Misinformation?

September 25, 2007 at 3:12 pm

Misinformation is continually prevalent in our industry. The staff at Trew Audio has bit on it just as easily as you, our customers. One person’s experience can quickly become a generalized statement about a product to which everyone seems to adhere. Just last week we heard a nasty rumor that Maxell would soon discontinue their 2.8GB cartridge DVD-RAMs for the Fostex PD-6. After a short bit of investigation Fostex revealed the truth. In the USA, we are currently under a shortage, but in Japan, they have more than they can count. It is just taking some time to get large quantities here. Panic relieved, crisis averted.

So for my first topic, I’d like to quell some common misconceptions about an industry leading product line: Lectrosonics. Most misinformation stems from the transmitter end of the system. I like to lump them into two categories, lavs and input cables.

Lavs are tricky. First, no one wiring scheme works for every lav. For the most basic understanding of microphone electronic theory, please understand that a small voltage (usually 1.5-5 volts) is required for a lav to perform. This voltage is referred to as bias. Some wireless manufacturers have basic one-size fits all wiring for two different kinds of lavs, two-wire and three-wire. Two-wire mics carry audio and bias voltage together. The ground is on the second lead. Three wire mics have an audio lead, bias lead, and ground. Lectrosonics has done away with general wiring diagrams on their website for two-wire and three-wire microphones. Manufacturers release new mics, and additional circuitry, such as capacitors and resisters are common. Lectrosonics also has recommended wiring diagrams for specific mics such as the Sanken COS-11s, Tram TR-50, and Countryman B6. Though these wirings work, Lectrosonics provides just enough information to make you panic. Yes, the SM/UM400A series transmitters have their own wiring diagram, and no, it is not the same as the UM400 and previous series transmitters. Do not let this trouble you.

Let’s look at the Sanken. In the past Lectrosonics wiring for the UM400 and earlier transmitters differed from ours at Trew. This doesn’t mean we’re right and they’re wrong, or vice versa. When they released the SM series (and now the new UM400A and UM450) they added a new wiring scheme for the Sanken. But they didn’t stop there. They then changed their original UM400 wiring recommendation. This new UM400 wiring was also SM compatible. So now they have a UM400/SM wiring, and an UM400A/SM only wiring for the Sanken COS-11s. Where does this put Trew’s wiring? Well, we’ve never changed. Our original wiring is the same as Lectrosonics newest compatible wiring. The way we wire a Sanken will work on UM190, UM195, UM200 series, UM400, SM, and the newest UM400A/UM450 transmitters.

What does this mean to you? First, Lectrosonics is not wrong. All of their mic specific wirings work, they test them. In fact, if you order a mic from us and want us to use their wiring we’re happy to do so at no extra charge. However, the wirings we use in your mics come from years of experience in serving you. We take into consideration breakaways, which Lectrosonics and many of the lav manufacturers do not. Our goal is to provide what works best in the most situations.

When it comes to input cables there is also a fair amount of confusion. The transmitter will take mic level and line level. A cable with a pad is not needed. The TA5connector uses each of its pins for a different purpose. Pin 1 is ground, 2 is bias, 3 is mic level audio, 4 is a resistor path, and 5 is line. The line level connection on the Lectrosonics transmitter leads the audio through a pad circuit anyway. Most anyone who asks our sales department for a Lectrosonics input cable will receive a question right back. “Mic or Line level?” What this means is “What is your output?” The mixer output is the most important factor in this equation. Often I hear, “well it’s switchable.” If that is the case, the choice is totally up to you. Mic level outputs will need the mic level cable and line level outputs need a line level cable.

Skylor Morgan