My original post was this:-
A brand new out of the box tube ordered last week (JJ) - sounds as it should.
A 4 year old tube - zero sound, doesn't light up.
An original RCA tube with a sticker on saying low output. Sound present but slightly muffled - like there's a lot of fluff on the stylus.
An original Brimar tube, untested. Same result as the RCA above.
And my original question was, is the slight distortion due to low output on the original old tubes ? Surely at some point the lower DC output must have an effect on the rest of the amp, and is this a symptom of that effect ?
I suppose the answer is to test and verify what exactly the low output is on the 2 old tubes. But regardless, there is a difference in sound. I'm not trying to be like some audio fanatic who spends 1000s on fancy cables I've had this machine since 1985. I know what it sounds like and when things are different. And it's easily replicable by swapping out that tube
The old tubes are useable and great as spares, but not such a good sound to keep in there when I know there is a better sound to be had.
Nigel
On 12 Jun 2024 at 21:42, M De Simone via Jukebox-list jukebox-list@lists.netlojix.com wrote:
Those 2 scenarios make sense but if one tube tests at 100% and another tests at 75% and no shorts, they shouldn’t both produce the same voltage? I can’t see where there would be a difference. If the tube tested bad and wasn’t rectifying properly than sure the voltage would be low or it would be contaminated. Are we discussing a good rectifier tube vs a bad one or something else? A bad tube will obviously affect the whole amplifier but it sounded a bit like a comparison of different “good” tubes.
Sent from my iPhone
On Jun 12, 2024, at 4:26 PM, Tony Miklos via Jukebox-list jukebox-list@lists.netlojix.com wrote:
The same people using special rectifier tubes because they sound better, are some of the same folks that swear by having a SHIELDED power cord.
To the original question re: sound quality, sure if the tube is weak, it may not be supplying enough current to the filter caps so your voltages are all low.
I guess another way is if the 5U4 is shorting and sparking internally, yep, it won't sound good at all. A bit crackly! _______________________________________________ Jukebox-list mailing list -- jukebox-list@lists.netlojix.com To unsubscribe send an email to jukebox-list-leave@lists.netlojix.com %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s Searchable Archives: http://jukebox.markmail.org/
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