EF92 CV131 6CQ6 STC, NOS, milspec, premium matched pair, for Little Dot

Description

These tubes are made by STC, with STC “FB” codes printed on the glass. They come with different governmental prints (see pictures). No matter what print, they are all the same. I reserve the right to deliver either version. 

Some tubes may carry values written on them by the army personal or may have slightly faded prints. This does of course not affect the proper operation.

This is the early 1950ies version with big horseshoe getter. These tubes came in bulk from Swiss army surplus. All tubes are tested and burned-in/pre-aged (hence the colors on the tubes). The burn-in was done to secure stabilized operations in highly sensitive measurement instruments. 

You will receive a tightly matched, noise and distortion free pair! Guaranteed!

Matching is done on a milspec Neuberger RPM375, still one of the best tube testers out there… 

EF 91 and EF92 tubes can be noisy at times in the Little Dots amps. While some noise during heat up is normal with these tubes it should disappear after 60 seconds latest. To guarantee that you will receive a pair that is noise free after warm-up, we will listen to each pair ourselfs on our LD MK2 with super neutral and noise free Neumann studio headphones.

We do have plenty of different versions of the EF91 and EF92, please drop us a line, if you would prefer another brand or just check our other offers. All are from the same provenance and most are burned in. We also do have many other kinds of 7-pin tubes, which you may want to try. We will be happy to check our stock for you!

Using EF91/EF92 instead of EF95: You may use this kind of tubes in your Little Dot headphone amp after changing the settings on your amp. This is a less than 5 minutes job and can be done by really everyone. No expert know-how necessary! Please consult your user manual how to do this prior to using these tubes in your particular amp!

From own experience we can tell you, it is more than worth it!