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
I can't hear the difference either, and there's the POV that half of all recordings are inverted anyway. But I have my speakeer leads reversed at the amp just the same as Emmannuel Go is quite insistent about this.

And Paul, as many have mentioned, plug it straight into the wall. After a while, you will want to play with aftermarket power cords.
Id be lying if I said I could always hear the difference, but on some, the bass is off. On other recordings, i cant tell. Mostly i bring it to your attention because emmanuel really really feels strongly about it....
No question that FS owners should swap speaker leads according to Emmanuel's suggestion. There is no argument from me on that issue. I'm just really interested to know what to listen for regarding absolute phase. Alex Peychev has an absolute phase switch on his APL Denon3910 that is remote switchable, too. I've switched that thing back and forth a dozen or more times. Sometimes I think I hear a slightly more expansive soundstage. Other times I'm not sure. It's more of a brain teaser for me at this juncture.
Oldpet,
I like my Supratek very much. It is a very musical preamp. I was lucky because a friend had a nearly new Chenin(less than two months old) that I was able to buy immediately when I found out that the H-Cat wasn't my cup of tea. I must say that another preamp on my short list was the First Sound. Best of luck on your audio adventures. Bob
Two updates:

FIM Model 88 Outlet. Emmanuel recommended it over the more expensive wattgate I had, and he nailed it. This thin gis a must-have for this preamp. Quiet as I'll get out, smooth as silk, yest highly resolving/transparent. This one doesn't rob dunamicsd or over-smooth things - it's very neutral. At $60, you can NOT go wrong. Trust me, this was pretty impressive, not subtle....

next up: early 1960's US-made pinched waist Amperex 6922's. I returend the "Siemens 7308 gold pins" when i discovered (while trying to resell them here) that they were manufactured in 1980. Yeouch! they really didnt hold a candle to the Amperex D-getter 6922's or Phillips Miniwatt 1959/1960 (aka Bugle Boy)tubes I had on hand, no matter how much I tried to like their "transparent" sound - they sucked - and now I know why. Boys and Girls: it's a jungle out there. make sure you know a priori what year your tubes were made before you buy....

On that note, Andy at Vintage Tube Services is 100% bone fide honest and waaaay more knowledgable than most out there.