Originally Posted by Deckard71
My Amp is a BC Acoustique EX332D. I cannot find the damping factor, but still I don’t know if a DF is better to be low or high. Naim and Musical fidelity have low DF and they are claimed to attack speakers very well. I think my Amp has a couple of output transistors (one per output) but not sure
OK, first I have to make some disclaimers: I am not an audiophile enthusiast, I am engineer that is very interested in amplifier design and designed SS hifi amps and guitars amps. I never go around and listen to every speaker and amp. I comment on this because I suspect my 913.1 is in the same class as yours. That I have done a lot of experiment and design amps around the 913.1. So you have to take that into consideration.
For med/high end speakers like ours, One important thing is the crossover. The better the speakers, the better the components used in the crossover. Better components are lower loss components. The better the components in crossover means the impedance spike and dip much sharper. It can swing up to high impedance very sudden at some frequency and impedance can dip very low and sharp at some other frequency. We called this resonance and the better the components, the higher the "Q" and the peak and dip gets sharper and more extreme. There's no other way about this. Cheap speakers use lower grade components and the Q is low and no extreme impedance swing and easier on the amp.
I found my 913.1 very sensitive to speaker cables. Even using a good amp, with subpar cable, sound doesn't come out, I lost dynamics, sound stage, 3D and clarity. I need very low loss cables to get good sound. Amp is the same way, One needs very low output impedance ( high damping factor) so the peak and dip of the speaker impedance will not affect the output signal. Amp and speaker cable work together as one far as I concern. I look at damping factor AT THE CABLE END at the input of the speaker, not just at the output of the amp. You need very high damping factor ( low output impedance) at the input of the speaker. So I look at the amp and cable as one.
First the amp, I am pretty comfortable to say any amp that has only one pair of output transistor will not work very well with my 913.1. It is a 4ohm speaker and I believe it will dip below 2ohm ( say 1ohm) at some point. One pair of output transistor just won't do it. It might not burn, but it's going to increase distortion. There is no way out of this. That's the reason why Krell, Mark Levingston type of high end amps use 10+ pair of transistors. I can assure you that's not marketing hype. For speakers that are easy to drive, you really don't need good amp.
Like the pair of Kef floor standing Uni-Q I have before, It's 8ohm and must not have very good clossover network components. It's not hard to drive. I got by with smaller cable and never complained. When I first bought the 913.1, I just hooked it up. I almost cried. Paid over 3 times the Kef and not sounding any better. Then I start using monster 12 gauge, it got better, sound started to open up a little. I add the second pair in parallel, it got better. I ended up using 3 pairs of monster 12 gauge for each speaker. At the time, I use the Acurus ( 4 pairs).
I did extensive experiment and measurement on THD ( distortion measurement) during the time I was designing my own amp. I found the monster cable is way too lossy, I had to start experiment with cable design. I am born cheap, there's no way in hell I'm willing to pay hundreds of dollars for stupid cable!!! So I use theory and experimented in cables using cheaper stuffs. I found using 5 pairs of those red/black 16 gauge cables I bought on ebay and twist them together and make one cable. It beats two pairs of 12 gauge monster cable in parallel. With my new amp, the sound really open up, When I run in monoblock mode using two amps( so I can shorten the cable to 4ft long only), the sound stage, 3D and separation almost sounded like a very high quality headphone that you hear the sound around me like in my head.
One thing, I never say damping factor of amps is everything. There are tube amps that has very low damping factor and people swear by them. It all depends on the type of speakers. Tube amps "WORK" with the speaker rather than control the speaker. I am not experience enough to comment. I can only tell you I built a single ended tube amp and tried on the 913.1, it sounded absolutely crap. Sound just did not come out. That shows me my 913.1 is NOT one of those that work with the speaker. Based on my experiment with amps and cables, I believe my speakers need to be controlled, not working together.
I could be wrong, I think you need a better amp and look into the cable. I don't believe the RCA cables at the input is important at all, only the speaker cables.