Need to learn about Audio Research

ARC tube amps have a definite warm “Tube house sound. And while I don’t currently have anything, I can assure you they make great products.  Having said that, the sound isn’t for everyone and or every speaker.  
Also, depending on your listening levels and whether you use sub’s, 100 watts might not be enough power for the 3.7i’s. (They really like current) but If you use an active crossover and roll the Maggie’s off @65 htz,, 100 watts is way more power than you need. There are a bunch of other variables you will need to consider also. Room size and and acoustics to name a couple.

Have you ever considered getting a hybrid amplifier?  Tubes on the input section and Mosfets for the output stage?

All the best.

Apropos @richardbrand ’s post upthread, I got to meet Peter Walker at McCormick Place in Chicago during the 1976 CES. I had a pair of Quads which I bought in 1974 and they are still in use today! (Sympathetically restored by Kent McCollum in 2017). I run them with an old pair of Quad IIs that were redone by the late Bill Thalmann with first rate glass.

Walker was notable for a couple of famous quotes, including the type of wire necessary for his equipment. It went something like this (I’m paraphrasing): First, it must be long enough to connect from the amplifier to the speaker, and secondly, it must be conductive.

Another brilliant guy in a quirky, fascinating industry filled with colorful characters.

~

I have the 3.7i and pair it with a Pass 250.8 the sound is magnificent. I purchased the Pass after reading it had won the best of show when paired with the Maggie’s.

plenty of power and no hassle with tubes.

good luck and good listening.

@whart 

Not to mention his "we don't actually listen to our amplifiers, we let our customers do that".

He described his amplifiers in engineering terms "unconditionally stable into any load".

I am a bit surprised that nobody has done a digital version of the Quad ESL-63 but then very few seem to understand the principle behind the eight concentric rings with their time delays ...

@traudio you have some great equipment.  The Hegel is a great integrated.  I agree that it is likely silly to put a tube pre in front of it but if you are already planning on going the separates route, you might by the pre first, try it, might surprise you.  Hegel makes great amps and the amp in your integrated can drive most speakers without issue.  Now, preference on the sound signature difference between the amps is a different animal, for sure you might prefer the sound signature / pairing with your Maggie’s if you swap amps / pre’s.  I have compared Tube amps / pre’s to SS.  I’ve landed on liking a tube pre with SS.  As others have mentioned, can give you the best of both worlds.  Pass, Krell, Coda would all be great pairings with your Maggie’s, known to drive difficult speakers loads across a wide range, handle dips into the 2 ohm range.  A couple of less expensive options would be Parasound and Music Fidelity, both design SS amps that are great at driving difficult loads and punch well above their weight class.  A Parasound A21 was my fist serous 2 channel price of equipment, added into my HT set up, starting me down the 2 channel rabbit hole, great amp.  Adding Subs would be my first move, before changing up your pre / amp.  Those would be a game changer.  Might find that with the subs, you love the Hegel handling the mids and highs.  Good Luck!