A Look Inside the Upscale Audio Tube Testing Room
Triplett Model 3444-A: Sometimes, new isn't always better. This is one of the best all-around tube testers ever built. I was able to find a couple in great shape, back before people figured out just how good they were. Now... EVERYBODY wants one, and they are demanding big bucks; if you can even find one!
The Triplett tests tubes at real-world voltages, ensuring the most accurate testing and matching. It does not use the same real-world voltages for power tubes though, so we only use this to test small signal tubes.
Here's Kevin testing a 7308 on the Triplett. Once the tube has been tested for shorts and grid leakage, the measurements for each triode is taken. Next, the tube is tested for noise and microphonics in the Kaye Labs Small Signal Tube Checker.
The Kaye Labs Small Signal Tube Checker is an incredibly useful piece of equipment. It's the perfect unit for grading tubes for noise as it allows us to listen to the tube in real-world conditions. The tester actually simulates a phonostage circuit. Why is this important? Phonostages amplify a very small signal, sometimes by as much as a factor of 1000. This means if a tube is even a little noisy, we will hear it.
The sensitive circuit also allows us to check each tube's individual microphony level. This is what separates Gold and Platinum graded tubes from Driver grade. Upscale Audio has the experience to know how much microphony is acceptable, so if you don't know for sure, ask us!
For a more in-depth discussion on how Upscale Audio grades small signal tubes, click here.
The Amplitrex T-1000A is an incredible one-box tube testing system. We use it more for certain power tubes that we cannot accurately test with any other tube tester; such as triodes like 845 and 300B tubes. We can even use it to grade small signal tubes for noise and microphonics, though we still prefer the Kaye Labs. We also use it for critical re-testing on a case-by-case basis, depending on the product our customer is planning on re-tubing. This meticulous process takes longer, but you pay us for the best testing in the industry, so that's what you get.
Meet Tubezilla and Son of Tubezilla. These two machines are our burn-in racks where we burn in power tubes up to 72 hours before we even begin to test them. Each machine was custom-built by the former chief engineer of Svetlana USA, and are one-of-a-kind! A massive fully regulated power supply feeds these beasts, ensuring the most accurate and consistent screening process.
We are able to test and match power tubes in these machines, but we want the ultimate in precision, something we can only get by testing tubes one at a time, at three different operating parameters.
For matching power tubes, we use the TM-101. The TM-101 is also custom-built and fully regulated. We load up four power tubes at a time, then each tube is tested individually for three separate operating parameters.