ARC VSi75SE v. MF Nu-Vista 800

Wow, I didn’t expect that.

Here’s why: Without the ability to audition, my expectations were based on: comments from knowledgeable people like you; trusted reviews; manufacturer reputations; and pricing. One key element was Fremer’s Nu-Vista review -- "the best product that this company has ever produced” — as well as lots of owner comments about the unique sonics produced by nuvistor technology.

The Nu-Vista 800.2, which replaced the 800 model I’m considering, differs primarily in its power-supply design & aesthetics (minimal if any change to the audio signal path). Sure, I know that PSs are critically important in any amplifier, but in my application, the 800’s 330wpc means that my Harbeths -- nominally requiring 25wpc -- will rarely suffer from lack of overhead. And my system includes $10K of power-conditioning. So I suspect that the 800.2’s improvements, wouldn’t be as dramatic in my system as they would in one built around, say, power-hungry Wilsons, or even Maggies.

OK, given all that: The 800.2 is a $22,000 box that probably sounds more like than unlike the 800. The VSi75 is ARC’s mid-performance integrated, normally selling for about $8K; and you & others have said here that, despite sounding more like than unlike ARC’s Reference amps, it’s not in a class sonically with the Ref 75.

So I wouldn’t have been surprised if you’d told me that the Reference 75 boasts clearly superior sonics than one of MF’s $5-10K MX-Series amps. But the VSi vs. the Nu-Vista? I’m not contesting what you say, because your opinion is far better informed than mine. I’m just saying that such an unequivocal statement was a surprise. Your initial comments about not being too familiar with MF products suggest that you might not be taking into account the Nu-Vistas’ reputation for sounding very different than MF’s more popular MX amps. Nonetheless, your comment pushed me far in the direction of going ARC.

But then you brought up another important point that I hadn’t considered. My listening is split pretty much 50-50 between "critical" SACD/phono/hirez streaming stereo and HT multi-channel. Do I really want to "waste" that much tube life watching TV? Maybe tubes are just a poor match for this application. And maybe the VSi is simply not configured to work in a HT Bypass application – no sub out & no bypass input. So am I back to Square One?

I’d originally hoped to find a way to share the Harbeths between two distinct sources: That is, drive them from the AV/receiver when watching TV, but switch them to better-quality electronics for critical listening. I finally gave up. Maybe some speakers have multiple, auto-switching inputs (like my MartinLogan sub), but not the Harbeths.

So since the solution I really need is out of reach, I’ve spent a lot of time trying to shoehorn products like ARC & Pass Labs integrateds into an application they weren’t really designed for.

None of this should imply that this conversation is not very, very helpful. I’ve always wanted ARC in the house, but maybe it’s just not in the cards. So that’s why I’ve been trying to get a fix on what the Nu-Vistas sound like *directly compared to* other products I’m considering. Your above comments are the most helpful I’ve found so far, so thank you again.

ghdprentice, I have a related question.

I see that the recent Stereophile review of the entry-level I/50 integrated notes that "When power tubes or the tube set are replaced, the I/50 must be biased by a trained technician to ensure proper operating values."  Holy cow, does this sound right to you?

Given that the likelihood of finding an appropriately trained technician is pretty low out here, does that mean that I'd have to ship my ARC integrated to the factory every time I need to replace a tube?

FWIW, I have a degree in Physics and decades of experience working with electronics, so it's hard to believe that something as simple as biasing vacuum tubes can't be done by an experienced user with a voltmeter.

Get the MF NuVista!  Why?  Because it's fits into your setup best.  Will it sound just like the ARC?  No, but so what.  It will sound great anyway.  If these are really you're only choices, then don't overthink this.

Now to overthink it, I would worry about having that much power being fed to the Harbeths, especially with other family members using them in the HT setup.

@cundare2 

Wow, that does not sound right.. but I can’t refute it with any knowledge. I’ll do a little research. I’d like to know. But it sure does not sound right.

This is from the manual.  But one has to wonder if they are afraid a person new to audio and tubes will shock themselves or if the unit is just unfriendly for anyone, even with experience, to bias.

MAINTENANCE

Vacuum Tubes It is recommended that you replace the vacuum tubes of your I/50 in sets. All of the tubes in your amplifier have been matched to have similar operating characteristics, to provide the best sound quality and reliability. 6550WE tubes should be replaced at approximately 2000 hours. 6922 tubes should be replaced before 4000 hours. Upon replacing a power tube or tube set, the I/50 must be biased by a trained technician to ensure proper operating values.