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Very large tubes from radio transmitting tower

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Hello ,
new YL1260 have the same number on the tube and the package .
Kind regards , Alexander .

1260a.jpg

1260b.jpg

.....and DIY sockets made by a friend .

An externally hosted image should be here but it was not working when we last tested it.
 
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So are these new YL1260 available for buying somewhere?
How much $$$$$$

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Now here is a big surprise. Seems to be a shadow grid version of the EL34 available now: (and for $12 !)

EL34B - Valve Art | Antique Electronic Supply

Anyone tried these? Have you looked inside to see if there is an extra grid? (maybe they are just -aligned- grids 1 and 2)
Reliability?
 
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Anyone tried these? Have you looked inside to see if there is an extra grid?

I have 4 of them, purchased from AES several years ago. They look just like the tubes in the picture. EL34B is the marking on the BOX. The tubes are marked EL34 same as the tubes in the picture in the ad. Nothing special about them. Three normal grids. I haven't used them enough to judge reliability.
 

PRR

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The dates are wrong!
Correct:Ug2=+225V,Ug3=+30v

Did you read the datasheet?

The "G2" "G3" functions are NOT like conventional pentode structure.

I also doubt that looking at wee-tiny "shadow grid" tubes of the 1930s really sheds light on this late LARGE design. I understand the camshaft in a Model T. My Honda has a camshaft. But there's a LOT of differences in what happens. (The T has 8 bumps, the Honda has 20...)
 
The estimated lifetime is ~ 8000h (daily on / off) or ~ 16000 hours (24/365 or continuous operation without switching off). Experienced practice tells me that the YL1260 works much longer than ~ 30000 hours (permanent work) with a very small and slow emission drop. My experience is based on monitoring the YL1260 in the linear amplifier for VF and I have no experience in working on audio frequencies.
 

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I see the YL1260 listed at 2414 DM in 1985.

Which would be about $1528 by today's conversion. Of course inflation would have at least doubled or tripled that from 1985. ---$5000---
Only 857 pieces were made. And probably about a dozen still work.

I'm afraid I max out at about $5 for tubes, preferring $1 tube lists.

Let's see, to get 250 Watts diss., that'll take 25 pieces of $1 12HL7 in parallel, and the total gm1 will then be 525,000. That'll beat some Mosfets! Plus 25 $2 sockets. But then all those bias adjustment pots.... And then two of those banks to do P-P. But then 1,050,000 gm in class A would be really something. The Million uMho single stage amplifier. Stability? Heat?

Or I could go with 9 pieces of 21LG6A at $4 each. These have aligned grids too.
Total gm1 of 103,500. Could be done.

Or 6 pieces of 36LW6. Aligned grids. 72,000 total gm.
Or 5 pieces of 4D32. " " 100,000 total gm.

Where would one get an OT for 500 Watts though. Could almost go OTL. And then speakers.
Ehh, forget it. Probably all go up in a big fireball. Just Day-dreaming.

.
 
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Actually, the most square curves are with Beam Tetrodes with non-aligned grids, the beam is the whole electron flow, designed really well such tubes are pretty much perfection of all screen-grid tubes. Until now, I always thought E130L was non-aligned too, because it has near perfect knee, which is typically impossible to achieve using aligned grids. I write an article about the singular-beam Tetrodes as I prefer to call them now: Vacuum tube / Valve appreciation Society

A perfect example is YL1130, the control grid is actually a mesh similar but smaller to that of mesh anodes from the 20s-30s, yet screen is large pitch and horizontal.
This new discovery for me of E130L being aligned-grid changes a lot, I am really surprised about this, but now it does make sense, since the percentage of kinks in the curves is still higher than a typical last generation non-aligned tetrode.
 
I've also got this number of just 857 tubes that were manufactured at the Telefunken Ulm plant from an former employee there who has salvaged the books before the plant was shut down. Maybe Alexander's source is the same. Also maybe that Alexander and me know each other ;).
So, this is a very valuale tube that should not be worn out.
Best regards!
 
They look impressive.

Certainly a margin more usuable than some high power tubes (certainly that I've seen)

I wrote a thread about a pair of Ediswan V1505, when I first joined DIYA, or shortly after.


V1505 @ The Valve Museum

Those triodes looked interesting, just I dont fancy 2kV or more on the plate! Discovering those valves and learning a little about them was what began my interest in the technology. Many years later and I still know nothing haha
 
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Actually, the most square curves are with Beam Tetrodes with non-aligned grids

My experience has been that design and voltage of grid 3 is the key determiner of how square the plate curve knees are. If g3 is too effective (either too fine a mesh, or negative V), then off axis electrons are returned to grid 2 when plate V is low. This is often intentionally the case for tubes like 6BQ5 where the rounded knees remove much of the 2nd Harmonic for SE use. A tube with a fine mesh grid 3 (a so called dual control pentode) provides a good illustration of varying the voltage on grid 3 and the effect on knee curves:

https://www.diyaudio.com/forums/tubes-valves/160240-suppresor-grid-feedback-6.html#post2083612
 
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