Here's what I got from Lord Valve on my question about tubes for an SVP-PRO: "The NOS Beijing-production Chinese 12AX7s are excellent for bass preamps. $10 each. I have NOS JAN 5814A or JAN 6189A for the 12AU7 holes, at $9 each." And here's what I asked him: "I'm a bass player looking for interesting tube replacements for the four 12AX7 and one 12AU7 in my Ampeg SVP-PRO preamp. Power amp is a QSC RMX2450 and cabinets are Eden 210XLT and 115XL. There's a Behringer MDX2200 compressor/expander/limiter in the effects loop. I play mostly vintage rock and blues and am looking for a bit thicker tone than I'm currently getting with the EH tubes that are in there now. Price is a consideration but is not _the_ consideration. Got any ideas? thanks -"