The Reference 6SN7 Thread

[mordy]

Comparisons between Sylvania 6SN7GT "Bad Boy" & Sylvania 6SN7GTB.

I will refer to both as just Bad Boy & GTB going forward.

Used HD800S, LCD 4,Topping D90 & Schiit Lyr +

Overview:

The Bad Boy definitely has more detail in the midrange and instruments just "pop" more than the GTB. The imaging and soundstage also sound a bit better and more open and is especially more noticeable on the 800S. They have now has notes extending to the outer reaches on the 800S. The GTB was a terrible match with the 800S as it sort of sounded a bit muddy and not as clear or as precise as my Topping A90D. The Bad Boy is more relaxed in the treble region and more dark which is now a perfect match with the 800S. You get crystal clear mid range and no notes are missed or smoothed over and you get a vast and ever extending soundstage unlike the Topping A90D. The timbre of instruments is spot on with the Bad Boy with 800S now and no longer muddy sounding and its been a great joy to go back to this headphone as I have only used it for mostly gaming these days. Lastly because I get fatigue from higher frequencies with the 800S, the Bad Boy now has put that peaky ness down and is a vastly better experience.

The LCD 4 also benefits with the Bad Boy as the bass hits harder with better imaging and detail. The weak point is the treble region as vocals don't have the same amount of body in the higher frequencies which makes you sort of miss the clarity with the GTB however, this is the only win with the GTB.

Bass:

More control and impact on the Bad Boy. Bad Boy - 9.5/10 GTB - 8/10

Detail:

Better detail in the background and more instrument separation on the Bad Boy. Bad Boy - 9.5/10 GTB 8.5/10

Vocals:

More body and clarity to the vocals in the GTB. Bad Boy 8.5/10 GTB 9.5/10

Treble:

Better treble extension and sparkle up top for the GTB however headphones like the 800S will much better benefit the Bad Boy. For treble on 800S the Bad Boy is 9.5/10. GTB 8/10. On the LCD 4 the Bad Boy is 8/10 and GTB 9.5

Soundstage & Imaging:

Ultimate soundstage for both 800S & LCD 4 with the Bad Boy and the imaging feels more precise especially in the stereo imaging. Bad Boy 10/10 GTB 9/10

Overall:

I just wish the Bad Boy had kept that vocal clarity and it would have been the perfect tube. Alas, the advantages with the Bad Boy in mostly every other department will mean it will be my main for now. The 800S has been given a fresh lick of paint and you get better detail in the midrange and better bass impact and control. If you are a treble head the Bad Boy isn't your tube.

How many hours do you have on the new BB tube?

 

[TheAbyss2022]

How many hours do you have on the new BB tube?

Around 7 hours so far, bought it listed as a NOS but who knows if it actually is as it came in a white box and not the military green box that came with it originally

 

[mordy]

Around 7 hours so far, bought it listed as a NOS but who knows if it actually is as it came in a white box and not the military green box that came with it originally

Based on my personal experience new tubes usually require at least 30 - 50 hours to be burned in. It may very well be that the Bad Boy tube will sound better after more time and perhaps the areas in sound that you did not like will improve quite a lot.
As a side issue, most very old tube boxes have disintegrated over time, and IMHO it is the exception when you get an old tube where the original box is in good condition or even included. I think that it has to do with the climate of the country where the tube box is stored as well - colder climates (Scandinavia as an example) seem to preserve the boxes better. But usually, when you get an intact old tube box, it starts to fall apart the minute you open it...

 

[Isaacc7]

Based on my personal experience new tubes usually require at least 30 - 50 hours to be burned in. It may very well be that the Bad Boy tube will sound better after more time and perhaps the areas in sound that you did not like will improve quite a lot.
As a side issue, most very old tube boxes have disintegrated over time, and IMHO it is the exception when you get an old tube where the original box is in good condition or even included. I think that it has to do with the climate of the country where the tube box is stored as well - colder climates (Scandinavia as an example) seem to preserve the boxes better. But usually, when you get an intact old tube box, it starts to fall apart the minute you open it...

Also remember that tube boxes were expected to last about as long as cereal boxes. They were never expected to last 60+ years. I have been reboxing tubes as I need to. Thought the “bad boy” tubes were originally supplied in bulk boxes anyway. Weren’t they a government bulk order or something?

 

[TheAbyss2022]

Also remember that tube boxes were expected to last about as long as cereal boxes. They were never expected to last 60+ years. I have been reboxing tubes as I need to. Thought the “bad boy” tubes were originally supplied in bulk boxes anyway. Weren’t they a government bulk order or something?

Yes the government bought a bunch of them for the Korean war to use in long distance communications etc.

 

[ARCXENOS]

I kinda have amassed a collection of tubes (that will continue to grow) to warrant getting a tube tester

Any recommendations? Don't really need something super precise (and too expensive!), just enough precision for a hobbyist

 

[Ranger Ron]

I kinda have amassed a collection of tubes (that will continue to grow) to warrant getting a tube tester

Any recommendations? Don't really need something super precise (and too expensive!), just enough precision for a hobbyist

I like my Hickok 600A. Use tubes you know are strong as a baseline when testing tubes you are unsure of.

 

[sam6550a]

I kinda have amassed a collection of tubes (that will continue to grow) to warrant getting a tube tester

Any recommendations? Don't really need something super precise (and too expensive!), just enough precision for a hobbyist

The B & K 707 is fine for what you want, and a lot of them were made--meaning that they are less expensive than the Hickok or other more exotic testers.

 

[prima186]

tube tester purchased on ebay.
Although it is a simple type, it has sufficient ability for matching tests.

 

[ColSaulTigh]

tube tester purchased on ebay.
Although it is a simple type, it has sufficient ability for matching tests.

That looks pretty cool!

Mind providing details? Make/model, or link to builder?

 

[jonathan c]

 

[TLO]

tube tester purchased on ebay.
Although it is a simple type, it has sufficient ability for matching tests.

Yeah, I have one too, test results are pretty close compared to those vintage military graded testers...I will say around 3% plus or minus. One thing to note though, the top panel is quite flimsy due to material used and is only tightened down with screws at the 4 corners. Mine was torn at one corner after some uses.
I bought 2 pairs of long copper studs and secured them between the screws on the sockets and the bottom of the box. This will help to spread out the tension when pushing in or pulling out the tubes. Just remember to use huge washers at the bottom end of the studs.

 

[bcowen]

Yeah, I have one too, test results are pretty close compared to those vintage military graded testers...I will say around 3% plus or minus. One thing to note though, the top panel is quite flimsy due to material used and is only tightened down with screws at the 4 corners. Mine was torn at one corner after some uses.
I bought 2 pairs of long copper studs and secured them between the screws on the sockets and the bottom of the box. This will help to spread out the tension when pushing in or pulling out the tubes. Just remember to use huge washers at the bottom end of the studs.

Does it have any provision for shorts / interelement leakage testing?

 

[leftside]

That looks like great value for money! My only concern would be the 180 plate voltage being used. For the 12AT7 for example, the typical operation is 250V. Your tubes could test quite differently at 180V than they do at 250V. So, even if they match at 180V in this tester, they might not match when actually being used in the amp.
https://frank.pocnet.net/sheets/093/1/12AT7.pdf

I see the tester tests for plate current. Is there also a version that tests for Mutual Conductance (Gm)?

Great to see testers out there like this. I would have thought that adding extra features such as having a 250 plate voltage test, a test for Gm, shorts, leaks, etc shouldn't be too costly to add. Even at the $1000 price mark this thing would sell a lot.

 

[prima186]

Thanks guys.

Selected tubes are used in Schiit Freya.