Carver TFM 35 vs TFM 35x

I'm guessing you'd be using half of each for the top and bottom. I haven't heard the THX, I don't think there would be much volume gain, if any volume gain, and I think it would be trial and error as to which one would be best for the highs and lows. One thing I do remember is the first Transfer Function Calibrated (non-THX) one is polite and laid back sounding. The soundstage was closer to the speakers or wall behind them. If the other newer doesn't have it, I would guess it might sound a little more forward (out in the room ) if it has a different sound.

They use a different set of capacitors, that I know.

I was lucky enough to buy a NOS TFM-35 on eBay somewhere around 2009. Seller had posted one image of an unopened, sealed box! I am familiar with the box graphics since I bought a new TFM-15 back in 1995. Price was comparable to good used units at the time, so I took a chance and bought it.

Capacitors are Nichicon (No bulging to this day). Transistors are Toshiba. This amp still sounds very clean and tight today. High end is very open and easy/relaxed but sparkling...very pleasing to say the least. Bass was clean and tight but just a little lacking. I recently bought a Don Sachs preamp and this combination is really nice! Bass is kinda spectacular now on some material (mostly listen to vinyl on a Technics 1200G).

This preamp/amp combo throws a decent but not huge sound stage. 

I have a pair of Dynaudio emit m30 a Marantz sr5006 and a tfm 35. It’s sounds great.nice and warm and bass.