Preamp tube recommendations

[cn2667]

Im getting ready to swap out the headshell on my Nitro and figured I will change out the preamp tubes while Im at it since they havent been changed in awhile according to the former owner. What do you guys recommend?

[gtrjunior]

A preamp tube can and often does last years....and I mean decades. They are not subjected to the type of heat a power tube is.
If it ain’t broke, don’t fix it.
That said, it really depends if whether you feel you want to make some subtle tonal changes.
Do you feel that the amp needs more of something...or less etc?

[cn2667]

Not really just figured I would kill two birds with one stone.

[gtrjunior]

My opinion...
You don’t need to do anything with them.

[briman]

I change my pre amp tubes every second set of power tubes. Probably not necessary but i still do it.

[cn2667]

thanks guys!

[briman]

I used electro harmonics and Tung sols in my Splawns and loved them.

[gtrjunior]

That’s funny...I didn’t like them. Lol
I thought they were too bright.

[splawndude]

Never played a Nitro but I'll give you some of my standard advice that you can do with what you want.


Don't change preamp tubes unless you need to (or you want to alter your tone).
Don't buy into snake oil stuff.
If you have money to buy preamp tubes for the sake of it - buy NOS
If you have money to buy preamp tubes and you gig then you'll need spares anyway
If you buy NOS - play around with some Telefunkens, RFTs, Phillips, RCA, stuff like that
Do yourself a favor and just leave the back panel off the amp. That way you can see, test and replace at any time.
Do clean/lube tube pins with electrical contact cleaner
Test your tubes with a pencil eraser end and tap with the amp turned up. Can you hear the tapping through the speaker?
If so - replace

I like JJ's and I really like the NOS 5751 alt replacement preamp tube in V1 or PI. Usually PI.

[gtrjunior]

I will add that the tubes that are your gain stages (V1/2) you will hear noise come through when you tap. That is normal. But if it makes a pinging sound or other high pitched sound that usually indicates a microphonic tube and needs to be replaced.



This is just my experience, but in the 20 or so years that I have owned tube amps I have only ever had 1 preamp tube fail on me.
That was in my JVM cathode follower position which is notorious for blowing out tubes if you put the wrong one in there.
That slot has a slightly higher voltage than the other preamp slots and it needs a tube that can handle it. I didn’t know that at the time and put the wrong tube in and poof....but the Splawn doesn’t use a CF in its design so nothing to worry about with our amps.

[briman]

Dec 29, 2018 17:17:08 GMT -5 gtrjunior said:

That’s funny...I didn’t like them. Lol
I thought they were too bright.

Yeah they were bright but very articulate and dynamic which i love. I just dialed down the brightness with splawn eq.

[splawndude]

I did the tap test on my preamp tubes yesterday and did not hear the tapping through my speaker. I could here it from the tube itself yes, but never through the speaker. It is of my opinion that if it is doing that then it is going microphonic. It may not be to a point where it bothers you or creates extra noises but all the same.

Also, I have had microphonic tubes because they are picking up radio stations.

Power tubes can also go microphonic, although that is much more rare. I actually believe my old Mullards are heading this way because I am getting some 'pingy' 'springy' type sounds. Probably tiny metal filaments in the tube that have broken loose and are now vibrating. Shame cause those were some of my favorite tubes.

I find EXH and Tung Sols too bright for me but I can see why people like them. I actually just bought a few brand new ones along with some Groove Tube 12AX7s as well because I had a $100 Guitar Center Gift Card and that is all they carry.

[gtrjunior]

When I first got my QR, I remember having some sort of issue that I emailed Scott about. It had something to do with preamp tubes.
I recall him saying something to the effect of some noise coming through during the tap test being normal for the tubes in the gain stages since this is where the signal is being amplified.

Now, what I really don’t remember is if at that time I had rolled my NOS tubes into the amp. That may be why I heard more noise than Splawndude.
You guys might remember that I had quite a time learning to get the amp to do what I was looking for it to do when I first got it. So there’s a good chance that some of my NOS tubes are microphonic and I never knew it.

Right now, I’m back to the stock preamp tubes again and I’m loving the results. I haven’t done the tap test on these tubes so who knows, these might be silent in comparison.

[splawndude]

IMO - it will be super noticeable. Pretty prominent. Safe to say, if you do hear it - you probably want to replace it and mark the old one with an 'M' or something. Meaning, you could take it to a gig as a spare but not to use it otherwise.

[gtrjunior]

Next time I take the back panel off I’ll check again.