Hey… if “they” can get $250 a bottle, why not keep making them bigger? OR $350.
In a way, they give into the very American penchant of “bigger must be better”. So, there is a perpetual market. With a pretty high gain front-end, both local and global negative feedback to “tame the beast”, the produced power could be quite sweet indeed.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
In a way, they give into the very American penchant of “bigger must be better”. So, there is a perpetual market. With a pretty high gain front-end, both local and global negative feedback to “tame the beast”, the produced power could be quite sweet indeed.
⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
⋅-=≡ GoatGuy ✓ ≡=-⋅
I think there can be some advantage to 2 tubes over 4 in a 250W push pull. Less tubes to go wrong..
However this is gonna be one crazy tube to drive. I remember reading about the 120 or 150 that you couldnt use over 39K of grid leak or so in fixed bias.
If this decreases with anode dissipation you could very well be looking at a 33K grid leak for reliabilities sake.
At which point your gonna either need a cathode follower or a 6BX7 or something of the likes as a low Ri RC coupled driver.
There is a point at which they make these things larger and larger, that the only way to drive the thing RC coupled is to use another output tube as a driver
Perhaps that japanese guy that drove a transmitting tube with the same transmitting tube was way ahead of the curve.
Every place has got problems, last time i filled up it was about 7.50 a gallon. And owning a car means you pay a fixed fee every 3 months for the privilege of having it, not even for using it: Case and point i rode a VW Caddy for a while and it set me back 1500 US in the year in road tax for just having the thing on my driveway.
However this is gonna be one crazy tube to drive. I remember reading about the 120 or 150 that you couldnt use over 39K of grid leak or so in fixed bias.
If this decreases with anode dissipation you could very well be looking at a 33K grid leak for reliabilities sake.
At which point your gonna either need a cathode follower or a 6BX7 or something of the likes as a low Ri RC coupled driver.
There is a point at which they make these things larger and larger, that the only way to drive the thing RC coupled is to use another output tube as a driver
Perhaps that japanese guy that drove a transmitting tube with the same transmitting tube was way ahead of the curve.Every place has got problems, last time i filled up it was about 7.50 a gallon. And owning a car means you pay a fixed fee every 3 months for the privilege of having it, not even for using it: Case and point i rode a VW Caddy for a while and it set me back 1500 US in the year in road tax for just having the thing on my driveway.
Yes. Instead of enlarging inefficient tubes they should spend their time duplicating the 8417.
There are a couple of sweeps that will work with some adjustments.
23mA/V transconductance... The E130L comes somewhat close but has even lower Ri. and a Screen grid that is a frame grid.
That tube looks a bit like a bigger EL36 in triode. There was an industrial version of the thing the E235L that is completely unknown.
23mA/V transconductance... The E130L comes somewhat close but has even lower Ri. and a Screen grid that is a frame grid.
That tube looks a bit like a bigger EL36 in triode. There was an industrial version of the thing the E235L that is completely unknown.
If i may be free to add, some sleeper tubes are the E83F E80L E86C and EF184 the latter was made by the millions by virtually every manufacturer and is actually one of the nicest pentodes around due to the fact it has a G1 and G2 frame grid. And you can find them for less than postage NOS.
GU50 : Triode curves like the 300B in triode mode, ugly Goring/Stalin* tube but cheap and indestructible.
GU50 : Triode curves like the 300B in triode mode, ugly Goring/Stalin* tube but cheap and indestructible.
Last edited:
I think but cant prove, so therefore purely speculative that the KT120 re-uses some cathode forming tooling from one of the bigger sweeps. 6P45S.
EI did something similar, they where sitting on the tooling to make every european tube tube for the replacement market. But someone figured you could use the plate structure and cathode/heater out of the EL509 to make a low Ri triode.
The problem is, that it is very hard to make a tube with over a GM of say 20K without using frame grids.
Frame grids are expensive to manufacture, and due to the marked situation , (Guitair is still the biggest slice of the pie) there is no incentive for them to do so.
I suspect some of the tooling is also lost.Expecially after EI was closed and the tooling junked.
There was a guy that was big on tube microphones, Oliver Archut? that posted on some forums. The VF14k could be made today, there is just nobody that is going to shell out 500K for a welder just to make the metal case.
Frame grids are expensive to manufacture, and due to the marked situation , (Guitair is still the biggest slice of the pie) there is no incentive for them to do so.
I suspect some of the tooling is also lost.Expecially after EI was closed and the tooling junked.
There was a guy that was big on tube microphones, Oliver Archut? that posted on some forums. The VF14k could be made today, there is just nobody that is going to shell out 500K for a welder just to make the metal case.
Right. But we're 50 years later and we have 3D printing, laser machining and all sorts of other technology not available in 1970. Just need a few bright and motivated engineers.
Edit: The key is not to re-use 70year old tools and fixtures. But create a modern, flexible manufacturing line that can make any tube relatively cheaply. Many industrial processes have switched from high-cost single purpose hard tooling to flexible, on-the-fly reconfigurable setups.
Last edited:
frame grids are tungsten wire around molybdenum supports. i believe a 6DJ8 has grid wires that are thinner than a human hair.
Tubes like that will never be made, unless extraordinary capital is expended to do so.
Just to name a problem at the top of my head.
But the problem is that some stuff is just not available anymore.
This video is unrelated...
Edit wrong video.
Why Can't we Remake the Rocketdyne F1 Engine? - YouTubehttps://youtu.be/xbvQBwnppQo
Tubes like that will never be made, unless extraordinary capital is expended to do so.
Just to name a problem at the top of my head.
But the problem is that some stuff is just not available anymore.
This video is unrelated...
Edit wrong video.
Why Can't we Remake the Rocketdyne F1 Engine? - YouTubehttps://youtu.be/xbvQBwnppQo
VF14, right, the tube used in the legendary U47 mic by Neumann.
Related: I recently read a very interesting review of the U67 reissue. The fellow that wrote it is very knowledgeable and experienced. Recommended reading.
Neumann U67 Reissue: Complete Tear Down and Analysis
Related: I recently read a very interesting review of the U67 reissue. The fellow that wrote it is very knowledgeable and experienced. Recommended reading.
Neumann U67 Reissue: Complete Tear Down and Analysis
I have an interest in how tubes where made, and im in contact with someone who handcrafts tubes from his garage. I finally got in contact with one of the last people that knows about tubes and where to source the materials.
I run a telegram group where ive posted every bit of information i could find about the materials used in electron tubes. Old catalogs and material datasheets.
This is about a little mom and pop business that was making tubes in California We corresponded for half a dozen emails about tubes..
The stuff is still available, and if you use some substitute materials you CAN make Directly heated triodes. Indirectly heated requires too many machines to make the cathode sleeve for example
Vacuum Tube Sealex Machine and Evacuation Stations - YouTube
I run a telegram group where ive posted every bit of information i could find about the materials used in electron tubes. Old catalogs and material datasheets.
This is about a little mom and pop business that was making tubes in California We corresponded for half a dozen emails about tubes..
The stuff is still available, and if you use some substitute materials you CAN make Directly heated triodes. Indirectly heated requires too many machines to make the cathode sleeve for example
Vacuum Tube Sealex Machine and Evacuation Stations - YouTube
That is laudable (both your efforts and the person that is making tubes out of a passion of his, I presume). I only have my own mouth to feed so I may endevour into audio in the future, out of passion too, because the profit will be small if any (I don't wish to make expensive stuff, only GOOD stuff that is affordable). If I do anything it will probably be solid state though.