all your help.

Cheers
Richard

[BlackDog]

Richard,

This sounds similar to what I have nearly finished building...(waiting for the last 2 channels to arrive...) it's a 6 channel amp based on BrianGT's Premium kits, (although the standard kit would work be pretty well too).

see http://www.briangt.com/order for ordering information

once you have the kits you will just need transformer(s), an enclosure, connectors and wire.....

Dick Smith sell most of this stuff, but Jaycar generally have a better selection. -- see http://www.jaycar.com.au

I used two of the Jaycar 300VA 18V toroidal tranfomers for mine, which works just fine. If you're new to this, don't try and get all the answers to your questions in one go......keep reading the posts on this forums.....and you'll soon realise that there is more than one way to skin a cat!

BTW, I am also using a Wharfedale Centre, and also Wharfedale rears....


SteveM

[rthorntn]

SteveM

Thanks for the info.

Can you tell me more about your setup, what kind of case you used and how the power supply is arranged, I was thinking of using a standard rack case and having the transformer external to the amp.

I am getting a quote for a 500 VA transformer from these guys http://www.tortech.com.au/ may work out less than $126 AU for two Jaycar 300 VA.

Do you think I would be able to get the premium parts that BrianGT has on his site in Australia for less than $70AU excluding the PCBs, the scots are thrifty

What front and sub speakers do you have and how do the rears perform?

Cheers
Richard

[BlackDog]

Originally posted by rthorntn
SteveM

Thanks for the info.

Can you tell me more about your setup, what kind of case you used and how the power supply is arranged, I was thinking of using a standard rack case and having the transformer external to the amp.

I am getting a quote for a 500 VA transformer from these guys http://www.tortech.com.au/ may work out less than $126 AU for two Jaycar 300 VA.

Do you think I would be able to get the premium parts that BrianGT has on his site in Australia for less than $70AU excluding the PCBs, the scots are thrifty

What front and sub speakers do you have and how do the rears perform?

Cheers
Richard

Hey Richard,

I used a Jaycar case...

http://www1.jaycar.co.nz/productView...=&SUBCATID=479

although, I'm not entirely happy with that case, so I wouldn't really recommend it. The single 500VA would probably work fine, although 18V worked okay for me, the general consensus seems to be that 22V is the optimum voltage to use. If you use one transformer, and BrianGTs PCBs, you'll need to work about a way to split the power from the two PCB outputs to your 5 channels. -- the PCB was designed to feed two channels, not five but with some additional wiring it can be made to work.

It would be very difficult to get all the Premium parts for AU$70. Firstly, the Caddock and Riken resistors are approx. US$5 each in small quantities. You may not be able to source them in Aussie at all.
The diodes, Panasonic caps, and LM3875 chips could all come from somewhere like RS or Farnell, but you'll end up spending lots more on postage, and won't benefit from the bulk discount that Brian got when he ordered for several hundred kits. If the pricing of the Premium kit is over your budget, go for the standard kit. You'll still save a lot of hassle and legwork, and the sound will still be good.

I have Acoustic Energy AE120's as front speakers (bought in England), and no subwoofer. The AE's generate plentiful bass, I'm not missing too much there. The centre speaker is a Wharfedale Crystal Centre, and the rears are Wharfedale Crystal 10's. The centre is pretty good, and the rears are good enough for me for HT use. (I'm not a real HT fanatic, my system is mainly for Music). The rears have nice smooth mid-range, but (in comparison to the fronts) lack depthj in the bass, and can sound boomy. also they quite inefficient - 86dB -- they have a large port at the rear, which doesn't help. They really are good for what I paid for them though (approx AU$150 pr pair), and for my system, they fit in quite well.

Back to work now,

Steve