Pre-amp tubes are some more important than others?

[Musical123]

Hi,

I was having an issue with my used LSC v1 that I just bought and with the help of this site I fixed it by replacing a preamp tube.

I was looking at the "Tube Task Chart" and see that V1 and V2 are part of the Drive and Gain path, V3 = FX loop, V4 Reverb and V5 phase inverter. I was thinking of replacing the pre-amp tubes and think that the most important ones would be the V1&2 since the signal goes through them followed by V4, V5 and lastly V3 (I never use the FX loop).

Does this make sense or am I missing something? So if I wanted to prioritize $ I should put the V1 and V2 1st? Any recommendations for V1 and V2?



Thanks

 

[MrMarkIII]

You are correct, sir! Generally, the closer the 12AX7 is to the input jack, the more effect it has on your tone. V1 more than V5.

 

[stephen sawall]

Every tube just like snowflakes is a little different. V1 in most amps has more of a effect on tone and gain than the rest.
Just switching around the tubes in different positions well confirm this and well allow you to fine tune your sound.
You can mark the tubes with magic marker so you well know what tube is what. This well help to get back to the sound you liked best and well not hurt the tube at all. I use numbers or abc's.

I write down notes when I do tube swaps. .... but I have hundreds of tubes.

 

[Barry]

I was having some problems with my LS a few years ago and Mesa suggested I replace the russian 12ax7 in the V3 position with a chinese one . Made a huge difference . The amp was weak and lacked warmth

 

[Musical123]

Thanks for the feedback. I am getting ready to by 5 new pre-amp tubes. any recommendations?

Should all 1 type say JJs or Mesa's? or mix them up? I play at low levels (mostly on tweed).


Thanks again

 

[Barry]

The chinese Mesa fixed my problem . Apparently, if you get into a place where the power isnt up to par the russian ones didnt perform very well .

 

[stephen sawall]

Thanks for the feedback. I am getting ready to by 5 new pre-amp tubes. any recommendations?

Should all 1 type say JJs or Mesa's? or mix them up? I play at low levels (mostly on tweed).


Thanks again

Only you can decide what you like best. Just like pizza toppings what you like some one else well hate. It is only a matter of taste.

Different tubes well work better with different amps. I do not recommend particular tubes much ..... because everyone likes different things.

 

[Barry]

Let me clarify that the people at mesa artist relations reccomended that I change out the russian tube for the chinese preamp tube . There was obviously a problem with those tubes in certain situations

 

[djw]

Thanks for the feedback. I am getting ready to by 5 new pre-amp tubes. any recommendations?

Should all 1 type say JJs or Mesa's? or mix them up? I play at low levels (mostly on tweed).

If you get into a discussion with your tube vendor, they'll probably tell you (among other things) that you'll need a tube with "balanced triodes" for V5. This is the phase inverter stage and the tube does need to be within a particular specification for optimal performance. (I'm not technically sure why -- but without googling it or anything, I'd guess that since it's called a "phase inverter" it needs to be "balanced" so that the harmonics don't get muddled by being slightly out-of-phase)

Do talk to the vendor -- if they know what they're doing, and have an idea of what you're after they can guide you. You can get different tubes to increase or decrease the amount of preamp gain. Depending on your style, you may want to look into this. I like a 5751 in V2 and a 12AT7 in V5, both of which are lower-gain tubes, which I like because it smooths out the drive a bit; others like a higher-gain tube in V2.

And DEFINITELY MARK YOUR TUBES' ORIGINAL POSITIONS before you take them out. I made the mistake of not doing this long ago, so now I don't know which of the Mesa's was in V5... ooops. Not fatal or anything, but it's nice to know in case you need a good backup.

 

[stephen sawall]

The balanced phase inverter thing most people believe is a myth. There is much more to that part of the amp that well cause the two sides to be unbalanced.

In general people that understand amps say it is nonsense. People who sell tubes want to charge you more for balanced tubes and with nothing more than claiming "they can hear a difference" say it is a fact.

When people have taken measurements at that point it is always off balance no matter what tube is used.

I have tried many tubes in a phase inverter .... some balanced, most not. I could at no time tell one or the other was better with my ear. Sure they all sound different. But none of the "magic" that tube sellers claim.

I for one see it as "snake oil". YMMV

 

[djw]

The balanced phase inverter thing most people believe is a myth. There is much more to that part of the amp that well cause the two sides to be unbalanced.

In general people that understand amps say it is nonsense. People who sell tubes want to charge you more for balanced tubes and with nothing more than claiming "they can hear a difference" say it is a fact.

When people have taken measurements at that point it is always off balance no matter what tube is used.

I have tried many tubes in a phase inverter .... some balanced, most not. I could at no time tell one or the other was better with my ear. Sure they all sound different. But none of the "magic" that tube sellers claim.

I for one see it as "snake oil". YMMV

Yeah, I guess I stand at least partly corrected. The only possibly convincing thing I can see about it is if you have things working a certain way and want to be able to repeat it, and have been using balanced tubes in a certain position, then it might provide desirable consistency. But I concur that I have never noticed a difference.

I suppose if vendors charged a LOT more for this option I might have researched it more before buying into it... but maybe they're smart that way and just nickel-and-dime it up the extra few bucks each, under the radar. :roll:

 

[stephen sawall]

Even if the tubes have the same output, balanced or not every tube has different balance of frequencies or low to high differences. I just use my ears to find what tubes work best where.

One thing is certain .... I do not know any of this and only am saying what I have read some place else. Maybe I am full of snake oil myself.
I say just use your ears when deciding what tube goes where.