Off Topic Let's talk tubes...

[Bass Control]

I just recently picked up an NOS Eden WT550B on eBay and I am expecting to replace the preamp tube when I get it. The amp is two years old, is a demo model, and I'm betting the tube has never been replaced. The Eden website says that they recommend the Ruby 12AX7 as a direct replacements. Ruby's are not an easy acquisition for me (I'm cheap and don't want to pay $10 shipping on a $15 tube). So, I've been looking at locally sold tubes such as Groove Tubes or Mesa Boogie tubes at my local GC.

Now, to me personally, a tube is a tube. But I suppose that is just because I'm uneducated about tubes. So the question is what kind of tubes have you all had good experiences with? What's the difference between all the codes and differing brands? And what tube would you highly recommend to check out?

Thanks guys!

 

[toomanyslurpees]

I haven't experimented a ton with tubes, I guess I just found what works for me and stuck with it. I've been happy with JJs. I have jj KT-88 power tubes in my SVT, I just replaced the groove tube 12ax7s I had in the preamp because I was getting a glassy pinging kind of noise from one of them, so now there's JJs in there too. I was kinda suprised to change preamp tubes before power amp tubes (they had all been changed at the same time previously) so I don't know, could have just been a bad tube though. I've read that groove tube and mesa tubes are just branded low end tubes, but like I say, I've been happy with JJs and experimenting can get expensive, that being said I've had the same set of groove tubes in a musicman 100rd I bought in 2001 and driven hard as a practice amp for bass with zero problems...

 

[Caca de Kick]

The amp is two years old, is a demo model, and I'm betting the tube has never been replaced.

This isn't like a real tube amp situation. Preamp tubes last forever, unless they're dropped or damaged by shock.
We tube heads have to worry about poweramp tubes failing on us (but again it would be from dropping or banging them) bringing us to a halt. And that's why many of us replace those every once in a blue moon. But no, not preamp tubes.

But, you can use whatever brand 12AX7 you want in there, it does not matter. The only real reason to change a preamp tube would be is that the various brands give slightly different tones.

 

[projectapollo]

So, I've been looking at locally sold tubes such as Groove Tubes or Mesa Boogie tubes at my local GC.

I've used both the Mesa and Groove Tubes as replacement tubes in an Eden amp. I could tell no difference in tone whatsoever. I'd go with the in-stock from GC.

 

[Kirby]

I personally use NOS Mullard tubes in my Demeter and NOS RCA tubes in my Alembic F-1X. While it is true that any old 12AX7 should work, there are definite differences in tones. I really did not believe there was that big of a difference until I borrowed a set of early Mullards and used them in my Demeter. They are not cheap, but there are a couple of tube collectors that are very reputable and will sell you tested tubes and matched if you need a set.

The basic difference is in the manufacturing process. To my knowledge there are no tubes made locally now due to EPA regulations becoming more strict. I have not used any of the newer tubes other than replacing them, but all the ones I currently see are made in China, Russia or what used to be Yugoslavia. None of the newer tubes seem to have the warmth or clarity of the older manufactured tubes in my experience. If you are talking in the $10 range though, I imagine they would all pretty much sound similar.

 

[maddog]

Have you checked in with AL&M?

 

[AnthonyD]

...Preamp tubes last forever, unless they're dropped or damaged by shock....

Is this correct? Why would the preamp tube not suffer any degradation over time? Why different from power tubes?

 

[toomanyslurpees]

Well, not forever, but they usually last a whole lot longer than power amp tubes because they don't work nearly as hard, of coarse like everything, it all depends how often you use an amp, how hard you run it, and yeh, like was mentioned, how hard you bang the amp around.

 

[maddog]

they last longer because they are low-current and low-voltage devices. they work less as toomany pointed out so they last longer. But they do wear out.

 

[Bass Control]

Have you checked in with AL&M?

I haven't checked AL&M yet, haven't been there in years, but I was told by a friend of mine that they closed/were sold. May need to make sure.

 

[maddog]

well phooey.

Might want to check around with the ham radio peeps in the area.

 

[nashman]

Check this out. I am not endorsing or tried myself - I think it's a cool idea though ...


Welcome to WattGrinder Engineering, Inc.


Watch the video on their page. Here's also a direct link, just in case:

[ame="http://www.youtube.com/watch?v=Dh886Yw6-cI"]YouTube- NAMM '09 WattGrinder ToneGrinder Preamp Tubes[/ame]

 

[bassmonkey]

Doesn't the question depend on the amp? I have an Aguilar DB750, and from my reading it seems that the DB750 responds to tube swapping whereas other amps apparently don't. I have a Tung-Sol in V1 now, tried JJ(too hi-fi) and Mullard(too wooly). The Tung-Sol is great.

 

[maddog]

metal can tubes have been around for years. peeps don't like them because you can't see the heaters.

as to tube-swapping, yes, circuit topology and choice in operating points can make tube-swapping less pronounced.

 

[AnthonyD]

Well, not forever, but they usually last a whole lot longer than power amp tubes because they don't work nearly as hard, of coarse like everything, it all depends how often you use an amp, how hard you run it, and yeh, like was mentioned, how hard you bang the amp around.

they last longer because they are low-current and low-voltage devices. they work less as toomany pointed out so they last longer. But they do wear out.

Thanks guys!

 

[slow roasted]

Preamp tubes do last a heck of a lot longer than power tubes, but with a used Eden I would go ahead and replace the tube unless it tests out well on a meter or an amp you are familiar with.

The tube world has almost as much snake oil and voodoo B.S. as the modern hi-fi scene FWIW! The 12AX7 in your amp isn't as critical as a first stage in an SVT or a Bassman for example. It's more of a buffer/enhancer in the Eden circuit. That said, swapping out several different types is going to give you a different tone each time.

Out of the newer tubes available I really love the JJ Teslas. I've used them in many bass and guitar heads, and hi-fi setups as well. Their ECC803S really shines in the Eden circuit IMHO. They are competitive price wise with just about anything else out there, and they really give the expensive NOS tubes a real run for their money....

 

[keko]

Preamp tubes last forever, unless they're dropped or damaged by shock.

That's true in fact!

Just for example, ECC 83 preamp tubes last about 100.000 hours!

So we can confirm what Caca said is true in real life!

 

[maddog]

100,000 << infinity.

the just saying,

 

[Steamthief]

When I first bought my Fender TB-600, I did some tube rolling experimentation. I scored a dozen tested 60's/70's 12AX7s for $50 on craigslist, inclusing GE, Sylvania JAN, RCA, Tungsram and Telefunken.

Most of the tubes sounded very similar, except for one microphonic RCA, all better than the stock Sovteks, which were harsh in the high-mids and highs. The Telefunkens sounded significantly better than all the others - much more harmonic richness throughout the tonal spectrum. They also boosted the volume, bonus!

For my amp, the Telefunkens made a good thing even better. YMMV.

 

[r goldsmith]

I also have the WT550 - I think I replaced mine with a JJ some time ago. It sounds fine, and suspect (in that amp at least) it's not as critical as some cork sniffers might suggest.