[Ranger Ron]

The round plate 7N7 tubes are indeed a dead ringer for the NU 6f8g. I think I have figured out why I can't make them work well in my system. I think they sound soft, at least they are softer sounding than the various 6sn7 and other 7N7 I have tried. They lack detail and the top end isn't exactly subdued, but it doesn't have the extension or sparkle or however else you might want to phrase it. I also am not getting as much bass out them. I do think these tubes could be useful if your system leans towards brightness or just kind of nervousness like some Lowther single driver speakers are. If you like trying different headphones they might be a handy flavor to keep on hand. Here in speaker land I don't change those very often. I'll keep them around and see how they fare in the new amp. For now they go into the provisional pile.

I'm back to the normal tall 7N7. Will probably stick with those for the next week or so and see if they change much. Using the GE 6bg6ga as outputs. Bass galore, very "active" sounding. Not as clear or open as my now regular Cossor 807 but quite enjoyable.

Just goes to show again how system dependent tubes can be. In my experience with the NU 6F8G round plates they are everything but subdued.

 

[Ranger Ron]

I’ve also had the most troubles with the NU 6F8G. Some circuits they sound absolutely glorious, others just ok, and a few they just refused to work in.

 

[triod750]

No. The 6H7C (6N7S) is closer to a 6N7. Compared to a 6SN7, it has higher heater current, higher amplification factor, and different pinout (so an adapter would be required).

If the same construction as 6N7 they also have common cathode which can be important to be aware of in some applications.

 

[jbua5150]

Speaking of NU 6F8G, there are a couple pairs on eBay for a reasonable price. I have no prior business dealing with the seller, so proceed with caution. I purchased 2 pairs myself(seller accepted my reasonable offer)that I will test before I install into my amps. Fingers Crossed
https://www.ebay.com/itm/165659928332?hash=item269219e70c:g:uOkAAOSwZtRjFUi0&amdata=enc:AQAHAAAAoLeiYC+PZgsKCckgdQRGo22VE0wClHpTJlNvZ46IPrLOQmyZLDhT+3uaPHILog+RBFF9DXyizWAmd0QKMr0YqlOW8xN+lruw9a2dwdVhmvg1hPPJPi1ONmyhHPp4MnKv+hpoDZirgO7j0HVhRJ2ipsIz86abCIqTbnqQzmF8ItXpFq37shMU6ryxn8JA0iQWezY0nbGxIte7Nvum18i7gac=|tkp:Bk9SR9rYzI7lYA

https://www.ebay.com/itm/165659927903?hash=item269219e55f:g:8F4AAOSwQHZjFUfD&amdata=enc:AQAHAAAAoLY43RPCE6tZKIGO4oQoBO5GHDo20Gfv6NXSIE4tO5S+1PKKRRq8q9cY+/8YQAC/DU6Ta/tTxifAwfyPwcFJwBjrFM8eJ6dzKeBFv9WvDD8nKAMaovZB90YhJx7Mhth3AHfhQb08MtRNFBtJ1P5sA322neDKvhn5NyZELwcvgWCLvxEkXiR1mTIohXJ77cRXMVznrUuXXAdGVSvJ+xXszDc=|tkp:Bk9SR9rYzI7lYA

 

[Isaacc7]

I have been obsessed with finding alternatives to high quality 6sn7 tubes. The prices have just shot up so much. I've been using 7N7, 14N7, 12sn7, 2c50, gf8g, 6/12j5, and CV1102 and kind of forgot about the 6sn7 tubes I own. Popped the Sylvania brown base 6sn7w in to my amp. Not going to lie, felt like I was cheating or something lol. It was so easy to just pop it in without an adapter!

Compared to the tall 7N7 I was using, the 6sn7w is more extended in the treble and sounds a little smoother. It does sound more upwards tilted and seems like it's lacking a bit in bass. It also looks a bit silly with its short envelope in front of the big 6bg6ga tubes on their adapters lol.

 

[LoryWiv]

I have been obsessed with finding alternatives to high quality 6sn7 tubes. The prices have just shot up so much. I've been using 7N7, 14N7, 12sn7, 2c50, gf8g, 6/12j5, and CV1102 and kind of forgot about the 6sn7 tubes I own. Popped the Sylvania brown base 6sn7w in to my amp. Not going to lie, felt like I was cheating or something lol. It was so easy to just pop it in without an adapter!

Compared to the tall 7N7 I was using, the 6sn7w is more extended in the treble and sounds a little smoother. It does sound more upwards tilted and seems like it's lacking a bit in bass. It also looks a bit silly with its short envelope in front of the big 6bg6ga tubes on their adapters lol.

Have you tried 6V6 family instead of 6SN7's, with adapters of course? Some of them sound great and generally quite a bit more affordable.

 

[Isaacc7]

Have you tried 6V6 family instead of 6SN7's, with adapters of course? Some of them sound great and generally quite a bit more affordable.

I have not. There are adapters that use a pair of triode wired 6v6 instead of 6sn7? That's kind of crazy. Of course once you go down the path of triode wiring pentodes there would seem to be a lot of other potential tubes to use like 6sj7, ef86, etc.

 

[LoryWiv]

I have not. There are adapters that use a pair of triode wired 6v6 instead of 6sn7? That's kind of crazy. Of course once you go down the path of triode wiring pentodes there would seem to be a lot of other potential tubes to use like 6sj7, ef86, etc.

You are right of course, but results are excellent in my amp. Thinking about it more broadly, there's nothing crazy about using 50-70 year old vacuum tubes in modern audio equipment. We are all quite sane, yes, really we are.

 

[PeterNL]

Hello guys.
Can someone help me to identify this beauty ?
Hytron JAN-CHY 6SN7GT from 1951.
I bought it for 10€ from my friend. Is this tube comparable to Sylvania, RCA, Tung-Sol...?

 

[triod750]

Amazing photos...

 

[PeterNL]

Hello guys.
Can someone help me to identify this beauty ?
Hytron JAN-CHY 6SN7GT from 1951.
I bought it for 10€ from my friend. Is this tube comparable to Sylvania, RCA, Tung-Sol...?

I have found some information on tubedepot but don't know of this is true:

@Paladin79 What do you think ?

 

[PeterNL]

Amazing photos...

Thanks, just photos from chinees phone

 

[triod750]

But somebody took them... Chinese?

 

[jbua5150]

Hey gang!
My 4 National Union 6F8G just showed up!
I need some help from the experts here.
They all have the same date code of EN.
Does anyone know the date of these?
ONE of the 4 is clearly marked VT-99.
I wonder if these ALL are VT-99, with the print rubbed off the bases?
Super anxious to have these tested.

Edit: The boxes these came in have a date of 5/66.
My previous knowledge was that NU used 2 digit date codes UNTIL the 1950's.
If so, these appear older than the boxes would suggest?

 

[ColSaulTigh]

Hey gang!
My 4 National Union 6F8G just showed up!
I need some help from the experts here.
They all have the same date code of EN.
Does anyone know the date of these?
ONE of the 4 is clearly marked VT-99.
I wonder if these ALL are VT-99, with the print rubbed off the bases?
Super anxious to have these tested.

Speak of the devil!

Mine just arrived, too! I haven't even bothered looking for a date code, but both of mine are marked 6F8G.