Unlike tubes that degrade and alter the amplifier’s tone as they age ... that guitarists should consider. For example, replacing a tube rectifier with a solid-state rectifier often tightens ...

There are a small handful of old tubes that need an impressively low voltage to work, though, and [J.G.] has put a few of them to work in this battery-powered audio tube amplifier. The key to the ...

With the wealth of cheap and highly integrated audio amplifier modules ... from junk, your tube-making game gets a lot harder. Given all that, you’d expect the tubes to look a lot rougher ...

First made in 1959, this is the best-selling tube amplifier ... replacing the board you essentially change the entire circuit ...