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Had a oddball kind of idea and I wonder if you all would humor me a little over it. I wanted to build a couple of low wattage amps for practicing or recording and thought I could kill two birds with one stone if I put both amps in one cabinet. One speaker, one power transformer, one reverb, two output transformers and a couple extra parts. So I came up with this arrangement and hope it is a workable solution, but I need some sober second thought.
As it is a cheap build I have a few limitations, the 12v heater is limited in current being one of them. I need to have the SE amp running or the P-P amp running, I can not feed both sets of heaters at the same time. I have two output transformers supplying one speaker so obviously I need to switch between them. In no case do I want the high voltage on the output transformer without the speaker switched in so I am switching the speaker and the high voltage along with the heaters at the same time with a three pole two position switch.
The first stage of the amp is a MOSFET that is on for both amp types. This feeds a Fender style tone network which has a switch to reduce the mid cut or open the path to ground effectively taking the circuit out. Next is a volume control feeding gain stages for either amp type.
The first question that comes to mind is will there be any interaction on the input or the output when one tube is powered and the other is not. I can see a minimal amount of capacitance but not much else. (the pentodes in the schematic have no screen components to keep the schematic simpler. Also the reverb section is just roughed in, not concerned with it right now.)
Next comes a Tweed style volume/tone stage. This feeds a reverb circuit and the SE output tube and the cathodyne splitter for the P-P output tubes. Again I do not know if the tubes that are not powered will cause the powered tubes any grief. I am guessing not otherwise I would not be considering it. So I throw it out to brighter minds than my own. Can you see anything wrong with the concept?
As it is a cheap build I have a few limitations, the 12v heater is limited in current being one of them. I need to have the SE amp running or the P-P amp running, I can not feed both sets of heaters at the same time. I have two output transformers supplying one speaker so obviously I need to switch between them. In no case do I want the high voltage on the output transformer without the speaker switched in so I am switching the speaker and the high voltage along with the heaters at the same time with a three pole two position switch.
The first stage of the amp is a MOSFET that is on for both amp types. This feeds a Fender style tone network which has a switch to reduce the mid cut or open the path to ground effectively taking the circuit out. Next is a volume control feeding gain stages for either amp type.
The first question that comes to mind is will there be any interaction on the input or the output when one tube is powered and the other is not. I can see a minimal amount of capacitance but not much else. (the pentodes in the schematic have no screen components to keep the schematic simpler. Also the reverb section is just roughed in, not concerned with it right now.)
Next comes a Tweed style volume/tone stage. This feeds a reverb circuit and the SE output tube and the cathodyne splitter for the P-P output tubes. Again I do not know if the tubes that are not powered will cause the powered tubes any grief. I am guessing not otherwise I would not be considering it. So I throw it out to brighter minds than my own. Can you see anything wrong with the concept?
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