We show you our test gear -
why doesn't everyone else?

We have two different test racks, Son Of Tubezilla for burning in and preheating, and Tubezilla for matching and screening. We had these custom-built for Upscale Audio by the former Chief Engineer of Svetlana USA and published author Eric Barbour. These two racks weigh in at about 200 lbs and will operate with up to 40 tubes simultaneously. Up on the top shelf above the testers is a Hewlett Packard fully regulated power supply. This sucka has enough juice to kill you and anyone holding your hand next to you. A fully regulated power supply is vital to ensuring an accurate and consistent test for each tube being screened. If one goofy-ass tube is drawing more current than the others, it will not throw the tester out of whack. Additionally, it allows us to get you a set of tubes 3 years from now that match the set you purchase today.                       Click image to enlarge.

This is Tubezilla. We use Tubezilla for additional burn-in and screening at real voltages, and physically inspect each tube looking for signs of stressed screens that may fail prematurely or tubes that will not remain stable. Notice there are three meters on the left side. The bottom meter measures transconductance. The others you won't find at other dealers. We screen for excess screen current draw. We know of no other company that does this. The reason we do it? Some amps don't like tubes that draw excessive screen current. And they kindly let you know it when you fry some resistors. We greatly reduce the chance of severe amplifier damage.                                               Click image to enlarge.

This is Son of Tubezilla. This rack is what we use to burn in each power tube for 72 hours prior to testing. We don't just heat the filaments like some companies. We run each tube in circuit with real voltages. Experience shows us that up to 25% of power tubes will change measurements after burn-in, sometimes as much as 20%. In some cases this can upset the bias of your amp. On the left side is a single meter that monitors Cathode current on each tube, and lets us know if the tube is drawing too much, or too little current. We also check for heater and grid leakage. Any tube that has a leak pops a fuse and lights up an LED next to the tube.                                               Click image to enlarge.

Finally - matching. We could match tubes on Tubezilla, but instead we measure most all power tubes at three operational points on our custom built, fully-regulated, single ended TM-101. It tests tubes four at a time, giving us precise measurments for bias, transconductance, and G2 current. All of this requires a lot of attention to detail, and is done without regard to cost.

You can refer to your supplied measurements at a later date to get a replacement tube if needed. If you have an amp that requires 4, 8, or 12 tubes, and lose just one, it makes your life very simple.