Description
Description
One pair of Octals.
Octal is a solid-state power tube alternative designed for 8-pin, push/pull circuits.
Octals are designed for most tube amplifiers
- However, there are some incompatible circuits, for example:
- Single-Ended Amplifiers (Fender Champ, 5F2, etc…)
- Amplifiers with a paraphase phase inverter (Fender 26, 5A3, 5B3, 5C3, Gibson GA 40, some Valco and Supro circuits, Benson Amplifiers…)
- Amplifiers that use tube cathode as signal input (Musicman HD series)
- Amplifiers that use EL84 power tubes (Vox AC15, AC30, DR Z MAZ 18, Top Hat Club Royale…)
- Amplifiers that use the 7591 octal power tube (Ampeg Jet, Premier 50, etc…)
Limited Run
We will be producing and releasing Octals in limited batches. These are handmade to ensure the proper quality and testing as we refine the manufacturing process and grow our manufacturing capabilities. This ensures the highest quality.
What is the Octal?
Octal is a plug-and-play alternative for the power vacuum tube used in audio amplifiers. Unlike traditional vacuum tubes, it uses modern electronics to deliver consistent, high-quality sound with improved reliability, durability, and efficiency.
Generally what amps can use Octals?
The Octal is designed for amps with a push/pull circuit (not single-ended or triode connected) and a standard 8-pin power tube (EL34, 6L6, KT series, 6V6, or similar common octal pinouts). Please read the warranty section in this FAQ.
Why do we need Octals?
Nearly all new vacuum tubes are made in just three places: Russia, China, and Slovakia. This limited production makes the supply chain fragile and prices more unpredictable. After they are made, vacuum tubes have to be sorted, matched, and tested for things like microphonics, transconductance, and stability. Over time, they wear out from heat, use, and vibration, so they need to be replaced regularly. Tubes also handle high temperatures well and sound great, and we hope they never go away — but as an alternative to counter some of these issues, we came up with the Octal.
Does my amp need any modification to use Octals?
Some tube retainers can be a little awkward. We recommend removing them if you want to prevent scratching your Octal. The Octal pins have had a pretty healthy grip in every amp socket tested thus far.
Also amplifiers with a B+ plate supply voltage over 500V will need fan cooling. Most such amps already include fan cooling (Ampeg SVTCL , etc..), but we offer a fan kit for amps that run hot without a fan (Sunn Model T, Sovtek Mig 100 etc…)
What is a push-pull amplifier?
Your amp's power tubes have one job: make your speaker move air so you can hear your guitar. Your guitar signal swings back and forth constantly, positive then negative then positive again, and the power tubes push that swinging signal into your speaker to recreate the sound.
Single-ended amps (like the Fender Champ) use one set of tube(s) to handle that entire swing alone, positive and negative both.
Push-pull amps split the job between two sets of tubes: one handles the positive half of the swing, then hands off to the other, which handles the negative half. They take turns, back and forth, thousands of times a second, like a two-person relay team instead of one runner doing the whole lap solo.
About 95% of commercially available amps are push-pull, and that's what Octal is built for today. A single-ended version will be in development.