12AX7 alternative

[krellmk]

You can buy ready made adapters which convert a WE 420A / 5755 to a 12AX7. You can also buy 2 for 1 adapters, which convert a pair of 6SF5-GT to a single 12AX7, the 6SF5-GT has 110% of the gain of a 12AX7. Finally you can buy adapters, which convert a 5687 to a 12AX7. The 5687 was designed by TungSol in 1952 to be a superior audio tube. Audio Note's current DAC's all use the 5687.
With quality 12AX7 getting scarce and loads of counterfeits around the WE 420A maybe a better alternative to the 12AX7.

 

[J!m]

Personally, I find way too many compromises with tubes to use them for primary amplification.

Counterpoint used them in the predeiver, and derated them to last 20 years.

But even in a (my opinion) less critical guitar amplifier, brand to brand and even lot to lot variance of output tubes is huge. It lust doesn’t make sense to me. But it is certainly audible.

I don’t want coloration in my hi fi. I know the counterpoint does it, but I can’t really afford much better. Sort of why I’m considering the Krell mod- and hoping it will be what I want.

A pair of those Benchmark amps really seem like they’d fit the bill; I can’t afford to pay the bill…