Skip to main content

akg solidtube

Vocal Test with an AKG SolidTube


I recently replaced the stock 12AX7 tube in this mic to a 12AT7. The original reason I changed the tube wasn't to get a tonal difference, it was just that the old tube was causing noise, and the only spare tube I had lying around was a 12AT... but I think it did change the tonal characteristics of the mic, not dramatically, but a bit.

This is a public domain song, an old folk song, "Maggie"..
I think it's either Irish, or Irish-American in origin, written sometime in the 1860's.

AKG SolidTube problem - solved!

Several months ago, I had a conversation with Bos about a mic I own - the AKG Solidtube, and how it was making some noise after it heated up.

The noise was similar to what you would hear if you took a tissue or a paper towel in your hand and scrunched it.

Yesterday, I dug the mic out again, thinking I'd pop the top on the power supply to see if there were any obvious indicators - like blown caps, etc...

Noisy AKG SolidTube

Bos... (or whomever else might be able to help)

I have an AKG SolidTube that I really like, although in the last week or so, it's become noisy.

When I say "noise", I don't mean buzz or hum, crackling or other familiar signs of problems.

This is an audible sound, I could only describe as "soft" and "random". It would be very similar to the sound you would hear if you held a piece of paper towel or tissue paper in your hand and scrunched it and moved it about.

AKG SolidTube

This past week, a friend of mine returned my AKG SolidTube Condesner mic after using it for the last several years.

I had forgotten how warm and smooth this mic sounds.

I know it was never accepted to the level that AKG had hoped for at the time of its release, and my suspicions as to why are below.

My guess is that the price tag - $900 at that time - was too close to other already well established mics - like the 414, and because mics like the 414 had proven history and the ST did not, people were hesitant to buy.

AKG SolidTube

Anyone have a schematic of the AKG SolidTube or know the transformer ratio?

I can trace it but I thought I would ask.

I bought one on closeout today. Stock out of the box did not sound that great. I pulled the foam inside the grill and replaced the 12ax7 with a GE 6072A, that helped a lot. The stock output level makes me think the transformer might be about 10:1 or 4:1 if they use a CF. If I change any other parts I will take pictures.