One of the excellent writers for Gearslutz.com recently wrote an absolutely amazing review of the DM1 - not just because it’s complimentary (though we do enjoy that), but mostly due to the level of depth and thoughtfulness involved.
We received permission to share some of it here, but you should definitely click through and read the whole thing if you have a little more time! There are a lot more in-depth measurements and technical explanations in the original review, and it’s really fascinating stuff.
Excerpts reprinted with kind permission from Gearslutz.com
sE Electronics Dynamite - Active Inline Preamp
by: Sound-Guy (Dennis Wilkins)
“Although I haven’t been recording in live venues for years, the idea of a phantom powered preamp for dynamic and ribbon mics in my studio has been tempting. In fact, I thought of building a simple inline module a few years ago, but didn’t get around to it before Cloud Microphones introduced the Cloudlifter, which, when you think of it, is a rather obvious idea. Condenser mics always have an onboard amp/impedance converter, and dynamic mics, including ribbons, with their very low outputs, typically 20-25 dB lower than condenser mics, are usually expected to work directly connected to a preamp. This can require the preamp to be run near its maximum gain which often creates a few problems. First, with some “more affordable” preamps the highest setting may bring up considerable analog hiss and digital noise. Second, the frequency response of many preamps rolls off at the highest gain setting, dropping up to several dB at 20 Hz and 20 kHz. And third, the gain control of many preamps has low resolution in the last 10% or so of the control range, making it difficult to set it near the maximum setting.”
“And anyone needing to feed a dynamic mic signal over a long cable, and possibly in a venue with lots of electrical interference should really benefit if the unit does what it claims. Even with the very best preamp, any hum and noise picked up by a cable will be amplified, so increasing the mic signal by 28 dB will reduce hum and noise by the same amount.”
“My Focusrite interface doesn’t suffer from any measurable noise at the highest gain, and the lowest and highest audio frequencies drop only tenths of a dB at maximum gain, but the gain control is very touchy near the highest gain setting. I figured the Dynamite might be worth a look and listen even in my electrically quiet studio.”
“The tubular case is metal and feels rugged enough to drive a truck over it without damage (I didn’t try this, however!). It weighs less than three ounces (80 grams) and is under four inches (about 96 mm) long. The finish is excellent, pins are gold plated, mic lock works smoothly, and it feels very solid overall.”
GAIN & IMPEDANCE
“I found the gain of my Dynamite to be 28.9 dB at 1 kHz and it varied only +/- 0.05dB over a frequency range of 10 Hz to 24 kHz. That is flat! I measured the same gain with a direct signal measurement using Room EQ Wizard, and using a ribbon mic with an output impedance of 300 Ohms on a mic stand a few inches from a speaker. I did not (and can not) test it out to 120 kHz, but have no need for such bandwidth! Phase response was also text book flat - essentially zero degrees from 10 Hz to 24 kHz, meaning no signal inversion and no phase shifting."
“Using a variable input impedance preamp, I found the gain dropped only 0.1dB when driving a 300 Ohm load, and above that, up to a 3 k Ohm load, gain was always 28.9 dB. Loading it with 150 Ohms reduced the gain by about 3 dB, but most mic preamps run 300 Ohms to 3 k Ohms.”
“Distortion was difficult to measure since using an input in the low millivolt range did not produce harmonics above the noise level. To get a clean reading I had to use over ten millivolts and found total harmonic distortion appears to be composed primarily of the second harmonic with a smaller level of third harmonic. Fourth and higher harmonics are much lower and contribute nothing really measurable to the total. THD measured from about 0.1% with 10-15 mV rms input (equivalent to about 110 dB SPL into an SM58) up to 0.2% at the highest level I tested (equivalent to about 125 dB SPL into an SM58). And the distortion level is even across the audio frequency range. This is good distortion performance, certainly below the threshold of human hearing.“
THE BOTTOM LINE
“If you are looking for a solid, high gain signal booster that almost meets the old engineering goal of a “wire with gain”, I’d say sE Electronics have created it. There are other mic boosters available, and I admit I haven’t tested any of them (be glad to do so if they send me one to test!). From what I’ve heard and read, other brands have higher output impedance (gain not as stable with changing load) and higher noise levels, but some have variable input impedance (to affect mic tonality) if that is of interest, and may be suited for your needs. For me, the Dynamite fits the bill.”