VAC Phi 70 good match for Vandersteen 5As?

While I love my McCormack DNA--500, I 'm thinking of making the move (1st time!!!) to tubes and have the VAC Phi 70 on my mind. I'm not sure if the output power of the Phi 70 is enough for the 5As. Opinions? Room size is 22 x 17.
I could also go with the Phi 110/110 stereo or Phi 220 monos. How will the 300B tubes in the Phi 70 compare to the KT88s in the Phi 110/220.

I didn't hear it my system, but I absolutely fell in love with the VAC Phi Beta Integrated. I don't need the integrated as I have the EMM DCC2 as my preamp already.

One of the speakers used by VAC is the Thiel CS 3.6--and they are even less efficient than the Vandersteens, IIRC. The Phi 70would probably work fine with the 5s--call Kevin Hayes @ VAC and talk to him personally:(941) 952-9695. He'll be glad to help.

Cheers, Bill
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If at all possible, audition the VAC before you sell your McCormack. I know from personal conversations with Richard Vandersteen that he thinks very highly of the McCormack amps, and has used them over the years with his various speaker models.

Because the 5A's have an excellent built-in powered sub, lower-powered tube amps can be an excellent match for the 5A's (and the Model 5). The DNA-500 is a superb amp, and may in some respects be better suited to the 5A's than the VAC, but the only way to be sure is to do an A-B listening test in your own system.
What kind of music do you listen most? If you like jazz, pop, chamber, or small orchestra; the VAC should be enough. But if you like rock, large-scale symphony, or pipe organ; you will need something more powerful.

Despite the built-in sub, Vandy 5 is not that efficient. I am driving a pair with a BAT VK-75SE and that is what I experience. When I save enough I will probably get another VK-75SE make a pair of 150W monos.
It's been a while, but I finally received my VAC Phi 220 monos to drive my 5As. After a wonderful discussion with Kevin regarding the Phi 70 and my 5As, he felt the Phi 220s would actually be the better amp sonically.

One thing I questioned (as others did), was I changing amps just for the sake of change, and would there be an improvement in sound quality (in a positive way, not JUST a change). The DNA-500 is a fantastic amp and tremendous value. I've owned quite a few solid state amps and the DNA-500 was by far my favorite. I thought my system sounded great, but wondered, could it get any better? Indeed it has.

I am absolutely thrilled with the Phi 220 monos and my 5As!!! They have mated "perfectly" with my 5As as if they were made for each other. They take all of the things I loved about the DNA-500 and improve upon them in a meaningful way. One area where the 220s really better the DNA-500 is in high frequency reproduction. The 220s are more extended, more natural, and most of all more musical. I also find myself truly engaged in listening, being immersed in the music with no distractions. The sound is just so "right" to me I've stopped trying to analyze for any shortcomings. Granted, they cost almost three times as much than the DNA-500, bit IMO they are worth every penny.

The 220s are also very quiet amplifiers and don't run too hot at all. In terms of build quality and appearance, these are the finest pieces of electronics I have ever owned. They remind me of a finely crafted, one-of-a-kind product that you know the builder takes immense satisfaction and pride in producing.

What can I say? I think Kevin created a masterpiece both sonically and visually. He's one of the most pleasant and responsive persons I have had the pleasure of dealing with. He personally auditioned the amps for two days prior to shipping, making sure they met his approval.

Kudos to Kevin and all at VAC for a "statement" product.
I plan on listing my equipment on the systems page, but here is the rest the equipment used with the 5As and 220s.

Vandertseen Model 5A (Bird's Eye Maple- stunning!)
VAC Phi 220 monoblock amplifiers
EMM Labs DCC2 DAC/preamp
EMM Labs CDSD- SACD/CD transport
Audioquest SKY 72V DBS XLR interconnects
Audioquest Kilimanjaro 72V shotgun biwire speaker cables
Silent Source AC power cords
Custom Power Cord Co. Model 11 Plus for 5A subs
BPT 3.5 Signature Plus balanced line conditioner
Critical Mass Systems platforms for EMM and BPT
Sistrum SP-101 platforms for VAC Phi 220s
The Sistrum stands are a great stand for the VAC. I believe it really helps. Glad to see you are using it as well.
Fsarc - My 2 cents - I currently also own a McCormack DNA-500 and I agree w/Tvad. You might try the Phi preamp to get the "tubes" you want without losing the strengths of the McCormack and find you like it better than the preamp you have now. Why give up something you love? Just augment it if you can. You can also do some tuning w/PC's, IC's, etc. I have a VAC preamp now and will be upgrading in a month or 2.
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The Phi 220 amps sound great in Fsarc's system and they ARE an improvement over the excellent DNA-500.

You lose a little on the bottom (but pretty much ANY amp loses a little on the bottom to the DNA-500), but you gain a little more texture and dimensionality. Those improvements help create a more engaging experience.

Not a night and day difference, but at this point I don't think you can expect that.