12AX7 vs 7025 vs 5751 (can they be used together?)

[dixienormous]

Hi, first post and thanks all for the woderful info that I've read here so far. I have an F-30 and my issue is that Channel 1 is very clean and sounds wonderful but Channel 2 has a huge amount of gain even set as low as 9 o'clock. So the problem is, on a scale of 1-10, the gain on channel 1 goes up to about a 3, however channel 2's gain starts at about 7. So there's a huge difference between the Ch1 and Ch2 gains. I'd like to leave channel 1's gain as-is and tame the gain on channel 2. I've read that this can be accomplished by replacing the 12AX7's with a 5751's. My question is this....can I keep a 12AX7 in v1 and then replace v2 with a 5751 or even a 7025 to reduce the noise. Or if I want to use a 7025 in any channel, do I have to replace all 4 preamp tubes with 7025's or 5751's for that matter or can 12AX7's, 7025's, and 5751's peacefully coexist together. As far as tone goes, my fave is Jerry's type of tone on songs like Eyes, Franklin's. Lead tone I like Trey's live tone. I'm not a hippie nor do I really like the Dead or Phish...I just think they both have great tone. Thanks so much for this resource.

 

[dodger916]

They can "peacefully coexist".

 

[crane]

The 7025 is basicaly a 12AX7.
Try a 5751 or a wonderfull NOS Mullard 12AT7.

 

[212Mavguy]

You might not get enough of what you want with a 5751, there will likely be too much gain still. I looked at the manual for the tube assignments, try a vintage 12at7 in V1, that will get you closer, if that is not quite enough, stick a 5751 in v2. Work you way down a bit at a time. They do not have to be unused, just strong and relatively low in microphonics, although in low gain preamp tubes microphonics are not quite as severe of a problem as in more gainful 12ax7's. My ears like having a less gain-y tube in front of one with more gain within a given channel. Here is how gain goes from more to less in 12__7 types:

12ax7/7025/ecc83/e83cc/ecc803s/12ax7a/7025a,

5751,

12at7/6201/cv4024,

12ay7/5965,

12au7/5963/5814a.

Peace.

 

[Drewtone]

As said above, they do coexist.

I've recently tried a Groove Tube 5751 M (mullard reissue) in my Makr III combo... the amp really liked it in the V1 or Phase Inverter. Really like how it put some 'butter' into the clean tone.

As far as trying an 12AT7, give'er a try. I just tried an EH 12AT7 in V1... clean channel sounded good, but when I pulled to CH 3 (lead), instant screeching feedback... that might be user error, however.

 

[Timbre Wolf]

I've recently tried a Groove Tube 5751 M (mullard reissue)

:lol: Mullard never made a 5751. Are Groove Tubes really touting their Russian 5751 as a Mullard reissue?? Seriously??? Wow!!!




Okay - back on thread... To reiterate: 5751 is a lower gain sub for 12AX7, and 7025 is a low-noise 12AX7 (same spec). Also, one need never use all one type of tube in a preamp (like all 7025, for example), nor do they need to be the same manufacturer's tubes.

- Thom

 

[stokes]

I've recently tried a Groove Tube 5751 M (mullard reissue)

:lol: Mullard never made a 5751. Are Groove Tubes really touting their Russian 5751 as a Mullard reissue?? Seriously??? Wow!!!




Okay - back on thread... To reiterate: 5751 is a lower gain sub for 12AX7, and 7025 is a low-noise 12AX7 (same spec). Also, one need never use all one type of tube in a preamp (like all 7025, for example), nor do they need to be the same manufacturer's tubes.

- Thom

It really irks me how these companies buy a name,like Mullard and Tung-sol and produce tubes they call "re-issues",I mean how do you "re-issue" what you never issued in the first place?