Why are some tube preamps so expensive when others are downright cheap?

This was the question that kept nagging me when I first started exploring tube mic preamps. I had owned a cheap "tube preamp" for a few years. It had a tube in it and I couldn't understand how the tube preamps I read about (like a DW Fearn or Manley) could be that much better.

I had been a Solid-state guy since the 70's. That's when I started and all the sales guys in the stores would say,"You don't want to mess with that old tube stuff. Just look at these specs. Who would want all that distortion and poor freq response?" Years went by, then decades, during which time I learned how to get a good sound with SS gear and a mess of effects. I had been striving for a certain sound. One example was the ultraclear vocals on many of James Talyor's albums of that era. Every mouth sound and nuance was right there. For a long time I thought it was the expensive microphones they used. Over time, I learned to use aural exciters, compressors, EQ, and such to get an approximation of that sound. LDC mikes had became affordable in the 90's and I found out it wasn't JUST the mikes. Hmmmm, ...

I read articles in magazines and online forums about the difference a true tube preamp can make but I didn't have the money. I was saving to buy a Groove Tubes Brick, when I saw an Ampex 601 for a couple hundred and decided to try it. I was so disappointed. It was noisy and muddy. I couldn't imagine anyone wanting to use such a device. Now I had been doing electronics as a hobby since about the age of 8. Dad bought me the Radio Shack DIY and educational kits. He and I built a variety of things from various magazines. I also learned some electronics as a physics major in college. I had enough knowledge to begin to learn the ins and outs of tube electronics. I replaced all the caps, cleaned it up, and tried it. It was like a religious experience for me. Here was the sound I had been looking for and it was nothing more than a mic and a preamp - totally dry. The next few years were spent studying and experimenting, improving and refining. I built preamps for some friends and then started my website in 2006.

A "true tube preamp" has a high voltage power supply. Anything with a wall wart (or lump in the line) power supply is not a true tube preamp. They run on low voltage where a true tube preamp runs on hundreds of volts. It is a gimmick. The high voltage rated parts cost much more than low voltage parts. The high voltage power transformers are more expensive. The audio transformers are more expensive and difficult to make. Most cheap "starved plate" designs don't have audio transformers at all - too expensive. The high voltage audio capacitors are much more expensive. Almost every single part in the circuits is many times more expensive than the low voltage parts used in SS electronics.

One main reason a true tube preamp sounds so different from a cheap imitation, is that the cheap imitations use transformerless SS circuits to interact with the microphone. A true tube preamp will almost always have its input transformer and the first tube grid as the connection to the mic. This circuit sets the input impedance which affects the loading on the mic. The cheap imitations use chips to interact with the mic, then they run the signal through a tube operating at low voltage to theoretically give it "that tube sound." This allows them to market the device as a "Tube Microphone preamp." The amplification primarily comes from the SS circuits. I consider this a bad joke. Most tube preamps sound better than most SS preamps because the MIKES sound better when feeding a good mic transformer and tube grid.