Vacuum Tubes
Tubes that are provided with your unit
Linear Tube Audio sources the best tubes we can find for use in our production units, tested and curated to provide the best experience for our customers. When you buy an LTA amplifier, know that it will come supplied with the highest quality, premium tubes we can find.
Additional Tube Burn-in
The tubes will have been burned in approximately 168 hours. They will continue to improve with additional burn-in as you play the equipment. Some customers have reported 2-300 hours are required for full tube burn-in.
Tube Quality and Sound Quality - Upgrading Tubes
As tube quality increases, ZOTL amps’ sound quality increases. ZOTL amps act as platforms for tube quality. The better the tubes, the better the sound. Also, the same tube, from different manufacturers, can change the sound. It might not be better, just different. LTA goes to great lengths to source the best stock tubes that ship with our amplifiers.
LTA Tube Upgrades
LTA also looks for tube upgrades for our different pieces of gear. We test upgrade tube candidates for improved sound quality and reliability. While we often come across exquisite rare tubes, we are focused on tubes that are consistently available. Ray Tubes are good examples of our curated tube upgrades.
In production Tubes vs NOS tubes vs ZOTL tubes
NOS, or New Old Stock, tubes are some of the best ever made. Most of these classics stopped being produced in the 1960s when transistors took over. The catch is, while NOS tubes sound amazing, they’re getting harder to find and can be less reliable simply because of their age. Many are 50 to 70 years old. We prioritize NOS tubes when we can get enough of them, especially if they have a reputation for quality.
Most audio tubes made today come from Russia, Slovakia, or China, with smaller productions of classic triodes in Germany, Japan, South Korea, Czech Republic, and the United States. Many of these factories have been making tubes for years and the quality and reliability keep getting better. Every tube in our products is carefully chosen, whether it’s a vintage NOS tube or one that’s still being made.
In some of our amplifiers, we use 12-pin Compactron tubes. These are fantastic, but they’re tricky to use with amps that have transformers and are hard to find because they were never that popular for Hi-Fi. Over the years, a lot of them were just thrown away. Luckily, we have a lifetime supply, so you never have to worry about running out. If you’d like an extra set, just let us know and we’ll be happy to help.
What about Biasing Tubes
There are no bias adjustments. All LTA products with tubes use self or autobias to optimize performance, every time the unit is powered on.
What if I have a tube problem
You might hear a rustling or rushing sound, or noticeable fluttering, or noise that doesn’t subside after startup. These are classic tube noise problems, typically only in one channel. Noise problems are noticed with nothing playing and do not trigger the protection system.
Your unit may have no sound output after turning on. This usually means something more drastic has happened and the protection circuit is activated. Our power amps and integrated amps all have sophisticated protection circuitry that monitors for tube issues, over current and a couple other things. If it detects a problem, it shuts down the power supply to protect the circuitry in your amp.
We created this helpful video to help guide you through the process of troubleshooting. Most tube problems can be fixed with a new tube or pair of tubes. We have all replacements in stock and our tech support team can help you through the process. If you’d rather not deal with it, just send the unit back to us under warranty. We’ll test it, fix whatever’s wrong, and return it to you in like-new condition.
Tube Product Support
Jacob is our tube expert with a decade of experience at LTA. You can ask him about recommendations, compatibility, or any issues you encounter. He responds to emails promptly M-F, and tries to check once a day on weekends.