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In the Forum: Analog Playback
In the Thread: The last phonocorrector: “End of Life" Phonostage
Post Subject: Gas tubes in the phonostagePosted by Romy the Cat on: 11/22/2011
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 AlexBerger wrote:
Hello Romy,

What brand of 0A2 do you use in your phonostage?
I used RCA, but after 1.5 years of work it began to spark when phonostage is switched on.
I tried Siemens, Mazda and now Sylvania 0A2.
Siemens has "disco sound", without mids, just metallic highs and punchy bass.
Mazda has strong sweet coloration with accent to upper mid and week bass.
Sylvania sounds good, actually more interesting than RCA did. But vocal doesn't sound smooth enough.
Maybe it needs some break-in time?

Alex,

They all are good questions

I have published a short survey: “150V Gas Tubes survival guide.” at:

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=2792

where I did explore hot the gas tube impact sound. However, that was in context of Melquiades amplifier, where the gas tubes drive bias – MUCH more sensitive element then anode supply in my view. Regardless if it was more sensitive or not I think the topological difference would make my experience with Melquiades’ use of gas tube not applicable to use of gas tubes in my phonostage.

I never made any tube roiling in the PS of phonostage, I should but I did not. I put in there Telefunkens and did not try anything else, the Telefunkens were not my the best choice with Melquiades, but since Telefunken tube are very reliable and I have no easy access to phonostage’s PS I figured that Telefunken will be a reasonable choice if I am not going to see those tubes for very long time, preferably never again.

Telefunken most likely made by Siemens, or versa versa, so it is possible that your Siemens and my Telefunken are the same tubes rebranded. Sylvania are very very good tubes, I always like them, in fact I use special Sylvania 12AX7 in the second stage of my “End of the life phonostage”. My the most beloved 150V gas tube is Amperex. They have not flat shields like all other tube but many small holes in the shield that make them to look very different and they do sound in my estimation much bettered. But again, it was in Melquiades, who knows how they will sound in phonostage.
 
The Cat

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