I'm a little confused about tubes and the 10w mode..

[jbow]

I have a Mark V combo. I've thought about trying EL34s but I like using the 10w mode sometimes. From what I have read it is not a good idea to mix 6L6 (outside) and EL34 (inner sockets) and run in 10w mode.
Can I pull the outer tubes (6L6s) and just run the inner sockets with EL34s and have n trouble in any watt setting? Of course I know to flip the switch to EL34 bias, but I'm guessing that only using 34s it wouldn't hurt anything if I used either bias.
So, can I mix and run in 10w or just use the inner sockets and EL34s in 10w, or should I pony up for 4 EL34s?
Also, I usually buy JJs but what would you recommend for an early cleanish, edgy tone. I noticed that JJ has a "blue glass" E34 with more headroom, same voltage here: https://www.tubesandmore.com/products/e34l-jj-electronics-blue-glass
The TS has a JJ 6CA7 and an EH 6CA7 high voltage. Are these the same as the "good" 6CA7 tubes? I've never used any of them.
So, 4 EL34s and 10w or two in the middle with empty outer sockets, or 6L6 outside, EL34 inside and 10w?

Another question, well two... what "number" should I look for in a matched tube, like (I forget which tube store sells matched tubes and numbers 1-10) what number is best for a MV?
Since the MV is, I think fixed bias.. is there a way to adjust the bias or would I have to change a resistor? ..and would that be a BAD idea? I ask because I had a "boutique 6V6 powered amp. A four holer design that would, if I slammed it hard with humbuckers cut out. The builder dropped the plate voltage to try and fix it BUT after that "fix" the amp lost something, lost it's mojo if you will. It always makes me wonder if biasing hotter or raising the plate voltage just a little will ADD mojo to an amp.
The Mark V is so complex I hesitate to even think about doing anything to it but a POT (which is a variable resistor at the end of the day) makes me think about adding one to control either bias or plate voltage, small range of course. Yeah, I probably should have asked this in another thread, I'm asking for drift but... yeah, there are really only a couple of questions here. EL34s and 10w, tube rating, and changing the bias or plate voltage. The last are probably bad ideas but nothing asked, nothing answered.

Thanks. My main concern is EL34s and 10w mode. I suppose I can use either or both in 45w or 90w.

JB

 

[SamuelJ86]

Mesa does not recommend mixing tubes like you can in older simul class marks. Some guys on the board have measured everything with a mixed set in and found that the EL34's are just too far outside where they need to be. I'd be suprised if anybody is using a mixed set. But you certainly can if you so desire.

You need to read the manual and get familiar with how and why the tubes work in each wattage setting. In 10 watt mode it uses the 2 sockets closest to the 5U4, not the middle sockets and not the outside sockets. The manual is on mesa's website.

 

[bandit2013]

jbow,
If you owned a Mark III or a Mark IV you could get away with integrated quad, meaning mix of EL34 pair and 6L6 pair. Since you have a Mark V, I am not sure what would happen. Yes, the center pair do run hotter than the outside pair, I was almost tempted to do what you were thinking but did not want to risk damage to the amp. If you want EL34s, best to have all tube types match. Never use the EL34 bias with a 6L6 tube in place as this would cause damage to the amp and tubes. The 6L6 bias would be too cold to run EL34's, my guess is that it would work with EL34 in the center and 6L6 in the outer pair with the bias switch set to 6L6. Note that the Simul-Class circuit of the Mark V is different than that used in the Mark III and Mark IV. I would not recommend running the mixed quad.

Also note: 45W and 90W operates in push/pull (class A/B) but the difference between the inner pair and outer pair is the bias and signal level based on the resister divider network that is shared between the left and right side. Extended Class A region just indicates the inner pair are enhanced in operating characteristic but still it is push/pull mode. 10W mode is way different. It uses one outer and one inner tube on the side closer to the power supply cord. The 10W power mode also reconfigures the power tube section to operate as a cathode biased circuit for class A. Best to keep the same tubes in all power tube sockets to prevent impedance miss match issues. Do not leave any power tube sockets empty.

The Mesa EL34 sound great especially once they heat up with use. The JJ 6CA7 are interesting too. Those share a characteristic of blending 6L6 and EL34. The one's I tried had a fault in one of the tubes but I like them when they worked. Pins are a little thin which may have contributed to that problem. Also they have several flavors of EL34s. One to avoid is the EL34L which is not suitable for the Mark V due to impedance. It used to be in the eurotubes website but I cannot find it now. I personally have not tried the EH6CA7, was planning on it someday. Mullards would be too hot, love those in my RA100. I had great luck with Gold Lion KT77 in the Mark V. Those blew me away, I still have them so when I want to switch over to EL34 type I will use those. This was before I heard not to run the EL34 type at full power, Mesa had recommended to use Variac power as the plate voltage may be too high for EL34 types. Not sure where I read this, it was in this forum so may not be actual message from Mesa Boogie. If you buy from Eurotubes, best to talk to someone for recommended EL34 type for a Mark V. When ordering else where, Say TubeStore, also indicate what amp you are using the tubes with so they can match the tubes to the fixed bias and plate voltage (at least that is what I think they do).

The fixed bias on the center pair is hot enough, nothing to gain from making any adjustments which would not be easy as the voltage divider that adjusts the bias voltage to the inner pair and outer pair also feed the tubes with the signal. Since the Simul-class circuit is not your typical Class A/B power section. If it was I would be saying to add this and done. Perhaps there would be something to gain with an adjustable bias on a cold biased amp like a Single or Dual Rectifier. Any hotter on the bias of the Mark V and you will be red plating tubes in no time. Perhaps a colder bias on the inner pair would make the amp sound better.

 

[jbow]

jbow,
If you owned a Mark III or a Mark IV you could get away with integrated quad, meaning mix of EL34 pair and 6L6 pair. Since you have a Mark V, I am not sure what would happen. Yes, the center pair do run hotter than the outside pair, I was almost tempted to do what you were thinking but did not want to risk damage to the amp. If you want EL34s, best to have all tube types match. Never use the EL34 bias with a 6L6 tube in place as this would cause damage to the amp and tubes. The 6L6 bias would be too cold to run EL34's, my guess is that it would work with EL34 in the center and 6L6 in the outer pair with the bias switch set to 6L6. Note that the Simul-Class circuit of the Mark V is different than that used in the Mark III and Mark IV. I would not recommend running the mixed quad.

Also note: 45W and 90W operates in push/pull (class A/B) but the difference between the inner pair and outer pair is the bias and signal level based on the resister divider network that is shared between the left and right side. Extended Class A region just indicates the inner pair are enhanced in operating characteristic but still it is push/pull mode. 10W mode is way different. It uses one outer and one inner tube on the side closer to the power supply cord. The 10W power mode also reconfigures the power tube section to operate as a cathode biased circuit for class A. Best to keep the same tubes in all power tube sockets to prevent impedance miss match issues. Do not leave any power tube sockets empty.

The Mesa EL34 sound great especially once they heat up with use. The JJ 6CA7 are interesting too. Those share a characteristic of blending 6L6 and EL34. The one's I tried had a fault in one of the tubes but I like them when they worked. Pins are a little thin which may have contributed to that problem. Also they have several flavors of EL34s. One to avoid is the EL34L which is not suitable for the Mark V due to impedance. It used to be in the eurotubes website but I cannot find it now. I personally have not tried the EH6CA7, was planning on it someday. Mullards would be too hot, love those in my RA100. I had great luck with Gold Lion KT77 in the Mark V. Those blew me away, I still have them so when I want to switch over to EL34 type I will use those. This was before I heard not to run the EL34 type at full power, Mesa had recommended to use Variac power as the plate voltage may be too high for EL34 types. Not sure where I read this, it was in this forum so may not be actual message from Mesa Boogie. If you buy from Eurotubes, best to talk to someone for recommended EL34 type for a Mark V. When ordering else where, Say TubeStore, also indicate what amp you are using the tubes with so they can match the tubes to the fixed bias and plate voltage (at least that is what I think they do).

The fixed bias on the center pair is hot enough, nothing to gain from making any adjustments which would not be easy as the voltage divider that adjusts the bias voltage to the inner pair and outer pair also feed the tubes with the signal. Since the Simul-class circuit is not your typical Class A/B power section. If it was I would be saying to add this and done. Perhaps there would be something to gain with an adjustable bias on a cold biased amp like a Single or Dual Rectifier. Any hotter on the bias of the Mark V and you will be red plating tubes in no time. Perhaps a colder bias on the inner pair would make the amp sound better.

Thank you Bandit. This is helpful. I'll just try a quad of 34s if I indeed decide to. I have not heard an RA 100 but I almost bought it instead of the Mark V, I sometimes wish I had. At almost 65, I don't play as much as I used to but I still love the roar. ALL the clips I heard of the RA sounded fantastic. I'll call Mesa before I spend any money on tubes, just to be sure. I'd be interested in trying the "blue glass" JJs, I like a "dirty clean" sound better than anything. IDK, I have an MEL9 pedal coming tomorrow and I think it will keep me busy for a while, lol.
BTW... 8), you didn't mention it but re the manual. I downloaded and read it before I even bought the amp, then read it twice while playing the Mark V. I realize it isn't "plug and play", but I forget things... and things seem to change. That is why I decided to ask here. To get the latest lowdown... and I appreciate the answer!
JB

 

[bandit2013]

You are welcome jbow.

Unfortunately the Royal Atlantic is no longer in production. There are many from time to time that I have seen for sale used. It is basically a two channel amp, clean channel and what would be referred to as Vintage, proper classification is Hi/Lo. It is a two stage channel with a High gain master and Lo gain master and the tone controls and gain are shared. Perhaps that would be similar to the Mark V if you switch between CH2 crunch and CH3 Mark IV but instead of two separate controls for each channel they are combined like the old school amps of the 1980s. The amp before that was the Electra Dyne which is similar to some extent but different. What is nice about the Royal Atlantic or RA100 is the easy to set controls. Much different than the Mark series amps or say a Rectifier series amp.

http://mesaboogie.com/amplifiers/electric/transatlantic-series/royal-atlantic-ra-100/index.html

I actually prefer the 2x12 combo version of the amp as it is easier on the ears in volume. Same amp as the head though. Also very heavy as it almost weighs as much as the Mesa OS Recto 412 cabinet. I bought both of mine used. Have head and combo. The head is very heavy too and would hate to drop it on my foot. Tone wise, the clean channel being EL34 tinted has a classic vibe to it. Great for clean blues as well as early rock when you push the gain up. The other channel, on the Lo setting is ideal for Classic rock, dirty blues and what ever else that suits some EL34 grit. The Hi setting bumps it up to Mark V CH3 territory with a moderate gain setting. Not as much gain as the Mark V but enough to push the authority of your tone. Sweet thing about the amp is the power soak feature which allows you to change the gain structure as well as volume of the amp. The Head through a 412 is much brighter in character than the Combo though the ported/open back enclosure. Either choice you make, tube changes will require a screw driver to remove the back plates to gain access of the tubes. Once the plates are out of the way, easy access to all preamp tubes with the head or combo. I really would love to see Mesa bring this back again as it has become one of my favorite amps.

 

[SamuelJ86]

Before I bought my JP2C I was looking at getting an RA 100. I found plenty of used ones online, and I also came across a couple brand new RA's. Still in the box, warranty and everything. I was getting ready to buy one, but then the JP2C was announced and I couldnt resist. I don't know if they're still out there, it's just that I'd rather buy new. You could always trade the V towards one, maybe get some cash too, or pedals! :mrgreen: The V is a great amp, but it just never blew me away. I never played it and thought; I'm completly, 100% satisfied by the sound coming out of this amp. It's great, but it just isn't my holy grail.

If you're playing rock, and dirty cleans, I think you'll like the V with mesa's el34's. Clean cleans and metal or hard rock are better suited for 6l6's. The el34's (str-447) will have a little bit less volume, a little bit darker, and they start to break up a lot quicker than the stock 6l6's. They seem to add an extra hazy layer of gain on channel 2 and 3. And my personal favorite is driving them hard in tweed mode, 10 watts and the variac switched on. It's still pretty loud and you can control the el34's with your guitars volume control. Roll it back for a great gritty, driven clean and its full on classic rock when you roll it up. It's definitely worth having a set of el34's to go with your V.

 

[Nicklotsaguitars]

Without looking at the manual to confirm. I think the 10watt mode uses the left hand pair in 10watt mode. Not the traditional inner or outer pair.
This is so one valve gives the 10watts, the other valve acts as an offset for some part of the signal (can't for the life of me remember the technical term) which fools the class AB transformer into processing a class A sound.

So pulling the inner or outer pair will at best do nothing, at worst hurt the OT, according to that

 

[TamiGeorge]

Hi...as per my knowledge 45W and 90W operates in push/pull (class A/B) but the difference between the inner pair and outer pair is the bias and signal level based on the resister divider network that is shared between the left and right side. Extended Class A region just indicates the inner pair are enhanced in operating characteristic but still it is push/pull mode. 10W mode is way different. It uses one outer and one inner tube on the side closer to the power supply cord. The 10W power mode also reconfigures the power tube section to operate as a cathode biased circuit for class A. Best to keep the same tubes in all power tube sockets to prevent impedance miss match issues. Do not leave any power tube sockets empty.