when an el34 is clipping - is that when the signal to the grid is too high
or is there other ways it can clip
in which way does - plate / heater current come in to play
and can the outtransfo have any effect to it
or is there other ways it can clip
in which way does - plate / heater current come in to play
and can the outtransfo have any effect to it
It can be clipped in either direction, plate current depends on the grid drive voltage in any case; the OPT plays a role in terms of the reflected load seen by the tube.
so as an example - if i where to put a larger OPT in my marshall 100w - the output tubes would clip more (and play louder ??)
i wasnt asking how it sounds - but the technicalities behind it please - or if you can suggest a good link i may read
Your el34 tubes will clip when the signal amplitude (voltage) reaches/surpasses the bias voltage. Said another way, when the grid hits zero volts during the swing.
1) Power tubes are *current* limited, there´s only "so many" mA they can put out when fully saturated which normally happens when grid voltage reaches 0 V.
May put out a little more if grid gets positive but then it starts pulling significant current from the Phase Inverter, and which it can not supply, so you reach a brickwall there.
2) and plates can only swing "so many" Volts, specifically from +V to ground, in practice some 50 or 60V from it, which is called saturation voltage.
Again a brickwall.
3) so since you are both voltage and current limited, you end up being *power* limited.
4) that peak voltage and current combination also defines an optimum load impedance, which in practice becomes a de facto standard in the Industry.
5) so in general it´s practical to get around 50W RMS out of a pair of EL34 or 6L6 , so 100W out of 4 of them, what you have in your Marshall.
Changing the output transformer will not give you more power, it has already been optimized by the designer.
6) IF you want some more power, you´ll have to provide more "muscle" which usually means rising +V (so enlarging power transformer, improving power supply, etc.) and using "larger/improved" power tubes such as 7027 or 6550which can take it.
In "the old days" (think Jimi Hendrix, Deep Purple, etc.) Marshall gradually crept up +V voltages , up to hairy +560V or so, while still using EL34, but amps became unreliable, with sometimes spectacular fireworks on stage.
Fender did something similar in their latest Ultra Linear amplifiers, reaching +520/540V, but they required special order 6L6, the famous Sylvania 6L6 STR (Special Tube Request) but get ready to fork over $100 ... each.
Nowadays voltages crept down to more manageable and reliable 450V or so.
Hope this answers your question.
May put out a little more if grid gets positive but then it starts pulling significant current from the Phase Inverter, and which it can not supply, so you reach a brickwall there.
2) and plates can only swing "so many" Volts, specifically from +V to ground, in practice some 50 or 60V from it, which is called saturation voltage.
Again a brickwall.
3) so since you are both voltage and current limited, you end up being *power* limited.
4) that peak voltage and current combination also defines an optimum load impedance, which in practice becomes a de facto standard in the Industry.
5) so in general it´s practical to get around 50W RMS out of a pair of EL34 or 6L6 , so 100W out of 4 of them, what you have in your Marshall.
Changing the output transformer will not give you more power, it has already been optimized by the designer.
6) IF you want some more power, you´ll have to provide more "muscle" which usually means rising +V (so enlarging power transformer, improving power supply, etc.) and using "larger/improved" power tubes such as 7027 or 6550which can take it.
In "the old days" (think Jimi Hendrix, Deep Purple, etc.) Marshall gradually crept up +V voltages , up to hairy +560V or so, while still using EL34, but amps became unreliable, with sometimes spectacular fireworks on stage.
Fender did something similar in their latest Ultra Linear amplifiers, reaching +520/540V, but they required special order 6L6, the famous Sylvania 6L6 STR (Special Tube Request) but get ready to fork over $100 ... each.
Nowadays voltages crept down to more manageable and reliable 450V or so.
Hope this answers your question.
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is there a general opinion that those higher V versions sound better ?
i think so - and at the same time i also do not think that the VariAC technique sounds any good - yeah you get more distortion - but it sounds muddy and compressed
i do have many amps 😉
in this Thread i am only asking how stuff principally works - im trying to learn and im interested in your opinions
in this Thread i am only asking how stuff principally works - im trying to learn and im interested in your opinions
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