Note: Because of its wider base diameter, the 5931 tube may not fit into all 5U4 tube applications.
5U4 Tube Types
Additional Information and Downloads
What does "NOS" mean, anyway?:
Commonly known as "NOS," the term New Old Stock simply refers to tubes that were made years ago but have never been used. Much like antiques, "NOS" tubes are currently not being manufactured and this means their supply is dwindling while the price continues to rise.
For most NOS tubes we have a variety of brands available. Typically these are the common brands such as RCA, Sylvania, GE, Raytheon, etc. However, there are instances where lesser known brands are in stock. If you have a particular brand you prefer you can simply request it in the Order Comment box when you place your order.
Warranty Information and Return PolicyWarranty Period: 3 months
All our tubes are guaranteed for 3 months from the date of purchase. (Any exceptions will be noted on that tube's Warranty tab)
If you receive a tube that does not perform to the manufacturer's specifications, please do the following:
- contact us to get a return authorization
- return it via regular mail within 90 days from when we shipped it, and we will provide an exchange or refund of the full purchase price of the tube.
Returns not related to warranty or defect will be considered at our discretion, and are subject to a 15% restocking fee.
We can not accept returns that don't have an authorization, are past 3 month, or are returned improperly.
These guidelines may be updated without notice.