5751 for 12AT7 for Dared SL-2000A

Can I use 5751 or 12AX7 tubes as replacement for 12AT7 for the Dared SL-2000A pre-amp?
Probably best to ask the manufacturer.
I don't think that's a very good idea. Different tubes and different operating points. Will it blow up? No it should be okay. But I think you should stick with one of the 12at7 variants. There are some nice tubes available in the ECC81 family. Just my two cents.
Never heard of replacing 12ax7 for 12at7, but you can use 5751 in place of 12ax7.But like Tp. says ask the manufactur.
Plate voltage,and amperage is different. Go with the factory specs.
If they offered a variety of tubes it would say so. It may work with a different tube But for how long.
My favorite 12AT7 type tube is the GE JAN 6201 preamp tube. They don't cost too much money and won't break the bank.