ARC VSi75SE v. MF Nu-Vista 800

@cundare2 Please keep in mind that my experience was/is with Harbeth M30.1 and SHL5+. It is quite possible that C7-ES3s are a different animal altogether. I have owned P3esr and 30.1, and still own SHL5+ (home office) and 40.2 (main system). Incidentally, the C7s are the only ones I didn’t like when I auditioned them. But later, I heard a pair at a friend’s house and was quite impressed. I can only assume they were not driven properly when I auditioned them in person.

The reason I proposed a stout SS amp to drive them is because I believe the Harbeths already give you a tube-like presentation on their own. Adding tubes (with the exception of SHL5+) or warm sounding SS can be too much of a good thing. Secondly, they really shine with a ton of power and current. I agree that the sound can be more than adequate with many amps including INT or XA25. I was quite happy driving the 30.1 with tube amps and even PL INT-25 and told myself that it couldn’t really get any better. But once I put the Luxman in the system, the synergy was off the charts. The Luxman’s lively presentation was a good balancing act given the slightly darker sounding character of 30.1s. It was also better than the Pass Labs INT-25. If you are sold on Pass Labs, then perhaps INT-60 might be a better option to really give them the current they are craving for. So yes, the lower-powered amps can be ’more than adequate’ but IME more power allows them to reach their full potential.

arafiq: Great feedback, exactly what I was looking for. Thank you.

Re: the C7 v. the 30.1, those two models are very similar, identical drivers & ports (admittedly arranged differently), similar cabinets, impedance curves, etc. The 30.1 is nominally 1 dB less efficient, so when I hear that a particular amp can drive the 30.1 well, I assume that I can extrapolate that recommendation to the C7.

FWIW, Alan Shaw claims that the C7 is his personal favorite model when driven with at least 80wpc. However, the XA25 is a high-current device (10A in the specs), and I suspect that its 30-ish wpc (into 6 ohms) is more powerful than you’d expect. And then there’s Herb Reichart’s high praise for the Harbeth+XA25 combination in his Stereophile 30.2 review. But still...

Your comments comparing the Lux & Pass are interesting. But I’d be even more interested in context. What size room, the type of content you played, volume levels, mounting, powered sub crossover freq, that sort of thing. I’m sure you’d agree that in this type of comparison, those details can make all the difference. In fact, your personal C7 experience seems to confirm Shaw’s (and Reichert’s) comments about these easy-to-drive yet finicky thin-walled boxes. Reichert found that even eliminating the blu-tak attaching his 30.2’s to Sound Anchor stands degraded their sound. And Shaw claims that, despite being designed to be insensitive to differences in cabling & ampflification technology, simply removing the grill cloths compromises his design. So again, devil in the details.

At this point, after digging through offerings from Levinson, PrimaLuna, ARC, Hegel, HiFi Rose, and Ayre, it looks like the XA25 & the Nu-Vista integrateds offer the best compromise among sonics, cost, connectivity/functionality, and form factor -- at least for my particular application. Even the INT-60, great as it must be, would not fit my system & room.

Unfortunately, there’s no way for me to hear these components before buying. All I can do is have long conversations with people who have had first-hand experience. And so far, there’s been no consensus about whether the XA25 is a good match with small-to-medium sized Harbeths like the C7 & 30.2. Many people, including trusted reviewers in Stereophile & TAS, describe in detail how beautifully they work together. But others, like you and Pass Labs’s & Harbeth’s own customer service reps, recommend more power.  Sigh.

One final question: Thinking of presentation, the things that the XA25 is noted for: holographic, three-dimensional soundstage, reproduction of room ambiance ("the players are in your room" v. "you are with the players in their own room"), realistic image size, Quad-ESL-like coherence, etc. -- did you lose any of that with the Luxman?

Re: bias procedure for the ARC VSi75, yes that is correct.  There is a bias button on both  the remote and faceplate that will step through each of the four kt150 power tubes and show the individual mA values. There is a bias pot in front of each of the tubes that can be adjusted with the plastic tool.  It’s easily accessible with no need to disassemble the chassis, flip it on its side etc…super easy from a maintenance perspective. 

It seems there is a lot of items discussed here

1,The sound is right or not

2, The installation and operation is easy or not.

3, The basic model is valuable or not.

I am a guy to pay Audio research with more than 20 years.

1, The sound is right with Audio Research? YES 

Audio Research might have a lot of marketing problem,but the sound is very good.

By the way,I also understand the amplifeir MF. I have no good impression on their sound althought it is fully subjective.

2,The installation is easy or not. 

With Audio Research, I will say NO. I have VT100 MKIII,I change the bias myself with VOLT meter. The products is not so nice to clients.

But there is a point here. Auto bias is not the best way in my opinion.  

With auto bias,the machine bring the IC and the IC running all the time,and interfere the circuit. DO YOU THINK IT IS BEST FOR THE SOUND???\

BIG QUESTION HERE!

3, Does basic model value the money? Just like I/50.  

If you are talking about the sound,you best buy a old model from used market.

If you talk about the re-sell price, Audio Resaerch still good or better than most of brand.

I have my bad example here, I bought a 300B amp with no name,although the inside circuit is hand made, If I like to sell,it is very hard and I am doubt if I can get back 30% value.