12AX7 vs. 5751 in V1/V2 on a Rocker 30?

[Stardust]

Yum! Love my Rocker 30 to death, but just for grins, I threw a pair of premium-grade 5751s into it a few weeks back (in V1 and V2), and it really seemed to tame some of the edginess or brashness of the 12AX7s. The cleans in the Natural channel seem richer and more musical, with noticeably better harmonics, and to my surprise, I haven't really noticed much overall loss in volume either, but unfortunately, the Dirty channel took a hit.

I play mostly cleans with it and I rarely gig with it either, so it never really gets pushed or dimed, but now, at least with single-coil guitars, any and all grit is pretty much gone from the Dirty channel, regardless of Gain and Volume settings. And so, not being an experienced tech, my question for everyone is this . . .

Does it make sense (in technical terms) to return the original (higher gain) 12AX7 back into V2, while keeping the mismatched (and lower gain) 5751 in the V1 slot? Is doing so considered dangerous or taboo in any way? In other words, given the fact that the second-half of the V1 triode provides the 1st gain stage for the Dirty channel, does it make any sense having a lower gain tube (the 5751), cascading into the next (2nd and 3rd) and higher gain stages of that same channel at V2 with a 12AX7? Or should I just make a hard choice and play it safe by sticking with matched pairs of either 12AX7s or 5751s in both V1 and V2 slots?

Thanks

[a.hun]

Not dangerous in any way. Just mix and match preamp valves and stick with the combination you like best yourself.


Andy.

[Stardust]

Andy,

My apologies for the delayed reply to this thread (I've been away on business for several weeks), but thanks for your response. I guess its time to start mixing and matching to see what sounds best, but I'm glad to know that it wouldn't be dangerous or harmful in any way. So thanks again.

[pedecamp]

Take the guess work out of it and speak to your tube supplier and explain the result you are looking for. There are many different brands and grades of 12AX7 tubes for instance, I bet your supplier can turn you on to something new that you'll like.

[nlimbaugh]

Yeah, mix and match.... I think the 12ax7in v2 brings up the gain a tad even if it is only a phase inverter IMO. Just like I think the 12ay7 or 12at7 bring the gain down a tad ifthey are used in V2. I've read different things about this but nothing compares to what your ears tell you. I've used two of the same nice pricey 5751 in v1 and v2 and thought it sounded worse than using a diferrent (albeit a pretty nice 5751) preamp tube in v2. And, Im still making adjustments depending on how the volume vs. gain is I'm wanting to convey.

[a.hun]

Yeah, mix and match.... I think the 12ax7in v2 brings up the gain a tad even if it is only a phase inverter IMO. Just like I think the 12ay7 or 12at7 bring the gain down a tad ifthey are used in V2. I've read different things about this but nothing compares to what your ears tell you. I've used two of the same nice pricey 5751 in v1 and v2 and thought it sounded worse than using a diferrent (albeit a pretty nice 5751) preamp tube in v2. And, Im still making adjustments depending on how the volume vs. gain is I'm wanting to convey.

Where have you seen V2 marked as the PI? Just as in THE SCHEMATICS HERE by Orange and Jondog I've always just called them V1-3 in the physical order running from the input socket with V1 being clean + dirty 1st gain stage, V2 being dirty 2nd + 3rd stages and V3 being the PI.


Andy.