RAM Goes Online
On July 1, the 21-year-old company announced the opening of its online store, offering the full line of RAM Labs' tested and matched tubes, select Music Reference components and accessories, interconnects, and several passive preamp kits. Of particular interest to owners of Music Reference RM-200 amplifiers is an upgrade KT88 output tube claimed to be capable of better bass and damping than the original device.
RAM Labs online also stocks ultra-low-noise 12AU7s for CAT preamps and a General Electric 6072A especially selected for the AKG C12 tube microphone. RAM is the current supplier of these tubes to AKG; all 6072A tubes are tested to AKG's specifications.
The site is more than a store, however. It's also an informational resource for tube audio fans, with archived articles about tube circuitry, the uses and applications of various types of tubes, and comparisons of same-type tubes from different manufacturers.
"We want to make it easy for our customers to find and understand what they need and to be sure of what they are getting," Modjeski said. "There's a lot of conflicting and inaccurate information out there when it comes to tubes." One common misperception is that static voltage testing is sufficient for matching tubes. RAM Labs subjects all of its tubes to extensive computerized testing, so that they can be matched for both noise and gain, or transconductance.
The "RAM factor" is a reliable indicator of sonic performance, according to Modjeski, who calls it "a highly accurate method for quantifying noise in a small signal tube." RAM driver tubes are graded for tight gain matching and operating bias so that they "enhance performance in push-pull balanced circuits," and output tubes are computer matched for bias current and transconductance. Each RAM tube is individually serial-numbered on the box and on the glass. All are warranted to meet specifications for 90 days.
Tube matching is important not only sonically, but also for getting the longest life from output tubes. Mismatching is a common cause of output failure, as Modjeski explains on the site. If output tubes intended for push-pull operation are "selected from opposite ends of the bell curve," one might carry twice as much current as its mate, causing early failure. Selecting the right tube type for the plate and screen voltages in your amplifier is also important. RAM Labs tests all its output tubes at several common screen voltages to predict their performance in real-world conditions. The Santa Barbara, CA–based company claims to have originated computer testing and matching of vacuum tubes.