why DIODE CLIPPING in AMP ?

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Your missing the point and I dont think its because you do not know how to read.. A tube is a diode true or false? regardless of function type
 
lespaul6":258is45u said:
Your missing the point and I dont think its because you do not know how to read.. A tube is a diode true or false? regardless of function type
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False for 600 :D

Your 6L6 is not capable of rectifying AC to DC.

There are many different tube designs that exist or have existed over the years. Tubes do exist to provide AC to DC rectification as you're pointing out here, but they operate fundamentally different than silicon diodes. So your statement that tubes are diodes is too general and incorrect.

MOSFETs, however, are a totally different story. They can be modeled like back to back diodes and in circuits 101 courses, they even teach it this way for troubleshooting.
 
"The tube diode was the first diode ever invented (in fact it was the first tube ever invented). For many years it worked quite dependably and it was the only choice for rectifying current for high voltage power supplies. When solid state technology was developed in the 1950’s, it was found that solid state diodes could do the job of tube diodes, only better." Better let Mike Soldano know to correct his website info
 
No, Mike is correct still in his wording. He's talking about a specific tube design capable of rectifying AC to DC. Silicon diodes were later used to rectify AC to DC. There's nothing incorrect about his statement at all.

Your statement claims all tubes are diodes. That's fundamentally incorrect from how I read your statement.
 
Then there is nothing incorrect when I said the same.... I was making the general point about what a thing IS.. not how it functions.
 
You cannot and will not get a tube rectifier to work in the locations used in the amps to provide clipping where silicon-based diodes are being used today. Your general point is wrong, and I've provided clear evidence as to why. Whether you want to believe it or not, your statement as it was worded is incorrect.
 
Again, I'm not talking functionality.. only the fact that the first tube was a diode and was called a diode or a tube interchangeably
 
lespaul6":vuhn4pjt said:
Again, I'm not talking functionality.. only the fact that the first tube was a diode and was called a diode or a tube interchangeably
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The first tube was a diode, but that does not mean all tubes are diodes or that all tubes are capable of providing rectification like a diode. The interchangeability stops as soon as you no longer talk about a tube rectifier aka a diode.

Tube rectifiers do not have a Beta rating to provide any type of amplification, and they have no grid for controlling current through the tube from the anode to the cathode. They're designed differently to perform certain tasks. Although the progression of tube technology started with a tube rectifier, this does not mean backwards compatibility as tube technology progressed.
 
lespaul6":3d8wyc8v said:
Thanks... that was my only point.
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If you'd said "tube rectifiers are like diodes" we'd not had this conversation :lol: :LOL:
 
Well the only difference would be the addition of control grids within the tube diode to allow for amplification etc.. right?

"The simplest vacuum tube, the diode, contains only a heater, a heated electron-emitting cathode (the filament itself acts as the cathode in some diodes), and a plate (anode). Current can only flow in one direction through the device between the two electrodes, as electrons emitted by the cathode travel through the tube and are collected by the anode. Adding one or more control grids within the tube allows the current between the cathode and anode to be controlled by the voltage on the grid or grids.[5] Tubes with grids can be used for many purposes, including amplification, rectification, switching, oscillation, and display."
 
lespaul6":31a9doyr said:
Well the only difference would be the addition of control grids within the tube diode to allow for amplification etc.. right?

"The simplest vacuum tube, the diode, contains only a heater, a heated electron-emitting cathode (the filament itself acts as the cathode in some diodes), and a plate (anode). Current can only flow in one direction through the device between the two electrodes, as electrons emitted by the cathode travel through the tube and are collected by the anode. Adding one or more control grids within the tube allows the current between the cathode and anode to be controlled by the voltage on the grid or grids.[5] Tubes with grids can be used for many purposes, including amplification, rectification, switching, oscillation, and display."
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Not quite. The entire tube has to change to provide amplification characteristics and to have a gain (beta) designed into its structure. There's a reason you're not finding tubes made for class A or AB operation used as rectifiers.

As for the voltage part on the grids, grids are biased to have a more negative voltage than the cathode otherwise the tube would short. It's called providing a common mode bias. You can google grid bias or cathode bias for examples. AC then modulates the tube's DC bias point providing amplification by the tubes beta rating for that given common mode voltage.
 
So in conclusion the vacuum tube was in fact used as a diode.
 
12ax7 are dual triodes, EL34 are pentodes, 6L6GC are beamed tetrode. IE tubes that are in your amp's signal path are not diodes.
 
Whowantsamustache":2zetqhsi said:
So in conclusion the vacuum tube was in fact used as a diode.
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Vacuum tube is a type of technology with many implementations, just like a semiconductor is a type of technology with many implementations.

The first vacuum tubes were indeed diodes, just as there are semiconductor diodes. All diodes do the same thing: they allow current flow in one direction and block it in the other direction. They are an electrical valve; hence the term "valve" being used to describe early tubes and later being used as a general term for tubes, despite the fact that triodes and pentodes don't actually act as valves.

A second vacuum tubes were designed as amplification devices and are the triode, just as the second semiconductors are similar amplification devices (also a triode, though that name isn't generally used for them). A BJT and a tube triode are analogous electronic devices, and in fact setting them up to function works similarly.

The statement above that "a tube is a diode" is false. A tube can be a diode. A tube can be a triode. A tube can be a pentode. A diode can be constructed using a tube. A diode can be constructed as a germanium semiconductor. A diode can be constructed as a silicon semiconductor.
 
rstites":1bq126in said:
Whowantsamustache":1bq126in said:
So in conclusion the vacuum tube was in fact used as a diode.
Click to expand...

Vacuum tube is a type of technology with many implementations, just like a semiconductor is a type of technology with many implementations.

The first vacuum tubes were indeed diodes, just as there are semiconductor diodes. All diodes do the same thing: they allow current flow in one direction and block it in the other direction. They are an electrical valve; hence the term "valve" being used to describe early tubes and later being used as a general term for tubes, despite the fact that triodes and pentodes don't actually act as valves.

A second vacuum tubes were designed as amplification devices and are the triode, just as the second semiconductors are similar amplification devices (also a triode, though that name isn't generally used for them). A BJT and a tube triode are analogous electronic devices, and in fact setting them up to function works similarly.

The statement above that "a tube is a diode" is false. A tube can be a diode. A tube can be a triode. A tube can be a pentode. A diode can be constructed using a tube. A diode can be constructed as a germanium semiconductor. A diode can be constructed as a silicon semiconductor.
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Wow you really showed me.

Next time though be sure to quote statements for what they really are.

I didn’t say “a tube is a diode”

I did say “ the vacuum tube WAS used as a DIODE”

You nerds make things so complicated. I know there are different vacuum tube configurations for different applications. Diode, triode, pentode...
 
godgrinder":a1kdij0b said:
12ax7 are dual triodes, EL34 are pentodes, 6L6GC are beamed tetrode. IE tubes that are in your amp's signal path are not diodes.
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I was in a museum with tube op amps the other day and it did get me thinking about what it'd take to put together a little tube screamer style circuit made entirely of actual tubes: tube op amp with tube diode for the clipping.

Yes, I do realize that actual operating voltages would mean it wouldn't serve the same purpose, and most unfortunately actual costs would make it pointless......still a fun little thought experiment. :)
 
Serious question, is there an amp modder out there that does a Jose mod with an extra pre-amp tube instead of diode clipping?

I know Jose did. I know MC does but it's pretty rare, his famous HG Jose is diode based. Other than that I wonder if there is anyone out the currently that does one?

FYI I don't need one, I already have one I am genuinely curious if there is anyone left that does one. I think everyone does diode clipping now.
 
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