Hi All,
I'm working on an amp based on the Friedman pink taco. I found a plan on the internet which i based my design on and ordered all the parts from tube town. A friend is building the TT PL18 kit so I've seen the TT PL18 schematic and it matches my plan with one or two minor changes.
My (first) problem is that the power tubes are running too hot. I'm measuring 403V on the plates and 9V across the cathode resistor. If I'm calculating things correctly the tubes are running at 116% maximum dissipation, and i can see they are starting to red plate.
I'm using 120r cathode resistor, i can see that has been upped to 150r in the TT PL18. I'll try upping that value when the new one I've ordered gets here, but don't think it will be enough to reign it in.
My power transformer is rated for 36W with a 600V secondary and centre tap. I have no idea what voltage the original Friedman transformer putts out?
Anyone have any suggestions what i can try?
Thanks in advance, Ben.