Advice

The first chapter, below, is condensed from Oliver Archut's historical knowledge of the AC701. What follows is a summary of my experience with this tube. "In the beginning, Telefunken had two different AC701 versions, both low noise but the version with the 'K' designation was a …

Sometimes you will want to remove stains or residue from adhesive badges or labels on mic bodies.The goal: to remove the stain without irreversibly altering or marring the mic’s surface.Here is my general rule when choosing chemicals or mechanical means to remove foreign …

I have arrived at a "semi-objective" test protocol which, over the years, has served me well to weed out marginal microphone tubes, including those with hidden defects. This article will use the VF14 as a prime example, but the method is equally helpful for other tubes used in …

Here is a rough overview of how to date K67/870 capsules installed in U67, M269, SM69, SM69fet, U87Ai; and K87 capsules used in U87 and U87i. (I will add photos later). The U67 and U87 types are identical in dimension, construction and acoustic design, except that the K87 uses a …

I frequently receive mics where a small silica crystal bag is tucked into the mic box. The idea: to let the hygroscopic (moisture seeking) silica pull excess humidity from the mic, especially from the capsule, whose performance is greatly affected by humidity.But simple logic …

Now that VF14 prices are in the stratosphere, how can you protect yourself from getting taken to the cleaners when you need to buy one? There is little any tube dealer or private seller can promise you when it comes to a microphone tube's functionality, noise, life expectancy, …