I have heard the Ref's with a McCormack DNA225 and McCormack per and the sound was pretty darn good.
What about a hybrid, or a fully tubed integrated that's very easy on the tubes?
The Pathos and Unison lines have hybrids, as does Audio Aero. I think generally the power tubes are the ones that cause the most headache. One of these hybrids that utilizes a tube preamp stage and an SS output might be the ticket. Alternatively, BAT makes a great integrated and the tubes are said to last for 10,000 hours. I have no personal experience to back that up, but I think it's worth mentioning.
Jeffrey, you didn't mention whether you used the Gallo bass amp. In case you don't, consider a 4- or 5-channel solidstate amp. Use 2 channels to drive the speakers full range and 2 more channels for the woofers' 2nd voicecoils. It would be fairly easy and inexpensive to create a low-pass filter for the bass channels, or you could look for an inexpensive low-pass electronic crossover/filter such as the ancient Dalquist DQLP-1 (one of which I just found!). It includes 2nd-order low-pass filters, a variable-bass-boost control, and, of course, bass-level controls. You would NOT need to run the full-range signal thru it.
I'd look at the B&K 200-series poweramps. Of course you'd then need a preamp, but you certainly can include one for your $4500 budget.
Based on my experience with the Gallo's and solid state, I can heartily reccomend the NuForce Referenc 8 Mono's for $1600 a pair. These are small, light, high-quality switching amps, cool looking and running... very, very good, especially when you realize how much money you have just saved.
Sound quality n the same league as my reference $3000 60wpc tube amp, but with the benefits of SS bass extension and speed. Also works well with a passive or transformer volume control (I use the Sonic Euphoria). You can spend more on amps that heat the room... but with NuForce's 30-day trial, don't take my opinion, have an extended listen, how can you go wrong? I didn't.
Ric Schultz, one of the original audio visionaries and one who has lived longer at the bleeding edge of audio technology than most; who is well known and respected for his mods to digital sources; and who is a Gallo Reference 3 user, is now also a dealer for the new NuForce amps. Ric includes his level-one mods to the NuForce with purchase, at no additional cost.
I would have purchased from Ric if he had been offering the amps when I got mine.
See his site:
I am using a Wadia 850 w/ GNSC Reference mods to directly feed 2 Electrocompaniet AW220s as monoblocks, which drive my Gallo Reference 3 speakers. It does very very well when compared to a 80K reference system. I have found that every improvement I make to my system makes the Gallo Reference 3 speakers sound just that much better. I have installed a pair of Bright Star IsoRock GR3 speaker stands which raised the speakers 8" and improved the clarity and bottom end. I installed IsoClean fuses into both Electrocompaniet AW220s and the Wadia 850. These made a big difference, believe it or not. I am using Shunyata Hydra 6 and a Shunyata Python Vx power cord and Taipans to the EC amps. Upgrading the power cords made a big palpable difference. I have had the Gallo Subwoofer Amp on order for about 5 months. I suggest you read the review on the Electrocompaniet AW220 in Stereo Times, which you can find via the Blue Book listing for the Electrocompaniet AW220 here on AudiogoN. On the other hand, the thirty day trial of the NuForce amps sounds like a good place to start. Ric Schultz knows his Gallo Ref 3 speakers inside and out.