how important is linestage preamp with vinyls only

The linestage provides two functions, if you are using an outboard phono stage. It adds gain. If the output of your phono stage is inadequate to drive your amplifier, that gain is needed. And it adds an attenuator in the signal path and possibly bass/treble/balance controls if you want to use such. Both the gain function and the control functions can also color the sound, for good or ill. If your phono stage has a robust output with the cartridge that is driving it, and if it has a volume control, there is no need for a formal linestage at all.

(There is a third issue with impedance matching; the phono stage has to have a low enough output impedance to drive the cables between it and the amplifier inputs, in order to do away with the linestage.)

If your question is whether or not to switch from a full function preamp (meaning a preamp with built-in phono) to separate phono and linestages, I would say that it is impossible to say, since only you can determine what pleases you most. But separate boxes will cost more, require another interconnect pair, etc. Rollling tubes may help, but what are you trying to achieve? Changing capacitors in the signal path would likely help even more than rolling 12AX7s in the CJ.

Dear Avs9, You have some top quality cartridges, a really good selection. Pardon my saying so, but the cartridges exceed the capabilities of your two tonearms. A tonearm upgrade might produce more results for you than tube rolling, not to mention that you should also check out your tt to be certain the belt is not stretched out, etc, and that it is running at correct speed even when under load while playing music. Those are easy things to do.

I don't want to take business away from anyone, but the price you quote for matched tubes is, shall we say, high. Remember that matched tubes can age at different rates such that eventually they are no longer matched, and in all but balanced circuits, I think matching is over-rated. So long as the tube is not noisy and as long as both halves of these dual triodes are in good condition, I would just use singlets. Lots of tube vendors will test for this standard.

I find it odd that CJ says they will not upgrade the coupling caps in your unit but they do so for other products. Any good local tech can do it for you, if CJ won't. Try some teflon output caps; you will be amazed. Finally, be aware, if you are not already, that you cannot just plug any old 9-pin miniature tube into any old 9-pin socket. To use 6DJ8, 6922, 6H30, etc, in your preamp would require some major re-design of the circuit. But if 12AU7 is begin used as a cathode-follower at the output, you might try an ECC99 there or any of several 12AU7 direct subs.

Sorry. I have no experience with any of those particular tonearms, but I do have a bias (why not?) in favor of the modern SME tonearms over the old SME tonearms, e.g., 309 vs 3009. For tonearms in the $1000 to $2000 price range, I like the Dynavector DV505 (no longer made but can be found used for about $1200). I suspect that the Ortofon tonearms are quite good as well, but with no direct evidence. I also like Technics vintage tonearms EPA100 and EPA500 and Micro Seiki MA505. These can be bought for less than $1K. Fidelity Research FR64S is in the price range and is said to be great for low compliance cartridges. Victor, SAEC, and Lustre are other vintage brands that are excellent for well under $2K. RS Labs RS-A1 is very odd to use but sounds good, too.

I must say I never imagined that 12AX7s had gotten so expensive, but you are paying a premium for "matched pairs", which I would not do.