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Tubes revisited

11/29/1999 3:29 PM
Tubes revisited
I just did a taste test of all the preamp tubes at my disposal. I was really anal about NOS tubes but have since found that there are some good sounding modern tubes out there. For the test I used a 64 Fender Vibro Champ and a strat with Fralins. Here are the tubes I had at my disposal.  
1. Zenith 12ax7  
2. Sovtek 12ax7wa and wb  
3. National (yugoslav)and (India)12ax7a  
4. Iec (great britain)12ax7a  
5. Mullard 12ax7a  
6. Motorola (great Britain) 12ax7a  
7. GE (small plate) (large plate) 12ax7  
8. Marshall (chinese) 12ax7  
9. Mesa STR (china) 12ax7a  
10. Pro Comm (china) 12ax7a  
11. Audio Glassic (china) 12ax7a  
12. RCA 12ax7a  
13. RCA (black plates)7025  
14. RCA (great britain w/small plates like AT7) 12ax7  
15. Telefunken (smooth plates) 12ax7a  
16. Tungsol 12ax7  
17. Standard 12ax7  
18. Sylvania 12ax7a  
First let me say that I am not going to get into textures on how these tubes sounded. What I will comment on is which tubes are the best and which are the worst. After all you can only repeat youself on texture so much before it becomes redundant.  
These are the tubes I thought sounded the best and these are not in order. The tone of these tubes was so close to the same that it becomes a purely subjective issue as to which one is better sounding.  
1. National (yugo)  
2. Tungsol  
3. Standard  
4. tungsram (hungary)  
5. Telefunken  
6. Ruby (china)  
7. Mesa (str)  
8. RCA (great britain)  
9. RCA grey plates  
10. Mullard  
11. Motorola  
All of these tubes sounded good with warm lows w/nice overtones and the mids were punchy with a nice break over at 6 on the champ. The highs were clear and definetly not thin.  
1. Zenith  
2. sylvania  
3. rca black plates  
These sounded clearer than the ones up above and had nice lows but without the overtones. Both the mids and highs were clear and crisp but didn't break over like the ones above.  
1. sovtek wa/wb  
2. audio glassic china  
3. marshall chinese  
These tubes were the bottom of the barrel. The sovteks were the worst out there. They were weak all around and had no coloration at all. You can bet I won't be buying these. The chinese tubes were not that bad but given the choice between the Mesa, Procomm, or Ruby I wouldn't buy these either. Even still they were better than the Sovteks.  
I'm going to try a test in a 64 Princeton Reverb sometime n the future to see how mixing some of these tubes thru the stages might make a difference in the overall sound of the amp. Mook did a test not long ago but I can't remember the results and I think the archives were lost. Mook if you have a copy maybe you could repost.  
I will say that the top 5 tubes that I will run in my amp is: (in any order)  
1. RCA great britain  
2. Tungsol  
3. Telefunken  
4. Mesa STR  
5. National Yugo  
Some consider the Telefunken the "holy grail" of tubes. The only thing I noticed were stronger mids than the other 4. Other than that any of those 5 are great tubes. Well thats it. Any comments are welcome...even flames if I hosed your favorite tubes.  
11/29/1999 4:16 PM

No flames, and thanks for the work. A few comments: Many of the tube brands were made by other companies which makes comparisons tricky. Fer instance, Zenith, Iec, Motorola, etc., were rebranders, not manufacturers. And, unless I'm totally off base here (better info?) most of the Chinese tubes seem to come out of the same factory so the brand on the tube may be somewhat irrelevent. It may be fair to assume that the tubes made in Great Britian are Mullards or British General Electric (can't think of the acronym right now).  
Secondly, how many samples of each tube did you have adn were they new tubes? Generally, a sample size of one is useless in drawing conclusions but it may hint of a direction to pursue. And, of course, the human ear is both our best, and the least accurate and dependable, measurement instrument - every time I pursued one of these "taste tests" my ear fatigued rapidly and I started to doubt comparisons distant in time.  
11/29/1999 11:37 PM

You know...... I could tell that a lot of these were rebrands mainly cause they sounded similar. I put them in here cause a lot of people, like me, don't know that these are rebrands and might pass on a perfectly good tube cause it doesn't have the right name on it. I had 3-5 of each brand. All are NOS. I noticed that the Zenith sounded like the Sylvania. I also had some RCA's that were made for Seeburg that sounded better than the standard RCA's. I was kind of amazed that the Black plate RCA's didn't sound as good as I have heard people say in here. The grey plates were better sounding to my ear. There was a big difference between the mesa and ruby's compared to the marshall and audio glassic's even though they were all made in china. I wrote on the Great britain tubes that the IEC, and the Motorola all sounded like the Mullard. Now the RCA (great Britain) was way different in design and sounded more like the telefunken. I know what you mean about ear fatigue. I compared tubes to each other in a close a/b test because to my ear they sounded real similar and I wanted to compare apples to apples. I worked on this all day and tested some of the tubes 4 or 5 times comparing them side by side to similar ones. I had a lot of fun even though it was tedious but I learned that if someone wants me to recommend a modern tube because of the cost variable I can tell them which ones I would stay away from. I wish I had some of the new Sovteks that everyone has been talking about. Right now I wouldn't recommend their tubes to anyone. What I am wondering is how long a set of say Ruby STR's would last compared to RCA. Well thats about it GW.  
12/1/1999 3:33 AM

I'm kinda anxious to hear the 12ax7's that are supposed to be released from Svetlana early next year.
12/5/1999 1:09 AM

I think sometimes the actual amp comes into play as whether or not a given "crappy" sounding tube sounds good or not.  
F'rinstance, Sovtek 12AX7WXT+ premium select sound absolutely perfect in some applications I have tried (Rivera Quiana, Holland Gibb Droll, Mesa Quad preamp). The 12AX7LPS sounds killer in my Champs, and the Quiana, but my Mesa Quad prefers Chinese tubes, even the crappy ones that usually sit unprotected on my workbench because I don't care about them. The Sovtek LPS is great for a clean tone in pretty much naything I recall trying it in. In my Mesa Quad I run an LPS on the clean channel and Mesa branded Chinese tubes or Ruby 7025STRs everywhere else.  
The one tbe I detest is the Chinese 12AX7WA(?). It baically just fills the hole and that's about it.  
I agree totally with your general direction though. British and US NOS preamp tubes seem to sound the best and as to which one is "better" is really as toss up. I think it depends a lot on the amp and the sort of music one is after.  
I really wish I had more Ruby 7025STRs...I am down to ONE. So far they work great in everything.  
I have an Audio Glassic 12AX7A which sounds okay in a Mesa pre but less than stellar in my Champ. Go figure.  
Thanks for the fun reading.  
12/5/1999 3:42 AM

What's a, new in the box, Ruby 7025STR worth these days. Barry?  
12/5/1999 3:57 AM

You mean to sell or buy? ;)  
I have one left from a handful I bought a ways back. I paid $14 for them then. They may as well be $1,000 now it seems -- none to be found.  
Do you still have a stash?  

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