I am currently building this guitar amplifier (PP-18 18W vintage plexi PP-18 Construction manual ) as a school project, and I was wondering if I could do some calculations.
How do I calculate output and gain?
Calculation suggestion are welcome 😀
How do I calculate output and gain?
Calculation suggestion are welcome 😀
"Output power:
The total output power can be closely estimated from the load line (again, we only need to look at one half of the circuit to do this).
Simply note the peak current Ipeak (i.e., where the load line crosses the 0V grid curve); in this case it is about 135mA. Also note the minimum anode voltage Vmin, which is about 35V in this case. The total (rms) output power is then approximately:
P = (HT-Vmin) * Ipeak / 2
P = (300-35) * 0.135 / 2
= 17.9W
Even without a load line you can estimate the output power for a typical pentode, assuming the load impedance isn't unusually small for the type of valve being used:
P = 2 * (HT-50)^2 / Rload
Where Rload is the anode-to-anode impedance of the transformer. The '50' in the above equation is an estimation of how low the anode voltage can swing in a typical pentode/tetrode. In this case we would have predicted a value of 15.6W, which is not much less than what load line is saying."
Above was quoted from Valve Wizard
The total output power can be closely estimated from the load line (again, we only need to look at one half of the circuit to do this).
Simply note the peak current Ipeak (i.e., where the load line crosses the 0V grid curve); in this case it is about 135mA. Also note the minimum anode voltage Vmin, which is about 35V in this case. The total (rms) output power is then approximately:
P = (HT-Vmin) * Ipeak / 2
P = (300-35) * 0.135 / 2
= 17.9W
Even without a load line you can estimate the output power for a typical pentode, assuming the load impedance isn't unusually small for the type of valve being used:
P = 2 * (HT-50)^2 / Rload
Where Rload is the anode-to-anode impedance of the transformer. The '50' in the above equation is an estimation of how low the anode voltage can swing in a typical pentode/tetrode. In this case we would have predicted a value of 15.6W, which is not much less than what load line is saying."
Above was quoted from Valve Wizard
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