2. amps-preamps
  3. 162171-110508

Do I need bi amping?

Hello guys

I have a pair of power amps, one Line Magnetic LM-508 (300B-805 tube my favorite) and one Hypex NC500 class D.

I'm using today the tube amp, wich has more than enough power to drive my speakers at every volume level possible and the class D amp is in a closet.

As I have both amps and my speakers accept bi amping, I was wondering to try it out, using the tube amp for highs-mids and the class D amp for lows. 

Would you recomend bi amping? Have you tried it? 

I listen to all of my music streaming Tidal and my 2.2 system today sounds superb for me (I've heard some much more expensive ones sounding much worse). I also have pretty good hi end gear for the money and paid attention to every detail I could: AC dedicated line, AC filtering, cables, audiophile switch, digital signal processing, antivibration tweaks, speakers and subwoofers positioning, upgraded caps and resistors on my tube amp, better tubes, etc etc. I'm not looking for extra power, just better sound.

By the way, my Audio-gd Master 1 has RCA and XLR outputs to drive boths amps, but thr only caveat is that I need to match the gain of the outputs as they are different. 

If I do it right, would I get better sound?
plga
plga OP
184 posts
 
Well @lloydc using a crossover will make more complex the issue.

With the passive XLR preamp I can level the XLR and RCA outputs and use the speaker's built in crossover. 

Less expense and easier set up.
lloydc's avatar
lloydc
734 posts
 
that passive preamp doesn't contain a crossover; you would only be using it to equalize the the volume of the two speaker lines; you'd still be running the full bandwidth signal through both amps and through all speaker wires, not getting the benefit of crossing the signal over over at 80 hz (or even try 280-300 hz, as oldhvymec suggested above), before it gets to the LM and Hypex.  You want each amp to play to its strengths and not amplify the signal frequencies it's not as good at reproducing.  "biwiring" without crossing it over in front of the amps could create more problems (e.g., phase) than it would solve.

   
  
plga OP
184 posts
 
Well yes, both amps will get full bandwidth from the preamp, but, as they will be connected to different binding posts (high and low frequencies of the speakers), wouldnt the speakers demand from them only those frequencies?

I mean, if the valve amp is connected only to the speakers high frequencies binding posts, wouldnt that amp only be amplifying high frequencies? If that’s correct, wouldnt that be a relief for the that amp?
georgehifi's avatar
georgehifi
10,312 posts
 
If that’s correct, wouldnt that be a relief for the that amp?
Yes as it only sees the load of the tweeter and it's xover
Same for the bass amp 

Cheers George
plga OP
184 posts
 
Ok. I think I will try it that way.

The only caveat is that the Concept 500 have the crossover at 2.5 khz so I will have the Class D amp runing a good part of the mid frequencies, maybe loosing some good 300B midrange smoothness. We’ll see.

I think even if I had a crossover between my preamp and both amps, to split the frequencies below the speakers crossover point, I still would be limited to their 2.5 khz. 

So I believe there's no point on buying a specific crossover.
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