Anyone mix 6L6s and 5881s...or am I nuts?

[igfraso]

says right in the manual, you can replace all 4 6l6s with 4 5881s, or run them on the outer sockets (class A) with 6l6s in the middle 2

I have checked every manual from Mark I to Mark V and I haven't found anything suggesting to run the STR-425 on the outer pair.
Maybe I have overlooked that paragraph
Where did you read that?
Thanks in advance
Daniel

 

[dodger916]

says right in the manual, you can replace all 4 6l6s with 4 5881s, or run them on the outer sockets (class A) with 6l6s in the middle 2

I have checked every manual from Mark I to Mark V and I haven't found anything suggesting to run the STR-425 on the outer pair.
Maybe I have overlooked that paragraph
Where did you read that?
Thanks in advance
Daniel

Check the tube task chart on Page 20 of the printed manual. That portion of the page in the on-line manual is cut-off!

Check this too: http://www.mesaboogie.com/Product_Info/TubeReference/TubeSalesReferenceGuide-11-10-08.pdf

 

[dodger916]

says right in the manual, you can replace all 4 6l6s with 4 5881s, or run them on the outer sockets (class A) with 6l6s in the middle 2

Thanks. That portion is cut off in the on-line manual, but it's in the printed manual!

 

[igfraso]

For some time the only 6L6 you could buy from Mesa was the STR-430 which was a Sovtek 5881 WXT.
The basic difference from the STR-425 was a taller base. Both the 425 and 430 are a 30W tube and are safe to run
in Simul's, 60's and 60/100's, The difference between NOS 6L6WB's or Tung Sol's is they were a true 25 watt tube.
With these, the plate voltage is not a huge concern nor is the IIC+ bias. The real issue would be what power transformer you have.
For a 105 you may not get the lifespan with up to 493V, but with a 100, X100 or X101 you will have a much lower plate voltage around 440V
much like the MK IV.

Hi Ed!
I have a II-A (5/79) with a 100 transformer. It is a huge one and it is difficult to read the stamp on it.
If I read correctly, it says: 100-162318, CSA TEST, 606-825.

Of course, no SimulClass for II-A's. I have been using 2 STR-425 in the inner sockets and 2 x 6L6 in the outer ones.

Fronzil says that MESA STR-425 (5881) can be used only in the outer sockets where they will be safer and that this is the recommendation given in the written manual of the Mark IV-A.

I understood that the inner pair is the safer place in a 60/100 watter and, if you have tubes that are not that strong, that is the place to put them.

Following that logic, I placed my MESA STR-425 in the inner pair and they sound very well.

Should I put them in the outer sockets? Or should I remove them from the amp and never use them again unless I use a quad of STR-425?

Thank you in advance!
Daniel

 

[igfraso]

Ed,
maybe you can give some precious advice here.

I understood that the inner pair is the safer place in a 60/100 watter and, if you have tubes that are not that strong, that is the place to put them.

Following that logic, I placed my MESA STR-425 in the inner pair and they sound very well.

Should I put them in the outer sockets? Or should I remove them from the amp and never use them again unless I use a quad of STR-425?
Best regards
daniel

 

[dodger916]

The Mark IV manual says you can run them in either the outer sockets or all 4 sockets.

I received my duet and have them in the Class A's. Early results are very favorable combined with STR 430s in the inner sockets.

 

[SonicProvocateur]

I took out my 5881's today and put my EH 6L6GCs back in today. I gotta say, as a personal preference, I'm still much more satisfied with the higher gains and depth of tones. I also notices for some reason, the 5881's seemed to have less upper midrange presence, and the blending of treble was different (less to my liking, IMO). For my genre, the 5881's turned my settings from "ultra-kill" to "super-crunch". Kinda a disapointment as the tubes got more and more hours on them. I was beginning to think my Mesa was getting sick.

I also changed out V2 from a dying Mesa to a Sovtek for more gain color and that rolled of the treble some and seemed to help. V1 is a Mesa, V3 and V4 are Mesa 7025's.

Clean tones are still remarkably similar, but my amp settings are designed for ultra-gain.

Id say for any genre other than death metal, this tube is a perfectly great tube though! I'm definitely keeping mine for spares. Has a great Van Halen sound with my settings!

 

[Boogiebabies]

Ed,
maybe you can give some precious advice here.

I understood that the inner pair is the safer place in a 60/100 watter and, if you have tubes that are not that strong, that is the place to put them.

Following that logic, I placed my MESA STR-425 in the inner pair and they sound very well.

Should I put them in the outer sockets? Or should I remove them from the amp and never use them again unless I use a quad of STR-425?
Best regards
daniel

The inner outer issue is only for Simul Class amps. They run different bias voltages and the outer pair is hotter.
In a 60/100 the bias is the same across all four. Most people opt for matched quads of the same tube as they will draw the same
bias and have the same natural current draw. Now, that is what most people do, but i've seen a guys have four different 6L6's
in a IIB and it still sounded great. The question in choosing tubes for a push-pull 100W is difficult to really answer because
a lot of people swear by matched quads only, but their is sometimes a little black magic in a slight mismatch.
The safe answer is to have all four of thew same tube type and color code.

 

[Boogiebabies]

I took out my 5881's today and put my EH 6L6GCs back in today. I gotta say, as a personal preference, I'm still much more satisfied with the higher gains and depth of tones. I also notices for some reason, the 5881's seemed to have less upper midrange presence, and the blending of treble was different (less to my liking, IMO). For my genre, the 5881's turned my settings from "ultra-kill" to "super-crunch". Kinda a disapointment as the tubes got more and more hours on them. I was beginning to think my Mesa was getting sick.

I also changed out V2 from a dying Mesa to a Sovtek for more gain color and that rolled of the treble some and seemed to help. V1 is a Mesa, V3 and V4 are Mesa 7025's.

Clean tones are still remarkably similar, but my amp settings are designed for ultra-gain.

Id say for any genre other than death metal, this tube is a perfectly great tube though! I'm definitely keeping mine for spares. Has a great Van Halen sound with my settings!

I listens to's your's clips ands I's don'ts thinks you's has problems gettings goods metals tones anyhows.

Bests Regards,

Skwisgaar

 

[igfraso]

Ed,
maybe you can give some precious advice here.

I understood that the inner pair is the safer place in a 60/100 watter and, if you have tubes that are not that strong, that is the place to put them.

Following that logic, I placed my MESA STR-425 in the inner pair and they sound very well.

Should I put them in the outer sockets? Or should I remove them from the amp and never use them again unless I use a quad of STR-425?
Best regards
daniel

The inner outer issue is only for Simul Class amps. They run different bias voltages and the outer pair is hotter.
In a 60/100 the bias is the same across all four. Most people opt for matched quads of the same tube as they will draw the same
bias and have the same natural current draw. Now, that is what most people do, but i've seen a guys have four different 6L6's
in a IIB and it still sounded great. The question in choosing tubes for a push-pull 100W is difficult to really answer because
a lot of people swear by matched quads only, but their is sometimes a little black magic in a slight mismatch.
The safe answer is to have all four of thew same tube type and color code.

Thank you, Boogiebabies.
Yes, it makes a lot of sense.
Then, until I buy another pair of 425's, I can put them back in the inner sockets. :lol:

I remember that, when I sent a 60/100 watter to Petaluma for a check up, Mike Bendinelli marked the weaker pair of the quad of STR-415 and told me to use them ONLY in the inner sockets.

Thank you again for your continuous help.
Best regards
Daniel

 

[Boogiebabies]

Ed,
maybe you can give some precious advice here.

I understood that the inner pair is the safer place in a 60/100 watter and, if you have tubes that are not that strong, that is the place to put them.

Following that logic, I placed my MESA STR-425 in the inner pair and they sound very well.

Should I put them in the outer sockets? Or should I remove them from the amp and never use them again unless I use a quad of STR-425?
Best regards
daniel

The inner outer issue is only for Simul Class amps. They run different bias voltages and the outer pair is hotter.
In a 60/100 the bias is the same across all four. Most people opt for matched quads of the same tube as they will draw the same
bias and have the same natural current draw. Now, that is what most people do, but i've seen a guys have four different 6L6's
in a IIB and it still sounded great. The question in choosing tubes for a push-pull 100W is difficult to really answer because
a lot of people swear by matched quads only, but their is sometimes a little black magic in a slight mismatch.
The safe answer is to have all four of thew same tube type and color code.

Thank you, Boogiebabies.
Yes, it makes a lot of sense.
Then, until I buy another pair of 425's, I can put them back in the inner sockets. :lol:

I remember that, when I sent a 60/100 watter to Petaluma for a check up, Mike Bendinelli marked the weaker pair of the quad of STR-415 and told me to use them ONLY in the inner sockets.

Thank you again for your continuous help.
Best regards
Daniel

I'm sure he was just trying to balance the inner and outer pairs. Even though they don't all match each other,
the inner pair should match and the outer pair should match even though the current draw/bias will be a bit
different on both pairs.

 

[igfraso]

Thanks again.
I think that I will need to buy another pair of 5881.
Or I could also get them out of the II-A and put them in my DC-5 since the DC-5 needs only 2 power tubes.
Regards
Daniel