# Trinity 5E3 deluxe question



## zurn (Oct 21, 2009)

Hey amp techs  I have a Trinity 5E3 Deluxe, I replaced the 12AY7 with a 12AU7 and I'm loving the sounds I'm getting. Is it dangerous or harmful for the amp ? 

Thanks.


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## keto (May 23, 2006)

Shouldn't be. Check the power tube bias maybe, but shouldn't be an issue. It surprised me to learn that the AY has substantially more gain than the AU, so you went down in gain, probably a touch lower voltage at places in the circuit. Less is not likely to be harmful.


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## vadsy (Dec 2, 2010)

I remember reading that the AU was a really low gain tube so to the point where it wasn't a safe substitution for tubes with higher gain, such as a 12AX7. I can't find the source and I could also be wrong but I would make sure someone who knows this stuff chimes in with a solid answer.


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## zurn (Oct 21, 2009)

vadsy said:


> I remember reading that the AU was a really low gain tube so to the point where it wasn't a safe substitution for tubes with higher gain, such as a 12AX7. I can't find the source and I could also be wrong but I would make sure someone who knows this stuff chimes in with a solid answer.


http://www.thetubestore.com/Gain-Factor

Yeah well this chart says this: 

12AX7 = 100% Gain
5751 = 70% Gain
12AT7 = 60% Gain
12AY7 = 45 % Gain
12AV7 = 41 % Gain
12AU7 = 19% Gain

So I basically lowered the gain from 45% to 19%, it makes the volume much more controllable. With the AY7 I would get full volume at around 2-3 and that's quite loud. To put it in perspective, I have to set my Deluxe Reverb to 5 to get the same volume.


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## vadsy (Dec 2, 2010)

That's the stuff, it was thetubestore. It looked different some time ago but I remember it saying that replacing the AX with an AU isn't a proper match but I also didn't realize just how low the AY was. You're probably fine.


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## WCGill (Mar 27, 2009)

12AU7 isn't a direct substitute for a 12AX7 like the 12AY7 and 5751 are. It will work, not optimally, and won't harm your amp.


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## zurn (Oct 21, 2009)

Cool thanks!


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