Sylvania 35W4 tube

Tubes tests great. I keep these around for "radio amps"-- the guitar amps based on radio circuits that were commonly sold under Harmony, Western Auto, Kay, and other brands in the 1960's.

I only sell tubes in very good condition. I treat reverb.com as my premium tube marketplace. If it tests at all weak, is noisy, or has the silkscreening worn off to the point you can’t positively identify it, I don’t sell it on Reverb.com. I have sold over 2,000 tubes on this site, and have only ever had one problem— and I replaced that tube at no charge.

I don’t sell smoke— meaning I don’t throw around rumors from the internet or make false claims about my tubes. I charge a fair price, treat my customers fairly, and happily answer questions about tubes and amplifiers at no extra charge.

FAQ:
Why don’t you list the data from your tube tester?

Some sellers name the data from their tube tester in the listing. While it may seem reassuring, I don’t list it because no two tube testers are alike— even two that came off the line the same day, and are calibrated by the same person. I don’t like people asking to return a tube because the reading on their tube tester was 1% different than the reading on my tester. Every tube I sell has been tested on at least one tester, usually two. They’re all guaranteed to be in great working condition. 

Doesn’t tube tester data tell me how long the tube will last or how it will sound in my amp?
No. Numbers from a tube tester show if the tube has problems, but it’s not like a gas gauge or odometer. Some tubes may show a reading that looks like it’s 80% of a comparable brand new tube. But its design may mean it will last 40 years longer than the new tube, and sound better, too. Most tubes in most applications will last for decades.

What about matched or balanced preamps?

Unless you have certain hifi amps where one half of a preamp tube serves left and one serves right, or some other special application, it doesn’t matter if your preamp tubes are balanced or matched. Output tubes need to be matched in pairs or quads.