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Post by chinook9 on Nov 16, 2016 17:02:43 GMT
Hello Frans!
I am intrigued by the idea of building/modifying two Garage1217 tube amps to operate independently as monoblocks.
I don't know much about electronics but I learned, when studying tubes many years ago, that in a tube amp (with a single tube) there would be some type of distortion caused by signals from both channels going through the vacuum tube simultaneously. If this is true, operating two amps as monoblocks could solve this problem, potentially improve the SQ, and increase power significantly. I'm not sure how volume control would be handled but I expect I could do that in the DAC.
If I'm all wet, please just say so.
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solderdude
Administrator
measureutternutter
Posts: 4,881
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Post by solderdude on Nov 16, 2016 19:29:29 GMT
The electrons in each tube section only go from the cathode to the anode. The anode is all around the cathode (with the grid inbetween) So electrons from Cathode one would somehow have to make it through the anode and cross over to the other anode. As electrons are attracted to the anode (because of a higher voltage) they simply do not fly past the anode. The tube sections are completely separated in the glass bulb. The only thing that is shared between the 2 halves is the heater filament. That one is connected to ground here (same potential as the cathode) and DC fed. It doesn't make electrical contact with the cathodes though. Any electrons going into the cathode would thus be conducted to ground and not to the other section.
It is true that some dual triode tubes have screens between them. This is to prevent HF leakage in radios (talking 1MHz etc) due to capacitive coupling. In receivers dual triodes were often used to save space (1 bottle instead of 2 bottles) where one tube half is used as an oscillator and the other half as a mixer or amplifier. There you do not want leakage through capacitance.
So no need to worry about poor channel separation or the left and right channel influencing each other. The effect of a poor ground/signal layout on a PCB or influence via the power supply rails will be much higher than leakage between the tube halves.
When going dual mono at some point you would have to connect the ground planes anyway unless you wire the headphones for balanced drive. You would need to control the signal (volume control) before going to the amps.
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Post by chinook9 on Nov 16, 2016 19:57:27 GMT
Thank you Frans. Another excellent explanation for those of us with limited knowledge.
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