What's the tolerance voltage wise? I got a fixed supply that runs at 12.25v (1.5a). My variable supply has vanished into the void so I can't check the exact output. I know 7dj8 will happily run at 6v (so will 7n7). Those 14n7 running on 12v?
An old friend of mine who was active in radio technology in the 50's and onwards told me that a 10% tolerance was perfectly acceptable in vacuum tube production.
Who made that one? Got a pic of the whole tube?All this talk about 7N7 has gotten curious me. Which version do you guys think that I have?
From my observation this has T plates and tall envelope like my Sylvania 6SN7W but without the support rod. Mica shape looks similar and there are 4 umbrella spokes from the top mica too.
The 7N7 do have a special dynamic to them, they reach out in a 3d like realm of sound. The 7A4 almost the same but those are single triode, you'll need an adapter for double duty.
Yup, as far as I can tell all of the tall 14n7 have the same construction and they sound better than all of the 7n7 varieties. I’m pretty well convinced that the 14n7 is the equivalent of the metal base 6sn7w. The short bottle ones sound the same to me and I can see the copper support rod on a few of them. The getter flashing covers most of them up though. Mind you, only a true 6sn7 cork sniffer like myself think it’s a difference that matters. 7n7 tubes are excellent. I think that the angled plates aren’t as good as the parallel plate.Here is a Unicorn 14N7 that I don't remember seeing before:
The markings on the glass are (nothing on the base):
MR
SA96
H 4 on top under the 14N7 designation
MR = Manufacturers Replacement. This dates the tube to 1942-45 when vacuum tubes were rationed and mainly going for military use. A small portion was allocated for civilian replacement use.
SA96 - don't know. Anybody?
H 4 looks like Sylvania codes and could be August 1944.
This is a tall tube and possibly the loctal equivalent of the Sylvania metal base 6N7W. Looks like T-plates and has a single copper support rod with oval bottom ractetrack mica. It sounds excellent!
Regardless of the brand, Sylvania made that tube. Sylvania made all of the 7n7/14n7 except for the very rare National Union round plate 7n7.
I had always heard that as well but it’s best to check the data sheets. Not all tubes have as big an acceptable range.
The 7a4 is a loctal Sylvania 6j5gt. Since the price of Sylvania 6j5gt isn;t all that much it might make more sense to get the 6j5 adapter so you can use other brands as well.
Might. I have em both. (Adapters) cheap.
That's what I'm hearing.. was wondering what branding was on his tube.
14n7.. now that's new to me, that can play on a 6SN7 socket (w/ adapter) ?
The 14n7 is a loctal 12sn7. You can get an adapter that lets you use an external power supply for the heater. It’s well worth it IMO. I’d get both a 6sn7 to 7n7 adapter and the one you can use an external supply in case you want to use 12v or other oddball voltages.
If I have 14N7, does it pay to get 14AF7 or 7AF7 tubes?
Well, they are different tubes so they will sound different. The 14af7 is pretty cheap so if you’re curious it wouldn’t be a very expensive experiment. The two I had didn’t set my world on fire but it does have its fans.
Thanks - at this point in my tube journey I am only looking for very special great sounding tubes. I found the 14N7 special...
