Interview with Groove Tubes President Aspen Pittman

A short while back, LegendaryTones spent some time with Groove Tubes President Aspen Pittman to discuss and learn about the current state of tubes today as well as to learn more about GT’s new U.S.A. production tubes and future plans. Enjoy!

LegendaryTones: What challenges or obstacles did Groove Tubes face when it first looked into manufacturing tubes in the United States?

Aspen Pittman: Oh man, this is a 2 hour answer, but suffice to say after doing dozens of audio projects/products over the last 22 years, including the Speaker Emulator development, the development of the original Groove Tubes tube performance matching systems, the many tube mics with parallel capsule development, the many tubes we started up in the 4 foreign tube factories…that this was by FAR the toughest adventure to date.

It’s not the common "EPA restrictions" that people site, because there is relatively little of that really, much less than making PCB’s for example, but the lack of material and processing that is tube specific that makes the job so hard. Where to get the Nickle or Plate materials, or mica, or the wire needed to make grids…all those suppliers are GONE! I had to develop new sources or resurrect old ones. And as for machines to make the grids or process the vacuum or sealing…these are not made anymore so you have to search out old ones and refurbish them…even the glass and stem are a BIG issue, and although they are relatively unimportant for achieving a tonal or performance goal…they still have to be specified and sourced. IT has taken me more than 4 years and more than 1 million dollars to get to this point, and we are still not doing all processes in house yet.

LT: Can you discuss other tube types that you are also looking into manufacturing? Will these also be based on GE tooling/designs or will some have elements from other well-known European companies from the past?

AP: The next tube which we are ready to put into production later this year is the GE 6CA7. We bought similar production specs and records and processing details, and materials as the 6L6, so this will be a relatively easier adventure this second time around…but all the parts except the glass, stems, and getters are new tooling and we are just starting up that now. To give you an idea, these parts are made on very old and very complex "4-slide" machines that input a strip of metal and output a finishes cut/bent/shaped part ready for heat processing. It performs four operations in the process and that means four tools to make up and set up. These machines have not been produced in more than 40 years, so finding the right vendor who will work with you to do this is tough, and expensive. The 6CA7 tools will run about $40k, before we make a single part! The mica tooling is also tough because of the hardness of mica it takes special dies; tooling for the 6L6 ran close to $20k.

We have plans for a new 6V6 GE tube, and also a 12AX7 Mullard-style reissue, but that will not be out this year, likely next year sometime.

LT: Tubes that were manufactured in the past from the well-known companies such as Mullard and Telefunken in Europe, and General Electric and Sylvania in the United States are generally thought of as being the "the best tubes" in terms of sonic quality, low microphonics, and longevity. What is it that makes these types of tubes superior from the manufacturing and component perspective versus a tube made in China for example?

AP: Processing, and materials, and perhaps commitment.


The processing is "dirty", the clean room environment makes for a more reliable tube and higher production yield; the amount of vacuum affects the life too, and we are pulling a harder vacuum than other currently produced tubes because we have invested in turbo molecular pumps ($20K a copy, just for the pump that could fit in your 35 mm camera case) which do not use oil (and so no chance for contamination).


Also, we discovered the plate materials used today are much different than the original material used by GE and others, not bad, but they sound different. Fortunately, we purchased from GE (indirectly)a large stash of this old plate material. We have enough for the next 3-4 years…but meanwhile we are trying to replicate it.


It takes far more dollars and time and passion than is economically feasible to build tubes in a modern western country today — which is why all the majors quit doing it. I do this because I believe that some customer, perhaps just the upper end really dedicated types, will pay for this extra effort we spend. But the tubes we build will not be in the next "Brand Name" amp you buy because they can buy a functioning tube for a fraction of what ours will cost. And the Brand Name tube amp companies are the bulk of the tube sales.

It also takes an understanding, as the tube manufacture, that the ultimate customer is not just using tubes to fix then be watching his TV set, as in days gone by. Our customer is using the tube to produce music…a very different application than either the "former" western factories or the current "off shore" factories will ever understand. I’ve been harping on them both from the beginning…they just don’t get it or can’t get it…whichever it is doesn’t matter. They need to be profitable, and making tubes to the older higher standard is NOT profitable as all the distributors want to buy a tube for $3 and sell it for $6. Or as we do, select the top

20% of the performance curve and sell them for $20 (scrapping out the 80% that are sub par). So once again, where’s the profit? Some folks think we are ripping them off because we charge $18 retail for a selected high grade 12AX7 while another distributor charges $10. But they will get 1/2 bad tubes they must return and deal with that shipping and refund hassles. Bad tubes, even for less money, give the whole aftermarket tube industry a bad name.

It reflects bad on us, for example, every time somebody bucks up for a better quality tube that a in the end is just an off shelf tube sold by a greedy distributor with a nice web site trying to snip a bit of our marketshare, and there are more than a few of those. I am sure many players switched to a Line 6 just because of the continuing "bad tube" syndrome and got tired of putting up with their tube amp.

To be fair, there are also truly committed distributors who have their way of sorting tubes that has value, but they are the exception. Most guys just run an old Hitchock and look at emission Pass/Fail and think they are testing something meaningful, and many do no test at all but have a liberal return policy, effectively making the customer do the testing.

However, any distributor is only as good as the stock he can buy to test and sort, and the overall quality today is much less than the days of old when dozens of tube factories were competing for market share so there had to be a good-better-best product range by natural selection. Other than Western Electric in Kansas City, there is no other factory today where quality is job one. BTW, the guys at WE are even more stringent than we are, and they make a heck of a 300 B for the HiFi market…but to prove my case, in order to be profitable, they must set a MSRP price for one of their 300 B tubes (a simple design large triode 15 watt power tube) around $400 per copy! IF they were making this 6L6, I imagine the musician would be looking at $1,000 or more to retube his Twin (which is why WE is not in the music market, but doing very well in the HiFi market). They are my best example of total commitment to quality, in the traditional USA style of manufacturing typified by the Western Electric former company they are resurrecting.

LT: Thank you so much Aspen for your time and sharing your tube wisdom!

AP: No problem, God bless.

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