Once you start to push a little air, however, your amplifier will show off what it can do and the power tube will display its individual characteristics more. Keep in mind, that by using pedals, you can make one amp sound pretty much like any other one, so this discussion is focused on how a few of the most popular power tubes differ from each other when using the amp, and not the pedals, to get your sound. So, here is a rundown of how these tubes differ in sound. EL84 Power Tube The EL84 tube has a snarly sound bright with midrange punch , and is usually found in smaller wattage amplifiers.

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According to the datasheets, they both have identical maximum ratings with the exception of the EL having a 3 watt lower dissipation figure. Try again. Bob Pletka of Eurotubes said: I have said many times in print that I personally am NOT an electronic design engineer or tech by trade, Click to expand Yet you continue to try and sound like a tech in order to increase sales. Bob Pletka of Eurotubes said: however having a decent working knowledge of how and why tube amps work is not rocket science.

Click to expand Bob Pletka of Eurotubes said: I do have many years of "gained by experience" understanding Click to expand The "experience" card And you seem to think that this was made possible all because they dropped the plate dissipation rating? Bob Pletka of Eurotubes said: For open minded people, think of it this way, all tubes of one flavor such as an EL84 will draw, pull, have - or what ever word you feel is correct - differing plate current values at specific voltages.

If this were not true then you would not have to adjust your bias or even match tubes. First off The components just provide the path for this current to flow. But it is the power supply drawing it. Valves are not perfect. It is for this reason why amps must have the bias checked when the power valves are replaced. You seriously think that the heat dissipated by the plate is what allows valves to "make power"? I can just see Sir Isaac Newton rolling over in his grave right about now.

Bob Pletka of Eurotubes said: So now for the billion dollar question! Wait for it The same reason why your EL exhibits a lower power transfer figure than the EL It has a lower transconductance and it knees over on the curve chart a lot sooner than the EL84, which amounts to a lower load power transfer figure. This has zero to do with "plate dissipation". If it were the plate dissipating all of the output power, then how would the load be getting any of it?

A simple fact. What happens to the plate voltage? Yes it does Less idle current is being drawn by the supply hence lower voltage drop.

Yes Jon, it does! Nothing to do with "plate dissipation rating". Bob Pletka of Eurotubes said: So let me state this again in simple terms. Tubes are simply valves, using a smaller valve will result in less power when done right. For the record, I would NEVER recommend to anyone that "you can replace a tube that can dissipate 30 watts with a tube that can only dissipate 14 watts".

Why is this??? Something called a "load line" If the load is sized such that the average plate dissipation is right at the dissipation rating of the valve at full output most Marshalls , installing a valve that is rated for LOWER than the original valve would send the lower dissipation valve into meltdown. Why is this?

Because the load would allow the power supply to draw too much current through it!!! It would be like mismatching down with a 4 ohm cab on the 16 ohm tap of the OT! The power supply does. Bob Pletka of Eurotubes said: and can dissipate 9 watts. What happens?

Plate dissipation has nothing to do with output power. Get over it. Characteristic curves Bob! Bob Pletka of Eurotubes said: Some may be able to call the terminology I just used "incorrect". Bob Pletka of Eurotubes said: Please remember that when you are explaining something to a large group of people with varying degrees of technological vocabulary, generic terms that are easily understood are best.

Generic terms Bob Bob Pletka of Eurotubes said: Aspen? Oh, and the shot depicting me killing Jesus Christ, it is in extremely poor taste, but after thinking it over I did get a serious laugh out of the extent someone went to, just for me All hail eljeffe!!! Bob Pletka of Eurotubes said: These posts really astounded me!

Anyone who has the ability of sight can look at an EL and easily see that it is not even remotely close to an EL Professing a tube to be a "substandard EL84 from their regular product line" or defective without ever even looking at one? Without testing one? Without listening to one? Bob Pletka of Eurotubes said: I personally never give an opinion on anything unless I have done the necessary research to give a valid honest opinion. Fender designed these amps to run hot because they sound good like this.

The limiting factor is what the valves can safely dissipate Bob Pletka of Eurotubes said: We spend our time helping players get the tone they want and answering questions they cannot get from other vacuum tube resellers.

And we spend our time correcting your bullshit answers.


valvulas jj el84

Only the machines are the same, and in the Tesla days they were new, and now they are old. The used materials definitely are not the same. Also wires, and nickel technology came from Tesla plants that are all closed now. They are regarded something different, which is correct. There was enough NOS around. Many people thought this situation would always stay that way, and the TESLA management thought so too. The machines were moved out of the building and reinstalled at a factory of a man called Jan Jorgo, better known as JJ.


JJ EL84 | 6BQ5

Use shielded wiring from the input jacks to the volume control and if more than an inch or so from the volume control to the tubes. Ground only one end of the shielded wiring. If signal and power wires must cross, separate them as much as possible and do so at right angles. Tightly twist AC carrying wires together such as to tube filaments.


JJ EL84 / 6BQ5



JJ EL84 Power Tube


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