[ScubaMan2017]

That is a fascinating experiment, Tom. Coming from a guy who knows nothing about tubes.
I thought you were supposed to be making cables

Source: https://i.ytimg.com/vi/HQjDcsKdtzM/maxresdefault.jpg ; uploaded July 30, 2019. Nope, not adding to the conversation anymore. -5% for @ScubaMan2017 ...

 

[ScubaMan2017]

Mind blown: a gallium nitride class D vaccuum tube. Alrighty then.

http://agdproduction.com/gantube.html

A circuit board encased INSIDE a tube?! God, it's beautiful. I'm curious to read the specs. Dang.

 

[Ableza]

Silliness. Although my company once put a flex circuit inside an acrylic tube because the customer wanted to watch the LEDs flash. Also silliness, but the customer is always right... when they are paying for it.

 

[Paladin79]

@Paladin79 Thank you for agreeing to send the tubes! At last month's SchiitrMeet I was thinking that I would love a tube shoot-out, as I've recently started exploring this space. I'm already looking forward to September!

Ashirin if you have any preferences and would like to know what people think of a specific tube please let me know. I am going to upgrade the choices some. One I was thinking of including is the Melz 1578, a russian tube that brings a lot of money each time it hits the market. Most folks I know love them but a few do not so it would be fun to get other reactions. There is always a certain mindset when you pay a lot of money for a tube and that is what this study is meant to dispel. I personally like that tube and run four of them in a Freya plus but others might like other tubes a lot more.

Luckily with the Lyr 3, you do not have to concern yourself with matched pairs of tubes and I own quite a few single 6sn7's.

I do put a four digit code on each casing so I always know which tube is which. Other than that, this is what they look like. Then final assembly with vent holes. I trust the folks I send them to but they understand if they try to see what is inside, it would get pretty obvious. Each tube was run in excess of three hours to insure no heat related issues.

Most likely I will get the tube info to Jason so he knows which tube is which at the end of any blind testing.

 

[ashirin]

Ashirin if you have any preferences and would like to know what people think of a specific tube please let me know.

That's awfully kind of you. I'm still learning... I haven't even had the time yet to A/B the 6SN7 tubes that I purchased a couple weeks back. I did recognized 6 out of the 9 tubes you mentioned, so I guess that's something. The only tube that I've read about more extensively that was not in your list is the red base 5691/5692 tubes. Any thoughts on those?

By the way, the way your covered all the tubes so thoroughly (including adding the bases) is awesome. It never would have occurred to me to do that. Then again, I'm not nearly familiar enough with any tube to be able to pick them out consistently in blind tests anyways. If I was a betting man, I'd end up paying for a lot of steaks.

 

[Pietro Cozzi Tinin]

@Paladin79 : Would you see yourself build a similar "ground control" as I build?

 

[Paladin79]

That's awfully kind of you. I'm still learning... I haven't even had the time yet to A/B the 6SN7 tubes that I purchased a couple weeks back. I did recognized 6 out of the 9 tubes you mentioned, so I guess that's something. The only tube that I've read about more extensively that was not in your list is the red base 5691/5692 tubes. Any thoughts on those?

By the way, the way your covered all the tubes so thoroughly (including adding the bases) is awesome. It never would have occurred to me to do that. Then again, I'm not nearly familiar enough with any tube to be able to pick them out consistently in blind tests anyways. If I was a betting man, I'd end up paying for a lot of steaks.

The bet was not my idea but I rarely turn down a challenge lol. I was just as happy to buy if I lost, this particular guy sent me a complete set of tubes for a Cary SLA 70. I sent such good tubes for the most part I figured it would come down to the GE and Electro Harmonix but the Melz was picked as the worst tube. I should have them back tomorrow and if that tube has any issues I want to get it out of the mix.

I have a couple CBS 5692 tubes in front of me, and could certainly encase one of those. I have used a pair if them in the Freya and they are pretty much my go-to tube at times. They are highly regarded and as long as you get them from a reputable seller, you cannot go wrong IMHO.

5691 is the 6SL7 version. A book such as Tube Lore can be very helpful identifying tubes, I also own Sylvania and RCA tube manuals that are very handy. 5691 on the left, 5692 on the right. The one on the right says CBS JAN (joint army/navy) and was probably sold as a Hytron but it sure looks like a Sylvania to me.

 

[wabe]

A circuit board encased INSIDE a tube?! God, it's beautiful. I'm curious to read the specs. Dang.

Isn't this, then, just a LISST in a glass tube?

 

[Whazzzup]

well i know a liss

 

[jseymour]

The bet was not my idea but I rarely turn down a challenge lol. I was just as happy to buy if I lost, this particular guy sent me a complete set of tubes for a Cary SLA 70.

I have a couple CBS 5692 tubes in front of me, and could certainly encase one of those. I have used a pair if them in the Freya and they are pretty much my go-to tube at times. They are highly regarded and as long as you get them from a reputable seller, you cannot go wrong IMHO.

5691 is the 6SL7 version. A book such as Tube Lore can be very helpful identifying tubes, I also own Sylvania and RCA tube manuals that are very handy. 5691 on the left, 5692 on the right. The one on the right says CBS JAN (joint army/navy) and was probably sold as a Hytron but it sure looks like a Sylvania to me.

Have you ever tried the 6SN7 variants: 6F8G, 6C8G and 7N7?

 

[Paladin79]

@Paladin79 : Would you see yourself build a similar "ground control" as I build?

I could see doing that, but mine would be copper instead of aluminum. I believe you said yours was an aluminum block right?

 

[Robert Padgett]

Here you make a valuable point. Bad or good valves... they still work and will be defined as a working valve/tube
A good wine is drinkable but a bad wine is thrown in the sink and not drank.

Saw your picture a few posts back. Much friendlier than the beardbearing Brother of Frankentein of your first avatar but that avatar had much more character.

Thanks. I am not trying to look younger, rather to not look as old...

 

[Paladin79]

Have you ever tried the 6SN7 variants: 6F8G, 6C8G and 7N7?

A 7n7 was in the challenge I spoke about, the Melz was a 6h8C. I was careful to use the word 6SN7 equivalent. The 7n7 was the loktal version of the 6sn7. I used a tall body tube but it was not the premium tall body version according to one very wise tube guy I know.

I went so far as to buy ten pounds of Loktal tubes in order to get both tall and short body 7n7's and I own some Lansdale and other NOS versions.

Most all Russian tubes use other designations of course, just as a military version would us VT 231. I would have to look up the other two tube numbers.

I also run a lot of single triode tubes in pairs but they were not usable in the challenge.

 

[jseymour]

I should have looked at your list closer. I have read that the Lansdale was made by Sylvania. I have the short Sylvania 7N7. Good tube.
This is the first time I have heard of someone buying tubes by the pound. Smart move when you have a tube tester.

 

[Paladin79]

I should have looked at your list closer. I have read that the Lansdale was made by Sylvania. I have the short Sylvania 7N7. Good tube.
This is the first time I have heard of someone buying tubes by the pound. Smart move when you have a tube tester.

I also purchasesd what were supposed to be dud tubes for projects like headphone racks and then figured out a way to give them the tube glow I wanted. In ordering some of those I got some black glass tubes that were working as well as some larger power tubes that were fine. I went for the ST shape in both types when I could.

Lansdale was also National Union according to one tube book I have so I could not say for sure. The tall body 7n7 that people like have to have an oval bottom mica and the long getter coverage.