[Paladin79]

I suspect some fondling occurred before you received it which probably diminished the print visibility.

Hell's ducks man! I do not have an attraction to Russian tubes, Sylvania naughty girls might be another matter.

 

[JKDJedi]

I suspect some fondling occurred before you received it which probably diminished the print visibility.

How did it past customs?? (up someones as.... never mind... )

And today's lesson is...

Among the common applications of vacuum tubes are amplification of a weak current, rectification of an alternating current (AC) to direct current (DC), generation of oscillating radio-frequency (RF) power for radio and radar, and creation of images on a television screen or computer monitor.

 

[bcowen]

Among the common applications of vacuum tubes are amplification of a weak current, rectification of an alternating current (AC) to direct current (DC), generation of oscillating radio-frequency (RF) power for radio and radar, and creation of images on a television screen or computer monitor.

Thanks for that...I had no idea. I thought they were only for making your stereo look cool.

 

[highstream]

6F8G not 6SN7, but not sure where to find a current thread where people are knowledgeable, so I'll try here... I came across this pair of Sylvania 6F8G-VT99 and noticed that they are different heights, which the seller confirms. Does that likely mean different years? Anything to know about that -- or otherwise? Thanks,

 

[JKDJedi]

6F8G not 6SN7, but not sure where to find a current thread where people are knowledgeable, so I'll try here... I came across this pair of Sylvania 6F8G-VT99 and noticed that they are different heights, which the seller confirms. Does that likely mean different years? Anything to know about that -- or otherwise? Thanks,

That would be mine conclusion, different years. Great tube.

 

[Tom-s]

Height difference is not related with tubes being from different years. Especially in the '20s, '30s and '40s a height difference within a batch was normal.
Here's an example of a same date (see Tax sticker), so about the same age, pair of Fivre 76 tubes. Notice the height difference?
In this post i show more of these also with a minor height difference. Even early 9 pin tubes, '50s pinched waist types, have this within a single batch.

 

[sennfan83261]

6F8G not 6SN7, but not sure where to find a current thread where people are knowledgeable, so I'll try here... I came across this pair of Sylvania 6F8G-VT99 and noticed that they are different heights, which the seller confirms.

If they are of the same age, it looks like one was sent off to war and the other one rode out the war while being in the National Guard, lol.

 

[Slade01]

If they are of the same age, it looks like one was sent off to war and the other one rode out the war while being in the National Guard, lol.

Lol. Seriously, maybe one is a b-stock tube. In all seriousness, I know from experience with RCA tubes, they had tubes that were deemed "substandard" or "M/R" that for some reason or other were not up to standard spec. Though I don't think glass height would affect operating specs that much.

 

[highstream]

Thanks for the replies. If the tubes have different histories, that could also account for the different external wear patterns.

Tom-s, interesting you linked to a Fivre. I picked up a couple different sized 1940's Fivre 5U4G's from an Italian dealer a few months ago, one of which turned out to be really enjoyable in my Supratek preamp, although a few weeks ago I got another USAF 596 which is a notch better for my purposes. I also have a Fivre 5R4GY, which is supposed to be the best of them, coming slow boat from Germany.

 

[JKDJedi]

This baby measured near death on the listing... (1700/1400Gm) And for $20 I couldn't resist .. will I still get the "sound" of the TSRP??

 

[Slade01]

This baby measured near death on the listing... (1700/1400Gm) And for $20 I couldn't resist .. will I still get the "sound" of the TSRP??

What is the branding listed on that tube?

 

[JKDJedi]

What is the branding listed on that tube?

Hyvac (I've never heard of them)

 

[Slade01]

Hyvac (I've never heard of them)

Really good find. The lettering print just looked interesting (stands out). Even if the tube us 1700/1400 it should last you a good long while.

 

[JKDJedi]

Really good find. The lettering print just looked interesting (stands out). Even if the tube us 1700/1400 it should last you a good long while.

Thanks @Slade01 did a quick (dirty resoldering) and will test this later this week. (see if the soldering changes things as far as measurements go)

 

[Paladin79]

I am going through some NOS 1963 Melz I just got. Some logos are more pronounced as @JKDJedi found out.