OT: Tubes.....your thoughts......

[AllyP]

I love my JCM 900 50 watt head.  I've had it for nearly 5 years and its served me through all sorts...untill about a month ago when my B channel died  After a lot of messing about I was told by the Marshall guys on their forum that it was a brokren pre amp tube....

Ive had it for 5 yrs and not changed the tubes once :wink: dya think I'm ready? :wink:

What power tubes should I go for?  Which pres should I go for?

What are my options :?

Thanks,
Ally

[The Tone God]

Your options are pretty wide open. One thing I notice is that most music stores and stores with small repair shops won't carry any good tubes. Just Sovtek, Groove Tubes (which most of the time are Sovteks), and maybe Mesa Boggie (china tubes). If the shop doesn't offer a good selection of tubes then your better off supplying the tubes to the shop yourself.

AS for what tubes you should buy depends on what you do or play. In general I recommend Svetlanas for power tubes. For the preamp you alot of choices. You could go NOS or Sovtek 12AX7LPS which aren't bad.

A good place to get tubes online is here:

http://www.thetubestore.com

Andrew

[Chris R]

On the same note... I have a Mesa Boogie Nomad 45 (el84's & 12ax7's).. the thing is there is no bias on the mesa amps.. which is how they get you to only buy their tubes.  

Should i just suck it up and buy mesa only ?  What are my other options ?

Chris

[Jered]

the thing is there is no bias on the mesa amps.. which is how they get you to only buy their tubes

 not true, just use good quality tubes. The Mesa tubes suck IMHO I use RCA or GE power tubes and Mullards and Telefunkens in the pre amp and it sounds GREAT ! Again IMHO
 Jered

[aron]

12AX7LPS which aren't bad

I like those. I got the early ones and they are good.

There is a NOS phillips tube that is reasonably priced (or it was).

[Gil]

Try to get some good NOS tubes, never go with Sovtek crap. The difference in sound is HUGE !!

[The Tone God]

On the same note... I have a Mesa Boogie Nomad 45 (el84's & 12ax7's).. the thing is there is no bias on the mesa amps.. which is how they get you to only buy their tubes.  

Should i just suck it up and buy mesa only ?  What are my other options ?

Mesa does order tubes that are matched to their specs so they/you don't have to go about biasing the amp. This doesn't mean you are stuck with their tubes. Good tube suppliers will probably know what the bias is for Mesa amps and be able to supply you a set of tubes that will work without biasing. Email their info/tech support to see if you can find out.

A few Mesas do have bias controls usually as an internal trim pot so you still need a tech to take apart the amp to get to it. I don't have the schematic for the Nomad so I can't tell if it does or not. A good tech should be able to add a bias control for you if you want.

If not you can still get different tubes and a good amp tech should also be able to bias a fixed bias amp. It will be a one time charge if you get the tubes from a supplier that matches and rates the tubes since then you can reorder tubes with the same rating and not have to rebias your amp.

Mesa tubes are from China. They are not a tough tube and can't stand high voltages but if you are just playing at home then tubes from China are actually better sounding I think. I find them alittle bit smoother then Sovteks.

I would recommend Svetlana 12AX7s but they are having problems. Some tube suppliers have actually stop carrying them all together. I hope Svetlana fixes them soon.

It is a shame about the Phillps NOS tubes getting expensive. Nice tube.

Andrew

[AllyP]

Cool....thanks guys!!

I'm more into heavier stuff.....I tend to just use the clean channel with lots of external fuzz!

ie CKY, Metallica, Punk, Smashing Pumpkins etc....

I wanna go LOUD!!! (but on a buudget...I hate being a student )

Any ideas would be great!

[aron]

I recommend trying the duncan tone stack simulator with a VOX tone stack. Fool around with the values and you can get a wicked mid cut.

Use this on the end of a circuit that generates lots of harmonics - try any Si distorter with a booster up in front if necessary.

Should give you lots of distortion AND a mean tone.

[AllyP]

But what about the tubes?

[Mike Burgundy]

I agree on the LPS (the wxt+ is also good, but stay away from sovtek WA/WB), and on Svet as far as 6L6's go.
For an affordable current production EL34 that holds iot's own against NOS (expensive!!) I'd advise JJ/Tesla.

[AllyP]

Any places I can get these tubes in the UK?  I fancy the Tesla E34Ls and the Sovtek 12AXLPS.

Whats the difference between EL34s,KT88s and 6L6s?

[Mike Burgundy]

basically an EL34 is the "marshall" tube, a 6L6 is the "fender" tube.
A KT88 is yet another beast. They all sound a bit different, especially when driven hard, and they all need somewhat different operating conditions to be happy.
As far as maximum power (which says nothing about how loud the amp is: it all depends on how it's designed and set up) is concerned an el34 is rated at 25W, 6L6 30 and KT88 40-something - the most powerful tube in current production.

[Chris R]

Thanks for the info guys.

I'll probably try to order a set matched for my mesa... i'll let you know how it turns out.

C

[Rory]

I know Billy Corgan was a HUGE fan of KT-88s.  He had his rig modded so he could use them in all of his amps.  They get that great low end sound, even with a strat.  Couple that with a big muff and you've got a freakin monster!

[runmikeyrun]

I would get the B channel working again and then worry about your power amp tubes.  

The only time you REALLY need power amp tubes are when you a) have a failure of one or more  and b) when they wear out.  When they wear out you will know... you'll have way less volume and your tone will suffer big time.  

Now, a lot of people change their power amp tubes for purely sonic purposes... if you're looking for a different sound then set out on a mission for different tubes.  Keep in mind that tone is subjective... people may rant and rave about a certain brand or NOS this or that but WHY they like them is more important.  What tonal characteristics do they have?  Tons of low end?  Earlier breakup?  More compression?  These are the things you need to know.

Also, keep in mind that getting new tubes will cost ya.  For two tubes it will be anywhere from $40-200 depending on what kind of tubes you buy, and then figure in the cost for a tech to rebias the amp to them, and you're usually up around $100 dollars to start out with.  And then you might not like the sound the new tubes give ya!

I would definitely fix the problem in the B channel first though.  Trying a new preamp tube would be a good start.

[AllyP]

Hmmm...I'll have to look into that!!  Thanks :wink:

[Johan]

most Marshall JCM900 sold in Europe was shiped with russian 5881 power tubes, and there are a few component changes between JCM900's built for Europe and the ones buillt for other markets....check what you've got before you run out to buy new tubes...
...its been a while since I poked around inside one of those, but if I remember corectly, both channels use all the preamp tubes but has a different setup with the gain and volume pots and the surrounding toneshaping components...do you have the dual highgain master-model or the reverb version?
again, if my memory isnt too off, I think the problem lies in one of the gain or master volume pots and not in the tubes....
...also..unless you leave your mastervolumes on "10" ( or close by )you're probably not hearing much poweramp distortion, and I woudnt worry too much about what type or brand they are...

Johan

[dubs]

I love my JCM 900 50 watt head.  I've had it for nearly 5 years and its served me through all sorts...untill about a month ago when my B channel died  After a lot of messing about I was told by the Marshall guys on their forum that it was a brokren pre amp tube....

Ive had it for 5 yrs and not changed the tubes once :wink: dya think I'm ready? :wink:

What power tubes should I go for?  Which pres should I go for?

What are my options :?

Thanks,
Ally

A good set of tubes properly matched will last about 2 years before tone begins to degrade. So you are way overdue! If you are serious about tone, you should never tun the tubes until they don't function anymore!

The best sounding current production of 12ax7 tubes are the jj ECC83S and 12ax7EH but tubes work/sound different in different amps so it can be matter of trial and error.

Bob at Eurotubes can hook you up with a set and is familar with amp bias of various brands.
I buy my tubes at vintage electron, they are really  cheap in prices and they thoroughly test their tubes before going out the door. I recently bought a matched quad of JJ EL84 , they platinum match after a 24 hour burn in.

The important thing about getting matched tubes is getting them dynamically matched, not statically matched as most tubes vendors do.
This will give you more life from your tubes and maximise output of your amp.

If you wanna learn alot about tubes and compare them, then I recommend checking out    www.guitaramplifierblueprinting.com it dispells alot of myths/perceptions people have of tubes and you can compare different brands etc.

//

[Paul Marossy]

For power tubes, I think J&J EL34's sound really good. The Sovtek EL34WXT's are the worst sounding power tubes I have ever heard! At least in my Seymour Duncan Convertible... I have seen some tubes labeled "Groove Tubes" that looked like they were made in the Sovtek factory, and it seems like one out of four is defective.
I have some Svetlana 6L6GC's in my vintage Twin Reverb, and I think they sound great.
I have heard that J&J preamp tubes are pretty good, too. But I have never tried any.