Fosi Audio Vacuum Tubes 7-Pin - 6CB6A

Replacing the wrong type of tube may damage your amplifier. If you are not sure this 5645W can be used as a replacement for your audio device, please check with your amplifier manufacturer. It has a fuller, wider sound stage.

The treble is smoother and the bass is a little bit tighter. And you can hear some details that you did not hear before while listening to more complex music. Every package you get goes through our careful packaging.

With 18 months warranty. If you have any questions, please feel free to contact us. Vacuum tubes such as the 5725 and 6J1 are products of a specific historical period, carrying strong historical significance and unique tonal characteristics.

Having long been discontinued, all available units are carefully preserved vintage stock, making them non-renewable and rare collectibles. Minor signs of aging on the tube surface—such as slight scratches, faded markings, or yellowed mica—are normal. We guarantee that every vacuum tube sold has undergone basic testing to ensure proper functional performance.

Given the uniqueness and scarcity of these products, all sales are final; no returns or exchanges will be accepted once purchased. Please do not place an order if you do not accept these terms. All vacuum tubes have been fully tested and strictly matched.

These vacuum tubes are compatible with audio equipment including BOX X2, BOX X4, P3, GR40, MC331, T20X MKII, etc. Using an incorrect vacuum tube model may damage your amplifier. If you are unsure whether these tubes are suitable for your audio device, please confirm with the amplifier manufacturer.