Good day, this listing is for (1) NOS 6AU6 tube, suitable for the Sony C800G and compatible microphones such as the Warm Audio WA-8000, Stam Audio SA-800G, and Golden Age Project GA-8000.

Each tube is unused as it is a NOS tube. These are vintage production tubes (1960s–1980s), and while cosmetic details like stamps or markings may vary: blue OTK, white OTK, or no stamp the internal construction and performance remain consistent. The Sony-branded version of this tube is the same type, simply labeled differently (SONY).

Before listing, each tube is visually inspected and tested in-circuit to ensure stable operation, low noise, and consistency. Only tubes that meet that standard are offered. I only list a small number at a time from the batch to ensure each one is properly checked and consistent.

In use, this tube offers a noticeable improvement over the stock tubes often found in modern recreations. The difference isn’t exaggerated, but it is clear especially on vocals. There’s more presence in the low-mid range (around 500Hz), which helps fill out the body of a voice, along with a smoother top end that avoids the brittle or harsh edge some users notice around the upper midrange (roughly the 3–4kHz area). The result is a more balanced, dimensional sound that sits more naturally in a mix, with clarity that doesn’t feel forced.

For context, this is the same type of tube I run in my own chain (WA-8000 → Gotham cable → Avalon M5 → UA Twin X). In that setup, it brought the mic closer to the sound I was aiming for more depth, less edge up top, and a fuller vocal that required less correction later.

For many, this is the missing piece in getting closer to the intended character of these microphones.

These tubes have become increasingly difficult to source individually, which is why many people choose to keep a reliable spare on hand once they find one that works well in their setup.

All tubes are handled carefully, stored properly, and packaged securely. Ships next business day, Individually protected for safe transit, From the same tested batch.

Thank you for your time. I hope this serves your setup well.

Important Handling Notes:
Avoid touching the tube with bare hands, as oils from your skin can affect longevity and performance. Use latex or non-latex gloves when installing, and ensure the tube remains clean.

Installation (WA-8000):
Remove the four screws holding the heat shrink in place. Gently slide it back to access the tube. Carefully remove the existing tube from the socket (do not pull on the wires). Insert the new tube securely, reassemble, and allow the microphone to warm up for a few hours on first use, then 30–45 minutes for normal operation.