how a TUBE can affect ur amps tone!

[nero1985]

i have a Marshal AVT150 wich works with a single ECC83, now ive been reading a lot of reviews and everybody that has this amp has changed the tube for a Groove Tubes ECC83 (erupean made, they have a ECC83 and a 12AX7 model ECC83 for more of an european tone and 12AX7 for more of a american tone) so everybody says change this tube gave their amp a lot of power and tone!

is a tube that important on a ciruit? i mean i know they are like the heart of the circuit but how can ecery tube have a different tone to it?? some say are clean and rounded, some are dirtty and powerfull, it just amazes me that a LIGHT BULB that do so much for our guitar tone, i gotta try this im gonna change my tube ASAP how hard can it be? just replacing a tube, my amp seems to have a Socket for the tube so it shouldnt be that hard, is there any info online o how to do this?

thanks!

[Hal]

a tube is an amplefying device, like a transistor.  The character of the amplefied sound has to do with the tube...the gian of the tube, the frequency responce, the saturation points, etc etc etc...

its more than a light bulb.

for a preamp tube, a simple plug and swap should be sufficent.

[wampcat1]

I'd also add that changing one preamp tube probably won't make a dramatic difference -- changing preamp and power tubes as a whole will, though IMO.

Take care,
Brian

[JimRayden]

i have a Marshal AVT150 wich works with a single ECC83, now ive been reading a lot of reviews and everybody that has this amp has changed the tube for a Groove Tubes ECC83 (erupean made, they have a ECC83 and a 12AX7 model ECC83 for more of an european tone and 12AX7 for more of a american tone) so everybody says change this tube gave their amp a lot of power and tone!

is a tube that important on a ciruit? i mean i know they are like the heart of the circuit but how can ecery tube have a different tone to it?? some say are clean and rounded, some are dirtty and powerfull, it just amazes me that a LIGHT BULB that do so much for our guitar tone, i gotta try this im gonna change my tube ASAP how hard can it be? just replacing a tube, my amp seems to have a Socket for the tube so it shouldnt be that hard, is there any info online o how to do this?

thanks!

First of all, there are no "european" or "american" tone differnces. The ECC83 and 12AX7 are just different code systems referring to the same tube. Although search for 12AY7 or ECC81 tubes for less gain (although I don't think a Marshall amp owner would want to do that.)

A tube has to have a heater filament (quite like a light bulb) and a glass envelope to create the correct working condition for the amplifier system inside. And I should mention, it's impolite to call it a light bulb. Anyway, people usually swap tubes because the japanese stock tubes are usually low quality and better tubes have improved tone. The change of tone are slight, but it does sound better.

The clean tube tones are sure clean and rounded, and when you crank it, the tube turns into a dirty monster. 

Tubes are cool thingies to have fun with. But a bit more expensive than your average $0.25 transistors.

----------
Jimbo

[Peter Snowberg]

The internal construction of a tube can make a huge difference in the output. I have a wide variety of "12AX7" tubes with radically different plate sizes and that factor seems to contribute to a character that I would call "fullness"... sorry to go a little audiophool. 

I have a Marshall Valvesate and when I replaced the stock tube with an Ei ECC83, the tone improved in the overdrive channel by a huge amount.

I did lots of tube swapping in a Fender Super Reverb while a friends's band played. The differences were much more that I would have expected. I've also built a whole bunch of little amps with reverb transformers for OTs and the differences in tubes there huge as well.

Tone differences between different 12AX7s are as varied as internal resistances of assorted JFETs. They're all over the map and then some. There is no "tube tone" as far as I'm concerned. Some tubes do sound downright bad and make transistors sound fantastic by comparison.

[bwanasonic]

I'm not real familiar with the architecture of the amp in question, but in general it's a good learning experience to experiment with not only tube brands, but tube types as well. Depending on how the tube functions within a circuit, lower gain types (5751, 12AT7, 12AU7) can yield good results. Changing one preamp tube can make a fairly drastic difference, at least in some all tube amp designs. It's a fun little science experiment, so try a few different ones if you can. The only down side for me was, once I started experimenting with NOS, I realized current productions tubes are mere shadows of what tubes once were.  I once salvaged 30+ year old used tubes, from a console stereo I found in the trash, and they still shame any current production tubes I've tried, even after serving more than a year in my amp. I wouldn't underestimate the power of the *lowly* lightbulb ! 

Kerry M

[wampcat1]

I have a Marshall Valvesate and when I replaced the stock tube with an Ei ECC83, the tone improved in the overdrive channel by a huge amount.

Wow...I wouldn've never thought!
I learn something new every day I guess.

Take care,
Brian

[nero1985]

hehehe yeah i just call it light bulb cuz thats wat it looks like but trust i RESPECT them alot! those things are the heart of pretty all those Great guitar tones ive heard in my life! from Hendrix to MAY to EDDIE VH to SLASH

i actually just bought a 12AX7R from Groove Tubes, they told me the R is for Russian Made,, how good are this tubes, i wont get to change it until i pick up my amp from the studio tomorrow

how hard is it to change a tube? like changing a light bulb?!?!?!?!?!

[Hal]

how hard is it to change a tube? like changing a light bulb?!?!?!?!?!

yea, just unscrew it.

you need to BIAS some tubes.  Like power amp tubes.  Your preamp tube should be good to go though.

[octafish]

DON'T UNSCREW IT!!!!!!!!!
Tubes have pins coming out the base. You pull then out and push them in.
I'm a nervous nellie and I only ever hold them with a clean cloth. If you leave fingerprints on a high wattage light bulb, like in a studio flash head or tungsten photographic lights, then the grease in your fingerprints can cause the globes to explode. Probably wouldn't happen with a tube but I'm not running any risks.

[JimRayden]

how hard is it to change a tube? like changing a light bulb?!?!?!?!?!

yea, just unscrew it.

DON'T UNSCREW IT!!!!!!!!!

LOL, this is some funny stuff... the guys at ax84 would get a good laugh.

Yeah, you'll have to pull it out and just push the new one in. Screwing a tube would most propably bend the pins beyond recognition. Repetitive screwing will make them brake off. 

---------
Jimbo

[bwanasonic]

Repetitive screwing will make them brake off. 

And that's where mini-tubes come from son...

Kerry M

[gaussmarkov]

Repetitive screwing will make them brake off. 

And that's where mini-tubes come from son...

Kerry M

lol

[brett]

I have a wide variety of "12AX7" tubes with radically different plate sizes and that factor seems to contribute to a character that I would call "fullness"...

That's interesting.  Large/long plates are usually a fairly bad idea in guitar amps coz they suffer more from microphonics.
The comment about the Ei tube is interesting, too.  Ei would usually be regarded as an average quality tube, so maybe it was replacing a bad/old sovtek or something.
The Groove Tubes "R" tube comes from one of the two Russian factories (probably the Reflector factory).  They are ok quality tubes.
In my experience, the tubes that really get people excited, like Mullards, Amperex and Brimars, sometimes sound good, but if they are used, often have problems with microphonics or low or uneven gain (for the twin triodes).

Reducing gain by going for a 12AT7 or even a 12AU7/12AY7 was mentioned (A 12AT7 has an amplification factor of about 65, compared with 90 for a 12AX7 (these figures from memory)).  Another otion is to increase gain by going for a Sovtek 12AX7WB.  They have 5 to 10% more gain than a standard 12AX7. 
There's really too much nonsense spoken about tubes to go into it all here (importance of matching/ how to bias and how "hot"?, etc).  RG has a good tube FAQ thingy over at geofex.com.

For sure you can have some fun with them, but don't expect your Valvestate to turn into a Plexi.

cheers
PS If anybody wants some of the best preamp tubes ever built, I have 4 UNUSED Mullard ECC88/01s.  Perfect match (about 1%) from triode to triode and tube to tube.  US$150 per pair plus postage and insurance.  You can check these tubes at www.tubeworld.com

[Alex C]

I have a (non-AVT) Marshall Valvestate (which I haven't used since upgrading, other than to mess around with stereo effects), and changing the preamp tube didn't seem to do much of anything.  At the time, this was my only amp, so I wanted to hear a change.  Mine was a VS265R combo, if that matters, although I'm pretty sure the preamp is the same in all VS models (Peter, I'm assuming you mean the older VS series, not AVT).

[petemoore]

 I came upon a sprung tube holder, and it was then simply screwed into the wood inside. A good Spare 12ax7 preamp tube is a good idea to have around if you're going to be using one, as a reference.
  I've tried changing to 'new' tubes, also different brands of tubes, except for the old Plexi that had {I would guess were still good} "Marshall tubes.
  I notice a big difference in types of pre and mainly output tubes, [seems like 12ax7 dominates most preamp tube type choices] like types of speakers.