5751 or 6072 to replace 12ax7's in 57 Twin reissue?

[Mickey64]

Still tweaking my Fender '57 Tweed Twin. Stock preamp tubes are 12AX7's, though the originals came with 3 12AY7's/6072 and one 12AX7.

Can anyone tell me what the effect would be if I replaced V1 and V2 at least with either 5751's or 6072's? I want the amp to break up, so I'm not necessarily after clean headroom, so is it worth trying either of these, or am I better off sticking to 12AX7's?

I'm just trying to get some advice before spending more cash on tubes I may not end up using!

[monstermike]

12AY7s will be sweeter with a bit less breakup.

[Timbre Wolf]

If you don't want less breakup, then don't go down in mu (5751 is clean, 6072/12AY7 is cleaner). Keep the amp as is, with 12AX7.

- Thom

[Mickey64]

12AX7's it is, then. Thanks.