2. amps-preamps
  3. 166419-141390

Passive bi-amp question

I understand this might have been discussed in the past, but wanted to get some better insight as to doing it correctly. I am looking to biamp (passive only, not crazy about active biamp) my speakers. I have MA PL500II, and after discussing with monitor audio, they strongly recommend passive biamping. Trust me, these speakers are already amazing with just stereo amp driving them now. I am trying to push the envelope to see if I can get best out of it. 
I am looking to use different amp brands for biamp. I know, ideal will be to use same amp or at least same company amp, but wanted to see if anybody have done passive biamp with different brand and what was their experience, pros, cons and how did you guys made decision while selecting different amps.
What are the amp specs that needs to be matched (or closely matched). Is it gain, input sensitivity, input impedance, watts per channel. Or in other words will results be still good if the amps have different gain, impedance, sensitivity and wattage. Anything else should I be looking for. Any valuable thoughts will be appreciated. I will be using same power cords and speaker cables in both (including the lengths). 
Currently I have thrax dionysos preamp with audia flight strumento no.4 mk2. 
romney80

Showing 6 responses by romney80

romney80 OP
150 posts
 
@tweak1 
I discussed with monitor audio and they advised against active cross over and I am not into it either. They did mention that the best results, will be with passive biamp. 
romney80 OP
150 posts
 
@yogiboy and @Georgehifi. 
Thanks for those suggestions. I would rather not do that, unless that is the only option. But, in the meanwhile, I will dig deep into this. 
romney80 OP
150 posts
 
Ok. 
The gain of my current amp is 29 db, input sensitivity is 1.4 volts RMS, impedance is 7.5 kohm, damping factor (at 8 ohm) >1000, power output 250 watts at 8 ohms.

I am considering Luxman M-900u, which also has gain of 29 db, input sensitivity of 1.24V/150W (8ohm), input impedance of 34 kohms (balanced), damping factor of 710, power output 150 watts at 8 ohms. 

The gain seems to be matched and input sensitivity seems to be close (even though different watts power at 8 ohms). Will this be acceptable for biamp with my current amp ?.
romney80 OP
150 posts
 
Sounds good. Thanks for those technical inputs. I am assuming, even if the companies mention 29 db gain, they may vary at best few decimal of decibels. I am OK with that. 
Just one question though. It may be silly. Does it matter even if the amp have different watts of power (like 250 vs 150 at 8 ohms) even if gain is same. 
romney80 OP
150 posts
 
@erik_squires 
let’s say if it is few decibels apart, how much of the impact will this have. In other words, if they are apart, how will the sound quality be affected. Will it be like one amp sounds more than other one ? Or will it affect the coherency in the music ?
romney80 OP
150 posts
 
Understood, as I said, the two amps which I stated will have same gain of 29 db. So, I will go with it. 
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