Need amp recs for active dipole speaker project

[goskers]

Hi all,

I am building the Linkwitz Lab Orion and need some help. I need 8 channels of amplification but don't want to spend half my college income to get it.

Are there any ideas that you can give me to get 8 channels of around 60-70 watts per that have a flat frequency response?

Any ideas are greatly appreciated. I am not sure what to do right now.

Thanks

 

[tl]

Hi all,

I am building the Linkwitz Lab Orion and need some help. I need 8 channels of amplification but don't want to spend half my college income to get it.

Are there any ideas that you can give me to get 8 channels of around 60-70 watts per that have a flat frequency response?

Since you are asking for 8 channels I assume that you want a separate power amp for each woofer. So your lowest nominal impedance will be 6 ohms for the tweeter.

A good and simple solution is the LM3886.

At +/- 35 V they will deliver 50W into 8 ohms. Linkwitz suggests to use them for the Phoenix Dipoles. You don't need much more power than this. More power might even be harmful to the woofers.

If you brigde them ("BR100", as described in AN-1192, see the link above) you will need a lower supply voltage (+/- 20V) and eight LM3886s instead of four.

The advantages of bridging are:

- More power.

and/or

- Less power dissipation in the chips.
- slightly lower distortion at the same power.
- ...

I am going to use 4 "BR100" for my Orions.

Thomas

 

[Matter]

HI tl

Have you got a PCB for the BP100?

Which active X-Over are you using?

 

[kb]

Hi,

Regarding amplification, Mr. Linkwitz states that because the Orion is such an easy load, using a more expensive amp than the ATi 6012 does not improve sound quality. This of course begs the question, how much cheaper can you go without compromising sound quality? With the 6012, you are, after all, paynig for four extra channels which are not needed with the Orion.

I too am strongly considering building the Orion, and the most promising low-cost amplification alternative I've found is the Rotel RMB-1048 (http://www.rotel.com/products/specs/rmb1048.htm), which is conservatively rated at 8x40 (8x50 is probably closer to the truth). It seems to have decent figures for distortion and damping factor, and sells for about $800 in the US. If anyone has had the opportunity to try it with the Orion, or in any other way compared it with the ATi 6012, please let the rest of us know!

-kb