help - GC for biamping line array

Hi there,

I'm about to order some cheap NSB drivers from partsexpress to build some line arrays for my HT. One array will consist of 16 NSB plus either single tweeter or line of tweeters. I was planning on doing active crossover using bruteFIR and soundcard. The way I see it I therefore need to have separate amplifiers for each channel. For my 7.1 setup I would therefore have 14 channels!

I'm most probably going to use BrianGT LM4780 kit and I guess I would need a monoblock for each channel. Now to the questions.

1. Would I need a separate TOROIDAL tranformer for each channel?
2. Since each transformer is for a single channel I'm guessing I don't need a large transformer. What is the minimum I can get away with for my line array?
3. I want to order from Partsexpress to minimize shipping costs since the items would be shipped to Europe. Would the following transformer be suitable?

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=129-080

4. Does anybody know what the rating is on these transformers? I searched and found somebody estimating (based on weight?) them to be 100VA. Is this the case and if so would it work?

I'm new to all this but definately want to try out the above line array/brutefir/amplifier setup for the DIY satisfaction.

Thanks for any help.

Exipnos
 
Hi Exipnos,
I also have two LM4780 sets, one for each channel. I use one transformer for each channel, 2 * 30V, 220VA, weight of one trafo is about 2 kg.

unfortunately there aren't any more data on your link so i would assume that a trafo with about 1 kg would deliver nearly 80VA Power.

For normal music - consumption it may be ok, for high volume, i would take two of those for one channel. Does this trafo delivers two secundary supplies? If not you always need two trafos for each channel becaus 32V regulated Supply is not much for this amp...:whazzat:

At that price even 4 trafos for an amp are a good deal - i paid 29,- Euros per Trafo (160VA would cost 23,- Euros) - so you pay nearly one third i had to pay ...:cool:

The lm4780 sets are really good ones - look in the forums to get the maximum of it (snubber and additional small elko).

Michael