My ARC SP6 has tone controls ...
If your preamp has tone controls, there's no way it's an ARC SP6. SP3, maybe.
Any High End Tube Preamps with *gasp tone controls?
After dropping in a vintage Scott 222C into my system while my amp was out for repair I'm really missing the tone controls now that my amplifier is back. It seems sacrilegious but I just can't get the bass where I want it without a bit of boost plus I'm sure my hearing is changing as I get older so why not be flexible... even if it results in me being thrown out of the audiophile club.