Question re: tube amp grounding/safety

[SIY]

Good question! I came up with it because I had the impression that people here generally complain about the poor quality of 300B tubes, for example, if they are not from the WE brand.

The brand is irrelevant. None of the tubes sold as 300B that I've seen are particularly good. I don't get the cult status of that particular number, but I'll admit to not being much of a fashion hound.

 

[egellings]

I agree. It’s very much like phono cartridges in my opinion. You have some pin compatibility and shared function. The branding issue is also true. Western Electric has some correlation to history, but even then the modern ALD carbonized nickel makes it a different product from before.

The other problem is tube lot to lot variability (my WE300B don’t seem all that well matched despite paying the extra money for matched pairs so it must mean that unmatched tubes are even more different!). I have been lucky with NOS US production tubes when using my tube tester, but even then, measurements on NOS tubes are only going to be accurate for the specimens in hand and cannot be generalized.

I definitely am looking forward to your write up of the 91E. It would be great to get your insights on the lack of standardization. At least back in the day, you had KT88 and 6550 as different descriptions. Today, you can imagine a companies changing glass shape and having a different label printed on the glass!

Out of curiosity, the Canary Audio monoblocks boast extremely low distortion. It makes me wonder if those amps show any similar dynamic frequency response changes or if they show more solid state like behavior. I don’t see any deep dives of those amps.

The tubes may be matched at some particular operating point, but that does not mean that the match holds over the entire operating region of the tube. A matched pair may also not wear out consistently, and may be out of match after several hundred hours' use even though they were initially matched.

 

[GXAlan]

The tubes may be matched at some particular operating point, but that does not mean that the match holds over the entire operating region of the tube. A matched pair may also not wear out consistently, and may be out of match after several hundred hours' use even though they were initially matched.

Agree. I was just thinking about the test reports.

The serial numbers aren’t sequential but they are close and the test day was the same day. Western Electric does say that the matching is done by computer algorithm, so maybe it’s the matching across curves and not just the numbers that are listed.

https://www.audiosciencereview.com/forum/index.php?attachments/1682091249932-png.280672/

 

[Grumpish]

The WE brand name has been licensed, as has other names from olden times (e.g., Tung Sol, Mullard...). What's made under that brand has zero relationship to original WE.

WE equipment, truth be told, was fine for 1932 PA use, but is laughably poor by later standards- and by later, I mean late 1940s and beyond. The cult of this mystifies me.

The prices that people will pay for NOS WE 300B tubes are totally insane, and the prices for new WE branded 309B tubes are not much better - on the other hand my DIY headphone amp using RCA Type 45 tubes that are older than I am, gets, with its probably 1%+ distortion, more use than my THX 789 headphone amp with its 0.0001% distortion - it is just more enjoyable to listen to.