the ultimate guide to tube-rolling
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The results of tube-rolling are dependent on your audio components, the room, and your ears. There is no “best” tube. A tube that adds “top-end sparkle” to one system, can be bright or harsh in another system, or to another listener. A tube with a wonderful “liquid midrange” might sound too rolled off and warm to some listeners. Tubes are a personal choice, so anything in this guide is just that, a guide. There are no definitive recommendations, and beware anyone who gives you any. First, a few basics:
Tube changes are not essential
PrimaLuna products, for example, come stock with a wonderful tube selection. The amps and preamps are voiced using those tubes and there is absolutely no need to change them. Tube rolling is about experimentation and fine-tuning.
Tube-rolling doesn’t fix problems
Issues such as bloated or absent bass, or excessive harshness are usually traced back to speaker placement, room issues, or component mismatches. They cannot (and should not) be fixed by changing tubes.
Tubes might have a sound, but so do circuits and systems
Every day we get questions about how a particular tube will sound in a product we’ve never heard, and often, haven’t even heard of. We simply don’t know the answer. A tube in one circuit can sound different from a tube in another. The best source for information on how a tube would work in your component is the manufacturer of that component. Tell your manufacturer to create a cool guide like the PrimaLuna Tube-Rolling page.
This is supposed to be fun
“Thanks for nothing” is a common response when we are unable to provide a definitive answer to “Which tube is best for my Acoustic Chutney Mk 4.2 that was made in a garage in San Ramone by a misunderstood audio legend who died in 1986?” If you want to change tubes in your component, understand that trial-and-error and uncertainty are intrinsic to the hobby. If tube-rolling is a chore or cause for anxiety (and rudeness!), then maybe stock tubes or solid-state amps are best for you.
Nothing in this guide is definitive
This bears repeating. This guide points you in the general direction, it does not--and cannot-- promise you will hear exactly what it suggests.
Yes, when you order a set of tubes, they will be matched. That’s what the Gold and Platinum grades are, a tight match, and a tighter match. All tubes at the Gold and Platinum grades test extremely well.
No, tubes are never discounted, no matter how many you buy, or how big a system you’ve bought from us. The testing process is time-consuming and extremely fiddly. For example, when we test for microphony we are listening to each and every tube in a specially designed phono preamp.
12AX7 / ECC83
These are miniature dual triodes with a high voltage gain, commonly used in preamplifiers. They are still in production, made by New Sensor in Russia, Shuguang and Quanzhen in China, and JJ Electronic in Slovakia.
12AU7 / ECC82
A medium-gain dual triode tube with many names for identical variants, or others that are designed for certain characteristics such as long life. They are still in production, made by New Sensor in Russia, Shuguang in China, and JJ Electronic in Slovakia.
6922 / 6DJ8 / ECC88 / E88CC / 6N23P / 6N11
A miniature nine-pin medium gain dual triode with a very high transconductance. First developed by Amperex / Philips for use an amplifier in TV tuners, and later used in high-quality oscilloscopes.
EL34 / 6CA7
A power pentode with an international octal base. In general, known for a beautiful midrange.
6550 / KT88 / KT120 / KT150
The 6550 is a beam tetrode, and is often interchangeable with the KT88. The KT88, another beam tetrode that offers high power and low distortion. The KT120 and KT 150 are beam pentodes developed for even higher power.
Triodes: 300B / 845 / VT4C
The 300B is a directly heated triode with a four-pin base.