Do New Preamp Tubes need to " Burn In " for a few hours

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robertkoa

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Question for Experts and Guys who have swapped a LOT of Preamp Tubes:

Do new Preamp Tubes need a few hours to Burn In to sound their best ?

A few years ago I had a Tech ( because you need to remove Circuit Board to change Tube ) replace the old Preamp Tube in my old black H@K Tubeman which I bought used and got a little narly /fuzzy in the higher gain ranges.

I hoped a JJ803s might have more headroom and clip more gradually with less Fuzz due to huge plate.

When he installed the JJ803s there was also a Fuzz sound ( different though and more constant ) after I took it home and played with it a bit in higher gain modes so was going to take it back next day and try an NOS GE but before I brought it back I decided to check one last time- BAM- fuzz was gone, very clear overdrive even high gain- and I hear much less diode clipping - more Tube.

Question- did the new Tube need to Burn In a few hours to sound Normal and optimum ? Is that normal ?

Should everyone wait a few hours before changing to a 2nd and 3rd and 4th Preamp Tube to "Make Sure" and let it burn in ?
 
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Re: Do New Preamp Tubes need to " Burn In " for a few hours

I've always just popped in the new preamp tube(s) and went...Same for trying/listening to different preamp tubes..They self bias as soon as they are introduced into the circuit.
 
Re: Do New Preamp Tubes need to " Burn In " for a few hours

robertkoa said:
Question- did the new Tube need to Burn In a few hours to sound Normal and optimum ? Is that normal ?
Click to expand...

Nope. Once you start using a valve, the clock is ticking towards the time it will die. May be soon, may be later, but will eventually happen.

That being said, the valve does not need to burn in, but may need to stabililze after turn on, which can definitely change the sound.

The power stage of your amp, in particular, will change as the amp runs after turn-on.
 
Re: Do New Preamp Tubes need to " Burn In " for a few hours

TwilightOdyssey said:
Nope. Once you start using a valve, the clock is ticking towards the time it will die. May be soon, may be later, but will eventually happen.

That being said, the valve does not need to burn in, may need to stabililze after turn on, which can definitely change the sound.

The power stage of your amp, in particular, will change as the amp runs after turn-on.
Click to expand...

As a rule a preamp tube goes microphonic before it actually wears out...Unlike power tubes..A reliable preamp tube can last many many years/hours in use.
 
Re: Do New Preamp Tubes need to " Burn In " for a few hours

STRATDELUXER97 said:
As a rule a preamp tube goes microphonic before it actually wears out...Unlike power tubes..A reliable preamp tube can last many many years/hours in use.
Click to expand...
Absolutely. But it is still entropic and every minute you have the circuit on, is another minute less on the valve's life.
 
Re: Do New Preamp Tubes need to " Burn In " for a few hours

TwilightOdyssey said:
Absolutely. But it is still entropic and every minute you have the circuit on, is another minute less on the valve's life.
Click to expand...

It's funny cause I have a set of 50s RCA 12AX7s in one of my BF Fender amps that have been in there since 1989 or so in V1 and V2...On about the third set of output tubes and this is my gigging out amp... ;o)

Higher gain circuits are surely tougher on a preamp tube though!
 
Re: Do New Preamp Tubes need to " Burn In " for a few hours

My OS JAN RCA's and GE's definitely seem to be longer-lived than my BVA and Philips Mullards ... and probably because of that very reason!
 
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