Dating / history of four 6CS7 Sylvania tubes

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kasperbergholt

Dating / history of four 6CS7 Sylvania tubes
« on: 6 Apr 2023, 03:37 pm »
Clever people,


After a several weeks of waiting time, my first four 6CS7 NOS tubes (for my Laben CS-600 amplifier) arrived yesterday by mail from the US. I think they're beautiful. Technically, I think they are what's called 'short black plates', but I'm not sure.

My plan is to get 3 to 4 good quads - if not exceptional - so that I have enough for a lifetime. Estimated lifetime is often said to be in the 10,000 hours range, perhaps.

I'm looking for a bit of history of these - e.g. how old they are. I'd also be interested in comparisons to more generally avaiable preamp tube such ECC81 or ECC82 in terms of sound signature / sonic qualities. Some compare them to RCA's ECC82 tubes.

Here are som pictures:







Some more info & images here

Thanks in advance,

Kasper

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Re: Dating / history of four 6CS7 Sylvania tubes
« Reply #1 on: 6 Apr 2023, 06:57 pm »
Nice tubes, please post the tubes history and sound quality info here when you get them.

thorman

Re: Dating / history of four 6CS7 Sylvania tubes
« Reply #2 on: 7 Apr 2023, 02:59 pm »
 Not sure if this helps or not but I have tried pretty much all the 6CS7 tubes in my CS-600 I could find and have found the Sylvania's to be the warmest ( not the best ) of the ones tried and GE's the opposite , more neutral . My best 6CS7 tube so far being the Favre ( Italy ) which to me has the best balance of Detail and Musicality.

Hope that helps some......Good Luck

kasperbergholt

Re: Dating / history of four 6CS7 Sylvania tubes
« Reply #3 on: 19 Apr 2023, 08:26 am »
Not sure if this helps or not but I have tried pretty much all the 6CS7 tubes in my CS-600 I could find and have found the Sylvania's to be the warmest ( not the best ) of the ones tried and GE's the opposite , more neutral . My best 6CS7 tube so far being the Favre ( Italy ) which to me has the best balance of Detail and Musicality. Hope that helps some......Good Luck

Thank you for your reply. It definitely helps, it was inputs like this I was looking for. I've got some 6CS7 from General Electric that needs to be measured out for a quad or at least two good pairs for each stage of the preamp stage. So I'll be able to do a comparison. After going down a rabbit hole with tube rolling in an Audio Note amplifier, I've decided to try and not swap very frequently.

The Fivres look interesting - produced in Italy, it seems? I've heard different output tubes from that brand highly recommeded too.

In relation to the bright / precise vs warm - which speakers do you have and what's the input signal(s) to the Leben? Here it's: Project X-2 with a Goldring 2300 -> Leben RS30-EQ (with stock tubes) -> Leben CS-600 (no X, old model) -> Harbeth M30.1. Tonearm and interconnect cables from Yannis Tonearm Studio (clio & silvercord duo).

Current tubes in the Leben are from RCA, and the overall impression is to the brighter - in terms of a more precise term - side.

Here's an image of one of the GE tubes.

General Electric 6CS7 tube marked 'Tassa Radiofonica':


And an image of my Leben.