Power tubes?? Who, What, When Where how??

[Jae]

Hello. I'd like for some users here to give us some input about Power tubes. I've heard the thread talking about the preamp tubes and found it very useful, but how about the main power tubes. So far I'm using EL34's, but which make and are there any other good types of tubes for alot of gain, or clean?

Can you give us a good description about the types of tubes you have or have tried and how they sounded. Which ones can be biased to have maximum gain or which ones have the best clean or both grit and clean?

Is it in fact better to go vintage, than modern? Like the GT tubes made in Russia or China or the Mullards or even Telefunken EL34's.

What are you experiences with these and what type would you recommend for a Marshall amp like a plexi, JMP MV, or even aa vintage modern or Fender Twin??

 

[Jesstaa]

You cannot beat N.O.S tubes, no questions about it, they were built to high standards, as they were the only viable option back then. Nowdays tubes are produced cheaply, as they're more of a... 'cultist' option (Couldn't think of the right word there).

 

[Jae]

You cannot beat N.O.S tubes, no questions about it, they were built to high standards, as they were the only viable option back then. Nowdays tubes are produced cheaply, as they're more of a... 'cultist' option (Couldn't think of the right word there).

Hey thanks alot Jesstaa! I'm looking for some good output tubes on Ebay. I came across some NOS Mullard tubes. Some are xf2-xf4. There is a Mullard from Dynaco as well. Do you know anything about these tubes?
I hear the Phillips were the first ones produced by Mullard.

 

[Jesstaa]

Not so great with specific tubes, but Marty talks a lot about them, wait until he finds this thread, he'll give you a good incite, but oh man, with the rep he gives them, and his experience, I would LOVE a nice set of Mullard EL34s (And my amp modded to EL34). Give you the real classic metal tone.

 

[Jae]

Not so great with specific tubes, but Marty talks a lot about them, wait until he finds this thread, he'll give you a good incite, but oh man, with the rep he gives them, and his experience, I would LOVE a nice set of Mullard EL34s (And my amp modded to EL34). Give you the real classic metal tone.

I think I'm going to get a pair of Mullards. It's good to be able to get a decent set of output tubes.

 

[Jae]

Also, just out of curiosity. What is it exactly that people find so alluring about Mullards in terms of sound. I've never tried them before, so can't say.

 

[Jesstaa]

I think it's just the fact they're so rich and full with their tone, and a nice full tone RULES.

 

[rockinr0ll]

lol at the thread title.

 

[MartyStrat54]

You cannot beat N.O.S tubes, no questions about it, they were built to high standards, as they were the only viable option back then. Nowdays tubes are produced cheaply, as they're more of a... 'cultist' option (Couldn't think of the right word there).

Jesstaa is one of the regulars on the Preamp Thread. Months ago, we expanded into talking about all of the tubes in a Marshall, but we mainly are preamp tube rollers looking for the best sound. Our experimentation has paid off and we have come up with certain tube combination's for certain Marshall amps.

If your preamp tubes are sounding like crap, your power tubes are going to amplify it. Therefore, tweaking your preamp tubes is the first step to achieving killer sound. Once the preamp tubes are taken care of, we can move on to the power section.

NOS vs Current Production (CP)-There is no comparison. NOS power tubes simply rule. You can talk about how good your JJ's sound or your Winged =C='s, but they are way behind an NOS tube in quality. First off, an NOS EL34 is rated for 800V on the plates. When they were tested, they were burned in at 600V. This is as high as you can go safely with an octal base. Going higher increases the chance of high voltage arcing.

Side note: There are certain online tube seller's that have a bunch of B-Stock EL34 tubes. Beware! They are listed as having a limit to the voltage they can take. Stay away from these "bargain" NOS tubes. They're crap.

Most modern EL34's are burned in at 400 to 450 volts. This is at or below what a Marshall power supply puts out. In fact, if you have certain models of Marshall amps the HT can be higher than 600V. I would strongly recommend using NOS tubes only in an amp like that.

When a CP power tube is burned in, there are many that fail. Those that pass are boxed up for sale or for OE use on an amp. I have talked to many employee's of the big music stores and they say it is a crap shoot every time they turn an amp on for the first time. This is due to a high failure rate of the power tubes that supposedly tested good.

I have been on the forum now long enough to see that someone will buy a matched set of CP tubes and within a week or a month, one will fail. This failure causes a great amount of current to pass and one bad tube can take out the others. If this happens, usually there is board damage, component damage and possibly a fried output or power transformer.

This is why I use NOS tubes. They are reliable. Do they cost more? Yes. You can get a matched quad of RFT's for $199 on EBAY. I highly recommend them. They add so much depth to your sound. They reflect the tone of the preamp tubes with ease. RFT's have a tight bass, pronounced, articulate mid's and a sparkle on the high end. A beautiful sounding power tube and worth the money. On top of that, NOS tubes last longer, because they are built better and designed to take more power.

I have an amp with xf2 Mullards. Wonderful sounding tubes. These are a little warmer in the midrange compared to the RFT's. The RFT's tend to break up at lower volume over the Mullards, but not by much. Not really a fair comparison due to different amps with different speakers, but turning up the volume, you can tell when the power tubes kick in and when they start to sing.

I would tell someone to get some good preamp tubes first, especially for V1 and V2. This should make a big improvement in your sound. If you are happy with your CP power tubes, then stay with them. However, if you want to take the next step, then you will want NOS power tubes. Those of you with 50 watt amps can pick up a pair for $70 to $99 a pair. Not bad, considering all the improvements you will get.

I have a lot of experience with CP tubes and a lot of people on the forum are always asking about which one to buy? It's like buying speakers, it's what sounds best to you...not me. For those of you who are happy with CP tubes, I say try different kinds out, because one brand may sound better in your amp over another brand. Don't buy the cheapest tube, you get what you pay for. I still think the quality of a Russian CP tube beats out a Chinese tube. The other thing is to remember that a lot of companies that sell tubes do not make tubes. Did you get that? There is a lot of relabeling going on and some of it is illegal. You can't get a 12AX7 Telefunken new for $30. It's a fake made in China. Only buy from a reputable company. Some relabeled tubes are very good and others are crap. There are also some new tube companies that are stirring up the tube community with their new tubes. Tech Tube is one of them. They are making 12AX7's at the old Mullard Blackburn factory. Due to legal issue's they cannot call themselves Mullard. However, their product is steadily getting better and I think by the beginning of 2010, they should have a solid product on the market that will rival the sound of any NOS tube. They have plans to make EL34's as well.

In closing, I understand that some of you are very loyal to the type of CP power tubes you use and that's not a problem. Not everyone is going to make the switch to NOS power tubes. I'm just pointing out that there are advantages to using NOS. I feel safer using NOS in my amps, because they are so damn dependable.

 

[Jae]

Wow! Thank you so much for the in depth explanation.
I found that very very helpful.

There is a quad set called Dynaco by Mullard that are xf2s that I'm interested in. Are these any good? Three of them are matched at 3800 MHOS (not sure what is meant by that). Again, I know it would be difficult to tell without actually hearing them, but I'm going to jump this one and go for them. These are also double o gettters (i'm not sure exactly what the difference would be in sound compared to a single o getter?? do you know??) I just know that the getters collect some unwanted electrical current or something like that (sorry for being stupid.)

I've never heard of Dynaco by Mullard, but I heard that no matter what a Mullard is a Mullard and doesn't matter what label they are under. Of course these are used old tubes from Gr. Britain.

 

[Jae]

I also have another question. I'm not sure what you meant by B-stock el34s. Are you talking about a reissue tube? Or one that has been "restored" to original. I've heard of some tube sellers who do some kind of cryogenic thing to them, not sure what that is or if it makes the tube that much more better sounding.

 

[MartyStrat54]

Wow! Thank you so much for the in depth explanation.
I found that very very helpful.

There is a quad set called Dynaco by Mullard that are xf2s that I'm interested in. Are these any good? Three of them are matched at 3800 MHOS (not sure what is meant by that). Again, I know it would be difficult to tell without actually hearing them, but I'm going to jump this one and go for them. These are also double o gettters (i'm not sure exactly what the difference would be in sound compared to a single o getter?? do you know??) I just know that the getters collect some unwanted electrical current or something like that (sorry for being stupid.)

I've never heard of Dynaco by Mullard, but I heard that no matter what a Mullard is a Mullard and doesn't matter what label they are under. Of course these are used old tubes from Gr. Britain.

Not stupid at all. The xf2 is a very desirable EL34 and they can be pricey. The Dynaco label means they were made for Dynaco amps, but they are still xf2 Mullards. When a tube is made the virgin getter contains barium. A vacuum is pulled and as much air and gas is removed as possible. The glass tip on the bottom of the tube is heated and the glass is soft. Once the vacuum is complete, the air hole is sealed off with hot glass. Once the glass cools, the getter(s) are heated and the "flashing" splatters on the inside of the tube. This splattering removes the last of the excess air and gas. Additionally, the getters continue to work throughout the life of the tube. If a tube develops a leak, the getter will turn white. Do not ever buy a tube with white inside of it. It is shot.

In power tubes, two getters are more desirable. They may not be any better than a single getter, but dual getter tubes demand more money.

If you are buying a "matched" set of quads and three measure at 3800, what does the fourth tube measure at? If it is way off, it will not bias right in your amp. MHOS is a unit for measuring transconductance. Transconductance is the opposite of resistance. Engineers decided to spell OHM's backwards and came up with MHO's.

All I can tell you is that an xf2 is a very good tube. However, make sure all four tubes are within a certain range, or you will not be able to use them in a 100 watt amp. If the other tube reads 3400-3600, you should be fine.

 

[Jae]

Hey Marty, Thanks alot for this amazing info. and for putting up with my lack of knowledge.

Sorry, the tubes measure at 5800, 5800, 5800 and 5700 mhos. I have a Superlead that I can put them in, or maybe put the two matched ones in my Marshall '78 JMP 50W.

The price is sky high though, but I'm willing to pay that price to hopefully get that tone. Even though it doesn't work out, I'm willing to pay to try, cause that's the only way to get there, right?

 

[MartyStrat54]

I also have another question. I'm not sure what you meant by B-stock el34s. Are you talking about a reissue tube? Or one that has been "restored" to original. I've heard of some tube sellers who do some kind of cryogenic thing to them, not sure what that is or if it makes the tube that much more better sounding.

B-Stock refers to a batch of NOS tubes that do not meet NOS specification. In this case, instead of being able to handle 800V on the plates, they can only handle about half of that. With a B-Stock tube, what that means is you are sticking a tube in your amp that may not be able to handle the 450V on the plates. Internal arcing and shorting can occur and this can cause serious amp problems. Usually, you will blow a fuse before any real damage can occur. These are not reissue tubes. However, many current production (CP) tubes are not happy when the plate voltage exceeds 450. What happens is the tube will wear out faster than normal.

When it comes to freezing tubes, I have to ask the following. If it's such a good idea, why didn't they do it back in the 50's and 60's? I'm not a fan of this whole cyrogenic process. I think it is just another gimmick to get a few more bucks off of a customer.

 

[MartyStrat54]

Hey Marty, Thanks alot for this amazing info. and for putting up with my lack of knowledge.

Sorry, the tubes measure at 5800, 5800, 5800 and 5700 mhos. I have a Superlead that I can put them in, or maybe put the two matched ones in my Marshall '78 JMP 50W.

The price is sky high though, but I'm willing to pay that price to hopefully get that tone. Even though it doesn't work out, I'm willing to pay to try, cause that's the only way to get there, right?

That's still a matched quad and a good one at that. The difference between 5800 and 5700 is not a problem at all. Let me know how much you paid for them if you win them. If you don't want to post it, leave me a PM.

They will sound killer in a Super Lead. Also, a Super Lead is one of the amps that can have high plate voltage, so the xf2's would work out perfectly.

 

[Jae]

B-Stock refers to a batch of NOS tubes that do not meet NOS specification. In this case, instead of being able to handle 800V on the plates, they can only handle about half of that. With a B-Stock tube, what that means is you are sticking a tube in your amp that may not be able to handle the 450V on the plates. Internal arcing and shorting can occur and this can cause serious amp problems. Usually, you will blow a fuse before any real damage can occur. These are not reissue tubes. However, many current production (CP) tubes are not happy when the plate voltage exceeds 450. What happens is the tube will wear out faster than normal.

When it comes to freezing tubes, I have to ask the following. If it's such a good idea, why didn't they do it back in the 50's and 60's? I'm not a fan of this whole cyrogenic process. I think it is just another gimmick to get a few more bucks off of a customer.

Is there any way of knowing if the tubes are in fact b-stock? I mean they could still have close to high test readings for a new tube, but may still not be able to handle the voltage of a Superlead.

I agree, I think the freezing of the tubes is some srot of gimmick, like you said, why didn't they do it in the 60's.

I'll let you know how much I paid for them.

 

[Jae]

I went up to a local guy here and he has a pair of Mullard xf2's with the original boxes and matched. I checked it out and found that one of them had a bit of the logo rubbed off , but he insists that these are NOS. They haven't been used according to him. I might get a pair and put it in my 50 watter. He's charging $350 US for the pair.
This seems like a lot of money since I managed to get a quad for about that much, but the quad was used.

The ones this guy is selling is NOS. Is this a good deal?

 

[MartyStrat54]

A guy on EBAY has a pair of used xf2's that are super strong and a very close match. He is wanting $150 for the pair. I think $350 for unverified NOS is way too much.

 

[Jae]

A guy on EBAY has a pair of used xf2's that are super strong and a very close match. He is wanting $150 for the pair. I think $350 for unverified NOS is way too much.

really, $150. That's a good deal. Can't find it though. Maybe it has ended.

 

[MartyStrat54]

Nice Matched Pair of Mullard xf2 DBL Halo EL34 Tubes - eBay (item 350247622709 end time Sep-11-09 18:31:18 PDT)

I'm doing you a favor. Hurry before I buy them.