Pre and Poweramp Tubes

[Essatic]

Hey Ibreathemusic.com

I'm currently changing tubes in my Lee Jackson XLS-500 head.
As of preamp tubes, I'm picking Tesla 12ax7, adviced by a guitartechnician.

But I'm doubting about poweramp-tubes. I've been using 6L6 tubes, because I like those tight high gain distortions.
Which brand would you guys advice?

Is it possible to give the amp more output volume by picking another brand?

Is there a difference between 5881 tubes and 6L6 tubes?

Thanks

Essatic

[EricV]

Hi again...
well, the 12AX7a are a good choice, they are used a lot and I think if you get good ones ( there are differences in quality and sound ), they will really fit well with the amp.
I used 12AX7As in the Lee Jackson-Marshall, BTW.

About poweramp tubes: they surely do influence the general sound of the amp. Marshalls i.e. are based on EL34s, which are partly responsible for the overall "Marshall-sound".
There are several different definitions of the sound of tube-models, and it also depends on the amp itself. But 6L6´s to me usually sound quite sweet and warm, while EL34s add a bit more of a raunchy, dirty character to the sound.
One special thing that some players do when using amps with all 6L6-tubes, like i.e. the Boogie Mark IV:
They have them replaced by a good amp-tech... replaced with a MIX of EL34s and 5881s. This HAS to be done by a tech, because the amp has to be set up for the different tubes to avoid damage and make sure that the tubes are used to their full potential.
A lot of the studio guys in LA had this done to their Boogies, and I tried it myself... I brought my Mark IV to a small store in NJ, and they set it up and put in 2 EL34s and 2 5881s.
I can tell you, that was a good decision. The amp sounded way better afterwards, a bit more agressive and "smokey" ;)
This is just one example, and maybe you should think about just replacing the 6L6 tubes with either EL34s or 5881s... those are the most common changes about poweramp tubes.
I think to have this done you should already contact one of the guitar techs from that list you got from Jason, because changing poweramp-tubes is something that should be done by / with the assistance of an experienced amp tech.
He might have to re-bias the amp or slightly modify the poweramp-section to set up the amp for the new set of tubes.
Get in touch with one and ask him what he would recommend...
Hope this helps
Eric

[Essatic]

Hey eric,

Sure I know about biasing your amp (I won't fry my tubes!) . And I always let it do by a good technician. I've read a method on the web, how you can do it yourself, but to be honnest... I prefer the scope method done by my technician. Actually there is a switch on my lee jackson, which have to be switched if you use El34 tubes instead of 6L6. So you don't need to rebias your amp.
But biasing your amp every year while changing tubes isn't a bad idea. I'v read that those 5881 tubes only have 70% of the output of a 6L6 tube. So I'll stick with 6L6. Thanx for your opinion anyway!

I'm currently reading a lot on amps, because being a guitarist, you should know your gear well. Can you imagine, once i saw a concert of a metalband with a good guitarplayer. In the middle of the show he broke a string, but didn't know how to replace them!!! It was a lo pro edge trem, so when you think of it... only 5min work! :(

[EricV]

Hi...

Sorry, I didnt mean to come over like a smart-a**, I was pretty sure you know about biasing and stuff. It´s just something I included for other members to read... after all it´s kind of a public conversation we´re having here :p

It´s good that you´re learning about fixing and maintaining gear, I agree and believe it´s something a player should know about... It´s something I include into my lessons too.
A lot of guitar techs at guitar stores are doing a good job but sometimes charge a lot of money for a job that the customer could do himself.
I mean, it sure is a good idea to let an experienced tech do some things ( like refretting, routing etc. ), but I also think that it is a good idea for a player to know how to adjust the intonation of his / her guitar, maintain and clean his / her guitar the right way, maybe how to change the action ( height ) of the strings, how to exchange pickups and all that.
I might be too picky about it, but I think it´s good to take care of your instrument, clean it, do maintenance work on your fretboard, the electronics and things like the whammy...

Your example is a good one. Another one would be about the guitar player who tried to raise the string action on his FR-equipped guitar without asking how to do that... he adjusted the knife edge-screws himself without detuning the strings and thereby kinda "stripped" or rather "filed down" those screws and the knife edges of the vibrato system.
There should be ( maybe there is ) a site or book with all the important advice on how to maintain and take care of your guitars and amps... stuff like how to be careful about exposing your guitar to extreme temperature- or humidity changes, or how to make sure your amp and amp tubes last longer etc...
If anyone would like to add book- or site recommendations... go ahead ! ;)
Warm regards
Eric

NP: King´s X- Tapehead

[Essatic]

lol Eric,

Yes indeed, there should be an article about how to maintain and fix gear... I know some guy at Ibreathe.com who could do a great job on this topic... hint hint! lol


Greetz Essatic

np.. symphony x - the relic

[EricV]

Hi Essatic,

OK, I´ll think about it and will then ask the dude ;)
I´m sure he wouldn´t mind writing something about it and finds the time to do so... :D
Thanks & warm regards
Eric

[Essatic]

Just something i wanted to share with the other visitors... I found an article concerning tubes and the difference between them.


6L6-This is a hard vacuum tube and be described as "hard hitting". They have decent harmonic content and are great for guitar amps. They also last for a while. Mesa uses these for the Rectifier series of amplifiers. Expect 40 to 60 watts out of a pair.

5881-A variant of the 6L6, slightly lower output.

EL34-These tubes have a soft vacuum. This is the sound of countless recordings. Think AC/DC, Van Halen, Hendrix. Marshall uses these tubes, for the most part. Expect 20 to 40 watts out of a pair.

6550-These tubes can be found in quite a few Marshalls. A bit harder hitting than 6L6 types. These can last a long time, especially the N.O.S. (New Old Stock). Expect 40 to 70 watts out of a pair. Not used much in guitar amps.

EL84-These are a 9 pin miniauture type power tube. Very similar in sound to an EL34. If run hard, they can be short lived. These are used in quite a few of the lower wattage combo amps. Expect 10 to 25watts out of a pair.

6V6-These can be found in some of the Fenders. Similar to the

EL84, but have a cleaner sound. Could be described as "bluesy". Expect around the same power from a pair as EL84's.

[Guni]

Thx Essatic.

Very nice summary.

NP: Wynton Marsalis - "Marsalis Standard Time"

[EricV]

Originally posted by Essatic
Just something i wanted to share with the other visitors... I found an article concerning tubes and the difference between them.

Hey, that´s cool... it´s a nice summary, thanks for putting it here. I would just like to add one little thing...


[i]6L6-This is a hard vacuum tube and be described as "hard hitting". They have decent harmonic content and are great for guitar amps. They also last for a while. Mesa uses these for the Rectifier series of amplifiers. Expect 40 to 60 watts out of a pair. [/B]
...as I mentioned above, it depends on what amp the tubes are put in. Although the 6L6 tubes are featured in the Rectifier ( and that combination really fits the term "hard hitting" *grin ), they are also used in the Mark IV, and there, they sounded rather sweet, silky, warm ( dontcha just love describing sounds with terms like that ?!? ).
And I installed the aforementioned combination of EL34s and 5881s to get a rougher, raunchier, more agressive sound...

Oh yeah, and it also makes a difference where the tubes were produced... depending on their country of origin, some of the tubes react different, last longer etc... There are tubes from Germany, Yugoslavia, China, and when purchasing tubes, many tube-fanatics pay attention to what country the tubes were made in...
Warm regards
Eric

NP: Vince Neil- X-Posed ( Guitars: Steve Stevens )

[szulc]

Vacuum Tubes

The most desirable preamp tube is the TELEFUNKEN these are rare and expensive, but have the best signal to noise ratio.

Power Amp tubes

The design of your amplifier really plays a greater role in the sound that the actual output tube does.
Class 'A' amplifiers have the cleanest reproduction, not necessarily the most desirable for distorted guitar. I believe the origanal Vox AC 30 is class 'A'.

This design usually has one set of tubes all on the same side of the center tap of an output transformer. Each tube generates the entire waveform both the top (positive) and bottom (negative) parts of the signal.

These are less efficent than the Class 'AB' amplifers which generate more power (Watts) with the same amout of tubes.

The Class 'AB' push-pull design is by far the most common, this type is found in most fenders and Marshalls and the amps which have been based on these.
In this circuit the wave form is split into the poistive and negative portions an then one set of tubes (on one side of the transformer center tap) reproduces the positve side while the other set of tubes (on the other side of the transformer center tap)reproduces the negative side.

Biasing and Balancing are critical here to eliminate crossover distiortion, this is really determining where each side quits and the other side picks up the ball. If there is a gap the signal is severly distorted if ther is overlap the signal can also be severely distorted.

After having worked on modified and built tube guitar amps for over 20 years , I believe the class 'AB' is well suited to distorted guitar partly because of the phase splitter circuit itself ( usually a 12AX7 or a 12AT7 in fenders. This is usually where the feedback signal (from the transformers speaker side) is remixed with the original signal. The design of this feed back determines the damping factor of the amp and also the 'Presence" control function.

Mesa Boogie make 'Simul Class ' amplifers that have coumpund transformers that allow one set of output tubes to operate in Class 'A' and the other to operate in Class 'AB'

A great deal of power in a guitar amp is not necessary these days since unless you are playing large venues you will be using only a few watts.