You CAN NOT mIx TuBeS on the Mark 5

[Uncle Muscles]

I just called MB and spoke to MARCUS in customer service who clearly told me that the Mark 5 is "EITHER OR". It is either all 6L6 or all EL34's - you can NOT put 2 EL 34's in the outer pair and run the amp in 90 watts mixing tubes like the Mark IV could -- as I was told at Mesa Boogie Hollywood when they were selling me a pair of EL34 tubes.

 

[lesterpaul]

I just called MB and spoke to MARCUS in customer service who clearly told me that the Mark 5 is "EITHER OR". It is either all 6L6 or all EL34's - you can NOT put 2 EL 34's in the outer pair and run the amp in 90 watts mixing tubes like the Mark IV could -- as I was told at Mesa Boogie Hollywood when they were selling me a pair of EL34 tubes.

..I talked to someone "else" at MB-told me to hold off for a while/the 10 watt mode throws a possible kink into the machinery,but it might a deal where is doesnt technically hurt anything unless you are in 10 watt mode-so, the safe answer right now def. is DO NOT( I am not..),but I was directed to call back at a later date for more info
-will keep everyone posted!

 

[Iconoclysm]

Hmm, looks like all KT77 for me.

 

[wnlively]

Well, I did put 2 EL34s in the 2 outer sockets and the amp was in the 45 watt mode.
Seems like I read some where that this could be none just like the MK 4 . The amp sounded great, but i had a lot of noise in cahnnel 3. Then I read this post, so I replaced the EL34s with 6l6s. So I stated looking for the place I read about the tube swap.
Cant seem to locate it,. So until I hear different it will be 4 6l6s

wnlively

 

[danyeo1]

I wish the manual was more clear on this. I was reading it looking for a CLEAR answer. Lots of people might assume you can run it with 2 EL34's since that's what were used to doing.

 

[rispsira]

It is clearly stated in the manual that you CAN do that.. and its a really bad mistake if you cant.

wnlively if youre not able to locate it i bet it was from the manual. i read that part again yesterday and it is very clear that you CAN use EL34 on the outer socket, though it doesnt say which bias you should put the knob on if you do that.

 

[danyeo1]

It is clearly stated in the manual that you CAN do that.. and its a really bad mistake if you cant.

wnlively if youre not able to locate it i bet it was from the manual. i read that part again yesterday and it is very clear that you CAN use EL34 on the outer socket, though it doesnt say which bias you should put the knob on if you do that.

What page # ?

 

[MrMarkIII]

Mark V Manual Page 6:
"Finally a BIAS SELECT switch is included that allows you to run EL34 power tubes in place of the stock compliment of 6L6’s. You can run EL34’s in just the outside pair or all 4 power tube spots."
So there! :lol:

 

[Uncle Muscles]

Well, I did put 2 EL34s in the 2 outer sockets and the amp was in the 45 watt mode.
Seems like I read some where that this could be none just like the MK 4 . The amp sounded great, but i had a lot of noise in cahnnel 3. Then I read this post, so I replaced the EL34s with 6l6s. So I stated looking for the place I read about the tube swap.
Cant seem to locate it,. So until I hear different it will be 4 6l6s

wnlively

In 45 watt mode you are only using the 2 inner pair of tubes - which in your case is 6L6. You need to run in 90 watt mode in order to be using all 4 power tubes. So your noise issue in channel 3 is not the replacement tubes. Also the Variac power switch regulates the voltage and has nothing to do with what tubes are being used in case anyone was confused.

 

[Uncle Muscles]

Mark V Manual Page 6:
"Finally a BIAS SELECT switch is included that allows you to run EL34 power tubes in place of the stock compliment of 6L6’s. You can run EL34’s in just the outside pair or all 4 power tube spots."
So there! :lol:

This is exactly what they told me at the Mesa Store. Have to be running in 90 watts on all channels to get the blend of all 4 tubes.

So can somebody call Mesa CS tomorrow and ask what the heck is the real deal?

**** it. I'm popping in the EL 34's and going to record some stuff with it. 8)

 

[phyrexia]

Alright, my Rep has had a Mark V for a couple months. I have talked to him a bunch about this specifically. Right now, he has EL34s in the outer sockets and 6L6s in the inner sockets of his amp. He has experienced no ill effects in any power setting.

(He also has talked to Randy about the 45W Class A mentioned in the manual, and this is indeed a typo. 45W mode is Class A/B, inner tubes, straight up.)

 

[MrMarkIII]

Mark V Manual Page 6:
"Finally a BIAS SELECT switch is included that allows you to run EL34 power tubes in place of the stock compliment of 6L6’s. You can run EL34’s in just the outside pair or all 4 power tube spots."
So there! :lol:

This is exactly what they told me at the Mesa Store. Have to be running in 90 watts on all channels to get the blend of all 4 tubes.

So can somebody call Mesa CS tomorrow and ask what the heck is the real deal?

f%&# it. I'm popping in the EL 34's and going to record some stuff with it. 8)

Having to run full power (90 watts) with all four tubes lit up in order to "get the blend of all 4 tubes" is exactly the way ALL Simul-Class amps operate.

 

[lesterpaul]

Alright, my Rep has had a Mark V for a couple months. I have talked to him a bunch about this specifically. Right now, he has EL34s in the outer sockets and 6L6s in the inner sockets of his amp. He has experienced no ill effects in any power setting.

(He also has talked to Randy about the 45W Class A mentioned in the manual, and this is indeed a typo. 45W mode is Class A/B, inner tubes, straight up.)

....LIVING ROOOM!!VARROOOOOOOM!pics???!!!

 

[rispsira]

It would be a shame it we couldnt have the option of EL34's in the outer socket! hope we will

danyeo1 i am not ignoring your question by the way, but just noticed its been answered above

 

[dmcguitar]

I suppose its time for Mark 5 (manual) stage II

Someone needs to re-write the manual, and correctly detail all of "features" Is it possible to speak to the guy who wrote the manual?

 

[JimmyB]

I suppose its time for Mark 5 (manual) stage II

Someone needs to re-write the manual, and correctly detail all of "features" Is it possible to speak to the guy who wrote the manual?

I'd like to find out who he or she is, if only to berate them mercilessly for the dozens and dozens of spelling mistakes! :shock:

 

[phyrexia]

Let's wrap this thread up.

The manual states it can be done.

My rep has repeatedly stated it can be done.

I am running my V now with EL34s in the outer sockets. Bias Switch set to 6L6. All three modes work fine. No redplating. 10W mode operates with no issues (and I have a hunch from the sound of it that the EL34 is the one doing the majority of the work in 10W mode).

Anybody have any objections?

 

[t2mike2]

Thing is reps are wrong ALL THE TIME, and the Manual has tons of errors in it. I am inclined to believe Marcus from mesa because hes one of only like 3 or 4 CS reps at mesa. He works with R.S. himself, if he needs to know something, all he has to do is ask the guy. Heck Marcus is the one doing the demo's in the demo videos!

Also consider that even though your amp works, it may not be biased correctly now. Its my understanding that its not really dangerous to run the el-34 in 6l6 mode, but it is dangerous the other way around. Also consider, if it didnt matter which tube type you used then there would be no tube switch. Either way the switch is set, the sockets are set up the exact same way, either for 6l6 or el-34. if it was an either or thing, then there would be no switch.
From expeirience in biasing my bugera, i noticed with 6l6's in , if i switched the bias switch to el-34 the bias jumped up dramtically ( as in got way hotter). So an el-34 and 6l6 configuration is definitely not interchangeable.
It may function the way you have it, but i guarantee the bias is not optimal.


But in the end, if you like the sound, and the amp doesnt blow up, then... its the right setting for you.
~mike~

 

[phyrexia]

I've worked with my rep for three years and he has given me only one piece of incorrect information. It was regarding an amp that had yet to be announced at the time.

The Bias for EL34s in the outer sockets of a Simul-Class power section has always been incorrect. That's my point. In a Mark IV, if you put EL34s in the outer sockets, they're biased cold, just like in a simul II or III, and in a V. I'm not trying to debate the bias points of EL34s and 6L6s - everybody knows that EL34s run 'hotter' than 6L6s, and what happened with your Behringer is normal. The same thing happens in a Boogie with a bias select switch.

That switch is present so you can run all EL34s. When you mix the 6L6s and EL34s in the method we're talking about here, part of 'the sound' is cold-biased EL34s. In EL34 mode, the bias for the whole amp is changed and I assume the amp is properly biased for EL34s (I am not going to get into Mesa's cold-natured biasing habits). Heck, You can stick four EL34s in any Mark IV, right now. Go do it. It'll sound fonky because the tubes are biased way too cold. But there is nothing keeping the amp from functioning. The EL34s would probably last forever. On the other hand, I can set the bias switch to EL34 and keep my 6L6s in there and it'll operate fine until the tubes blow.

The manual really only has two problems I can see: grammar and the 45W Class A parts. Everything else looked correct. I got an "EXPORT" manual and it is the same as the PDF posted here.

 

[t2mike2]

So basically.... we agree lol. I dont disagree with anything you are saying .
Basically it will work. And it will work "right" as in as designed, it just wont work "right" as in proper bias.

=).
~mike~