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Title: High plate voltage in S&M Post by: pepper on August 14, 2012, 01:34:45 PM Hey guys just finished a 50 watt OTS S&M sounds fantastic as usual and everything is working great. But my plate voltage is around 490,I am using magnetic trannys and have TAD 6l6gc-STR's for power and all jj's for the pre is this alright? As mentioned everything's working/sounding fine the bias is set at around 38 MA any thought's,thanks
Title: Re: High plate voltage in S&M Post by: pepper on August 25, 2012, 02:12:23 AM No one? :( ???
Title: Re: High plate voltage in S&M Post by: T Wilcox on August 26, 2012, 05:56:51 PM Checked the chart on the ceriatone website and it shows 466 volts on the plates on the 240 volt model. Nothing for the 120 volt model, but the voltage difference between 490 and 465 is around 5 % difference.
How do all your other readings compare to the chart? If you have not checked them I would suggest doing so and noting them down as well as the voltage on your wall outlet as well. Todd Title: Re: High plate voltage in S&M Post by: boldaslove6789 on September 19, 2012, 05:50:34 PM What does it measure on each plate resister and what value Dropping resistor are you using at each B+ node starting with the Phase inverter?
You should be getting somewhere around 200 to 205v on each plate on V1 and V2. I've seen Dumble ODS's with higher or lower V1/V2 B+ voltages depending on the voicing the amp had and what its output section consisted of. You'll really have to use your ears and find what voltages sound the best sonically as every amp is differnt. When the B+ is too low, the headroom won't be as high as it should be and the Gain will sound muddy. It should sound tight and Articulate. I'd change that dropping resistor for that node and calculate what you'll need to get around 200-205v at each plate. |