#1
Hey guys, I just wanted to talk a little about preamp/PI tubes. For the last few weeks I've been thinking my 6505+ hasn't been sounding quite as good as it's supposed to. So yesterday I tried moving some tubes around. I pulled my JJ 12at7 out of the PI position (it's probably been there for 2 years, maybe 3). I moved my 5751, which is a newer tube from V1 to the PI spot. I tried both a 12ax7 and a JJ ECC803 in V1....

The result was mind-blowing. Having the 5751 in the PI spot brought on a whole new level of kick-ass. With either the 12ax7 or the long-plate 12ax7 in V1, it sounds brutal. But the long-plate tube sounds richer, so I left that in.

The only downside, I've noticed, is the cleans are not *quite* as good without the 12at7 in there. My question is, do you think the major upgrade in tone was due to my 12at7 being worn-out, or will it always sound better with a 5751 there? I mean, I remember it sounding great on high-gain tones with the 12at7 in there in the past -- but the difference now is HUGE. It's so hard to tell when preamp tubes are getting old because they don't just suddenly sound bad -- it's a very gradual thing. I guess the only way to tell is to get a new 12at7 and compare -- or is that the only way?
#2
The 12AT7 was worn out.

How long have we been saying to stick a JAN Phillips 5751 in the PI?
Any old military 5751 would do well but the Phillips are really nice, especially in the PI. Everybody knows about them now though so they're getting pricey. Try TCtubes.
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#3
im a big fan of the 5751. i replaced the 12ax7 in V1 in my JVM and i felt that it really opened up the sound and made it a lot clearer at high gain. i havent tried one in the PI position yet though.

the 12at7 is a lower gain tube compared to the ax7 and the 5751 (60,100 and 75 respectively)

as for checking/comparing valves you would either need a tester or as you said, just switch them and see what you hear.
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#4
Quote by Cathbard
The 12AT7 was worn out.

How long have we been saying to stick a JAN Phillips 5751 in the PI?
Any old military 5751 would do well but the Phillips are really nice, especially in the PI. Everybody knows about them now though so they're getting pricey. Try TCtubes.


Would you go with a JAN 5751 over a JAN 12at7? (Because at7s can be had for $15 as opposed to $40+ ) The 5751 im running is aJJ.
#5
Quote by KailM
Would you go with a JAN 5751 over a JAN 12at7? (Because at7s can be had for $15 as opposed to $40+ ) The 5751 im running is aJJ.

I would, the 5751 has more gain than the 12at7.

Check here for NOS JAN 5751 tubes
www.tubedepot.com
wwwkcanostubes.com
www.dougstubes.com
www.thetubestore.com

I use all of them and have never been disappointed
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#6
With preamp tubes, there is a little give and take in what works best where.

You'll just have to land on a combination of tubes that YOU like best.

But yeah, I've been preaching the JAN 5751 in the PI for years

I wouldn't hesitate to get another 12AT7 though if your budget allows for it.
#7
Quote by 311ZOSOVHJH
With preamp tubes, there is a little give and take in what works best where.

You'll just have to land on a combination of tubes that YOU like best.

But yeah, I've been preaching the JAN 5751 in the PI for years

I wouldn't hesitate to get another 12AT7 though if your budget allows for it.


Well, honestly, I don't know how my high-gain tone could get any better . It definitely has the "sound in my head" and is literally a monster when I turn it up to 2 or higher. At this point I have not played a rig that sounded closer to my ideal sound, and that includes various Mesas, Oranges, Engls, and even the EVH 5150III.

It's just that a 12AT7 really helps the cleans on the amp quite a bit. But if a new AT7 would reduce the "punishment" this amp delivers now even slightly, hell, I'll stick with what I've got. I normally bury my cleans in reverb and delay anyway...

And the age-old question: Are Jan/Nos tubes really worth the extra money? I've been very happy with JJs, but tone is kind of an obsession...

I know preamp tubes are not such a big deal to most people, especially if it's just one that they need, but I'm at a time in my life where I have next to zero expendable income. Literally every penny I spend has to count for something. I got into the wrong hobby!
Last edited by KailM at Aug 13, 2014,