Tube Microphones – Buyer’s Guide by Alan Steward

So, do you want to buy a Tube Microphone?

It seems to be the holy grail of recording these days, getting that analog sound back into your recording. After more than 2 decades of recording digitally, we still long for that warm sound of the analog consoles and recording studio gear from yesterday.

We are still looking to add “tape saturation” to our recordings to give it some extra kick even though the good old 24-track tape machines have all but disappeared from today’s studios.

What is the fascination with that analog “tube sound”? How do you get it? Do you really need (or want) it?

Let’s start our exploration right at the beginning of the recording chain, the microphone.

• What really is a tube mic?

• Why did just about every manufacturer start producing tube mics again?

• What is it really that makes a Neumann tube mic so special?

First of all, in my opinion, there is no such thing as a tube microphone. At least not in the strict sense of the word. The sound of a microphone is shaped by air flowing through a diaphragm (or sometimes an aluminum ribbon). That is the part of the microphone that captures the sound.

You can think of a microphone as a loudspeaker in reverse. As a matter of fact, you can use any regular speaker as a microphone and record a sound (not a good one, I must admit) by singing into that speaker. A tube does not come really into play until that very weak signal created by the diaphragm gets amplified.

So, what we are really talking about is a microphone with a tube preamp built-in, not a tube microphone. You can’t sing into a tube. And yes, before transistors, that was the way a microphone’s signal got boosted to the level where it could be connected to an amplifier or recorder.

Once transistors were invented, transistors were used in the preamps of the microphones. But engineers still appreciated the warm sound of a vintage Neumann or AKG tube mic. I would say it only partly because of the pleasing sound of the tube amp inside but probably even more because they were simply damn good mics.

And this is the important part: No tube preamp will make a bad mic sound good. It might make a decent mic sound even better, but that’s it. So, if you buy a $100 tube mic, you get a $90 mic with a $10 tube in it. It will not magically sound like a $1,000 mic.

The second thing to watch out for is the tube itself when you buy yourself a brand-new tube mic. It’s not going to be a Telefunken or GE tube but something manufactured in China or Russia that does not come anywhere close to the sound of a vintage tube.

So, my first tip, if you must have a tube mic in your collection and can only afford a Chinese brand microphone? Change the tube!

You will find that there are lots of vintage tubes on sale on eBay including those magical “new old stock” tubes.

What does “new old stock” mean?

It means that some distributor or shop had a large number of old tubes lying around in a warehouse since 1965 that had not been sold and by now, the shop owner says to himself, “I will never sell this, let’s see if I can get rid of it”. And bingo, there it is.

A brand new GE 12AX7 tube is on sale for just 10 bucks on eBay. A quick and cheap improvement to your 60-dollar mic with that hollow-sounding Russian tube in it that just makes the sound worse instead of better.

Now here’s my next piece of advice if you absolutely must have a tube mic but have to consider a tight budget: Don’t buy a tube mic at all, buy a tube pre-amp!

Remember, it’s just the pre-amp of the mic that uses the tube, so you can just as well hook up your favorite mic to a tube pre-amp (preferably with a vintage tube in it), and voila….you’ve got the sound of a tube mic!