The 6V6 is very well behaved in class A2 and, with an appropriate driver, has a very unique sound when over driven. I like jumping back and forth between the two though. The Sovtek EL84 is often sold under their own brand name by other well-known electric guitar and guitar amplifier manufacturers – such as Fender or Mesa Boogie. Views Read Edit View history. I built a Spud amp that used the EL84 Pentode mode by itself to drive my speakers. Also if you lower the reflected impedance you will increase the bass if you connect a 4 ohm speaker to the 8 ohm output the reflected impedance will half so ohms instead of ohms so if bass response was down to Hz it would drop down to 50Hz. Can someone explain to me the difference between pentode vs.
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Also plate impedance 38k ohms approx for the pentode mode 2k ohms in the triode mode the result the amplifier is more dampened in the triode mode closer to a solid state amplifier sound then in the pentode mode So psntode mode not only drops power it reduce overshoot due to inductance, capactance and other effects relative to the speaker used over all it won’t sound as bright penfode the pentode mode.
Bottom line the greater the primary inductance of the transformer the lower the frequency response so in simple terms a bigger output transformer will give you more bass response.
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I have yet to see a truly high fidelity audio amplifier which benefited from such an arrangement. In simpler petode, triode is half of pentode. The EL84, with an even hotter cathode, would be even better although you would need a better transformer.
Generally, I agree with most of the previous posts and the concepts. Retrieved 25 May These used interstage transformers for coupling in every stage used a 56 triode for the input. Mon Jan 30, 6: The operating point is at V.
When we come to calculate the gain, we find that the anode characteristic begins to curve as we reach its intersection with the load line. You would have to change pentodde of the resistors ever-so-slightly to make up the difference. I do however feel that the thoughts relating to using something like a 12AX7 as a driver for a power tube are not entirely penode. In the long run, I concluded that the SRPP with tubes like a 12AX7 was superior over the single pentodw versions for driving power tubes.
Retrieved 22 May The only reason to do this is to run the power stage in class A2.
And these cap’s will soak some current. The tone is definitely not as brilliant as in pentode mode and does of course break up earlier. I’m making myself a tube-decorated throne.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum. Hi All, I didn’t know whether to get into this discussion or not, but Sat Dec 29, 3: If you needed to go to class A2 then for sure it will be inadequate.
Somehow, the sounds of these breadboarded amps are excellent! Retrieved 23 May The EL84 is smaller and more sensitive than the octal 6V6 that was widely used ell84 the world until the s.
It could also make a good LTP splitter because its increased power makes possible the driving of K ohm grid resistors in the power stage.
DESIGNING EL84 PENTODE AMPLIFIER
Originally Posted by TS So in the triode mode more power is lost across the output tube with less power to the speaker and the speaker is stopped quickly by the action of the tube lower harmonics you hear as less high frequencies.
Views Read Edit View history. Triode mode penntode has better low frequency response Something I just started to look into is the effect of the transformer on frequency response. Does an SET amp generally run in class A2? That’s also why we don’t generally use R-C coupling when you want to drive the grid positive; it charges the coupling capacitor and causes strange things to happen which generally are undesirable. To successfully use it you’d want to triode-strap it.
I have also pentodw this done, although it’s usually with large RF transmitting triodes. Still, if one transformer in the signal path is detrimental to the most accurate sound then I don’t know why people would want to implement more than one.
Now let’s calculate value of C4 in order to hold second grid at AC ground potential.