Mark IV Tubes - A few short questions...

[Shep]

JUST KIDDING!!!
There's a lot of questions
Sorry, but I really need the help and greatly appreciate it!

I have a Mark IV coming soon. Used, but only for less than a year, and 100% mint condition!

The problem is since the previous owner has been using it for about a year, I ever might or might not have to change tubes, depending on how heavily he used it.

So a few questions regarding tubes… starting with some basic ones.

1) How do I know when I need to change the tubes? Any objective indications? I’ve never owned a tube amp before, so it’s not like I can just “hear” that the tubes sound worn out and need replaced…

popping or sqealling

2) Do you guys generally let your tubes die or replace them, uh, preemptively?

as soon as anything starts to happend so it won't go complete in the middle of a gig

3) Basic question: Can you simply buy compatible tubes from ANY maker and put them into a Mark IV, or are there any adjustments that need to be made?

as long as the bais is right everything and anything will work..pre amp tubes don't need bais..

4) I read on the sticky that using GT tubes with a 4-7 rating will not void warranty. So, it follows that any other non-Mesa tube WILL void warranty? And what exactly is a 4-7 rating anyway?

bais rating .. 4 to 7 is with in mesa's range

5) Besides Mesa and Doug’s Tubes, what are some preferred retailers? Sources for NOS would be greatly appreciated to!
(Are Sylvania 6L6’s available anywhere? Or Mullard EL-34 Don’t worry, I won’t tell a soul… :wink: )

euro tube's ebay..


And now for some SPECIFIC tube questions…

Due to the board’s feedback on my previous question posts, I’ve resolved to keep the default Mesa tubes.


After some time, however, I’ll want to try different ones, so I might as well start deciding now.

By the way… the Mark IV can ONLY use four 6L6 or two 6L6 & EL-34 (outer) pairs for full functionality, right? I read something about other tubes, but then its limited to Tweed/Class A or something… Are 12AX7 the only preamp tubes it can use? I’ve read something about people using 6V6’s, 12A-something else…12AT7? 12AC7? What’s the deal with that?

it can use 6v6 and 5881's and ca7's too .. you can use the 12at7 and so on but i don't know why you would..

6) Anyway, I’m trying to decide between two configurations…
SED 6L6GC/EL34 with Tung Sol 12AX7A’s in the preamp section…
…or simply four GT 6L6-GE with GT12AX7-M’s.


Those are both good, yes? How would the EL-34’s effect my tone, though?
A few of you (Guitarzan, Platypus, etc) swear by Groove Tubes. How would this four 6L6 configuration compare to four SED 6L6GC’s?

both are good.. try them both and you will see which one you like more..
unless you are more crunch rhy than sweet lead.. you are best off with the 4 6l6

Does anyone have any corrections or alternate recommendations regarding those tube groupings I’ve chosen so far?
(Before anyone says JJ’s, I heard that they’re better for brighter/fizzier amps, and tend to suck a lot of the tone from the Mark IV, especially in the preamp section…)

they don't suck tone.. i use them in my mk Iv becase it's a brighter style amp.. sounds so smooth and sweet

I’m actually not sure about the preamp tubes at all… just picked up on the GT Mullard reissue’s from something boogiebabies said earlier…


Dunno about the Tung-Sol’s 12AX7 if I decide to go with SED 6L6 & El34 though. Is there something better? Boogiebabies says Tung-Sol’s are all marketing hype.


7) I’ve heard that V1 is by far the most important tube as far as determining sound, and the others can be viewed as “support tubes”. Is this the case? If so, would it be sufficient to put a more expensive tube in V1 and leave the rest as more affordable (but still reliable) tubes, or am I misunderstanding things?

V1 is on the whole time v2 v3 are in for different channel's..

And finally, some more technical questions… keep in mind I know NOTHING about tubes, unfortunately.

8 ) I know that Mesa utilizes fixed biasing, so their amps don’t need to be adjusted for different tubes, right?… but I don’t even know what biasing is to begin with!!! Can anyone give me an extremely condensed and un-technical explanation please?

No...

I’m also unsure about what the term “matching” refers to, in the context of tubes. that each tube is drawing the same amount of current


9) I came across something about different colors on identical Mesa tubes… something about different idle amounts… what’s that all about?


............
Well that covers almost everything. So here comes the grande finale!
A clump of vague, unsorted questions



10) As far as tubes go, any other favorites?

What do you guys think of Sovtek, Shuguang, Penta Labs, Ruby, Svetlana… etc?

cold beer!

I’ve read Russ’s recommendation for Telefunken, Mullard, RCA, RFT, Mazda gray plates, Amperex, Bugle Boy, Brimar, Tungsram, Tesla…
So many names! Some of these seem like classics, as I’ve seen dougtubes refer to certain tubes they carry being similar to this or that one, but I’ve never actually heard of these out of that context. Any information anyone can give?

they sound really good

By the way… what’s the deal with SED? Dougstubes describes their 6L6GC as “The legendary 6L6 formerly known as Svetlana. Why are they so “legendary”? I see Svetlana tubes being retailed, so what's the connection between the SED and Svetlana?

they are based off the str 415.. that's a big enough legend in it's self

And at last! Final question!

Sylvania's 6L6s are the "Holy Grails" of the 6L6s, just like Mullard EL34s are the "Holy Grails" of the EL34s.

What, then, if I may ask, is considered to be the “Holy Grail” of 12AX7/12AC7/12-WHATEVER the best ones for the preamp section are?

12A () 7 the letter is the type of gain factor it has.. the X highest.. then T U not sure after that

Once again, THANKS A LOT, guys!!!

i tried !!

 

[Tyrant]

Of course, I STRONGLY recommend a rebias when changing ANY output tubes. I use the analogy of the ouput tubes biasing as setting the gaps in your spark plugs of your car. Sure, you can just stick them in and go, but if you want peak performance, set the gaps appropriately and you'll have better gas milage and better performance.

Is this just a blanket statement or are you referring to Mesa amps and the Mark IV specifically.

 

[Storm]

I thought the Sovtek 12ax7LPS are long plates. LPS ?

They are - long plates with a spiral filament.

Ciao ...

 

[HipKitty]

Of course, I STRONGLY recommend a rebias when changing ANY output tubes. I use the analogy of the ouput tubes biasing as setting the gaps in your spark plugs of your car. Sure, you can just stick them in and go, but if you want peak performance, set the gaps appropriately and you'll have better gas milage and better performance.

Is this just a blanket statement or are you referring to Mesa amps and the Mark IV specifically.

Tyrant, yes, this is a "blanket statement" as all tube amps should be biased to their tubes...even cathode biased amps can stand to have the biasing/voltages checked and tightened up to the new tubes.

Saying this does not say that dropping in new tubes will sounds bad...to clarify, biasing gets the best performance out of the amp.

There are times when replacing tubes with new ones...more specifically, when you put new output tubes in and see what is called as "red plating" of the output tubes....the plates of the output tube(s) is/are glowing a cherry red color...in this case, if you were to continue for much longer, you will cause total tube failure...and possibly greater damage as well.