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08-17-2019, 12:02 AM
So what I meant was, let's call Rc-b R1 and Rb-sw R2. The simulations helped me figure out that R1 needed to be 100x R2, so I went with R1 = 330k and R2 = 2.21k (what I had on hand). But it sounds like you kept R1 = 30k1 and eliminated R2, making it 0 ohms. So you save a part because 30k1 is surely 100x 0 ohms, lol. Those are things that are easy to overlook.
Then my mixed bias comment was that if you kept R2 30k1, it could be any value to suit really, and hooked up a switch to short it, you'd effectively have mixed bias provided you also switched an appropriate resistor in the cathode at the same time. R2 shorted = cathode bias, R2 in circuit = mixed.
If the amp was the same circuit in the earlier TUT5 like I have, then you likely wouldn't need a 10W part because you'd have mixed bias (if R1=R2), which would cut down on the power. I actually thought that's what you meant to do. Since the cap makes it a form of fixed bias, but removing the cap requires a larger part and generates a lot of heat, you could add a portion of the fixed bias voltage back. This would allow the cathode resistor to still bounce around like you'd get with it unbypassed, but you'd get the heat savings because of the fixed bias portion.
I can see it being good for some styles with a lot of expression in the fingers. This was my first experience with cathode bias...I really thought it shined with single ended settings.
Thank you again!
Then my mixed bias comment was that if you kept R2 30k1, it could be any value to suit really, and hooked up a switch to short it, you'd effectively have mixed bias provided you also switched an appropriate resistor in the cathode at the same time. R2 shorted = cathode bias, R2 in circuit = mixed.
If the amp was the same circuit in the earlier TUT5 like I have, then you likely wouldn't need a 10W part because you'd have mixed bias (if R1=R2), which would cut down on the power. I actually thought that's what you meant to do. Since the cap makes it a form of fixed bias, but removing the cap requires a larger part and generates a lot of heat, you could add a portion of the fixed bias voltage back. This would allow the cathode resistor to still bounce around like you'd get with it unbypassed, but you'd get the heat savings because of the fixed bias portion.
I can see it being good for some styles with a lot of expression in the fingers. This was my first experience with cathode bias...I really thought it shined with single ended settings.
Thank you again!
