I see a lot of audio products for sale recently that have a tube inside, and claim to provide “that vintage sound.” The odd thing is that the “vintage” period they all talk about is a period where transisters were already widely used in pro-audio equipment.
Tubes have their place . . . . in guitar amps. Tubes add something to the sound, due partially to the way they distort, but primarily because they add second-order harmonics to the original signal, and this tends to sound “fuller” and “warmer.” These are good qualities in a guitar amp, but not necessarily in pro-audio gear. There is one major difference between guitar amps and pro-audio gear. A guitar amp is a part of the sound generation (production) process. It is the various distortions, non-linearities, and non-flat responses that make a guitar and guitar amp sound ‘good.’
Conversely, pro-audio gear should add nothing to the sound, the frequency responses should be flat, and the dynamics should follow the original exactly, with no compression (except what you purposely add) and no ‘ringing.’ It is sound RE-production. It should neither add, nor take away, anything from the original – unless you purposely do that.
A guitar plugged directly into a hi-fidelity system sounds horrible, and likewise, playback of a mix through a guitar amp is even worse.
Beware of claims that a tube mic preamp will provide you with cleaner sound somehow. If used on someone’s vocal mic, it may indeed make it sound somehow “warmer.” But, don’t be fooled. What you are hearing is simply distortion (“distortion” technically is anything that changes the waveform). You are using the tube mic preamp as an effect. It (as an effect) is not a normal part of the signal chain, and you wouldn’t want to use it on everything (just as you wouldn’t stick a chorus on everything in a mix).
Tubes would have some serious problems if used in pro-audio gear: size, weight, heat, reliability, durability, as well as sound quality.
There is a reason that all of the manufacturers went to solid state as soon as it was possible, and this is what made portable sound systems as we know them today possible. Don’t get sucked into the marketing hype. Certain companies hope that you buy into their marketing hype so that you’ll shell out a couple of thousand dollars for a tube mic preamp. There are an awful lot of six and seven figure consoles out there, (both recording and live consoles) such as Neve, SSL, Harrison, NeoTek, MCI, Soundcraft, Allen & Heath, Yamaha, that have been the top brands for the past 30-35 years, and not one of them has a tube preamp. Most of the major recordings you heard between the late 70’s and about 5 years ago were made using one of the first 5 in that list. (they were also being tracked on Studer, 3M, or MCI 24 track machines using (probably) Ampex 456) . THAT is the “vintage sound,” and no $2000 tube mic preamp is going to recreate that.
If you are used to using cheaper consoles, the internal mic preamps are probably not all that good quality-wise, and a $200 tube mic preamp is very likely a better preamp – NOT because it is a tube preamp, but simply because it is a $200 mic preamp.
If you really want to spend a couple of thousand to improve the sound of the vocals you record, I would suggest a Neumann U-87 might be money better spent.