The carpathian, yes, 12AU7 and 6 or 12v FQ7 are interchangeable, but you have to choose the version of FQ7 that matches the available filament voltage. Same specs for all other parameters, more or less.
A day doesn’t go by where I don’t see an ad for the tubes or the equipment they sell. I also tried to find out where their stuff was made and nobody will say for sure. Though they are very generous. You can get 5% off your first order!
Carpathian, it’s really not that hard to understand the differences among tubes, if you read some basic texts on the subject. Of course before substituting one type for another you need to understand how to read the data sheets.
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