Why wont anyone post th MA reading of the Mesa power tubes?

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halebox

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Its too mysterious and makes you have to buy their tubes. Im tempted to buy one of each just to post readings so everyone can buy whatever tube they want. I have a bunch of sylvania str387 ranging from 20 ma up to 70 ma. I had one mesa 415 from 80's that seemed to read 46 ma so Ive been using in that range.
 
If you look at some of my posts, you will find some information about the mA reading of some Mesa tubes. Try searching "talltxguy roadster bias results" for some info. I also posted some info about the Lonestar and the DC-3.

I think it'd be cool if we were able to have some database that provides mA ratings for various Mesa tubes in different Mesa amps. The only thing stopping me if money. If you wanna purchase me every Mesa color code, I will gladly provide mA ratings along with plate voltages for every possible mode in the Lonestar. 8)

Good luck on the tone quest!
 
halebox said:
Its too mysterious and makes you have to buy their tubes. Im tempted to buy one of each just to post readings so everyone can buy whatever tube they want. I have a bunch of sylvania str387 ranging from 20 ma up to 70 ma. I had one mesa 415 from 80's that seemed to read 46 ma so Ive been using in that range.

The current draw of each tube will be different depending on the particular brand of tube (Mesa uses many different brands), and the particular amp in which that tube is used. It would be near impossible to rate Mesa's tubes' current in a way that would be meaningful for every Mesa amp. The readings for the tubes that you've posted above likely will not be the same if those tubes were to be installed in another amp, due to several factors, such as different Plate voltage, different bias voltage, etc. At the same time, a Mesa 6L6 will be rated such that it should work in any Mesa amp that requires a 6L6, even though there might not be a current rating on the tube, for the reasons that I just mentioned.

No mystery if you want to use brands other than Mesa, just ask the vendor for tubes rated for Mesa ________ amp, (fill in amp name). Other brands of tubes will have some kind of current rating, usually labeled on the box. However, the current rating used by other brands will almost certainly not be the actual current drawn when installed in the amp, because the current rating on the box of a tube is from some type of tube tester, or Maxi Matcher. As mentioned above, many forum members have posted the mA draw of the tubes that they use in their particular amp.

Sometimes, using other brands of tubes in your Mesa amp, can lead to the wrong conclusion about the sound of that particular tube brand due to the tube not being rated for that amp, therefore not biased right leading to poor sound.
 
Well I ordered 8 mesa 6L6GC 440's. I will put them in my Coliseum and 60 watt IIC+'s and post result. Stay tuned for the big reveal! Unless I get threatened with legal action from mesa boogie :) **** this place is a ghost town I guess I arrived too late!
 
Ok the Mesa 6L6 440's arrived and they measure at 40 MA in my 60 watt export. Was too lazy to remove chassis for Coliseum but I believe they will read similar in that amp. The Sylvania STR387 I had in there were at 45 so I guess somewhere in the 40-46 range is good for IIC+'s or at least mine
 
Here's a cross reference for Mesa colors and how they relate to Groove Tube numbers. If your tube dealer an cross reference with Groove Tube numbers (most should be able to) this will get you what you need:

Mesa vs Groove Tubes scale

Red = 4
Yellow =4
Green =5
Gray =5
Blue =6
White =6
 
Mine are yellow. The mesa tubes are an improvement in coliseum as mine were a mix of tubes before. Have not got to crank my 60 watter with the mesa tubes. At low volume they sound good just not quite deep and musical as my sylvania str387 but I cant make a judgement until I try with band
 
Joey B did some measurements a while back. Check his post on the bottom of page 1. http://forum.grailtone.com/viewtopic.php?f=16&t=16487

Here's an excerpt:

"I did some testing with the "bias-rite" hooked to a simul C+, and came to these conclusions:

The Mesa tubes that I tested, demonstrated these readings with 480 volts on the plates.

STR-440 6l6 "red" - 17 mA inner sockets
- 44 mA Class-A sockets

STR-440 6l6 "green" - 20mA inner sockets
- 50 mA Class-A sockets

STR-447 EL-34 "green" - 17 mA Class-A sockets

STR-447 EL-34 "grey" - 23 mA Class-A sockets

The color codes are assigned to pair the tubes by the amount of idle current draw. There may be other factors as well, but this is most certainly part of it. The grouping is going to be very tight with maybe only about 15 mA difference of current draw from "red" to "whte"color codes, at the most."



Hope it helps.
 
brrrrrr Those are some cold numbers......inner sockets...30% disp. at best.....look on the bright side, they should last forever.

Just buy a Probe and install the tube with the probe and if you not red plating any brand tube will work. I've seen Mesa tubes in many amps run from 20-70% disp. I do not run mesa tubes in any of my Mesa amps. I do however use some of there preamp tubes.

The probe ($100) is your life key. I have bought so called matched Mesa Tubes and other brand that are not even close. One at 30mA and the other at 20mA . Not a match duet.. Also would advise on some kind of preamp tube tester. Picked up 2 brand new Mesa 12ax7a's the other day from Mesa. Tested before putting them in. One was 100/95. Great, the other brand new in box was 79/80. I have 50 year old preamp tubes that read higher than that. While still technically useable, a new tube should never be at the min good of 80. If you did not know this, and stuck that crappy tube in V1? "Why does my amp sound so dull. Duh? Mesa makes great tubes and are hand picked because their ranges are all safe. Nothing wrong with that. The Fixed bias is like the Key to make sure you do not unlock the door.
I have tested several of my Mark series amps. Not one yet has tested to the so called 70% disp. sweet spot of any tube brand I used.
I should be receiving one of my Mark III black stripe back that I had an amp guru friend put 2 bias pots in, any day now. What if you could turn those EL 34's up to 70% and those 6L6's up to 50% in a simuclass Mark series amp. Won't hurt the amp..Tone,...We shall see...Mesa's already sound amazing with their cold fixed bias. I unlocked the door, just using a different key.
 

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