bi-amplifier @ 4 ohms ??

[jeff_free69]

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-774

general consensus has been that this is the identical unit already available at MCM. But MCM didn't rate at 4 ohms whereas PE does (58W instead of 40). Is that a concern to any of you circuit-savy types? perhaps just a matter of more stress testing of the same unit?

(I needed 2 immediately so i had to order from MCM; if it works out I can wait until Jan for a followup order for 4 more)

[philiparcario]

I HAVE 5 OF THEM IN USE. I have 5 more for a future project. They use 3886 gainclone chips. At least mcm ones do. a 3886 chip can put out 68 watts max at 4 ohms with proper transformer/ power supply. I run 3 focal mtms for my home theater. two use 7w4411 in parallel here is the pdf for them

http://www.zalytron.com/Specs/7W4411.pdf

so that is 3.9ohms or lower the center uses focal 7k4411 in parallel see thumbnail that is also about 3.9 ohms I use a 12db hi pass at 100hz for the sats of this home theater. so 4 ohms is most likely okay. also the noise ratio is most likely 90-92 not 80 like the mcm cat reads

[dthomas]

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-774

general consensus has been that this is the identical unit already available at MCM. But MCM didn't rate at 4 ohms whereas PE does (58W instead of 40). Is that a concern to any of you circuit-savy types? perhaps just a matter of more stress testing of the same unit?

(I needed 2 immediately so i had to order from MCM; if it works out I can wait until Jan for a followup order for 4 more)

They use the LM3886 chip so 4 ohm loads should not be a problem...

[jeff_free69]

ALSO: Some people mentioned adding a capacitor to the tweeter for protection on powerup, and that sounds like a good idea to me.

If this already XOed @24 db / 3k, what's a good value for a blocking on an 8 ohm tweeter ? something like 18uF? that would be an additional 6db rolloff around 1.1k, so it shouldn't affect the sound too much

[philiparcario]

ALSO: Some people mentioned adding a capacitor to the tweeter for protection on powerup, and that sounds like a good idea to me.

If this already XOed @24 db / 3k, what's a good value for a blocking on an 8 ohm tweeter ? something like 18uF? that would be an additional 6db rolloff around 1.1k, so it shouldn't affect the sound too much

you got it 15 to 22 uf is good

[dthomas]

ALSO: Some people mentioned adding a capacitor to the tweeter for protection on powerup, and that sounds like a good idea to me.

If this already XOed @24 db / 3k, what's a good value for a blocking on an 8 ohm tweeter ? something like 18uF? that would be an additional 6db rolloff around 1.1k, so it shouldn't affect the sound too much

I would have said around 20uf but 18uf is fine.

[jeff_free69]

cool - thats what I happen to have laying around ATM
thanks