Sweetwater is showing "new" mesa tubes

[bandit2013]

I sort of wonder were the straight bottles after the coke bottle shape? Those I would assume were the predecessors to the STR440 tubes.

 

[cgscotto]

I don't know which came first. But I do know the straight bottle in the picture is prior to the coke bottle in the previous post. The straight bottle does not have the label with tube color/spec seen on the coke bottle, only a color dot. But I did have straight bottle 420s that had the later label. Wish I still had those tubes.

 

[bandit2013]

I think it was yesterday, was looking for the information on what the Mark IV power tube choices were and noticed a different STR# STR454. Any clue what those were? Never mind, I found them, they were the SED =C=6L6GC tubes.

 

[Ascendance]

This is a convoluted concept so it may be a long post:

If I understand the color codes correctly, Red has the least early gain characteristics. White has the most early gain characteristics. Considering a fixed bias amp, The reds will not get into clipping as easily as the whites. In other words, you will have more headroom with Reds vs Whites. The color codes I think run Red, Yellow, Green, Gray, Blue, White. The green and gray codes sort of fall into the middle. Not sure how much of a difference there is within the narrow band of tube gain for the fixed bias design. Another key to understand is how the tube responds to frequency. I would assume the gain response is different at lower frequencies vs higher frequencies. The STR440, STR443 are similar such that the low frequency response is much stronger than say the STR448. So when a tube with early onset of gain or tendency to clip for a given signal level is used an a bass dominant amp, it can get muddy until the signal strength of the upper frequencies gets higher in magnitude. Example, the STR440 or STR443 having the same color code would be bass dominant in the JP2C at a reduced volume. The only way to compensate for this was to use shred mode in order to get more influence on the upper frequencies. Even at gig level, it became a burden to some extent. The STR440 had an advantage over the STR443 as it seemed to reveal more upper frequencies and harmonics at gig level. Comparing that to the STR441 in the JP2C they seemed too relaxed. Not best for this amp. The STR448 on the other hand, did not follow the same frequency gain characteristic. It was more balanced. So at reduced volume the low end and upper end was at the same volume and note definition was retained. At gig level the low end bloomed as well as the rest of the frequency range such that it was an epic experience. WOW, I cannot believe what I am hearing sort of deal. Note that a Mark amp sounds best when it can get into power tube saturation and clipping. Ideal when the power tube does not have a low frequency dominance. There is plenty of low end, probably more than I expected but it is quite different than the STR440. Just a tad looser but yet just as tight. Hard to describe.

For the Roadster, that is a different amp in its entirety. More of a low end sub-harmonic generator due to the cold clipper and the following tone stack lends itself to difficult to manage when the power tubes tend to be more low-end dominant. STR440 yellow would have more headroom than the gray. Not sure how much of a difference but you can hear it. What I mean by too much, too much bottom end and the early clip effect did not provide enjoyment. More of a muddier tone and lack of definition. I did not want to push the amp with stupidly loud settings in hopes the top end would eventually be noticeable. It does not take much plate current to make a difference in characteristics. In some respects, it could be related to being more familiar with one given color code in the amp vs the other. If there was not much of a difference between the color codes, why have them in the first place? When you feel you need to dial out specific settings on the parametric tone controls (Bass, Midrange, Treble) it may be the power tube is too dominant in one particular frequency that lends itself to be undesirable. Sometimes you can compensate but sometimes you cannot. The early onset of clipping of the Grays was one of those cases for me. Yellow in the Roadster had more content without the mud. Never tried the reds though.

Im for sure grabbing some of these.

Is it ok to get non mesa branded tubes. I found just the tube amp doctor ones and thet legit $50 less.

Am I putting my amp at risk using non mesa branded tubes?
$75 after shipping and everything is nothing to sneeze at.

 

[bandit2013]

Sure it is ok to get non-Mesa branded tubes. I have used many other brands in my amps, most of the time, the warranty had expired.
The SED =C= 6L6GC and the EL34 tubes I have used did not have any Mesa logo. I did however grab up some of the SED =C= EL34 Mesa STR442 when they were available through Mesa back in 2019-2020. I also found some from Ness Tubes that were Mesa tested.

Sometimes vendors will get it right if you specify the amp the tubes will be used in. Sometimes they don't. What the early distortion characteristics of the tubes and at what bias voltage and plate current/plate voltage may matter. I found the Gold Lion KT77 tubes worked best in the Mark V90, but when used in the RA100 they were not as spectacular. On the flip side, they were also really good in the TC50. that is a wide range of plate voltages from 400VDC for the RA and 450VDC for the TC and Mark V. Then comes the MWDR and Roadster, they run a bit higher plate voltage. What would be helpful would be to state the plate voltage, current and bias voltage and what amount of early distortion you need. Not sure most vendors can define wat a grey code represents and for what amp? That is just my opinion. I am not a tube expert.

 

[JPBoogie]

Hey guys, so how are the STR 446 doing in time since you posted? Thank you

 

[bandit2013]

I only tried them in a few of my amps to get an idea how they sound. They sounded great in the Badlander. The Triple Crown did not change much in character. I have them on reserve for replacements when the tubes I am using need to be replaced. As for the RA100, did not like them, too similar to the STR447. Much prefer the SED =C=EL34 in that amp. Bummer.

 

[Joey1970]

I think it was yesterday, was looking for the information on what the Mark IV power tube choices were and noticed a different STR# STR454. Any clue what those were? Never mind, I found them, they were the SED =C=6L6GC tubes.

View attachment 2439


View attachment 2440

 

[Joey1970]

The STR-454 6L6 and STR-442 EL-34 tubes were the best since the Sylvanias, in my opinion. I bought up all the Sylvanias that I could afford, back when you could actually find them. Mainly for the life expectancy of them. Hell, that is what the early Marks were designed around.

 

[Jamme1961]

IMHO the power tubes don’t change the tone much - I just want reliable power tubes - the change in tone is in the preamp - IMHO

 

[TheSoulsRemain]

The STR-454 6L6 and STR-442 EL-34 tubes were the best since the Sylvanias, in my opinion. I bought up all the Sylvanias that I could afford, back when you could actually find them. Mainly for the life expectancy of them. Hell, that is what the early Marks were designed around.

Original Svetlana tubes