Audio Research 75 SE

I'm also interested in hearing how much of the upgrade comes from the tubes vs. the circuit changes (one obviously is much cheaper than the other).

Rrolack ... I just dropped 2 quads of KT-150s into my Ref 150. Sound is better, but not transformational. So I wait to hear back from Oregonpapa and Carey1110.

I actually found the KT-150s to be a huge step up in the Ref 75, particularly in the bottom end. Best money I ever spend in audio.

That said, I'm also super curious to hear how the upgrades change things.

According to my source, the KT-150 tubes account for about 40% to 50% of the improvement in the SE amps.

On the KT-150s ... they take a good 100 hours of break-in to start sounding their best.

Hmmmm, well Obfiscation Central were hardly going to leak any other set of percentages were they? when one does the math on the residual $3000 for a handfull of resistors and capacitors, together with a meter or so of silver plated copper wire!!! Or are we being taken full circle back to ' costly proprietary Teflon ' Capacitor Gate once again?

Those ARC technicians must charge more per hour than my Wife's Orthodontist and Gynaecologist put together!