45 tube sounds really good with use of good OPT.
I built two amplifiers for my friends with Lundahl 1620 OPT, with one standard and the other with amorphous. They are very happy with them and said they worth for their investment.
Johnny
I built two amplifiers for my friends with Lundahl 1620 OPT, with one standard and the other with amorphous. They are very happy with them and said they worth for their investment.
Johnny
Just last night, I redid the curves for the 45, and came up with the following results.
Transformer 5K
Bias -56V
Plate Voltage 280 V
Plate Current 36 mA
Cathode Resistor 1555R
B+ 331V, say 350V
The above seems to imply a plate dissapation of 10W, which is right on the edge of the limitations of the tube. And from this, I say around 2W of output power. Is this running it too hot?
This is nothing new, but for me, it was doing it all myself, using the charts and a calculator to confirm what everyone has already figured out!
This would require around plus or minus 50V to avoid A2 but to achieve almost full power. Which means the driver stage would need to swing 35 Vrms. Assuming a 2Vrms source, then the gain on the first driver stage would only need to be 17.5, with some headroom, say gain of 20 as a minimum. Would this assumption be correct?
Transformer 5K
Bias -56V
Plate Voltage 280 V
Plate Current 36 mA
Cathode Resistor 1555R
B+ 331V, say 350V
The above seems to imply a plate dissapation of 10W, which is right on the edge of the limitations of the tube. And from this, I say around 2W of output power. Is this running it too hot?
This is nothing new, but for me, it was doing it all myself, using the charts and a calculator to confirm what everyone has already figured out!
This would require around plus or minus 50V to avoid A2 but to achieve almost full power. Which means the driver stage would need to swing 35 Vrms. Assuming a 2Vrms source, then the gain on the first driver stage would only need to be 17.5, with some headroom, say gain of 20 as a minimum. Would this assumption be correct?
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