Question about byamplification

Hi guys

A question for those with experience and knowledge.


I'm thinking about experimenting on byamping with my valve amp, the Line MagneticLM-508, and a class D power amp I have, both driven by my Audio-GD HE-1 preamp.


As my speakers, the Q Acoustics Concept 500, have two pairs of binding posts, I was thinking about connecting the LM-508 to the highs binding post and the class D to the lows ones of the speakers.


I don't have an active external crossover, so I was suggested on splitting the RCA output of my preamp to both amplifiers. I know that I will probably have trouble matching the gains of the amps as they are likely different, but I have tubes with different gains and also the LM508 has a knob with different negative feedback settings (different gains) so I can try to match them, at low volume levels of course.


The one millon dollars question is if I'm risking on blowing a tweeter with the LM-508? The speakers manufacturer said I should be careful since the LM-508 will only be running the tweeters and it could "see" a high impedance load at frequencies below the crossover point (2.5 Khz).


On the other hand, people with experience on byamping told me that it should not a risk, I should only start with low volume levels and go up carefully.


Has anyone experienced something similar? Am I risking the tweeters or the amps?


Any thoughts or suggestions are appreciated.


Well, there is something I don’t quite understand.

If I connect one amp to the highs binding posts and the other amp to the lows binding posts, the internal crossovers of my speakers will divide the frequencies at 2.5 Khz. So, what’s the point on adding an external crossover if I won’t be able to change the crossover point at the end of the chain.

I guess external crossovers are for speakers without internal crossovers. Am I missing something?

I guess external crossovers are for speakers without internal crossovers. Am I missing something?

Setting levels for two different amps.

To do it right, you need an external electronic crossover, like a Marchant crossover (see link below). You are going to have to disconnect at least the bass driver from the passive crossover. Not sure if your speakers are 2-way or 3. If 3-way, you can leave the tweeter and mid connected to the passive crossover. You going to have to find a way to deal with the gain level between the two amps. When you are done, your speakers will sound like they cost at least 5 times what you paid for them, I kid you not.  The point of the electronic crossover is that it will address the weakest link of your speakers, namely the passive crossover.

Thanks for the answers.

Yes, that's a good idea, but for now I would like to know if I can try byamplifing with the passive crossover of the speakers without risking the tweeters or the amps.

The point of biamplification is to allow the amps concentrate on the frequencies specific to the load. So you need to cross over the signal before it gets to the amplifiers. You need the electronic crossover if you are to do this right.