When I published my last two reports, the JJ803S and Tung Sol 12AX7 reissue, I was asked about NOS. Below are some NOS results.
|Tung Sol Reissue|
Update: Today on the weekly 65 Amps webcast Dan and I spoke on the subject of tubes and some of the points in this post. Below is the recorded broadcast from today, 3/7/12
I am posting a bit of dialogue from the Dr. Z Amp forum where somebody asked me a few questions:
How far above and below specification would you consider using a tube? For example a 12AX7 in a tone driver position, and in a phase inverter position.
You mention a true gain reading of 104 as performing better. Is there point on the true gain scale where a higher reading becomes a problem?
Is there a low reading where you would not use a tube? The new JJ true gain reading goes down to about 73 while the new Tung Sol goes down to about 85.
Please advise, thanks.
Below is one more reason that tubes were better in the past.
|Here is the pile of rejects from the 1920's & 30's before the Tube Smashing machine was built.|
|This little chart from the folks over at Tubeworld is their point of view on some 12AX7|
types. It might be a very nice guideline for folks.
I don't think it would be fair to omit the work that was done in 2009 on the Blackburn front by TechTube. If nothing else these folks proved that high quality tubes could be made today.
I have some photos with captions and data at
Below I will copy and paste some of the commentary on facebook in regard to this post and perhaps some of the other vacuum tube posts.
Myles Rose Today only a small percentage of tubes are tested. If they are not flat dead they are shipped. The supplier's warranty is the QA when somebody ends up with garbage IF the end user wants to pack the tube up and ship it back to the tube vendor. That is only one issue. A bigger issue is the question / worry in regard to when the tube will fail. It is not a matter of "if", it is a matter of when. Tubes in the past would fail but it took years and decades to wear them out so it was really not much of a concern or worry. Unfortunately today you have the concern from the day you plug in the new tube.
Dan Boul Can you post this on the tube manufac's FB's? This is like a fantasy . . .
Myles Rose Dan Boul - when I was at the last tube place I worked I would send the reports that I now do over in your shop to the manufacturers for each run. In the case of JJ they would respond very quickly and were usually already aware of the problem. In the case of another company they did not care and at one point even tried to joke with me that they were the only game in town. Another supplier, Ruby Tubes, was always ahead of the curve and quite consistent.
Hopefully consumers will try to push the tube manufacturers harder in the future. Some of them listen (Tom McNeil / Ruby Tubes). He has a strong relationship with the manufacturing side of his operation due to a good personal relationship. One of the folks I was close to was the largest in regard to buying from some manufacturers but had something a poor personal relationship. There were two of the same product from Shuguang where the Ruby was terrific and the other vendors product was not as consistent.
The best solution would be for somebody like Blackburn / Mullard to get some sort of funding again and resurrect their operation. They were on the right track. All it would take is one manufacturer to make a good ECC83/12AX7 that even at $70 a tube, if it sounded nice and lasted more than a few years would raise the bar. What these folks showed to me is that good tubes can be made today.
None of the current tube makers have anything to be proud about from my own observations over more than the last decade. It is almost as if there is a secret society of tube manufacturers that meet in the dark shadows and agree to raise prices and reduce quality to raise profit substantially above what is considered fair in many other industries. As one tube is discovered to be an over priced item that has performance that does not support it's retail price the maker just slaps on a new name and label. Sometimes they will change a cheap part that does not cost them any more, a part that does nothing to change the performance of the tube but is visible to the naked eye. Perhaps gold pins will even be employed to allow them to sell the tube as TWO new models with a higher price.
Myles Rose It is a crap shoot for sure. You can push the odds more in your favor by having a good/trusted vendor who tests properly. That is half the battle where you still have some control. Where you have no control is the reliability of the tube. What works today will probably fail during the next year.
Myles Rose 52,000 reads as of 3/18/12 at 2:47pm PST. Not too shabby.
Hopefully one of the folks at New Sensor, JJ, Shuguang or one of the other tube makers were one of the readers. Tip for any of them: Make a 12AX7 (that is a good first step) that retails for $50.00. It would meet design spec for a 12AX7 that was published from 1950-1970, the same spec that you folks say you follow today. The tolerance allowed would be +/- 10% on transconductance, plate current and plate resistance. The tube would carry a life guarantee of 10,000 hours against failure or physical microhonics.
This type of performance was commonplace in the 1950s, 1960s, 1970s.
Scott Lerner I don't have a single new production 12AX7 that sounds better than a good NOS. I have a ton of both. I always wind up with NOS when I roll tubes!! Thanks Myles...
Myles Rose Scott - that is pretty much right in line with what I see on a very very very regular basis. Since 2002 or so things have been on the decline each year. Prices go up, quality goes down but the number new new names on the same tubes increases the number of the same choices as we had before with reduced quality and declining expectations on the part of the amp user/builder/owner toward the tube manufacturer.
I was asked about plate resistance. Sometimes mathematics is the only easy way to try to explain:
|Some people think that a 6CA7 is the same tube as an EL34. They are not. They are interchangeable but are NOT the same tube. New tubes called 6CA7 tubes are little more than big bottle EL34 tubes. Not the same. This is a real example of a real 6CA7.|
|6L6GC RCA black plate NOS same date codes around 1970, original CJ date codes.|
|OK ... what the heck ... one more tube porn shot. These go for about $300 each today. As I said in my NOS article, folks that have what they call an NOS tube collection actually have a financial investment portfolio. I talked about this the other day with Ritchie Fliegler. During the economic dive in 2008 gold top Les Pauls even lost some of their value. NOS tube costs continued to rise.|
A bit of an update. I posted the below on facebook and copied it over here.
|Are you kidding me? This is a pretty decent tube, the Tung Sol Reissue, but ....|
|.... but does the reissue directly above look similar in any way to the original?|
The two shots above, some of the dialogue:
Scott Frye If the OLD Tungsol was so kick-ass why didn't the make the re-issue just like it??
Myles Rose Because that would have cost a lot of money and would take time and effort. It is a lot cheaper to take an existing tube, the 12AX7EH and just silk screen on a new name that you purchased the right to use.
Producing a true reissue is very costly. Groove Tubes re-created the Mullard 12AX7. The initial runs were great but each revision had more and more problems surface. In the end the tube was garbage. Their GE 6L6 was a fantastic reissue right down to the 5 clad plate material and micas made in the same factory that made them for GE. Still my favorite 6L6 tube. Their Mullard XF2 EL34 reissue was great in some versions and a bit less terrific in other versions. All in all I liked the tube a lot. Their 6CA7 GE reissue, again... an attempt at an exact copy, was plagued with problems. Right as GT was being sold to Fender it was discovered that the factory had not followed the design drawings properly and there was a problem in the relationship between grid number one and two.
Aspen Pittman, as much as I can complain about some of his antics at times, did some really great things. When he produced a tube reissue he paid for the design, the tooling and hired the expertise such as the folks that worked in the original factories. He made a good strong effort, no expense spared, at making a true reproduction of the original tube right down to the materials whenever possible. Others in this industry just slap a grand old name on a current production tube that has nothing in common with the original other than having a glass bulb and in most case, the proper number of pins sticking out of the base.The original tube designs of GT such as the 6L6CHP (black plate high performance) and the 5881 short bottle were both terrific tubes. Aspen and Steve Sanett of Penta Labs had a great relationship with Tesla and later JJ. The KT88SV was a 50 watt tube with heat sinks on the plates. The E34LS was a 30 watt EL34 that also had a different plate assembly than the JJ which was a 25 watt tube as were other EL34 tubes. These were GT exclusive. The KT66HP was a grand tube. It compared with the real Genelex KT66s of the past. It was made under contract in the Reflektor Factory in Moscow before Mike Matthews took over the entire place. The tooling was GT developed and owned. Around the time that Sovtek was taken over by New Sensor the tooling mysteriously vanished and that was the end of the grand KT66HP.
Aspen Pittman was directly responsible for some terrific tubes, both accurate reproductions and some great original designs. He is the only person at this point that you can point to and make that statement.
Myles Rose Economics lesson update for Scott on his original question .... the total cost to turn an existing 12AX7EH into a 12AX7 Tung Sol Reissue would be less than $15 for a new silk screen. Perhaps less, that is what one cost over at Groove Tubes to make a new silk screen from scratch. If New Sensor did not mind tossing out the old 12AX7EH boxes or timed it right when you ordered new boxes that say Tung Sol on them, the cost of new artwork would have to be added. Same for the Mullard reissue preamp tube New Sensor sells or the "Mullard" EL-34.
My guess based on a bit of experience would be under $100 with enough change back to buy a pretty nice dinner for two at a chain like Black Angus.
As a side note, the cost to re-produce the Groove Tubes 6L6GE was in the ballpark of $400,000. Like I said, when Aspen Pittman wanted to make a recreation he went full bore in the right direction. Side note ... Aspen has an extensive microphone collection. One type uses a tube that is very hard to procure and very costly. There would be a market for these tubes, may a few hundred at the most. He was seriously considering remaking that tube.
Here are a few links folks may find interesting: