Amp choice and/or passive bi-amping for ML hybrid electrostat?

[KEW]

This regards my Martin Logan Vista'a.

I know the general wisdom is passive bi-amping is a waste of time/wire, but wanted to make sure the electrostat speakers don't alter that equation.

The design is a 8" ported woofer module with a "Vojtko" (whatever that is - the designer?) crossover at 450Hz to the electrostatic panel.

Unfortunately, I cannot find an impedance graph for the Vista.

The manual states 4 Ohms Nominal and 1.2 Ohms minimum at 20kHz and sensitivity of 90dB/2.83 volts/meter.

The manual recommends a 100 - 200WPC amp, then goes on to say "it is important that the amplifier be stable operating into varying impedance loads: an ideally stable amplifier will typically be able to deliver near twice its rated wattage into 4 ohms and should increase again into 2 ohms."

That is a pretty high bar and I'm not sure my XPA-2 gets me there, so I am wondering if I should use my 5 channel Monolith instead (either in stereo or 4 channels to passively bi-amp), or neither of the above!

Here is a link to a review by Home Theater Review (no measurements) if anyone is curious:
https://hometheaterreview.com/martinlogan-vista-hybrid-electrostatic-loudspeaker-reviewed/

 

[yepimonfire]

This regards my Martin Logan Vista'a.

I know the general wisdom is passive bi-amping is a waste of time/wire, but wanted to make sure the electrostat speakers don't alter that equation.

The design is a 8" ported woofer module with a "Vojtko" (whatever that is - the designer?) crossover at 450Hz to the electrostatic panel.

Unfortunately, I cannot find an impedance graph for the Vista.

The manual states 4 Ohms Nominal and 1.2 Ohms minimum at 20kHz and sensitivity of 90dB/2.83 volts/meter.

The manual recommends a 100 - 200WPC amp, then goes on to say "it is important that the amplifier be stable operating into varying impedance loads: an ideally stable amplifier will typically be able to deliver near twice its rated wattage into 4 ohms and should increase again into 2 ohms."

That is a pretty high bar and I'm not sure my XPA-2 gets me there, so I am wondering if I should use my 5 channel Monolith instead (either in stereo or 4 channels to passively bi-amp).

Here is a link to a review by Home Theater Review (no measurements) if anyone is curious:
https://hometheaterreview.com/martinlogan-vista-hybrid-electrostatic-loudspeaker-reviewed/

Might need to go with pro gear to handle that severe of an impedance dip.

 

[Irvrobinson]

I think you'll be perfectly fine with the XPA-2.

 

[everettT]

The lowest impedance dip on almost all hybrid MLs is very high in th FR and with no difficult phase angles. Yours is 1.2 @ 20khz. Most any amp will drive them (as noted on esoteric forums, with an somewhat equal split with tubes and ss amps). If it where a full range electrostatic panel only, I'd imagine then a stout amplifier would be in order. When I had my older Ascents I used a 140wpc B&K that had no issues.