Myth ore truth tube swapping Guitar Amp.

the signal goes through tubes in almost every guitar amp ever made

Speakers was clear to me because I played different ones.
About the tube bias I heard the first time when the tube swapping thing came to my mind.
I will ask my tech about it.

Speaker upgrade is the next step for my sweet little amp.
Thinking also about to change the OT for more headroom, lesser load on the primary.

EVERYTHING sounds different. 12AX7 is usually the first stage, so it's effects are amplified by subsequent stages; you hear it's imprint the most in many cases because of it. Most amp guys keep a variety of tubes around and can be known to swap them on the fly depending on the gig at hand. They lose strength over long periods of time and sound different too, sometimes the worn-in tube is the one that wins. Noise is a different question, that's generally a crap shoot with too many variables to call a trend.

Wiz, what were your preferences after trying all those variables?

My favorite pornstar!

Cool I was about to buy another amp but now this little thing rocks.
SRV is still alive, his advise to swap a 12AX7 with a 5751 did exactly what he said.

The amp now stays longer clean, I can control the distortion way better with my pick.
If I want to stay clean I get thick and open tone... think Wind Cries Mary, or Lenny.
The amp noise is reduced by 50% - this is great for tracking.

If you have an Bugera-Vintage 5 and you think this China-Amp sucks because of its distortions... do the tube swap and save yourself some money.
With my pedals I now can have a lot of tones without leaving my writing mixing environment.

It was exactly my aim because of my left leg problem..... no more walking.

The best 28 Euros I ever spend for anything in the studio.

Believe it or Not (TM) capacitors, transformers, or any other component can be just as substantial as tubes in the grand scheme. Believe it or not it all makes a difference, it all matters. It's something to pay attention to, or not, at your own peril. But it's all good fun, too.

I spend a good amount of play time rolling different tubes when I get a new amp. But, it's like cooking--it's a total recipe, not like "here's the magical 5751 so now it's all better"--I like them, but they just change the gain structure--some amps benefit more than others....and a GOOD 12at7 or ax7 will beat a shitty 5751 most days of the week. And some amps benefit from NOS tubes more than others....some are engineered with the assumption of new production tubes and their "sound"....so, there's no myth--unless the myth is that it's as simple as good and bad tubes....or whatever--it matters what guitar/pickups are interacting with the v1 tube--it's all a trial and error to a large degree.

What I WILL say is that at this point in my guitar playing life--some 30 years in or so....I can drop a Royer in front of my amps and hit record--and do next to nothing to achieve the recorded sound I want. This is due in large part to years of whittling down to what amps and pickups and guitars and tubes and pedals and whatever that get the sound I want at the source.

Conversely, can a "dark cap" be put in to make a bright amp more tame? I'm thinking of some of the Dr. Z amps I own are a little TOO bright.