Well, I too use the Vandersteen 3A Sigs and a pair of 2wq's. I have vertically biamped them using McCormack DNA .5 amps which are 100+ per ch. at 8 ohms. They double down and provide more than adequate power for anything but ear damaging levels. I have definitely concluded that vertical biamping is more transparent and better sounding than a single bi-wired amp.
The fun part came trying to get the high pass correct. I have not used the Model 5 crossover so I can't comment on that. However, I have used the fixed crossover. I found it to impart a slight veiling to the sound compared to being the circuit vs being out. Using the formula 1 divided by 2pi(6.28) x f(crossover freq.) x z(input impedance)to find the capacitance required, I have made my own filter plugged directly into the channel input for the bass on each amp using Infinicaps. The crossover is out of the amp channel driving the mids and highs. This provided transparent and seemless sound to a level I don't feel the need to change. I ran this by Richard Hardesty (Audioperfectionist) and this is what he has done also. He also said he would make a statement after his research if it was better to run all channels through the filter or just the bass. So we'll see what he says. My conclusion is this is the way to go.
Back to the original question of power, the 3A Sigs really need no less than 100 watts per side in my opinion even with the subs. I can say that they open up more with more power. That is why I'm anxious to try the Theta Dreadnaught with these speakers.
The fun part came trying to get the high pass correct. I have not used the Model 5 crossover so I can't comment on that. However, I have used the fixed crossover. I found it to impart a slight veiling to the sound compared to being the circuit vs being out. Using the formula 1 divided by 2pi(6.28) x f(crossover freq.) x z(input impedance)to find the capacitance required, I have made my own filter plugged directly into the channel input for the bass on each amp using Infinicaps. The crossover is out of the amp channel driving the mids and highs. This provided transparent and seemless sound to a level I don't feel the need to change. I ran this by Richard Hardesty (Audioperfectionist) and this is what he has done also. He also said he would make a statement after his research if it was better to run all channels through the filter or just the bass. So we'll see what he says. My conclusion is this is the way to go.
Back to the original question of power, the 3A Sigs really need no less than 100 watts per side in my opinion even with the subs. I can say that they open up more with more power. That is why I'm anxious to try the Theta Dreadnaught with these speakers.