Since 1993 Copyright Notice

Normal Version, with red print. Original boxes.

KEN-RAD 6SN7GT. Very beautiful and exclusive US NAVY tubes. These are the WWII series, of highest quality ever made 6SN7's. In this family is VT231, and the RCA smoked glass as well. Used in ships communication systems, made by USA factory employees, that knew the soldiers out there need to win the war with those. Lots of effort was made and very reliable audio tubes were needed.

These have gray glass, and you can only look in from above. These are either NOS, or from unused equipment.

These have the nice 'chrome' getter like many WW2 VT231. Some info about this is here

I bought those from an experienced and reliable collector, who worked for the military, and got the tubes from the stock. He was selling off his complete inventory. These are perhaps the best 6SN7 ever made, together with 5692 and generally with all 'Chrome' getter tubes.

Top view

These are shipped with a printed test report

The tube is in an older white box, with a Telefunken stamp on it. Original Telefunken. Perfect Test data. FULL TEST PORT HERE.

Sold in 2016, but I leave the tube here because of the rare pictures.

Large Picture of Telefunken 6SN7

Picture of Telefunken 6SN7

550,-
Sorry this tube was sold

This 7N7 is a loctal version of 6SN7-GTB. It is an upgrade of 6SN7, with a ground shield around the base. This may solve some hum problems. For metal base EL34, people pay 300 Euro, where there is no need. Here you have a metal base tube with a good purpose.

Loctal is a similar socket as Octal, but the pins are thinner, as with EL84, and two connections are exchanged. So almost pin compatible, but not fully. The METAL SHIELD is connected to the centering pin of the socket. The loctal tube socket have a connection to this, so you can now use the metal shielding electrically as well, and because it's thick, and in the center, this works well. In case you don't want to use the ground connection, just don't connected anything to it. I cannot repeat often enough how IMPORTANT this ground connection is, to remove hum from a 6SN7 circuit.

If you want to replace 6SN7 by 7N7, we have very nice gold plated loctal sockets already for 2 Euro. Or, we have a small stock of German NOS sockets, which cost a little more, and then of course the Teflon ones from Yamamoto.

Why use 7N7? Well first of all because of the metal base shield. It reduces hum in very sensitive circuits. Another reason is, NOS is nicely available, in fine quality. Untouched quality in never opened before boxes. I have very good stock of Sylvania here. When you look inside the glass, you see the angled anodes, same as with 6SN7-GTB Sylvania. Also they perform out of the box very close to the average operating point, which we can definitely not say about new production. Pay for matching of those 7N7 is not needed. When you buy two, changes they are a pair is close to 100%.

The price is a give away, but please search for 7N7 in the general price list.

About the AMAZING Quality of this 7N7 lot. With 6SN7 NOS, we need to look at the original data here . As a tube dealer, I can tell you, most of the time 6SN7 NOS I get offered is medium quality. The are not at 9mA anymore, as they are supposed to be. By itself this is not a complaint for a random tube. At 8mA, even 7,5mA they can be a fine tube, it depends on the rest of the test. However, my observation is always the same: They are most of the time below 9mA and rarely above. Like 90% is around 8mA or fractional lower. (Same problem is with USA made 12AX7 NOS, many are below average nowadays, and they don't get better from storage, and burn in won't do the magic trick). So each time I can find some NOS 6SN7, the same story repeats: I hope for 9mA or above, and what I get is 8mA or below, and boxes that have been opened 50x before by somebody with dirty fingers, and boxes fall apart just from taking out the tube 50 times. People that have a good tube tester, and tested many 6SN7 will definitely know what I mean. Also Russian NOS, it is the same. 8mA average Even new made Electro Harmonix, it is the same: 8mA average Though specially for new made tubes, there is no need for most of them to be around 8mA, but they are. This quality issue is across all 6SN7 you get. This is why I am so extremely happy with this 7N7 stock, the average test value of those is REALLY 9mA indeed. So some are 8...9mA, some are 9...10mA, and most of them are close to 9mA. The way they were, at the day they were made :) This lot is so exceptional nice quality! The boxes were not opened before. So sure nobody way picking out the good ones. I was the first one to open each 100-pack. Since this is nothing but a 6SN7 with another socket, I decided to buy them all. I am sure it was a good investment.

These are branded TRU-VAC 1960, as on picture. However inside is the same system as the extremely expensive SYLVANIA CHROME TOP VT-231. You can go looking for VT-231 on Ebay, and they sell for a minimum of 40 Euro for tubes of unclear condition and unpopular brands. The better brands NOS VT-231can cost quickly 300 Euro for a matched pair. Not so for most wanted of all: The SYLVANIA CHROME TOP VT-231 is around 1941 production, in those brownish military boxes, with a separate inside part which you can slide out. NOS pairs of these are traded at any crazy price, the problem is not to sell them, but to buy them.

For sale here is not SYLVANIA CHROME TOP VT-231, but something which comes close! These 7N7 have an identical glass bulb and internal construction as the SYLVANIA CHROME TOP VT-231, and it is evident they are made by Sylvania indeed. Note, the VT-231 has parallel plates. (So not the more recent angled plates, which is the most common form, found today).

These have of course the LOCTAL socket of 7N7. So in order to use these as VT-231, the 7N7 to 6SN7 adapter needs to be purchased along with it. (The adapter has part number 399-125-92)

One Pair normal glass, Pair is 120 Euro.

One Pair Long glass, (pictured here). Pair is 130 Euro.

One Pair long, smoked glass, Pair is 150 Euro.