Tube preamp (do I dare bring up modelers!?!?!?)

[vigilante398]

Some companies out there have tried making solid-state, drop-in replacements for tubes. Has anyone tried any of them out?

I have yet to go down that rabbit-hole, but it would be a dream to be able to replace a 12AX7 or EL84 with something that is more consistent, not NOS and is going to have 10x the lifespan.

I have a couple of the AMT Warm Stones which are 12AX7 replacements. As a tube fanatic I was skeptical, but I have to admit they did an excellent job and it's damn hard to hear a difference when I A/B them against real tubes.

That being said AMT is in Russia so difficult to buy now, and a single Warm Stone is right around $50.

 

[daeg]

I have a couple of the AMT Warm Stones which are 12AX7 replacements. As a tube fanatic I was skeptical, but I have to admit they did an excellent job and it's damn hard to hear a difference when I A/B them against real tubes.

That being said AMT is in Russia so difficult to buy now, and a single Warm Stone is right around $50.

After I posted I went through a few forums and the consensus is that no one would be able to tell the difference in a blind test.

I might try one out. No one is doing this with Power Tubes or Rectifier Tubes right? It seems like it's just AMT and their 12AX7 preamp tube.

 

[vigilante398]

After I posted I went through a few forums and the consensus is that no one would be able to tell the difference in a blind test.

I might try one out. No one is doing this with Power Tubes or Rectifier Tubes right? It seems like it's just AMT and their 12AX7 preamp tube.

Yeah a drop-in replacement for a power tube is going to be incredibly difficult, I don't think anyone has done it. You would need to have a class-A amplifier that could be coupled into class-AB that can successfully produce the same power levels of tubes at the same impedances as tubes in order to play nicely with your output transformer. Output transformers really ruin everything. Solid-state amps don't need them as it's possible to have much lower output impedances than tubes just due to manufacturing, so forcing a solid state device through an output transformer is just a messy thing to ask.

I'm already pretty impressed at the Warm Stone, but I would be beyond impressed if someone could design a drop-in power tube replacement.

Oh it has been done with rectifier tubes though, there are a few companies that do it. I have a Weber "copper cap" rectifier that's a drop-in for a tube rectifier, and CE Distribution (the wholesale arm of Amplifiedparts/Antique Electronic Supply) makes one as well.

 

[daeg]

Yeah a drop-in replacement for a power tube is going to be incredibly difficult, I don't think anyone has done it. You would need to have a class-A amplifier that could be coupled into class-AB that can successfully produce the same power levels of tubes at the same impedances as tubes in order to play nicely with your output transformer. Output transformers really ruin everything. Solid-state amps don't need them as it's possible to have much lower output impedances than tubes just due to manufacturing, so forcing a solid state device through an output transformer is just a messy thing to ask.

I'm already pretty impressed at the Warm Stone, but I would be beyond impressed if someone could design a drop-in power tube replacement.

Oh it has been done with rectifier tubes though, there are a few companies that do it. I have a Weber "copper cap" rectifier that's a drop-in for a tube rectifier, and CE Distribution (the wholesale arm of Amplifiedparts/Antique Electronic Supply) makes one as well.

Great info. Ty.