A little Christmas HiFi ambition this year was to compare some ECC83 Tubes - NOS Telefunken vs NOS Tesla. I have had a pair of matched Telefunkens sitting in the cupboard for a month or so now but not had time to compare them against the Teslas I currently use.
The tubes I swapped were in the phono stage of my Croft 25 R+. I have had many many tubes in this position and Teslas have simply bested everything that has come along by some margin, however NOS Telefunkens have a reputation and are just about the only serious ECC83 contender I have not tried, until now!
After a warm up period the Telefunkens filled out a little as they sounded a bit lean when first installed. But how did they compare to the Tesla NOS ECC83? Could they improve on these marvellous little beauties. In a word yes but with some caveats.
So to give you an idea of NOS Tesla ECC83 tubes they are are so clear, transparent and detailed with just the right amount of weight and warmth without sounding too lean. They give you an incredible insight into the recording and tell you everything. They are not romantic and let you hear everything warts and all. They are musical and with the good recorded material they deliver an incredible transparency with a hint of ethereal valve magic.
The NOS Telefunkens delivered a tad more detail and maybe a little more clarity with amazing imaging. They seem to be able to separate out every strand of the recording with ease. Teslas are a little behind in this respect and sound tiny bit distorted. The Telefunkens however have a little less fullness/weight. They are certainly dynamic and super clear and dare I say they seem to reveal more detail. Finally I would say the Telefunkens take the sound stage half a step back. Recorded ambience and acoustic information is highly impressive.
I will be leaving the Telefunkens in for some time to get a complete handle on their ability but I do feel the NOS Teslas have met their match!