Amp gurus...do preamp tube covers change an amps sound/tone?

  • Thread starter Thread starter Gooseman
  • Start date Start date
I am surprised there are no You tube videos on this.

I like Crystal or Titanium tube covers best. They are the best sounding.
 
whatever bro take your covers off you're right it makes all the difference,
 
Well I finally tried this on my Friedman Plexi and Dave your right it does change the tone when I remove the tube covers. Better?....worse?.....not sure, but the amp's tone definately became brighter, slightly louder, and in your face. Pretty cool. :rock:
 
All I can say is if you have been loud guitar for 20 -30 years there is no way you could hear that difference. Put it this way. My vintage 30`s sound like greenbacks. Ya know why? Because my amps are on 2-3 o`clock. Anybody that claims they can here all these little nuanses still has their hearing. ;)
 
Pickup":10xszl6r said:
All I can say is if you have been loud guitar for 20 -30 years there is no way you could hear that difference. Put it this way. My vintage 30`s sound like greenbacks. Ya know why? Because my amps are on 2-3 o`clock. Anybody that claims they can here all these little nuanses still has their hearing. ;)
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Did you try it? I was skeptical too, and I've got 30+ (yikes) years in.
 
I would have to try it in reverse. My preamp covers were gone years ago.
 
Hey everybody!

Did you know that electrons and photons behave differently when you observe them! Isn't that neat! When you're not looking they act as a wave. When you're staring 'em down, they behave as a particle! Supercool! So, next time you're playing your guitar and rocking out to some Poison or Gwar, take a peep at your preamp tubes and those totally rad (lol get the pun? rad...) electrons in your tubes will no longer be waves, they'll be particles. And that will change the sweet sweet tone of ur amps!

Thanks, quantum mechanics and particle-wave theory! You're awesome! Also a quick shout-out to my bro, Erwin Schrödinger.

So, go ahead and play peek-a-boo with your amp. I can hear the difference. Can you!?
 
Okay, so let's get this straight.

- It's not perceivable with Vintage 30's.
- It's not perceivable by anyone with less than "sensitive" ears...
- It's most perceivable on really old Marshalls...
- Everyone who thus far in this thread swears they hear a difference are people who tried it because someone else said it makes a difference, hence they had an expectation.

I've yet to see someone who said "Man my amp was sounding different, and I could not, for the life of me, figure out why. I did some investigating and come to find out, I forgot to put the tube covers back on! lulz". :lol: :LOL:
 
MississippiMetal":2fzvvqow said:
Okay, so let's get this straight.

- It's not perceivable with Vintage 30's.
- It's not perceivable by anyone with less than "sensitive" ears...
- It's most perceivable on really old Marshalls...
- Everyone who thus far in this thread swears they hear a difference are people who tried it because someone else said it makes a difference, hence they had an expectation.

I've yet to see someone who said "Man my amp was sounding different, and I could not, for the life of me, figure out why. I did some investigating and come to find out, I forgot to put the tube covers back on! lulz". :lol: :LOL:
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:) Power of suggestion maybe .... I say we need a blind test. May be best to have the subject not be a guitar player and have decent hearing. Large amount of subjects and samples to get a valid conclusion.
 
Christ almighty, as soon as I can get an amp cranked in the next few hours I'll do some clips to settle this once and for all.
I'll even overlay some spectrum analyzer screen shots to show that it doesn't make a difference tone wise.

I'll do one of my companies amps, a 5150, a SLO, and a Valve Jr just to see if a specific amp makes a difference.
 
psychodave":1vejablm said:
wolfeman28":1vejablm said:
Christ almighty, as soon as I can get an amp cranked in the next few hours I'll do some clips to settle this once and for all.
I'll even overlay some spectrum analyzer screen shots to show that it doesn't make a difference tone wise.

I'll do one of my companies amps, a 5150, a SLO, and a Valve Jr just to see if a specific amp makes a difference.
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You have already shown a bias (and conclusion) that you don't believe it based on this sentence " I'll even overlay some spectrum analyzer screen shots to show that it doesn't make a difference tone wise."

FWIW, the 5150 doesn't have individual preamp tube covers so I expect no change. I am not sure about the Valve Jr's size either...

I do find it entertaining to see the doubters comments... Little by little people try it and are shocked they actually hear changes. :thumbsup:
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My 5150 does have preamp tube covers. Maybe I should have been more specific as to what 5150 I had.
I wouldn't say I'm biased, I like to do experiments and get proven wrong. So I will do it scientifically, and if it does make a difference I'll openly admit it.

But I doubt it will.
 
Here you go. https://dl.dropbox.com/u/2033066/Preamp% ... 20Test.zip

Tested 4 amps I have here, all of which have covers on the preamp tubes that I could remove.

I used a test DI track, and ran it into all 4 amps. Once with the covers on, and once with them off. Cab and mic position stayed the same throughout the test. I just simply switched the cables to the next amp between tests.

After the recordings, I put the files through Blue Cat's Analyzer plugin, which allows you to layer them and turn down the transparency, so you can see both graphs on top of each other.

Guys, it doesn't make a difference weather you have the covers on or not.

I went ahead and circled(in red) the 'slight' differences on the pics. They were all on the low end of the spectrum, which would have been different no matter how many times I ran the DI through the amps.

Otherwise, there is absolutely no difference between the 2. Don't believe me? Use the DI and do the test yourself.


But hey, if the mojo of the covers helps you play better, then do as you will. I will personally keep mine on, I like the idea of my tubes not coming loose. And at least in a V1 tube, the spring pressure seems to help keep the microphonics down.
 
I can do the test with a Marshall too, it won't be any different of a result though :-)
 
Hmmm.....I've got nothing to say regarding this subject. I just felt the need to say that. :thumbsup:
 
Preamp tube covers are aluminum/metal. It conducts heat away from the tube. Glass and air are insulators. That's why covers are made of a conductive material. Preamp tubes will run cooler with the covers on.

And yes, tubes do have varying characteristics based on heat. You can see them in most data sheets. I think most hot tubes run a little gainier.

An amp left on for a long time might mellow out a little due to a number of characteristics of components changing with heat.

It probably doesn't matter in the slightest, but a good ear could detect it. I'm sure.
 
srinivassa":c2154olc said:
Preamp tube covers are aluminum/metal. It conducts heat away from the tube. Glass and air are insulators. That's why covers are made of a conductive material. Preamp tubes will run cooler with the covers on.

And yes, tubes do have varying characteristics based on heat. You can see them in most data sheets. I think most hot tubes run a little gainier.

An amp left on for a long time might mellow out a little due to a number of characteristics of components changing with heat.

It probably doesn't matter in the slightest, but a good ear could detect it. I'm sure.
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So a good ear can detect it, but a Fast Fourier Transform or spectrum analyzer can not? That's some ears you must have...
 
I can tell a difference in my amp with the preamp tube covers on and off primarily on the V1 tube. The Tung sol in my combo amp is just barely microphonic and with the cover on, the extra noise that's produced by a slightly microphonic tube is diminished because it's not being jarred around by my 2x 12 speakers. So yes, there can be a noticeable difference.
 
fast fourier transform is a method of spectral analization using a sample frequency and applying limits dealing with nyquist rates. FFT = spectral analysis. spectrum analyzers were originally designed using bandpass filters.

if you dont know what the term is, you probably should not be using it :)
 
Actually in my experience, frequency analyzers are pretty next to useless when it comes to decision making. You could have two very audibly different guitar tones and they both look the same or very similar through an analyzer. When we start talking about little tweaker splitting hair stuff like this that is tough for your ear to hear, you'd be wasting your time looking at an analyzer. If it makes enough of a difference to you that it makes you want to pick up your guitar and play more then it's a good change. There are some things that I can clearly hear in person when playing my guitar, but set up a mic and the difference is gone. It's just the way things are, don't fight it.
 
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