Tube Comparisons with a CAD M9 Tube Condenser

We’re doing some tube comparisons today in The Pajama Room.  I recently acquired a CAD M9 Tube Condenser mic. I used one on a guitar amp years ago and was impressed with how this mic delivered.  The original tube was beginning to sizzle and produce noise, so it’s time for a swap. There are a few gearslutz pages about the CAD M9 and tube swapping, but nothing definitive.  So I’ve chosen 2 new tubes, the favorites from all my webcrawlin’ research. I’m looking for a little more headroom and frequency extension out of the M9. The original is a 12AX7 tube, which is what’s recommended by CAD, but I’m going with a few lower gain 12AT7’s in order to achieve the desired outcome for this mic.  In order to compare apples to apples, the only thing changing is the tube. All gain settings, mic position, drumsticks and drum beat are the same.

My trusty Gretsch is pushing the air for this demo. Nothing fancy about the mic placement, I like this spot normally.

The Original Sovtek 12AX7WA; It’s still quite nice sounding. I recorded an acoustic guitar with it and the zip and clarity was great.  There’s plenty of presence in the high end, some could say hype. You can see on a spectrum analyser and hear while not tracking the tube is beginning to fizzle and produce noise. The tube fills up fast when playing loud, which is one of the attributes about tube mics in general.

New JAN Philips 12AT7WC; WOW, this tube is three-dimensional sounding, all of the drums and cymbals sound individual and separate. It seems to tame the presence on the hi end of the capsule better than the Sovtek, but leaving all that sparkle for which these mics are known. The frequency extension I was looking for is there, the lows are lower and the highs are higher.  There’s a real sub *poof* for the kick drum and a clear stick attack on the cymbals.  With a brand new tube, there’s a wonderfully low noise floor and no microphonics.  This tube doesn’t seem to fill up and compress in the same way as the Sovtek.

New Gold Lion 12AT7; This tube sounds similar to the Sovtek, just slightly more hi-fi. By hi-fi, I just mean punchy and bright like a smiley-face EQ curve.   There is less presence on the high end than the Sovtek.  The tube fills up and begins to compress like the Sovtek, but still retains definition that was lacking on the Sovtek.  This makes sense if the Sovtek is beginning to break down and show its age.  I usually love using these Gold Lion tubes in swaps, and end up choosing them in the end, but the three-dimensional quality brought by the JAN is absent for this mic, as is the frequency extension.

From Left to Right: Sovtek 12AX7WA, JAN Philips 12AT7WC, Gold Lion 12AT7. You can see just how different the internal architecture is between these tubes.

And the winner is The JAN Philips 12AT7WC!  I was anticipating leaving the Gold Lion in the mic after the test, and that’s why it was last in the order.  But after listening and comparing in headphones, the clear victor for me is the JAN.  It really is 3D sounding in that great mono single mic way that only truly great mics can pull off.  And putting a loud drum kit through as the test put it through the paces as far as compression properties; nice open and clear.

The CAD M9 with the JAN Philips 12AT7WC tube installed. FOR KEEPS!

With the circumstances of corona-virus and isolation, these kinds of A/B tests are the perfect way to spend your afternoon.  I can’t wait to try this mic on an electric guitar amp, the original source that turned me onto this fabulous microphone all those years ago.

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