So I have a DIY valve phonostage that I made a good few years back. Its really stood the test of time and has seen off many comers over the years (for anyone interested, its the valve itch from Salas on DIYAudio with vintage sowter step up transformers). However, the time had come recently for a new set of valves. This phonostage uses 2 x 6n2p (which is similar to 12ax7 but much cheaper) and 6SN7 (or 6N8S as I had in there now). I'd tried a few different 6SN7 when I was building and testing initially, and while there was a little difference, there wasn't much in it really. But what to replace them with?
If you read around on fora, the widely regarded very best 6SN7 are Russian ones from melz factory with a particular internal configuration (black hole plate) and these fetch quite the premium now - expect to pay some €250 a pair. In the course of my research, I also came across a few who had done some experiments with another valve, 6J5 which got great reviews, as good as if not better than the melz 6SN7 and at a fraction of the price. The problem with the 6J5 is that its actually just half a 6SN7 - so those hardy souls modified their amps to add another socket so they could use 2 x 6J5 instead of the original 6SN7.
Well, roll on a bit of time and I see a guy in Hong Kong making and selling an adapter that takes 2 x 6J5 and mounting it on an octal base to fit where one 6SN7 would have been. I was originally thinking of making something myself, but the one h was making looked so good and I thought the price was reasonable that it was worth the punt.
So roll forward a few weeks and the set of valves land from somewhere in Germany, and a week or so later the adapter arrives from Hong Kong and its time to fire it all up!! So first was a listen with the stock valves to get a fix again in my head on the sound. Then I swap over the new 6J5 adapter and listen again..... no fireworks or mushroom cloud at least! There definitely seems to be an improvement there with the new valves alright. There is more bass definition, and a bit more bass overall. I haven't been listening that long, so things might change a little after the first few hours, but there does also seem to be more solidity to the sound. Its actually hard to put a descriptor on it, I think I can only say that its a little tighter all round and more defined. As a bit more time passes, I'll post again with more impressions....
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Fran
