Giaime said:
Seriously, what is needed to sell High End, is hypnosis. "Trends", "Gurus", "Brand names", are parts of mass-hypnosis.
sure a LS50 is better than a KT....
in a transmitter...
or oscillator...
but I thougth we are talking about amplifiers?
in a transmitter...
or oscillator...
but I thougth we are talking about amplifiers?
the LS/50GU50 was designed for use in military transmitters
and it follows that the construction of the tube is optimized for that service.
The KT... was designed for audioamplification.
It follows that this tube was optimized for audio.
If you want a engine for a racingcar you would not buy the engine of a WWII tank build for military use, even if you can get it cheap and the costs of manufacturing where high...
and it follows that the construction of the tube is optimized for that service.
The KT... was designed for audioamplification.
It follows that this tube was optimized for audio.
If you want a engine for a racingcar you would not buy the engine of a WWII tank build for military use, even if you can get it cheap and the costs of manufacturing where high...
gorgon53 said:
Yes!
I have couple of similar designs, one with 4x6L6 per channes, another with 2XGU50 per channel, the difference is only in output transformer's ratio (6K CT vs 4K CT)and arrangement of power supplies (375+375V vs 375 only). 6L6 version gives me 80W of maximal power, GU-50 version gives me 120W of power, and sounds tastier. I use GU50 with 300V on screens despite their ratings differs from LS50 originals (Soviet manufacturers required from designers to use them in more relaxed mode, I believe they did not want to go to Stalin's jail if tubes don't survive that's why took such preventive measures).
gorgon53 said:
Wrong analogy. If compare tanks vs racing cars, use KT88 VS 12AX7. If you compare Gu-50 vs KT88, use tank vs tank.
Take simplified Humvee and you get it. Looks like Humvee, works like Subarban. If you want a look, buy Hummer-III. But don't expect it to go on snow and on sand like real Humvee does.
The same with tubes. Ray pentodes require more strict grid alignments, they were are more expensive. Also, anodes of GU-50/LS-50 were made of nickel that can survive higher temperature. More linearity and more power don't mean they sound worse, actually they sound much better than cheaper tubes designed especially for mass production audio amps.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Hmmm... After posting pictures I realized that my analogy is wrong as well, because GU-50 looks much better than KT88. 
astouffer said:
Good question! Also, why Allies used 807 where Germans used LS50 if 807 is "worse for RF"?
May be Hitler lost the war because he needed to spend much more money buying from Telefunken much better tubes than were really needed? 😉
The GU50 is a RF-tube, sturdy grid construction wich has to withstand high levels of POWER, vibrations, and such
This calls for heavy construction, rigid fixing and so on (therefore I called it a "tank"). Those kind of construction is necessary for a transmittingtube intended for military use BUT for a audiotube it is not the best way to go.
The KT is build much more fragile BUT grid wires can be made thinner and the grid can also be more closer to the cathode
This calls for heavy construction, rigid fixing and so on (therefore I called it a "tank"). Those kind of construction is necessary for a transmittingtube intended for military use BUT for a audiotube it is not the best way to go.
The KT is build much more fragile BUT grid wires can be made thinner and the grid can also be more closer to the cathode
gorgon53 said:
Ok, let's call Tubelab on the stage now, to open both tubes and measure/compare internals. 😀
I've compared "externals" for myself, GU-50 sounds much tastier, is more powerful (however, I am comparing now 2 nearly identical amps, with 4x6L6 vs 2xGU-50, though 6L6 and KT88 are a bit different, but they are very similar).
Military ray pentodes won against guitar ray tetrodes.
The GU50 is a 50W RF pentode
The 6L6 is a offspring of the 25W beampowertube 807 (small transmittingtube)
The KT88 is a further developement of the 6l6 especially for audio use
The 6L6 is a offspring of the 25W beampowertube 807 (small transmittingtube)
The KT88 is a further developement of the 6l6 especially for audio use
Be carefull when comparing tubes, 80W from a pair of 6L6 means you drive them very hard. Compare 25W anodedissipation tubes with 25W, GU50 with 50W pentodes, or 2+2 of 6L6 t a pair of GU50
gorgon53 said:
Right, except 6L6 was developed before 807, and GU50 is not a pentode, it is a ray pentode clone developed by Telefunken. They could afford such typical German accuracy and build ray pentodes.
gorgon53 said:
Be careful reading my posts, actually I wrote several times about 2 (2 means two) pairs of 6L6 (80W, vs 120W from one pair of GU-50), i.e. I compared very similar amps with 4x6L6 vs 2xGU-50:
...also, 6L6 is rated for 30W, GU-50 is rated for 40W of plate dissipation, I would advise you to be more careful reading specs. 😎 😎
LS50 was a PENTODE (grid1,2 and3 NOT shadowing each other, therefore it was NOT a BEAMPOWER) tube, just a ordinary pentode)from begin of the 40th
L=Pentode
S=Senderöhre
50=50W anodenverlustleistung( means Pa)
maybe the russians derated there GU50, dont know
S=Senderöhre
50=50W anodenverlustleistung( means Pa)
maybe the russians derated there GU50, dont know
I even got data on 6l6 where it is rated at only 18W anodepower
(depends on the operationconditions and live-expectations)
(depends on the operationconditions and live-expectations)
