Eminent Technology 8b Speakers - Amp/wattage Recommendations

The plan is to use:

1.  a HP filter between my preamp and the QS amp, which will driver only the mid and high frequency panels. I am not sure of the filter frequency just yet, but probably somewhere in the 50-100Hz range. If I'm not mistaken the mid panel driver plays down to 100Hz. 

2. Use the on-board Xover on the 8s to handle the crossover between the mid and high frequency drivers; and 

3. the built-in DSP/crossover functionality in the QSC to drive my subs. . 

With the above arrangement, I believe the low frequency drivers on the 8b's will be eliminated from the equation altogether.

I assume if the QS amps does not have to amplify the low frequencies, I am hoping to get more bang out of those 100 watts. This a fair assumption? 

I would think it might be good assumption, but I'm not sure about tube amps.  It would be better to ask tube amp experts like atmasphere.

@atmasphere Ralph, could you chime in?  Does limitting low end allow to play louder?  I know that with some amps, like class D  Zobel network  limits power at high frequencies anyway.

Eminent Technology says "The LFT-8b is biampable.". So just ask the designer, the best way to do that.

Hello. I’ve owned several Magnepans over the last few decades, and I’ve used dozens of different amplifiers (tube, SS, and hybrid). You’ll have to try the amp you’re considering in your system, in your own room to truly know if it will work. I know that sounds like a Non-answer, but unfortunately, it’s the truth. For what it’s worth.. I’ve been using a 60 wpc tube amp to power my MG-3.7s for almost a year now, and they’ve never sounded better. I listen in the range of 70-85 dB average spl. A sound meter is an important tool to figure out how much power an individual needs. I’ll bet the Quicksilvers will sound great. They might not like 95 dB avg spl, but they might sound so good that 95 dB isn’t necessary. Good luck

I would think it might be good assumption, but I’m not sure about tube amps. It would be better to ask tube amp experts like atmasphere.

@atmasphere Ralph, could you chime in? Does limitting low end allow to play louder? I know that with some amps, like class D Zobel network limits power at high frequencies anyway.

The ET8b is surprisingly tube friendly and if you have 100 Watts you should be good in most rooms. If bass is filtered from the HF amp then of course you can get more sound pressure, if there is also an amplifier for the bass.

IME doing this without an electronic crossover (whether active or not) in front of the amplifier is problematic. If you don’t have such a crossover, IME you’re better off just driving the speaker with the amp you have.

One of the founders of BAT, Steven Bednarski, was a customer of ours and had 8bs. He drove them with our MA-1s which at the time (1990) were 100 Watt mono OTLs. That is why I say this speaker is tube-friendly. Steven’s warranty form says that the amp was the best he had ever heard so I have to assume it worked pretty well.

So I’d just hook that QS up and play tunes! Use the 4 Ohm tap if memory serves.