tube upgrade for first sound


Has anyone been able to improve on the stock tubes in the First Sound preamps? I was thinking about trying the Russian 6H23. Any thoughts? thanks
84audio
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Hmm. Thanks Tvad. I hadn't considered that. I suppose, if Emmanuel entered the info, that would generate a tracking # automatically. 5 more days, can't wait. Hope I'm not letting my expectations be too high.

:-)
relax. BTW, I was underwhelmed when i plugged my brand new unit into my system. The thing takes TIME to break in, so be patient. Also, follow Emmanuel's recommendation for breaking it in, and dont tweak it (Power cords, tubes, etc) for 1 month! all good things come to those who wait!
Oldpet, send Emmanuel an eMail and he will sort out the mystery. On the other hand, it would not be the first time that UPS gives a package the grand tour of the nation, before deciding to route it finally to its intended destination.
Having said that, UPS is not as bad as the US postal service. Three years ago I sent a Christmas present by US mail from Austin (Tx) to Milano (Italy). It took just over three months. Reason is that prior to finally routing the package to Milan, my nephew's toys were sent all the way to Manila in the Philippines, where the box was opened, fully inspected, repackaged, then sent on its way to Milan.