wahwah
GumbyLoveologist
Re: NOS tubes vs. the best of today's tubes.
The RCA black plates have a more open quality than the grey, which seems to come from an extended frequency range. They have a punchier bottom end which still remains tight and focused, and a sweet top end that rivals the best of the European tubes of the era. The midrange seems quite neutral, without any obvious peaks. They are also renowned for their low noise and microphonics. I've had about 15 of these tubes and have tried them in 4 different amps, and I've been amazed at how similar each example is, a testament to the quality control of RCA's 50s production. Obviously each amp has to be assessed on its own merits with any tube type, and if you're really happy with the grey plate RCAs, you've already found a winning combination. It can certainly be the case that the grey plates will suit a certain amp better. For me, the openness and broad frequency bandwidth of the black plates really suit the sound I'm going for with these specific amps, so they are a clear favourite.
Here's a few members of my RCA 12AX7 family. On the left, an original 1950s black plate, in the middle, a fairly rare transitional long grey plate with 'D' getter, circa 1960, and on the right, the later 60s short grey plate 7025.
Cheers........................................ wahwah
The RCA black plates have a more open quality than the grey, which seems to come from an extended frequency range. They have a punchier bottom end which still remains tight and focused, and a sweet top end that rivals the best of the European tubes of the era. The midrange seems quite neutral, without any obvious peaks. They are also renowned for their low noise and microphonics. I've had about 15 of these tubes and have tried them in 4 different amps, and I've been amazed at how similar each example is, a testament to the quality control of RCA's 50s production. Obviously each amp has to be assessed on its own merits with any tube type, and if you're really happy with the grey plate RCAs, you've already found a winning combination. It can certainly be the case that the grey plates will suit a certain amp better. For me, the openness and broad frequency bandwidth of the black plates really suit the sound I'm going for with these specific amps, so they are a clear favourite.
Here's a few members of my RCA 12AX7 family. On the left, an original 1950s black plate, in the middle, a fairly rare transitional long grey plate with 'D' getter, circa 1960, and on the right, the later 60s short grey plate 7025.
Cheers........................................ wahwah
